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BACKGROUND: Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood. RESULTS: In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence. CONCLUSIONS: These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.

SUMMARY Ascorbic acid (AsA) serves as a key antioxidant involved in the various physiological processes and against diverse stresses in plants. Due to the insufficiency of AsA de novo biosynthesis, the AsA regeneration is essential to supplement low AsA synthesis rates. Redox reactions play a crucial role in response to biotic stress in plants; however, how AsA regeneration participates in hydrogen peroxide (H2O2) homeostasis and plant defense remains largely unknown. Here, we identified a Golgi vesicle‐membrane‐localized cytochrome B561 (CytB561) encoding gene, GhB561‐11, involved in AsA regeneration and plant resistance to Verticillium dahliae in cotton. GhB561‐11 was significantly downregulated upon V. dahliae attack. Knocking down GhB561‐11 greatly enhanced cotton resistance to V. dahliae. We found that suppressing GhB561‐11 inhibited the AsA regeneration, elevated the basal level of H2O2, and enhanced the plant defense against V. dahliae. Further investigation revealed that GhB561‐11 interacted with the lipid droplet‐associated protein GhLDAP3 to collectively regulate the AsA regeneration. Simultaneously silencing GhB561‐11 and GhLDAP3 significantly elevated the H2O2 contents and dramatically improved the Verticillium wilt resistance in cotton. The study broadens our insights into the functional roles of CytB561 in regulating AsA regeneration and H2O2 homeostasis. It also provides a strategy by downregulating GhB561‐11 to enhance Verticillium wilt resistance in cotton breeding programs. [ABSTRACT FROM AUTHOR]

Continuous high ambient temperature in hot summer months leads to a sharp decline in turf quality of cool‐season turfgrass. Verticillium dahliae Aspf2‐like protein (VDAL) is a secretory protein of V. dahliae that can improve crop yield and resistance to disease, but its role in improving heat tolerance of cool‐season turfgrass has not been reported so far. The objectives of this study were to explore the effect and mechanism of foliar application of VDAL on improving heat tolerance in cool‐season creeping bentgrass (Agrostis stolonifera) and to further examine the advantage of foliar spraying with VDAL in mitigating summer bentgrass decline (SBD) in the US transition zone or other regions with similar climate. The results demonstrated that the optimal dose of VDAL for improving thermotolerance of two creeping bentgrass cultivars (heat‐tolerant 13 M and heat‐sensitive Seaside II) was screened as 0.2 g L−1 based on analyses of chlorophyll content, photochemical efficiency of PSII, and cell membrane stability under controlled heat stress conditions. Foliar application of the optimal dose of VDAL significantly restricted chlorophyll loss under heat stress and also alleviated heat‐induced declines in net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency. In addition, overaccumulations of superoxide anion radical and hydrogen peroxide could be significantly alleviated by the exogenous application of VDAL through improving the activity of antioxidant enzymes including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase in two cultivars. A further 2‐year field trial showed that foliar application of VDAL improved turf quality, chlorophyll content, photochemical efficiency, and cell membrane stability of the two cultivars during hot summer months of 2022 and 2023. The results indicate that the appropriate dose of VDAL plays a positive role in photosynthetic performance and antioxidant capacity for thermotolerance of creeping bentgrass, and foliar application of VDAL could be considered an effective approach for alleviating SBD. [ABSTRACT FROM AUTHOR]

CAP (cysteine-rich secretory proteins, antigen5, pathogenesis-related proteins) superfamily proteins are widely distributed, can be subdivided into 11 subfamilies, and form a unique branch in fungi, named PRY proteins. Verticillium dahliae is a soil-borne fungal pathogen of vascular plants that causes plant Verticillium wilt. However, the roles of CAP superfamily proteins in this fungus is unclear. Here, four CAP superfamily members with a conserved domain were identified in V. dahliae: VdPRY1, VdPRY2, VdPRY3, and VdPRY4. VdPRY1 and VdPRY3 were found to be key in suppressing plant immune responses. Moreover, these four members are highly expressed during early infection of cotton by V. dahliae. Deleting VdPRY1, VdPRY2, or VdPRY3 reduced the fungus’s ability to cause disease, but VdPRY4 deletion did not affect virulence. Deletion of any of four members did not impact fungal growth or carbon source use. Yeast two-hybrid experiments suggest that these proteins may function through interactions with each other. This investigation has, for the initial time, elucidated the pivotal roles of V. dahliae CAP superfamily proteins in inhibiting plant immunity and exerting virulence during interaction with the host plant. [ABSTRACT FROM AUTHOR]

Introduction: Verticillium dahliae causes a serious decline in cotton yield and quality, posing a serious threat to the cotton industry. However, the mechanism of resistance to V. dahliae in cotton is still unclear, which limits the breeding of resistant cultivars. Methods: To analyze the defense mechanisms of cotton in response to V. dahliae infection, we compared the defense responses of two upland cotton cultivars from Xinjiang (JK1775, resistant; Z8,susceptible) using transcriptome sequencing at different infection stages. Results: The results revealed a significant differential expression of genes in the two cotton cultivars post V. dahliae infection, with the number of DEGs in JK1775 being higher than that in Z8 at different infection stages of V. dahliae. Interestingly, the DEGs of both JK1775 and Z8 were enriched in the MAPK signaling pathway in the early and late stages of infection. Importantly, the upregulated DEGs in both cultivars were significantly enriched in all stages of the phenylpropanoid metabolic pathway. Some of these DEGs were involved in the regulation of lignin and coumarin biosynthesis, which may be one of the key factors contributing to the resistance of upland cotton cultivars to V. dahliae in Xinjiang. Lignin staining experiments further showed that the lignin content increased in both resistant and susceptible varieties after inoculation with V. dahliae. Discussion: This study not only provides insights into the molecular mechanisms of resistance to Verticillium wilt in Xinjiang upland cotton but also offers important candidate gene resources for molecular breeding of resistance to Verticillium wilt in cotton. [ABSTRACT FROM AUTHOR]

Syntaxin of plant (SYP) plays a crucial role in SNARE‐mediated membrane trafficking during endocytic and secretory pathways, contributing to the regulation and execution of plant immunity against pathogens. Verticillium wilt is among the most destructive fungal diseases affecting cotton worldwide. However, information regarding SYP family genes in cotton is scarce. Through genome‐wide identification and transcriptome profiling, we identified GhSYP121, a Qa SNARE gene in Gossypium hirsutum. GhSYP121 is notably induced by Verticillium dahliae, the causal agent of Verticillium wilt in cotton, and acts as a negative regulator of defense against V. dahliae. This is evidenced by the reduced resistance of GhSYP121‐deficient cotton and the increased susceptibility of GhSYP121‐overexpressing lines. Furthermore, the activation of the salicylic acid (SA) pathway by V. dahliae is inversely correlated with the expression level of GhSYP121. GhSYP121 interacts with its cognate SNARE component, GhSNAP33, which is required for the penetration resistance against V. dahliae in cotton. Collectively, GhSYP121, as a member of the cotton SNARE complex, is involved in regulating the SA pathway during plant defense against V. dahliae. This finding enhances our understanding of the potential role of GhSYP121 in these distinct pathways that contribute to plant defense against V. dahliae infection. [ABSTRACT FROM AUTHOR]

Carbon catabolite repression (CCR) is a common transcriptional regulatory mechanism that microorganisms use to efficiently utilize carbon nutrients, which is critical for the fitness of microorganisms and for pathogenic species to cause infection. Here, we characterized two CCR genes, VdCreA and VdCreC, in Verticillium dahliae that cause cotton Verticillium wilt disease. The VdCreA and VdCreC knockout mutants displayed slow growth with decreased conidiation and microsclerotium production and reduced virulence to cotton, suggesting that VdCreA and VdCreC are involved in growth and pathogenicity in V. dahliae. We further generated 36 highly reliable and stable ΔVdCreA and ΔVdCreC libraries to comprehensively explore the dynamic expression of genes and metabolites when grown under different carbon sources and CCR conditions. Based on the weighted gene co-expression network analysis (WGCNA) and correlation networks, VdCreA is co-expressed with a multitude of downregulated genes. These gene networks span multiple functional pathways, among which seven genes, including PYCR (pyrroline-5-carboxylate reductase), are potential target genes of VdCreA. Different carbon source conditions triggered entirely distinct gene regulatory networks, yet they exhibited similar changes in metabolic pathways. Six genes, including 6-phosphogluconolactonase and 2-ODGH (2-oxoglutarate dehydrogenase E1), may serve as hub genes in this process. Both VdCreA and VdCreC could comprehensively influence the expression of plant cell wall-degrading enzyme (PCWDE) genes, suggesting that they have a role in pathogenicity in V. dahliae. The integrated expression profiles of the genes and metabolites involved in the glycolysis/gluconeogenesis and pentose phosphate pathways showed that the two major sugar metabolism-related pathways were completely changed, and GADP (glyceraldehyde-3-phosphate) may be a pivotal factor for CCR under different carbon sources. All these results provide a more comprehensive perspective for further analyzing the role of Cre in CCR. [ABSTRACT FROM AUTHOR]

Key message: GhMAC3e expression was induced by various stresses and hormones. GhMAC3e may regulate plant growth by influencing auxin distribution, and play important roles in Verticillium wilt resistance via mediating SA signaling. The MOS4-Associated Complex (MAC) is a highly conserved protein complex involved in pre-mRNA splicing and spliceosome assembly, which plays a vital role in plant immunity. It comprises key components such as MOS4, CDC5, and PRL1. MAC3A/B, as U-box E3 ubiquitin ligases, are crucial for various plant processes including development, stress responses, and disease resistance. However, their roles in cotton remain largely unknown. In this study, we first cloned the GhMAC3e gene from cotton and explored its biological functions by using virus-induced gene silencing (VIGS) in cotton and transgenic overexpression in Arabidopsis. The results showed that GhMAC3e is ubiquitously expressed in cotton tissues and could be induced by salt stress, Verticillium dahliae (VD) infection, PEG, ABA, ETH, GA3, MeJA, and SA. Silencing GhMAC3e retarded primary stem growth and reduced biomass of cotton coupled with the reduced auxin content in the petioles and veins. Silencing GhMAC3e up-regulated expression of cell growth-related genes GhXTH16 and Gh3.6, while down-regulated GhSAUR12 expression. Ectopic expression of GhMAC3e in Arabidopsis significantly enhanced its resistance to Verticillium wilt (VW) in terms of decreased pathogen biomass and lowered plant mortality. Overexpression of GhMAC3e dramatically upregulated AtPR1 by around 15 fold and more than 262 fold under basal and VD inoculation condition, respectively. This change was not associated with the expression of GhNPR1. In conclusion, GhMAC3e may not only regulate plant growth by influencing auxin distribution and growth-related gene expression, but also play important roles in VW resistance via mediating SA signaling independent of NPR1 transcription level. [ABSTRACT FROM AUTHOR]

Verticillium wilt, caused by the soilborne fungus Verticillium dahliae, poses a serious threat to the health of more than 200 plant species worldwide. Although plant rhizosphere‐associated microbiota can influence plant resistance to V. dahliae, empirical evidence underlying Verticillium wilt resistance of perennial trees is scarce. In this study, we systemically investigated the effect of the soil microbiota on the resistance of smoke trees (Cotinus coggygria) to Verticillium wilt using field, greenhouse and laboratory experiments. Comparative analysis of the soil microbiota in the two stands of smoke trees suggested that Bacillus represented the most abundant and key microbial genus related to potential disease suppression. Smoke tree seedlings were inoculated with isolated Bacillus strains, which exhibited disease suppressiveness and plant growth‐promoting properties. Furthermore, repletion of Bacillus agents to disease conducive soil significantly resulted in reduced incidence of smoke tree wilt and increased resistance of the soil microbiota to V. dahliae. Finally, we explored a more effective combination of Bacillus agents with the fungicide propiconazole to combat Verticillium wilt. The results establish a foundation for the development of an effective control for this disease. Overall, this work provides a direct link between Bacillus enrichment and disease resistance of smoke trees, facilitating the development of green control strategies and measurements of soil‐borne diseases. Summary Statement: Bacillus was the key microbial genus responsible for Verticillium wilt disease suppression and plant growth‐promoting and the combination of B. subtilis with a fungicide represented a promising effective control to combat Verticillium wilt. [ABSTRACT FROM AUTHOR]

Introduction: Verticillium dahliae causes a serious decline in cotton yield and quality, posing a serious threat to the cotton industry. However, the mechanism of resistance to V. dahliae in cotton is still unclear, which limits the breeding of resistant cultivars. Methods: To analyze the defense mechanisms of cotton in response to V. dahliae infection, we compared the defense responses of two upland cotton cultivars from Xinjiang (JK1775, resistant; Z8,susceptible) using transcriptome sequencing at different infection stages. Results: The results revealed a significant differential expression of genes in the two cotton cultivars post V. dahliae infection, with the number of DEGs in JK1775 being higher than that in Z8 at different infection stages of V. dahliae. Interestingly, the DEGs of both JK1775 and Z8 were enriched in the MAPK signaling pathway in the early and late stages of infection. Importantly, the upregulated DEGs in both cultivars were significantly enriched in all stages of the phenylpropanoid metabolic pathway. Some of these DEGs were involved in the regulation of lignin and coumarin biosynthesis, which may be one of the key factors contributing to the resistance of upland cotton cultivars to V. dahliae in Xinjiang. Lignin staining experiments further showed that the lignin content increased in both resistant and susceptible varieties after inoculation with V. dahliae. Discussion: This study not only provides insights into the molecular mechanisms of resistance to Verticillium wilt in Xinjiang upland cotton but also offers important candidate gene resources for molecular breeding of resistance to Verticillium wilt in cotton. [ABSTRACT FROM AUTHOR]

Purpose: Soil management exerts profound impact on the structure and function of the microbiome. Organic practice is believed to positively affect disease suppressiveness compared to conventional systems. While Pseudomonas has been established as a major player in conferring suppressiveness, the impact of farming practices on its diversity at species level has not been conclusively understood. Also, translation of such knowledge into application requires a mechanistic understanding of the mechanism of action of potent biocontrol strains of Pseudomonas. Methods and results: We compared fields under conventional and organic farming, under long-term (~19 years) management. Profiling of Pseudomonas community structure using rpoD-based amplicon sequencing revealed a higher diversity of known antagonistic Pseudomonas spp. in soils sampled from organic fields compared to conventional field. Cultivation and genome sequencing of selected Pseudomonas isolates from the organic field identified species with multiple secondary metabolite biosynthetic gene clusters and antagonistic activity towards phytopathogens. The selected Pseudomonas isolates showed colonization of wheat root system as confirmed by scanning electron microscopy. In vitro tube assay using wheat also revealed the suppressive activity of potent Pseudomonas isolates against Fusarium oxysporum and Verticillium dahliae. Production of metabolites with antimicrobial activity was verified using untargeted metabolomics (LC/MS). Conclusions: Overall, the mechanistics involved in the contribution of Pseudomonas spp. to disease suppressiveness in the field under organic farming could be established. This study reports that microbiome from organic field exhibits enhanced diversity of antagonistic Pseudomonas spp. effective against phytopathogens, compared to the conventional practice, and has the potential to promote sustainable agriculture and disease management. [ABSTRACT FROM AUTHOR]

The document discusses various research studies presented at the Atlantic regional meeting in 2023, focusing on plant pathology in Canada. Topics include the use of fungal endophytes for managing Apple Replant Disease, population structure of the late blight pathogen Phytophthora infestans, correlation of soil properties with pathogen population densities, battling Fusarium spp. with iChip for biopesticide discovery, genetic characterization of extreme resistance against potato virus A, trends in detecting plant pathogenic bacteria, and the development of simultaneous qPCR for Verticillium and Root Lesion Nematode. The studies aim to address challenges in plant disease management and enhance crop productivity through innovative approaches and scientific research. [Extracted from the article]

The polygalacturonase inhibitory protein (CkPGIP1) of Cynanchum komarovii can effectively inhibit the activity of polygalacturonase (VdPG1) of Verticillium dahliae. To further enhance the disease resistance of CkPGIP1, this study started with site-directed mutagenesis of the disease-resistant protein CkPGIP1 to investigate its enhanced inhibitory effect on V. dahliae. Using overlapping extension polymerase chain reaction (PCR) technology, mutant variants T152VCkPGIP1, D202SCkPGIP1, and 1250KCkPGIPI of CkPGIPI were successfully obtained. The corresponding prokaryotic expression vectors were constructed for the induction expression and purification of 923 CkPGIPI and its mutant proteins. The inhibitory effect of the mutant proteins on VdPG1 was determined by 3,5-dinitrosalicylic acid (DNS) method and agarose radial diffusion method. The results of DNS assay showed that the mutant proteins effectively inhibited the activity of VdPG1 in a dose- dependent manner. Among them, the inhibitory effect of D202SCkPGIP1 on VdPG1 was most significant, followed by T152VCkPGIP1, and the inhibitory effect of 1250KCkPGIP1 was not obvious. The results of agarose radial diffusion were consistent with those of DNS assay. D202SCkGIP1-treated V. dahliae showed the most obvious decrease in the halo area of VdPG1, indicating that D202SCkPGIP1 had the most significant inhibitory activity. Further study revealed that the mutant proteins could inhibit the expansion of V. dahliae on cotton leaves, confirming that the key amino acid mutations in CkPGIP1 enhanced its inhibitory effect on V. dahliae. [ABSTRACT FROM AUTHOR]

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The occurrence and spread of Verticillium dahliae (V. dahliae) in cotton depends on the combined effects of pathogens, host plants, and the environment, among which temperature is one of the most important environmental factors. Studying how temperature impacts the occurrence of V. dahliae in cotton and the mechanisms governing host defense responses is crucial for disease prevention and control. Understanding the dual effects of temperature on both pathogens and hosts can provide valuable insights for developing effective strategies to manage this destructive fungal infection in cotton. This study was based on the deciduous V. dahliae Vd-3. Through cultivation at different temperatures, Vd-3 formed the most microsclerotia and had the largest colony diameter at 25 °C. Endospore toxins were extracted, and 48 h was determined to be the best pathogenic time point for endotoxins to infect cotton leaves through a chlorophyll fluorescence imaging system and phenotypic evaluation. Transcriptome sequencing was performed on cotton leaves infected with Vd-3 endotoxins for 48 h at different culture temperatures. A total of 34,955 differentially expressed genes (DEGs) were identified between each temperature and CK (no pathogen inoculation), including 17,422 common DEGs. The results of the enrichment analysis revealed that all the DEGs were involved mainly in photosynthesis and sugar metabolism. Among the 34,955 DEGs, genes in the biosynthesis and signal transduction pathways of jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) were identified, and their expression patterns were determined. A total of 5652 unique DEGs were clustered into six clusters using the k-means clustering algorithm, and the functions and main transcription factors (TFs) of each cluster were subsequently annotated. In addition, we constructed a gene regulatory network via weighted correlation network analysis (WGCNA) and identified twelve key genes related to cotton defense against V. dahliae at different temperatures, including four genes encoding transcription factors. These findings provide a theoretical foundation for investigating temperature regulation in V. dahliae infecting cotton and introduce novel genetic resources for enhancing resistance to this disease in cotton plants. [ABSTRACT FROM AUTHOR]

Background: The GT64 subfamily, belonging to the glycosyltransferase family, plays a critical function in plant adaptation to stress conditions and the modulation of plant growth, development, and organogenesis processes. However, a comprehensive identification and systematic analysis of GT64 in cotton are still lacking. Results: This study used bioinformatics techniques to conduct a detailed investigation on the GT64 gene family members of eight cotton species for the first time. A total of 39 GT64 genes were detected, which could be classified into five subfamilies according to the phylogenetic tree. Among them, six genes were found in upland cotton. Furthermore, investigated the precise chromosomal positions of these genes and visually represented their gene structure details. Moreover, forecasted cis-regulatory elements in GhGT64s and ascertained the duplication type of the GT64 in the eight cotton species. Evaluation of the Ka/Ks ratio for similar gene pairs among the eight cotton species provided insights into the selective pressures acting on these homologous genes. Additionally, analyzed the expression profiles of the GT64 gene family. Overexpressing GhGT64_4 in tobacco improved its disease resistance. Subsequently, VIGS experiments conducted in cotton demonstrated reduced disease resistance upon silencing of the GhGT64_4, may indicate its involvement in affecting lignin and jasmonic acid biosynthesis pathways, thus impacting cotton resistance. Weighted Gene Co-expression Network Analysis (WGCNA) revealed an early immune response against Verticillium dahliae in G. barbadense compared to G. hirsutum. Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) analysis indicated that some GT64 genes might play a role under various biotic and abiotic stress conditions. Conclusions: These discoveries enhance our knowledge of GT64 family members and lay the groundwork for future investigations into the disease resistance mechanisms of this gene in cotton. [ABSTRACT FROM AUTHOR]

ABSTRACT Verticillium wilt caused by the soil‐borne fungus Verticillium dahliae Kleb., is a destructive plant disease that instigates severe losses in many crops. Improving plant resistance to Verticillium wilt has been a challenge in most crops. In this study, a V. dahliae secreted protein VdSP8 was identified and shown to activate hyper‐sensitive response (HR) and systemic acquired resistance (SAR) to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and Botrytis cinerea in tobacco plants. We identified a β‐glucosidase named GhBGLU46 as a cotton plant target of VdSP8. VdSP8 interacts with GhBGLU46 both in vivo and in vitro and promotes the β‐glucosidase activity of GhBGLU46. Silencing of GhBGLU46 reduced the expression of genes involved in lignin biosynthesis, such as GhCCR4, GhCCoAOMT2, GhCAD3 and GhCAD6, thus decreasing lignin deposition and increasing Verticillium wilt susceptibility. We have shown that GhBGLU46 is indispensable for the function of VdSP8 in plant resistance. These results suggest that plants have also evolved a strategy to exploit the invading effector protein VdSP8 to enhance plant resistance. [ABSTRACT FROM AUTHOR]

ABSTRACT Verticillium wilt (VW) caused by the soil‐borne fungal pathogen Verticillium dahliae reduces cotton productivity and quality. Numerous studies have explored the genetic and molecular mechanisms regulating VW resistance in cotton, but the role and mechanism of strigolactone (SL) is still elusive. We investigated the function of SL in cotton's immune response to V. dahliae infection by exogenously applying SL analog, blocking or enhancing biosynthesis of endogenous SLs in combination with comparative transcriptome analysis and by exploring cross‐talk between SL and other phytohormones. Silencing GhDWARF27 and applying the SL analog GR24 or overexpressing GhDWARF27 decreased and enhanced V. dahliae resistance, respectively. Transcriptome analysis revealed SL‐mediated activation of abscisic acid (ABA) and jasmonic acid (JA) biosynthesis and signaling pathways. Enhanced ABA biosynthesis and signaling led to increased activity of antioxidant enzymes and reduced buildup of excess reactive oxygen species. Enhanced JA biosynthesis and signaling facilitated transcription of JA–dependent disease resistance genes. One of the components of the SL signal transduction pathway, GhD53, was found to interact with GhNCED5 and GhLOX2, the key enzymes of ABA and JA biosynthesis, respectively. We revealed the molecular mechanism underlying SL–enabled V. dahliae resistance and provided potential solutions for improving VW resistance in cotton. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus) is a globally significant field crop, and disease resistance is crucial for ensuring yield stability and crop quality. Verticillium dahliae is a notorious soilborne pathogen that causes Verticillium Wilt (VW) and threatens sunflower production worldwide. In this study, we conducted a comprehensive assessment of sunflower resistance to V. dahliae across 231 sunflower cultivar lines, from the Sunflower Association Mapping (SAM) population. We employed EMMAX and ridge regression best linear unbiased prediction (rrBLUP) and identified 148 quantitative trait loci (QTLs) and 23 putative genes associated with V. dahliae resistance, including receptor like kinases, cell wall modification, transcriptional regulation, plant stress signalling and defense regulation genes. Our enrichment and quantitative real-time PCR validation results highlight the importance of membrane vesicle trafficking in the sunflower immune system for efficient signaling and defense upon activation by V. dahliae. This study also reveals the polygenic architecture of V. dahliae resistance in sunflowers and provides insights for breeding sunflower cultivars resistant to VW. This research contributes to ongoing efforts to enhance crop resilience and reduce yield losses due to VW, ultimately benefiting sunflower growers and the agricultural sector. [ABSTRACT FROM AUTHOR]

Potato Verticillium wilt (PVW) caused by Verticillium dahliae is a vascular disease, that seriously affects potato (Solanum tuberosum L.) yield and quality worldwide. V. dahliae occupies the vascular bundle and therefore it cannot efficiently be treated with fungicides. Further, the application of these pesticides causes serious environmental problems. Therefore, it is of great importance to find environmentally friendly biological control methods. In this study, bacterial strains were isolated from agricultural lands on which potato had been cultured for 5 years. Five strains with a broad-spectrum antagonistic activity were selected. Among these five strains, Bacillus velezensis XS142 showed the highest antagonistic activity. To study the mechanism of XS142, by which this strain might confer tolerance to V. dahliae in potato, the genome of strain XS142 was sequenced. This showed that its genome has a high level of sequence identity with the model strain B. velezensis FZB42 as the OrthoANI (Average Nucleotide Identity by Orthology) value is 98%. The fungal suppressing mechanisms of this model strain are well studied. Based on the genome comparison it can be predicted that XS142 has the potential to suppress the growth of V. dahliae by production of bacillomycin D, fengycin, and chitinase. Further, the transcriptomes of potatoes treated with XS142 were analyzed and this showed that XS142 does not induce ISR, but the expression of genes encoding peptides with antifungal activity. Here we showed that XS142 is an endophyte. Further, it is isolated from a field where potato had been cultured for several years. These properties give it a high potential to be used, in the future, as a biocontrol agent of PVW in agriculture. [ABSTRACT FROM AUTHOR]

Background: Verticilium dahliae is the most important wilt pathogen of olive trees with a broad host range causing devastating diseases currently without any effective chemical control. Traditional detection methodologies are based on symptoms-observation or lab-detection using time consuming culturing or molecular techniques. Therefore, there is an increasing need for portable tools that can detect rapidly V. dahliae in the field. Results: In this work, we report the development of a novel method for the rapid, reliable and on-site detection of V. dahliae using a newly designed isothermal LAMP assay and crude extracts of olive wood. For the detection of the fungus, LAMP primers were designed targeting the internal transcribed spacer (ITS) region of the rRNA gene. The above assay was combined with a purpose-built prototype portable device which allowed real time quantitative colorimetric detection of V. dahliae in 35 min. The limit of detection of our assay was found to be 0.8 fg/μl reaction and the specificity 100% as indicated by zero cross-reactivity to common pathogens found in olive trees. Moreover, detection of V. dahliae in purified DNA gave a sensitivity of 100% (Ct < 30) and 80% (Ct > 30) while the detection of the fungus in unpurified crude wood extracts showed a sensitivity of 80% when multisampling was implemented. The superiority of the LAMP methodology regarding robustness and sensitivity was demonstrated when only LAMP was able to detect V. dahliae in crude samples from naturally infected trees with very low infection levels, while nested PCR and SYBR qPCR failed to detect the pathogen in an unpurified form. Conclusions: This study describes the development of a new real time LAMP assay, targeting the ITS region of the rRNA gene of V. dahliae in olive trees combined with a 3D-printed portable device for field testing using a tablet. The assay is characterized by high sensitivity and specificity as well as ability to operate using directly crude samples such as woody tissue or petioles. The reported methodology is setting the basis for the development of an on-site detection methodology for V. dahliae in olive trees, but also for other plant pathogens. [ABSTRACT FROM AUTHOR]

Verticillium dahliae is a soil-borne fungal pathogen that can cause severe vascular wilt in many plant species. Kelch repeat proteins are essential for fungal growth, resistance, and virulence. However, the function of the Kelch repeat protein family in V. dahliae is unclear. In this study, a Kelch repeat domain-containing protein DK185_4252 (VdLs.17 VDAG_08647) included in the conserved VdPKS9 gene cluster was identified and named VdKeR1. Phylogenetic analysis demonstrated a high degree of evolutionary conservation of VdKeR1 and its homologs among fungi. The experimental results showed that the absence of VdKeR1 impaired vegetative growth, microsclerotia development, and pathogenicity of V. dahliae. Osmotic and cell wall stress analyses suggested that VdKeR1-deleted mutants were more tolerant to NaCl, sorbitol, CR, and CFW, while more sensitive to H2O2 and SDS. In addition, analyses of the relative expression level of sqe and the content of squalene and ergosterol showed that VdKeR1 mediates the synthesis of squalene and ergosterol by positively regulating the activity of squalene epoxidase. In conclusion, these results indicated that VdKeR1 was involved in the growth, stress resistance, pathogenicity, and ergosterol metabolism of V. dahliae. Investigating VdKeR1 provided theoretical and experimental foundations for subsequent control of Verticillium wilt. [ABSTRACT FROM AUTHOR]

Verticillium wilt (VW) is a disruptive symptom caused by Verticillium dahliae, which affects fiber yield and quality of cotton in China. AP2/ERF transcription factors play prominent role in plant growth, development and stress response. In order to excavate the genes related to resistance to VW in cotton and explore their biological functions, the candidate gene GhERF020 (XM_016842745.1) was obtained by homologous alignment of AT1G22810.1 related gene of Arabidopsis thaliana against V. dahliae. Bioinformatic analysis showed that the open reading frame length of GhERF020 was 441 bp, encoded 147 amino acids. GhERF020 contained a conserved AP2 domain, the relative molecular weight was 16.16 kD without transmembrane structure, belonging to the hydrophilic protein. It was predicted that the promoter region contained response elements of salicylic acid (SA), methyl jasmonate (MEJA), abscisic acid (ABA) and other response elements. The expression of GhERF020 was induced by V. dahliae infection. Subcellular localization analysis showed that GhERF020 protein was localized in the nucleus. As the expression of GhERF020 was downregulated by virus-induced gene silencing (VIGS) technique, the susceptibility of cotton plants to V. dahliae was significantly enhanced, and the disease index and pathogen biomass were distinctly increased. Above results indicated that GhERF020 was a positive regulator in resistance against V. dahliae in cotton. [ABSTRACT FROM AUTHOR]

The olive tree is crucial to the Mediterranean agricultural economy but faces significant threats from climate change and soil-borne pathogens like Verticillium dahliae. This study assesses the dual role of an onion extract formulation, rich in organosulfur compounds, as both biostimulant and antifungal agent. Research was conducted across three settings: a controlled climatic chamber with non-stressed olive trees; an experimental farm with olive trees under abiotic stress; and two commercial olive orchards affected by V. dahliae. Results showed that in the climatic chamber, onion extract significantly reduced MDA levels in olive leaves, with a more pronounced reduction observed when the extract was applied by irrigation compared to foliar spray. The treatment also increased root length by up to 37.1% compared to controls. In field trials, irrigation with onion extract increased the number of new shoots by 148% and the length of shoots by 53.5%. In commercial orchards, treated trees exhibited reduced MDA levels, lower V. dahliae density, and a 26.7% increase in fruit fat content. These findings suggest that the onion extract effectively reduces oxidative stress and pathogen colonization, while enhancing plant development and fruit fat content. This supports the use of the onion extract formulation as a promising, sustainable alternative to chemical treatments for improving olive crop resilience. [ABSTRACT FROM AUTHOR]

Copyright of Glasnik Zastite Bilja is the property of Zadruzna Stampa D.D. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study assesses the effectiveness of using arbuscular mycorrhizal fungi (M) and compost applied alone or in combination (vs. conventional chemical fertilizer application (NPK)) on tomato resistance to vascular wilt caused by Verticillium dahliae. In this study, ten treatments were applied: (1) Control (2) M: Rhizophagus irregularis (3) C: Compost (4) MC: The combination of M and compost (5) NPK: conventional chemical fertilizer (6) V: plants infected with V. dahliae (7) MV: plants infected with a conidial suspension of V. dahliae and M, (8) CV: The combination of compost and V. dahliae, (9) MCV: The combination of M, compost and V. dahliae, (10) VNPK: V. dahliae and NPK. The combination of biostimulants reduced disease severity and incidence, as well as the leaf alteration index compared to control plants (V). However, the area under the disease progress curve (AUDPC) and final mean severity (FMS) were reduced by 37% and 46% respectively by the application of the combination of M, compost and V. dahliae (MCV) compared to the V control. Additionally, the MCV treatment showed the greatest increment in protein content (152.6%), in TSS content (54.6%), and CV increased proline content by 46.6%. Furthermore, MCV also protected the photosynthetic apparatus from pathogen-induced oxidative stress and reduced the accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) by increasing the activity of antioxidant enzymes, such as polyphenol oxidase (PPO) (215.03%), ascorbate peroxidase (APX) (74.73%) and peroxidase activity (POX) (101.91%). MC also enhanced superoxide dismutase (SOD) activities by 166.19% compared to their controls (V). M alone or in combination with compost, remains a favourable interaction for suppressing plant diseases and improving antioxidant defense systems. [ABSTRACT FROM AUTHOR]

Copyright of Arab Journal of Plant Protection is the property of Arab Society for Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

CAP (cysteine-rich secretory proteins, antigen5, pathogenesis-related proteins) superfamily proteins are widely distributed, can be subdivided into 11 subfamilies, and form a unique branch in fungi, named PRY proteins. Verticillium dahliae is a soil-borne fungal pathogen of vascular plants that causes plant Verticillium wilt. However, the roles of CAP superfamily proteins in this fungus is unclear. Here, four CAP superfamily members with a conserved domain were identified in V. dahliae: VdPRY1, VdPRY2, VdPRY3, and VdPRY4. VdPRY1 and VdPRY3 were found to be key in suppressing plant immune responses. Moreover, these four members are highly expressed during early infection of cotton by V. dahliae. Deleting VdPRY1, VdPRY2, or VdPRY3 reduced the fungus’s ability to cause disease, but VdPRY4 deletion did not affect virulence. Deletion of any of four members did not impact fungal growth or carbon source use. Yeast two-hybrid experiments suggest that these proteins may function through interactions with each other. This investigation has, for the initial time, elucidated the pivotal roles of V. dahliae CAP superfamily proteins in inhibiting plant immunity and exerting virulence during interaction with the host plant.

Verticillium wilt (VW), induced by the soil-borne fungus Verticillium dahliae (Vd), poses a substantial threat to a diverse array of plant species. Employing molecular breeding technology for the development of cotton varieties with heightened resistance to VW stands out as one of the most efficacious protective measures. In this study, we successfully generated two stable transgenic lines of cotton (Gossypium hirsutum L.), VdThit-RNAi-1 and VdThit-RNAi-2, using host-induced gene silencing (HIGS) technology to introduce double-stranded RNA (dsRNA) targeting the thiamine transporter protein gene (VdThit). Southern blot analysis confirmed the presence of a single-copy insertion in each line. Microscopic examination showed marked reductions in the colonization and spread of Vd-mCherry in the roots of VdThit-RNAi cotton compared to wild type (WT). The corresponding disease index and fungal biomass of VdThit-RNAi-1/2 also exhibited significant reductions. Real-time quantitative PCR (qRT-PCR) analysis demonstrated a substantial inhibition of VdThit expression following prolonged inoculation of VdThit-RNAi cotton. Small RNA sequencing (sRNA-Seq) analysis revealed the generation of a substantial number of VdThit-specific siRNAs in the VdThit-RNAi transgenic lines. Additionally, the silencing of VdThit by the siVdThit produced by VdThit-RNAi-1/2 resulted in the elevated expression of multiple genes involved in the thiamine biosynthesis pathway in Vd. Under field conditions, VdThit-RNAi transgenic cotton exhibited significantly enhanced disease resistance and yield compared with WT. In summary, our findings underscore the efficacy of HIGS targeting VdThit in restraining the infection and spread of Vd in cotton, thereby potentially enabling the development of cotton breeding as a promising strategy for managing VW.

Verticillium wilt of pistachio (Pistacia vera), caused by Verticillium dahliae, is one of the most important diseases in this crop. The most effective and economical control measure is the use of resistant rootstocks. The main objective of this work was to evaluate the resistance of five rootstocks commonly used in pistachio against the disease under field conditions. Pistachio plants (cv. Kerman) grafted on the rootstocks Pistacia atlantica, Pistacia integerrima, Pistacia terebinthus and cv. Platinum and UCBI hybrids, were planted in a field with high inoculum density of V. dahliae in the soil. Plants grafted on P. terebinthus, followed by P. integerrima, showed significantly higher disease severity values than the rest of the rootstocks almost 53 months after planting; also, plants grafted on P. atlantica were more resistant than those grafted on P. integerrima. These results highlighted the intraspecific variability in resistance to the disease. In addition, the disease was monitored in pistachios grafted onto P. terebinthus or UCBI in an established commercial field with three different zones of V. dahliae inoculum density in the soil (none, low or high). In the high‐density zone, the percentage of diseased plants was significantly lower for plants grafted on UCBI than for those grafted on P. terebinthus. The results indicate the importance of rootstock species and specific genotype or seed population used, concentration of V. dahliae inoculum in the soil, and previous history of crops on the plot, on the development of the disease under natural conditions. [ABSTRACT FROM AUTHOR]

Bacillus subtilis, a gram-positive bacterium commonly found in soil, is an excellent organism for plant biocontrol. B. subtilis KRS015, an endophyte isolated from the seed of Gossypium hirsutum ‘Zhongzhimian No. 2’, has been proven based on its antagonistic activity against diverse fungal pathogens of plants, including Verticillium dahliae, a fungal pathogen of Verticillium wilt in various plants such as cotton. Here, we report the complete genome sequence of B. subtilis KRS015. The size of the KRS015 genome is 4,331,506 bp. Fifteen gene clusters for antibiotics and secondary metabolites and 412 genes involved in plant–bacterial interactions were identified in this genome. These findings qualified the potential of B. subtilis KRS015 as a biocontrol agent and may help reveal the molecular basis of its antagonistic mechanisms. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Introduction: Sessile plants engage in trade-offs between growth and defense capacity in response to fluctuating environmental cues. MYB is an important transcription factor that plays many important roles in controlling plant growth and defense. However, the mechanism behind how it keeps a balance between these two physiological processes is still largely unknown. Objectives: Our work focuses on the dissection of the molecular mechanism by which GhMYB33 regulates plant growth and defense. Methods: The CRISPR/Cas9 technique was used to generate mutants for deciphering GhMYB33 functions. Yeast two-hybrid, luciferase complementary imaging, and co-immunoprecipitation assays were used to prove that proteins interact with each other. We used the electrophoretic mobility shift assay, yeast one-hybrid, and luciferase activity assays to analyze GhMYB33 acting as a promoter. A β-glucuronidase fusion reporter and 5′ RNA ligase mediated amplification of cDNA ends analysis showed that ghr-miR319c directedly cleaved the GhMYB33 mRNA. Results: Overexpressing miR319c-resistant GhMYB33 (rGhMYB33) promoted plant growth, accompanied by a significant decline in resistance against Verticillium dahliae. Conversely, its knockout mutant, ghmyb33, demonstrated growth restriction and concomitant augmentation of V. dahliae resistance. GhMYB33 was found to couple with the DELLA protein GhGAI1 and bind to the specific cis-elements of GhSPL9 and GhDFR1 promoters, thereby modulating internode elongation and plant resistance in V. dahliae infection. The ghr-miR319c was discovered to target and suppress GhMYB33 expression. The overexpression of ghr-miR319c led to enhanced plant resistance and a simultaneous reduction in plant height. Conclusion: Our findings demonstrate that GhMYB33 encodes a hub protein and controls the expression of GhSPL9 and GhDFR1, implicating a pivotal role for the miR319c-MYB33 module to regulate the trade-offs between plant growth and defense.

Magnaporthiopsis maydis is a maize pathogen that causes severe damage to commercial corn fields in the late growth stages. Late wilt disease (LWD) has spread since its discovery in the 1960s in Egypt and is now reported in about 10 countries. The pathogen has a hidden endophytic lifecycle in resistant corn plants and secondary hosts such as green foxtail, watermelon lupin and cotton. At the same time, it could be an opportunist and hinder the host development under the right conditions. This study uncovered M. maydis interactions with newly identified maize endophytes. To this end, six fungi were isolated from the seeds of three sweet corn cultivars having varying susceptibility to LWD. These isolates were identified using colony morphology and microscopic characterization, universal internal transcribed spacer (ITS) molecular targeting and phylogenetic analysis. Most of them belonged to pathogenic species. Compared to three previously identified bioprotective microorganisms, the new species were tested for their ability to secrete metabolites that repress M. maydis in vitro and to antagonize it in a solid media confront test and a seedlings pathogenicity assay. The opportunistic fungal species Aspergillus flavus (ME1), Aspergillus terreus (PE3) and the reference biocontrol bacteria Bacillus subtilis (R2) achieved the highest M. maydis inhibition degree in the plates tests (74-100% inhibition). The seedlings' pathogenicity assay that predicts the seeds' microflora resistance to M. maydis highlighted the bio-shielding potential of most species (23% or more epicotyl elongation over the infected control). Fusarium sp. (ME2) was the leading species in this measure (43% enhancement), and B. subtilis gave the best protection in terms of seeds' germination (50%) and sprouts' biomass (34%). The results of this study could enhance our understanding of the pathobiome's role in the context of LWD and represent a first step in using the seeds' natural protective microflora to develop novel management strategies. [ABSTRACT FROM AUTHOR]

SUMMARY: Verticillium dahliae, a soil‐borne fungal pathogen, compromises host innate immunity by secreting a plethora of effectors, thereby facilitating host colonization and causing substantial yield and quality losses. The mechanisms underlying the modulation of cotton immunity by V. dahliae effectors are predominantly unexplored. In this study, we identified that the V. dahliae effector Vd6317 inhibits plant cell death triggered by Vd424Y and enhances PVX viral infection in Nicotiana benthamiana. Attenuation of Vd6317 significantly decreased the virulence of V. dahliae, whereas ectopic expression of Vd6317 in Arabidopsis and cotton enhanced susceptibility to V. dahliae infection, underscoring Vd6317's critical role in pathogenicity. We observed that Vd6317 targeted the Arabidopsis immune regulator AtNAC53, thereby impeding its transcriptional activity on the defense‐associated gene AtUGT74E2. Arabidopsis nac53 and ugt74e2 mutants exhibited heightened sensitivity to V. dahliae compared to wild‐type plants. A mutation at the conserved residue 193L of Vd6317 abrogated its interaction with AtNAC53 and reduced the virulence of V. dahliae, which was partially attributable to a reduction in Vd6317 protein stability. Our findings unveil a hitherto unrecognized regulatory mechanism by which the V. dahliae effector Vd6317 directly inhibits the plant transcription factor AtNAC53 activity to suppress the expression of AtUGT74E2 and plant defense. Significance Statement: Verticillium dahliae effector Vd6317 regulates plant immunity. [ABSTRACT FROM AUTHOR]

Mitogen‐activated protein kinase (MAPK) cascade is the center of plant signal transduction system that amplify immune signals into cellular responses by phosphorylating diverse substrates. The MAPK cascade consisting of MAPK kinase kinases (MAPKKKs), MAPK kinases (MAPKKs), and MAPKs is well characterized in plants, in which Raf‐like kinases are generally regarded as MAPKKKs. However, it is rarely reported that Raf‐like MAPKKKs function as middle regulators to link MAPK and its downstream transcription factors in plant immunity. Verticillium wilt, caused by the soil‐borne vascular fungus Verticillium dahliae, is a serious disease in many plants, including cotton. The previous studies showed that GhMPK9 (a MAPK) is involved in the response to Verticillium wilt. Here, the Raf‐like kinase GhRAF39_1 is reported as helper regulates the phosphorylation of WRKY transcription factor GhWRKY40a by GhMPK9. The phosphorylated GhWRKY40a can further activate the transcription of GhERF1b to up‐regulate defense‐related genes while inhibit the transcription of GhABF2 to regulate the stomatal opening, thus improving the resistance to Verticillium wilt in cotton. This study reveals a new signaling module of GhMPK9‐GhRAF39_1‐GhWRKY40a to regulate GhERF1b‐ and GhABF2‐mediated defense responses, which triggers plant defense against Verticillium wilt. [ABSTRACT FROM AUTHOR]

Introduction: Verticillium dahliae, a soil-borne fungal pathogen, can cause cotton Verticillium wilt. In this study, VdP5CDH, the member of the ALDH_F4- 17 family of carboxylate dehydrogenases, was identified in the genome of V. dahliae and investigated function in regulating virulence by generating gene deletion mutants and complementary mutants. Methods: Homologous recombination method was used to construct mutants, transcriptome sequencing revealed gene-related metabolic pathways, and disease degree of cotton was observed through pathogen infection experiments. Results: The conidial surface of VdP5CDH deletion strains was dented and shriveled, and the number of conidial spores increased. Compared with the wild-type (WT), the mycelial diameter of deletion mutants increased by 10.59%-11.16%, the mycelial growth showed irregular branching patterns, and misaligned arrangement. Although capable of penetrating cellophane, deletion mutants were unable to produce melanin. VdP5CDH was mainly associated with glucose metabolism, nitrogen metabolism, ABC transporter activity as well as various amino acid metabolic processes. After gene knockout, raffinose and pectin were used as the main carbon sources to promote the growth of strains and the growth rate of deletion strains in the medium containing raffinose was higher than that of WT. Consequently, the deletion mutant strains decreased utilization efficiency with which they utilized various nitrogen sources. The deletion mutants maintain responsiveness to osmotic stress and oxidative stress stimuli. Additionally, compared to WT strains, the deletion mutant strains exhibited differences in culture temperature tolerance, UV exposure response, and fungicide sensitivity. After cotton was infected with deletion strains conidial suspension, its disease index increased dramatically, while it gradually decreased after spraying with 2 mM glutamate in batches. With the increase of spraying times, the effect was more significant, and the disease index decreased by 18.95%-19.66% at 26 dpi. Discussion: These results indicated that VdP5CDH regulates the pathogenicity of fungi and controls mycelia growth, melanin formation, conidia morphology, abiotic stress resistance, and the expression of infecting structure-related genes. [ABSTRACT FROM AUTHOR]

Verticillium dahliae is an important soil-borne fungal pathogen that causes great yield losses in many cash crops. Effectors of this fungus are known to regulate plant immunity but the mechanism much remains unclear. A glycine-rich nuclear effector, VdCE51, was able to suppress immune responses in tobacco against Botrytis cinerea and Sclerotinia sclerotiorum. This effector was a required factor for full virulence of V. dahliae, and its nuclear localization was a requisite for suppressing plant immunity. The thioredoxin GhTRXH2, identified as a positive regulator of plant immunity, was a host target of VdCE51. Our findings show a virulence regulating mechanism whereby the secreted nuclear effector VdCE51 interferes with the transcription of PR genes, and the SA signaling pathway by inhibiting the accumulation of GhTRXH2, thus suppressing plant immunity. [ABSTRACT FROM AUTHOR]

A survey of New Brunswick (NB) and Prince Edward Island (PEI) potato fields in crop rotation phase prior to potato production was conducted in fall (October and November) between 2017 and 2021. A total of 113 and 126 fields for NB and PEI, respectively, were surveyed with 20 to 35 fields each year tested in each province. Root lesion nematodes (RLN, Pratylenchus spp.) were detected in 99 and 98% of the fields for NB and PEI, respectively, and two root lesion nematode species, P. crenatus and P. penetrans, were identified in both provinces from 2017 to 2021. Based on 2019 and 2020 results, all surveyed fields in NB and PEI were detected with P. crenatus, while only 29 and 43% of the fields in NB and PEI were detected with P. penetrans, respectively. P. crenatus accounted for 96 and 89% of the populations for NB and PEI, respectively, while P. penetrans accounted for 4 and 11% in commercial fields, respectively. In a single in-depth sampled experimental field with a history of severe potato early dying complex in 2018 in NB, P. crenatus accounted for 88% and P. penetrans was 12%. Verticillium dahliae was detected in 94 and 92% of potato fields in NB and PEI, respectively. All isolates obtained from potato cv. "Russet Burbank" in a baiting trial were V. dahliae, belonging to two lineages. V. albo-atrum was detected in a few fields at very low level, except two fields in NB where V. albo-atrum was predominating over V. dahliae. Rotation crops did not affect V. dahliae population densities for NB and PEI, and did not affect RLN population in NB, but significantly affected RLN in PEI. Fall green cover crop did not affect the populations of RLN and V. dahliae in PEI. The present study revealed that the potato pathogenic root lesion nematode P. penetrans was present in less than 50% of surveyed fields and accounted for around 10% of root lesion nematode population in NB and PEI, and V. dahliae was the dominant species and was present in greater than 90% of surveyed fields in both provinces. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a result of the ineffectiveness of existing control methods against Verticillium dahliae, the causal agent of verticillium wilt of olive (Olea europaea; VWO), it is necessary to search for sustainable and environmentally friendly alternatives, such as bioprotection by products based on plant extracts and other naturally synthesized compounds. Therefore, present study aimed to evaluate the effects of seven natural‐based commercial products on the inhibition of mycelial growth, the germination of V. dahliae conidia and microsclerotia, and disease progression in olive plants (cv. Picual). Aluminium lignosulfonate and a copper phosphonate salt (copper phosphite) were included for comparative purposes. RESULTS: The seaweed and willow extracts and copper phosphite inhibited V. dahliae mycelial growth by more than 50% at the high doses tested. Most of the products inhibited conidial germination by up to 90% compared to the control at the high doses tested. However, none of the products showed efficacy above 50% in inhibiting microsclerotia germination. The willow extract was the most effective at reducing disease severity and progression in olive plants, with no significant differences compared to the non‐inoculated negative control. CONCLUSION: The results of the present study suggest that the use of natural‐based products (i.e. seaweed and willow extracts) is a potential sustainable alternative in an integrated VWO control strategy. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Introduction: Verticillium dahliae causes a devastating Verticillium wilt disease on hundreds of plant species worldwide, including cotton. Understanding the interaction mechanism between V. dahliae and its hosts is the prerequisite for developing effective strategies for disease prevention. Methods: Here, based on the previous observation of an xylosidase-encoding gene (VdxyL3) in V. dahliae being obviously up-regulated after sensing root exudates from a cotton variety susceptible to this pathogen, we investigated the function of VdxyL3 in the growth and pathogenesis of V. dahliae by generating its deletion-mutant strains (1VdxyL3). Results: Deleting VdxyL3 led to increased colony expansion rate, conidial production, mycelial growth, carbon and nitrogen utilization capacities, and enhanced stress tolerance and pathogenicity of V. dahliae. VdxyL3 is a secretory protein; however, VdxyL3 failed to induce cell death in N. benthamiana based on transient expression experiment. Transcriptomic analysis identified 1300 genes differentially expressed (DEGs) between wild-type (Vd952) and 1VdxyL3 during infection, including 348 DEGs encoding secretory proteins, among which contained 122 classical secreted proteins and 226 non-classical secreted proteins. It was notable that of the 122 classical secretory proteins, 50 were carbohydrate-active enzymes (CAZymes) and 58 were small cysteine rich proteins (SCRPs), which were required for the pathogenicity of V. dahliae. Conclusion: The RNA-seq data thus potentially connected the genes encoding these proteins to the pathogenesis of V. dahliae. This study provides an experimental basis for further studies on the interaction between V. dahliae and cotton and the pathogenic mechanism of the fungus. [ABSTRACT FROM AUTHOR]

Cotton is one of the world's most important economic crops. Verticillium wilt is a devastating cotton disease caused by Verticillium dahliae, significantly impacting cotton yield and quality. E3 ubiquitin ligases are essential components of the ubiquitin-mediated 26S proteasome system, responsible for recognizing ubiquitinated target proteins and promoting their degradation, which play a crucial regulatory role in plant immune responses. In this study, on the basis of the confirmation of differential expression of GhDIRP1, a RING-type E3 ubiquitin ligase encoding gene, in two cotton varieties resistant (Zhongzhimian 2) or susceptible (Jimian 11) to V. dahliae, we demonstrated that GhDIRP1 is a negative regulator of V. dahliae resistance because silencing GhDIRP1 in cotton and heterogeneously overexpressing the gene in Arabidopsis enhanced and compromised resistance to V. dahliae, respectively. The GhDIRP1-mediated immune response seemed to be realized through multiple physiological pathways, including hormone signaling, reactive oxygen species, and lignin biosynthesis. Based on the sequences of GhDIRP1 isolated from Zhongzhimian 2 and Jimian 11, we found that GhDIRP1 had identical coding but different promoter sequences in the two varieties, with the promoter of Zhongzhimian 2 being more active than that of Jimian 11 because the former drove a stronger expression of GUS and LUC reporter genes. The results link the ubiquitination pathway to multiple physiological pathways acting in the cotton immune response and provide a candidate gene for breeding cotton varieties resistant to V. dahliae. [ABSTRACT FROM AUTHOR]

The study explores anaerobic soil disinfection as an alternative to soil fumigants for controlling Verticillium wilt in strawberry crops. For this purpose, two agrowastes close to the strawberry-growing areas of Huelva province were tested as potential amendments for the control of Verticillium wilt: rice bran and residual strawberry extrudate. Furthermore, two application rates were evaluated: 13.50 and 20.00 t/ha for the rice bran and 16.89 and 25.02 t/ha for residual strawberry extrudate. Amended and anaerobically disinfested soils were compared with a non-amended soil under anaerobic conditions, a soil treated with the chemical fungicide metam sodium and an untreated soil. One week before the start of disinfection treatment, these soils were artificially inoculated with 250 microsclerotia/g dry soil of Verticillium dahliae. After disinfestation treatments, pathogens were quantified, and strawberry plants were cropped in a growth chamber to further evaluate Verticillium wilt severity, which was measured with a symptom scale in the same potting soils. Measurements of the anaerobic condition, pH and microbial population densities were performed, and the results showed significant differences between the different amendments. In addition, the treatment with rice bran at 20 t/ha recorded the lowest population density of V. dahliae. Likewise, it was possible to achieve a reduction in foliar disease severity in all amended treatments in similar percentage to those obtained by chemical treatment. These results suggest potential application of this technique for the control of Verticillium wilt in the strawberry-growing area of Huelva, reducing the use of chemical fumigants. [ABSTRACT FROM AUTHOR]

【Objective】The study was carried out to explore the distribution patterns of rhizospheric microbial communities in different resistant pepper varieties, aiming to provide a basis for the targeted optimization of rhizospheric microbial community structure of pepper.【Method】Taking the susceptible pepper variety ‘Hailan 99’ (HL99) and the resistant variety ‘Sanxiaqing’ (SSQ) as experimental materials, high-throughput sequencing technology was employed to analyze and compare the effects of susceptible and non-susceptible soil environments on the community diversity, species composition, correlation networks and function of bacteria and fungi in the rhizosphere soil of different disease-resistant pepper plants. 【Result】Through high-throughput sequencing, a total of 66 617 operational taxonomic units (OTUs) from soil bacterial samples were obtained, among which the dominant phyla were Proteobacteria and Bacteroidetes, with the relative abundances of approximately 40.1% and 15.3%, respectively. From soil fungal samples, 2 948 OTUs were obtained, among which the dominant phylum was Ascomycota, with an average relative abundance of approximately 47.8%. The rhizospheric microbial community structure and species composition of pepper varieties showed significant differences under different soil conditions. Under susceptible soil conditions, the diversity of bacterial communities in pepper rhizosphere decreased, while the diversity of fungal communities increased. The bacterial OTUs decreased by 6.5%-7.8%, and fungal OTUs increased by 8.8%-9.8%. The relative abundance of Fusarium fungi was significantly higher in the susceptible group (5.0%) compared with that in the resistant group (4.8%), while the relative abundance of beneficial fungi like Mortierella and Trichoderma and beneficial bacteria like Pseudomonas and Bacillus was significantly lower in the susceptible group than that in the resistant group. Overall, under the susceptible soil conditions, the abundance of beneficial rhizosphere fungi and bacteria in the resistant group was higher than that in the susceptible group, contributing to a better soil micro-ecological environment. Based on species abundance tables, the correlation relationships of fungi-fungi, fungi-bacteria and bacteria-bacteria species were calculated respectively at the genus level. The results indicated that the rhizosphere microorganisms of pepper formed a complex ecological network, with high co-occurrence between fungi-fungi and fungi-bacteria (with a positive correlation percentage higher than 50%), suggesting that cooperative relationships outweighed competitive ones. The bacteria-bacteria network structure was more complex, with a positive correlation percentage of about 49.9%.【Conclusion】The rhizospheric microbial community structures of different resistant varieties exhibit significant differences under different soil conditions. The interaction of rhizosphere microorganisms forms a complex microbial ecological network structure. The relative abundance of beneficial fungi and bacteria is higher in the resistant variety than that in the susceptible variety, which suppresses more pathogenic microbes, leading to a healthier soil micro-ecological environment. The key groups identified in this study, including Fusarium, Verticillium, Trichoderma, Bacillus and Pseudomonas, will provide important information for the targeted optimization of rhizospheric microbial community structures and offer crucial theoretical references for the biological control of soil-borne diseases. [ABSTRACT FROM AUTHOR]

This study was carried out to identification of Vegetative Compatibility Groups (VCGs) and pathogenicity of Verticillium dahliae isolates obtained from tomato plants in Iğdır province. As a result of survey studies conducted in 18 different regions, 14 isolates were obtained from 629 diseased tomato plants. In the complementation test, the seven isolates were found as VCG2A and VCG2B by using international reference isolates. VCGs of other isolates were not identified. Assessment of the aggressiveness of the KRS-2, YC-13, YY-14, and MLK3-4 isolates was evaluated on tomato (cv. Super). The disease severity was between 15-45% and MLK3-4 isolate had the highest disease severity (45%). Additionally, the effect of temperature on the growth of V. dahliae isolates (TSD-1, MLK3- 4 and YY-14) was determined. The isolates showed optimal growth temperatures ranging from 20 to 25 °C (except for TSD-1). In control of fungal diseases, it is very important to describe the disease and pathogen. Therefore, the results of the study are important for tomato growers and researchers. [ABSTRACT FROM AUTHOR]

SUMMARY: Alternative splicing (AS) of pre‐mRNAs increases the diversity of transcriptome and proteome and plays fundamental roles in plant development and stress responses. However, the prevalent changes in AS events and the regulating mechanisms of plants in response to pathogens remain largely unknown. Here, we show that AS changes are an important mechanism conferring cotton immunity to Verticillium dahliae (Vd). GauSR45a, encoding a serine/arginine‐rich RNA binding protein, was upregulated expression and underwent AS in response to Vd infection in Gossypium australe, a wild diploid cotton species highly resistant to Vd. Silencing GauSR45a substantially reduced the splicing ratio of Vd‐induced immune‐associated genes, including GauBAK1 (BRI1‐associated kinase 1) and GauCERK1 (chitin elicitor receptor kinase 1). GauSR45a binds to the GAAGA motif that is commonly found in the pre‐mRNA of genes essential for PTI, ETI, and defense. The binding between GauSR45a and the GAAGA motif in the pre‐mRNA of BAK1 was enhanced by two splicing factors of GauU2AF35B and GauU1‐70 K, thereby facilitating exon splicing; silencing either AtU2AF35B or AtU1‐70 K decreased the resistance to Vd in transgenic GauSR45a Arabidopsis. Overexpressing the short splicing variant of BAK1GauBAK1.1 resulted in enhanced Verticillium wilt resistance rather than the long one GauBAK1.2. Vd‐induced far more AS events were in G. barbadense (resistant tetraploid cotton) than those in G. hirsutum (susceptible tetraploid cotton) during Vd infection, indicating resistance divergence in immune responses at a genome‐wide scale. We provided evidence showing a fundamental mechanism by which GauSR45a enhances cotton resistance to Vd through global regulation of AS of immunity genes. Significance Statement: We found PTI‐ and ETI‐associated genes underwent genome‐wide AS in the immune response to Vd in cotton and SR45a collaborated with splicing factors U2AF35B and U1‐70K to regulate AS of immune‐associated genes. Our results provide evidence showing that SR45a may play a central role in the regulation of AS of plant immunity genes in response to Vd invasion, and thus deepen our insights into the mechanisms of VW resistance in cotton. [ABSTRACT FROM AUTHOR]

Verticillium dahliae is a kind of pathogenic fungus that brings about wilt disease and great losses in cotton. The molecular mechanism of the effectors in V. dahliae regulating cotton immunity remains largely unknown. Here, we identified an effector of V. dahliae , VdPHB1, whose gene expression is highly induced by infection. The VdPHB1 protein is localized to the intercellular space of cotton plants. Knock-out of the VdPHB1 gene in V. dahliae had no effect on pathogen growth, but decreased the virulence in cotton. VdPHB1 ectopically expressed Arabidopsis plants were growth-inhibited and significantly susceptible to V. dahliae. Further, VdPHB1 interacted with the type II metacaspase GhMC4. GhMC4 gene-silenced cotton plants were more sensitive to V. dahliae with reduced expression of pathogen defense-related and programmed cell death genes. The accumulation of GhMC4 protein was concurrently repressed when VdPHB1 protein was expressed during infection. In summary, these results have revealed a novel molecular mechanism of virulence regulation that the secreted effector VdPHB1 represses the activity of cysteine protease for helping V. dahliae infection in cotton. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cotton miR319c- MYB33 module regulates trade-offs between plant growth and defense. • GhGAI1 interacts with GhMYB33 and affects its transcriptional activity. • GhMYB33 binds to the GhSPL9 promoter and activates its expression to increase plant height. • Under Verticillium dahliae infection, GhMYB33 expression is repressed to promote GhDFR1 transcription, increasing plant resistance. Sessile plants engage in trade-offs between growth and defense capacity in response to fluctuating environmental cues. MYB is an important transcription factor that plays many important roles in controlling plant growth and defense. However, the mechanism behind how it keeps a balance between these two physiological processes is still largely unknown. Our work focuses on the dissection of the molecular mechanism by which GhMYB33 regulates plant growth and defense. The CRISPR/Cas9 technique was used to generate mutants for deciphering GhMYB33 functions. Yeast two-hybrid, luciferase complementary imaging, and co-immunoprecipitation assays were used to prove that proteins interact with each other. We used the electrophoretic mobility shift assay, yeast one-hybrid, and luciferase activity assays to analyze GhMYB33 acting as a promoter. A β-glucuronidase fusion reporter and 5′ RNA ligase mediated amplification of cDNA ends analysis showed that ghr-miR319c directedly cleaved the GhMYB33 mRNA. Overexpressing miR319c-resistant GhMYB33 (rGhMYB33) promoted plant growth, accompanied by a significant decline in resistance against Verticillium dahliae. Conversely, its knockout mutant, ghmyb33, demonstrated growth restriction and concomitant augmentation of V. dahliae resistance. GhMYB33 was found to couple with the DELLA protein GhGAI1 and bind to the specific cis-elements of GhSPL9 and GhDFR1 promoters, thereby modulating internode elongation and plant resistance in V. dahliae infection. The ghr-miR319c was discovered to target and suppress GhMYB33 expression. The overexpression of ghr-miR319c led to enhanced plant resistance and a simultaneous reduction in plant height. Our findings demonstrate that GhMYB33 encodes a hub protein and controls the expression of GhSPL9 and GhDFR1, implicating a pivotal role for the miR319c- MYB33 module to regulate the trade-offs between plant growth and defense. [ABSTRACT FROM AUTHOR]

Verticillium wilt, caused by the pathogenic fungus Verticillium dahliae, has emerged as a severe threat to cotton globally. However, little is known about the genetic diversity of this pathogen in an infected single cotton plant. In this study, we isolated three new V. dahliae strains from the disease stems of Gossypium hirsutum from the cotton field in Western China and assessed their pathogenicity to the cotton cultivar Xinnongmian-1 and its two transgenic lines, as well as two laboratory strains, VD592 and VD991. These three new V. dahliae strains were identified using DNA barcodes of tryptophan synthase (TS), actin (ACT), elongation factor 1-α (EF), and glyceraldehyde-3-phosphate dehydrogenase (GPD). Moreover, the haplotype analysis revealed that the three new races had distinct haplotypes at the TS locus. Furthermore, the results of culture features and genetic diversity of ISSR (inter-simple sequence repeat) revealed that there were separate V. dahliae strains, which were strong defoliating pathotypes belonging to race 2 type, as determined by particular DNA marker recognition. The identified strains demonstrated varied levels of pathogenicity by leaf disc and entire plant inoculation methods. Conservatively, these strains showed some pathogenicity on cotton lines, but were less pathogenic than the reference strains. The findings revealed that several strong defoliating V. dahliae pathotypes coexist on the same cotton plant. It indicats the importance of regular monitoring as an early warning system, as well as the detection and reporting of virulent pathogen strains and their effects on crop response. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to evaluate the antifungal activity of Osmotin against several important economically improtant plant pathogenic fungi. The Osmotin gene from Nicotiana tabacum was overexpressed in Escherichia coli (Rosetta DE3). Taguchi test was applied to optimize the conditions for protein expression, and Western blot analysis confirmed expression of the recombinant protein. The expressed Osmotin was found in the form of insoluble inclusion bodies, which were then solubilized and refolded. The purified and refolded protein's activity was verified by three different antifungal activity assays. The purified recombinant Osmotin demonstrated a wide range of antifungal activity against various types of phytopathogenic fungi: Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium oxysporum, Verticillium dahliae and Alternaria brassicola. Hemolysis biosafety test demonstrated that the protein is non-toxic to mammalian cells. All these findings suggest that the Osmotin gene from N. tabacum has promising potential as an antifungal agent against various phytopathogenic fungi and also to be utilized for production of antifungal agents and fungal-resistant transgenic plants. [ABSTRACT FROM AUTHOR]

SUMMARY: Verticillium wilt (VW) is a devasting disease affecting various plants, including upland cotton, a crucial fiber crop. Despite its impact, the genetic basis underlying cotton's susceptibility or defense against VW remains unclear. Here, we conducted a genome‐wide association study on VW phenotyping in upland cotton and identified a locus on A13 that is significantly associated with VW resistance. We then identified a cystathionine β‐synthase domain gene at A13 locus, GhCBSX3A, which was induced by Verticillium dahliae. Functional analysis, including expression silencing in cotton and overexpression in Arabidopsis thaliana, confirmed that GhCBSX3A is a causal gene at the A13 locus, enhancing SAR‐RBOHs‐mediated apoplastic oxidative burst. We found allelic variation on the TATA‐box of GhCBSX3A promoter attenuated its expression in upland cotton, thereby weakening VW resistance. Interestingly, we discovered that altered artificial selection of GhCBSX3A_R (an elite allele for VW) under different VW pressures during domestication and other improved processes allows specific human needs to be met. Our findings underscore the importance of GhCBSX3A in response to VW, and we propose a model for defense‐associated genes being selected depending on the pathogen's pressure. The identified locus and gene serve as promising targets for VW resistance enhancement in cotton through genetic engineering. Significance Statement: Upland cotton cultivars demonstrate limited resistance to Verticillium wilt (VW), with most studies indicating that upland cotton (AD1) possesses an inherent disadvantage concerning VW resistance. We found that the artificial selection of GhCBSX3A_R, an elite allele for VW resistance, achieved through enhanced reactive oxygen species accumulation, resulted in reduced VW resistance in improved accessions. This evidence supports the idea that the susceptibility against VW may be attributed to a significant decline in VW resistance during upland cotton domestication. [ABSTRACT FROM AUTHOR]