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The sclerotia of Sclerotinia sclerotiorum serve as a primary inoculum source for initiating infections. This study aimed to evaluate the effects of environmental factors on sclerotial germination under field conditions by establishing sclerotia depots to monitor apothecia appearance over four consecutive years. Additionally, the effects of soil moisture content (25%, 50%, 75%, and 95%), air temperature (10 °C/10 °C, 14 °C/10 °C, and 18 °C/10 °C), and light conditions (white and UV light) on sclerotial germination and apothecial formation were investigated under controlled conditions with a 17 h day/7 h night regime. Furthermore, variability in carpogenic germination among S. sclerotiorum isolates was examined. From 2021 to 2024, significant differences were observed in both the sclerotia germination rate and timing of germination within the season. High soil moisture, particularly prolonged wetness, and soil temperatures between 10 and 14 °C were key factors for apothecial formation under field conditions. Under controlled conditions, higher soil moisture levels (75% and 95%) accelerated sclerotial germination, with sclerotia incubated at 14 °C/10 °C germinating earlier after 38 days than those at 10 °C/10 °C or 18 °C/10 °C. Additionally, the type of light significantly affected apothecial formation, which was observed only in treatments exposed to a combination of white and UV light. Furthermore, significant variations were also found in the duration until sclerotia of different S. sclerotiorum isolates produced the first stipe and the first apothecium, indicating that the genetic characteristics of each isolate affect carpogenic germination. [ABSTRACT FROM AUTHOR]

Dragon's head (Lallemantia iberica) as an oilseed crop has been recently introduced to Iranian farmers and due to its tolerance to abiotic stresses grown in drylands and rain-fed areas of the country in rotation with cereals and pulses. In this study, fifty Iranian L. iberica landraces were evaluated for the prevalent diseases under field conditions during 2019–2021 in Gonbad-Kavous, North of Iran. A spot lesion/blight symptom was observed in the field and the subsequent classical and molecular mycological studies identified Alternaria tenuissima and A.atra as the causal agents. Subsequently, a complimentary experiment was conducted to screen genotypes for these disease agents under controlled conditions using the proposed scoring system invented in this study. Results showed a significant negative correlation of Sclerotinia stem rot with yield and plant height, while no relationship was observed between Alternaria spot/blight and agronomic traits. Two and twenty-one genotypes were identified as highly resistant and resistant to Sclerotinia stem rot in the field, respectively; where six of them showed additional resistance to Altarnaria spp. in the glasshouse. The resistant/high-yield genotypes identified through this research can be considered valuable sources to be released as new cultivars or exploited in breeding programs. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR), caused by the necrotrophic fungal pathogen Sclerotinia sclerotiorum, is a severe disease of broadleaf crops including canola/rapeseed (Brassica napus), leading to significant yield loss in conducive years. Replication of field conditions is challenging in variety disease resistance screening with testing required under a wide range of environmental conditions and at different plant growth stages. We investigated the role of thermal time in disease progression using three sowing times in the growing season, with six commonly grown Australian varieties of canola inoculated with four diverse West Australian isolates of S. sclerotiorum at 30% flowering. Area Under the Disease Progression Stairs (AUDPS), sclerotia production and weight, and seed production were measured. Time of sowing was found to be a crucial factor in explaining differences in AUDPS, stem width, seed production and sclerotia number according to the analysis of variance (P < 0.05), influencing isolate aggressiveness and disease progression. Linear mixed-effect models, regression decision tree models and principal components analysis were also conducted to determine the importance of a range of variables being included in variety screening for resistance. For all these analyses, both thermal time from sowing to 30% flowering when plants were inoculated, as well as thermal time over the 28-day inoculation period, in both canola and S. sclerotiorum, were important in explaining the variation. The study concludes by recommending that thermal time should be included in future SSR prediction risk models. [ABSTRACT FROM AUTHOR]

Sclerotinia sclerotiorum is an economically damaging fungal pathogen that causes Sclerotinia stem rot in leguines, producing enormous yield losses. This pathogen is difficult to control due to its wide host spectrum and ability to produce sclerotia. which are resistant bodies that can remain active for long periods under harsh environmental conditions. Here, the biocontrol methods for the management of S. sclerotiorum in legumes are reviewed. Baciltus strains, which synthesized lipopeptides and volatile organic compounds, showed high efficacies in soybean plants, whereas the highest efficacies for the control of the pathogen in alfalfa and common bean were observed when using Coniothyrium minitans and Streptomyces spp., respectively. The biocontrol efficacies in fields were under 65%, highlighting the lack of strategies to achieve a complete control. Overall, although most studies involved extensive sci·eenings using different biocontrol agent concentrations and application conditions, there is a lack of knowledge regarding the specific anti fungal mechanisms, which limits the optimization of the reported methods. [ABSTRACT FROM AUTHOR]

The sclerotia of Sclerotinia sclerotiorum serve as a primary inoculum source for initiating infections. This study aimed to evaluate the effects of environmental factors on sclerotial germination under field conditions by establishing sclerotia depots to monitor apothecia appearance over four consecutive years. Additionally, the effects of soil moisture content (25%, 50%, 75%, and 95%), air temperature (10 °C/10 °C, 14 °C/10 °C, and 18 °C/10 °C), and light conditions (white and UV light) on sclerotial germination and apothecial formation were investigated under controlled conditions with a 17 h day/7 h night regime. Furthermore, variability in carpogenic germination among S. sclerotiorum isolates was examined. From 2021 to 2024, significant differences were observed in both the sclerotia germination rate and timing of germination within the season. High soil moisture, particularly prolonged wetness, and soil temperatures between 10 and 14 °C were key factors for apothecial formation under field conditions. Under controlled conditions, higher soil moisture levels (75% and 95%) accelerated sclerotial germination, with sclerotia incubated at 14 °C/10 °C germinating earlier after 38 days than those at 10 °C/10 °C or 18 °C/10 °C. Additionally, the type of light significantly affected apothecial formation, which was observed only in treatments exposed to a combination of white and UV light. Furthermore, significant variations were also found in the duration until sclerotia of different S. sclerotiorum isolates produced the first stipe and the first apothecium, indicating that the genetic characteristics of each isolate affect carpogenic germination.

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, is a destructive disease in canola that significantly reduces seed yield and oil quality. This research aimed to identify the genomic regions and evaluate the potential of genomic prediction for S. sclerotiorum resistance by screening a diverse panel of 143 spring (SP), and 152 semi-winter and winter (SwW) populations through two rounds of plant inoculation during the full flowering stage. A comprehensive phenotypic evaluation involving four distinct traits identified several lines as potential sources of resistance, which showed superior resistance compared to known resistant check cultivars. A Genome-wide association (GWA) study using two different algorithms identified 29 and 19 SNPs in the SP and SwW populations, respectively, with two or more traits were regarded as significant. Ten and seven significant SNPs from SP and SwW populations, respectively, were co-localized with the previously reported SNPs/QTLs by linkage/GWA mapping studies. Within the regions flanking the significant SNPs, we identified a total of 33 and 22 putative candidate genes related to plant defense responses in the SP and SwW populations, respectively. The genomic prediction (GP) revealed higher predictive ability for the SP population (0.46–0.57) over the SwW population (0.10–0.19), depending on trait specifications. In summary, our study revealed that favorable alleles from significant SNPs from GWA mapping could be utilized as valuable resources for introducing and pyramiding resistance alleles to enhance SSR resistance in canola. Genomic selection could also be used as a potential genomics-assisted approach to improve SSR resistance in canola.

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, threatens oilseed rape (Brassica napus) crops internationally. The development of this disease is strongly controlled by the weather, which is why global climate change is likely to influence its spread and impact. Climate change may affect the pathogen directly or indirectly via the host plant. This study investigates the potential impact of climate warming on Sclerotinia stem rot severity in oilseed rape in Poland. The aim of this investigation was to assess the relationship between the direct impact (DI) and indirect impact (II) of climate change on disease severity using the 4.5 and 8.5 representative concentration pathways (RCPs). Under the RCP4.5 scenario, nearly 60% of the simulations performed for 16 regions in four periods (2020–2039, 2040–2059, 2060–2079, 2080–2099) showed reductions in disease severity in comparison to those conducted for 1986–2005, while under RCP 8.5, this reduction was generated for nearly 90% of the cases. The effect of the RCP scenario on clustering the regions according to the value of Sclerotinia stem rot severity was also investigated. The simulations revealed that, for all periods, the lowest disease severities are expected for Zachodniopomorskie and Pomorskie. The results obtained also show the superior effects of the II over the DI on Sclerotinia stem rot severity in the future. Under the RCP4.5 scenario, the rate of IIs was greater than that of DIs for 10 regions, while under RCP8.5, this relationship was registered for 16 regions. These outcomes result from the acceleration of the oilseed rape flowering period triggered by expected temperature increases. The novelty of this study lies in a detailed analysis of the relationships between the DI and II of climate change, expressed numerically, for 16 regions in Poland. The obtained results highlight the role of the indirect impact in shaping disease severity and indicate that it should be incorporated into assessment methods of climate change effects alongside the direct impact. [ABSTRACT FROM AUTHOR]

Abstract Background Oilseed rape (Brassica napus L.) is known as one of the most important oilseed crops cultivated around the world. However, its production continuously faces a huge challenge of Sclerotinia stem rot (SSR), a destructive disease caused by the fungus Sclerotinia sclerotiorum, resulting in huge yield loss annually. The SSR resistance in B. napus is quantitative and controlled by a set of minor genes. Identification of these genes and pyramiding them into a variety are a major strategy for SSR resistance breeding in B. napus. Results Here, we performed a genome-wide association study (GWAS) using a natural population of B. napus consisting of 222 accessions to identify BnaA08g25340D (BnMLO2_2) as a candidate gene that regulates the SSR resistance. BnMLO2_2 was a member of seven homolog genes of Arabidopsis Mildew Locus O 2 (MLO2) and the significantly SNPs were mainly distributed in the promoter of BnMLO2_2, suggesting a role of BnMLO2_2 expression level in the regulation of SSR resistance. We expressed BnMLO2_2 in Arabidopsis and the transgenic plants displayed an enhanced SSR resistance. Transcriptome profiling of different tissues of B. napus revealed that BnMLO2_2 had the most expression level in leaf and silique tissues among all the 7 BnMLO2 members and also expressed higher in the SSR resistant accession than in the susceptible accession. In Arabidopsis, mlo2 plants displayed reduced resistance to SSR, whereas overexpression of MLO2 conferred plants an enhanced SSR resistance. Moreover, a higher expression level of MLO2 showed a stronger SSR resistance in the transgenic plants. The regulation of MLO2 in SSR resistance may be associated with the cell death. Collinearity and phylogenetic analysis revealed a large expansion of MLO family in Brassica crops. Conclusion Our study revealed an important role of BnMLO2 in the regulation of SSR resistance and provided a new gene candidate for future improvement of SSR resistance in B. napus and also new insights into understanding of MLO family evolution in Brassica crops.

Sclerotinia stem rot is a destructive disease caused by the fungus Sclerotinia sclerotiorum, and it occurs in oilseed rape and many other broadleaf crops. The chemical control with fungicides is usually applied in fields. As a kind of succinate dehydrogenase inhibitors (SDHIs), bixafen showed higher efficiency in inhibiting mycelial growth. To establish the baseline sensitivity of S. sclerotiorum to bixafen in Henan Province, 119 isolates of S. sclerotiorum were obtained from diseased stems of oilseed rape collected from fields in different geographical regions in Henan Province, China, in 2015 and 2016, and their sensitivity to bixafen was determined based on mycelial growth rate method. The results showed that the 50% inhibition of mycelial growth (EC50) values of S. sclerotiorum ranged from 0.0417 to 0.4732 μg/mL with an average EC50 value (mean ± SD) of (0.1968 ± 0.1053) μg/mL. The frequency distribution range curve was narrow and unimodal, and the average EC50 value obtained can be used as the baseline sensitivity of S. sclerotiorum to bixafen in Henan Province. In order to determine whether bixafen can be mixed with other fungicides with different modes of action, the EC50 values of S. sclerotiorum to bixafen, carbendazim, fludioxonil, prothioconazole, dimetachlone, metconazole, and their mixtures were determined based on mycelial growth rate method. The results showed that the EC50 values for bixafen, carbendazim, fludioxonil, prothioconazole, dimetachlone and metconazole were 0.1256, 0.1122, 0.0229, 0.0651, 0.8057, and 0.0278 μg/mL, respectively. For fungicide mixtures of bixafen and carbendazim, fludioxonil, prothioconazole, dimetachlone or metconazole (1 : 1, 1 : 3, 1 : 5, 3 : 1 and 5 : 1, V/V), the synergistic ratio (SR) ranges from 0.54 to 3.57, which indicates additive or synergistic inhibition. These results suggested that bixafen could be used alternately or in combination with carbendazim, fludioxonil, prothioconazole, dimetachlone and metconazole to prevent and delay the development of resistance in S. sclerotiorum. These results provide important and scientific information for the control of sclerotinia stem rot and for monitoring the sensitivity of S. sclerotiorum to bixafen in Henan Province. [ABSTRACT FROM AUTHOR]

Management of Sclerotinia stem rot (SSR) disease in Brassica napus is heavily reliant on prophylactic fungicide applications at flowering, which often provides inconsistent control depending on timing of ascospore release in the field and environmental conditions. Understanding host response to Sclerotinia sclerotiorum infection is essential for sustainable disease management in the future. This study determined host response of nine B. napus varieties to four aggressive S. sclerotiorum isolates across two years by measuring four disease variables: area under the disease progress stairs (AUDPS), seed production, sclerotia number and average sclerotia weight. Brassica napus varieties varied greatly in their response to the four measured variables, with varieties producing the highest AUDPS not being the same varieties that had the lowest seed production, the highest numbers of sclerotia or heaviest sclerotia. Repeating the experiment over two years using the same varieties and isolates identified the impact of environment on measured disease variables as the most influential factor, highlighting the complexity of disease responses to diverse isolates and host genotypes under different environments. It was recommended that both long-term (such as inoculum production) and short-term (such as seed production) disease outcomes be combined with lesion length measurement (i.e., AUDPS) for future host screening studies. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating disease and can significantly reduce production in oilseed rape. To determine the sensitivity of S. sclerotiorum to fluopyram, 127 S. sclerotiorum isolates were collected from different oilseed rape fields from 5 cities in Henan Province in 2015 and 2016, and the median effective concentrations (EC50 values) of fluopyram for S. sclerotiorum isolates were analyzed by the mycelial growth rate method. The result showed that the EC50 values ranged from 0.0100 to 0.0989 μg/mL, and the mean EC50 value was (0.0546 ± 0.0228) μg/mL (mean ± SD). The frequency distribution of the EC50 values for 127 S. sclerotiorum isolates was a unimodal and continuous curve, which demonstrated that there was no resistant subpopulation among these isolates. Thus, the mean EC50 value could be used as a baseline for monitoring fluopyram resistance in field isolates of S. sclerotiorum in Henan Province. The allied toxicity of fluopyram and prothioconazole, metconazole, carbendazim, fludioxonil or dimethachlone at volume ratios of 1 : 5, 1 : 3, 1 : 1, 3 : 1 and 5 : 1 to S. sclerotiorum were detected by the method of mycelial growth assay. The result showed that the mixtures of fungicides with the volume ratio of 1 : 5, 1 : 3, 1 : 1, 3 : 1, and 5 : 1 showed a synergy ratio ranging from 0.51 to 5.86, indicating an additive or synergistic inhibition effect. The mixture of fluopyram and fludioxonil with a volume ratio of 1 : 1 was demonstrated to have the strongest synergistic inhibition effect with the maximum synergy ratio. The results indicated that fluopyram be used in combination with prothioconazole, metconazole, carbendazim, fludioxonil, and dimethachlone, and these results could provide a basis in controlling the Sclerotinia stem rot caused by S. sclerotiorum. [ABSTRACT FROM AUTHOR]

Background: Oilseed rape (Brassica napus L.) is known as one of the most important oilseed crops cultivated around the world. However, its production continuously faces a huge challenge of Sclerotinia stem rot (SSR), a destructive disease caused by the fungus Sclerotinia sclerotiorum, resulting in huge yield loss annually. The SSR resistance in B. napus is quantitative and controlled by a set of minor genes. Identification of these genes and pyramiding them into a variety are a major strategy for SSR resistance breeding in B. napus. Results: Here, we performed a genome-wide association study (GWAS) using a natural population of B. napus consisting of 222 accessions to identify BnaA08g25340D (BnMLO2_2) as a candidate gene that regulates the SSR resistance. BnMLO2_2 was a member of seven homolog genes of Arabidopsis Mildew Locus O 2 (MLO2) and the significantly SNPs were mainly distributed in the promoter of BnMLO2_2, suggesting a role of BnMLO2_2 expression level in the regulation of SSR resistance. We expressed BnMLO2_2 in Arabidopsis and the transgenic plants displayed an enhanced SSR resistance. Transcriptome profiling of different tissues of B. napus revealed that BnMLO2_2 had the most expression level in leaf and silique tissues among all the 7 BnMLO2 members and also expressed higher in the SSR resistant accession than in the susceptible accession. In Arabidopsis, mlo2 plants displayed reduced resistance to SSR, whereas overexpression of MLO2 conferred plants an enhanced SSR resistance. Moreover, a higher expression level of MLO2 showed a stronger SSR resistance in the transgenic plants. The regulation of MLO2 in SSR resistance may be associated with the cell death. Collinearity and phylogenetic analysis revealed a large expansion of MLO family in Brassica crops. Conclusion: Our study revealed an important role of BnMLO2 in the regulation of SSR resistance and provided a new gene candidate for future improvement of SSR resistance in B. napus and also new insights into understanding of MLO family evolution in Brassica crops. [ABSTRACT FROM AUTHOR]

Petal testing can be used to determine the presence of Sclerotinia sclerotiorum inoculum during canola flowering as an indicator of disease risk and the potential need for fungicide application. Traditionally, the culture plate method has been used to test petals, but this takes up to 7 days to obtain results, which is a drawback in terms of making timely fungicide use decisions. Therefore, the availability of a simple, faster detection technique for S. sclerotiorum infected canola petals would be an advantage. We have documented and compared a canola petal clearing and staining technique with the standard culture plate method to study sclerotinia ascospore infestation. The staining technique was found to be a rapid, simple and reliable method compared to the traditional culture plate system. [ABSTRACT FROM AUTHOR]

Individual plant growth-promoting rhizobacterial (PGPR) strains (Bacillus thuringiensis B2, Bacillus subtilis B10 and Enterobacter cloacae B16) and their combination were used, with or without Pythium oligandrum, against Sclerotinia sclerotiorum. In vitro, all biological control agents (BCAs) reduced successfully hyphal growth of the targeted pathogenic fungus. They displayed antifungal activity by more than 50% compared to controls. In planta trials were conducted two years in the row and led to a significant decrease in stem rot severity two months after the antagonist's application onto infected tomato plants. The reduction reached 75% using rhizobacterial mixtures and 72% using P. oligandrum alone, compared to controls. The plant growth-promoting potential of the three-strain consortium and P. oligandrum was also assessed. Increased height in disease-free plants was obtained with rhizobacterial mixtures (60%) compared to P. oligandrum (47%). The BCA's mixture increased the height of treated plants inoculated with S. sclerotiorum (up to 80%) compared to inoculated and untreated plants. The fresh weight of the aerial parts and roots of disease-free plants was increased by 42 and 30% over control following their treatment with mixtures of rhizobacteria and P. oligandrum alone, respectively. On plants inoculated with S. sclerotiorum in both trials, the highest growth-enhancing effect was achieved using the combined treatment based on P. oligandrum and the three-strain rhizobacterial consortium (Po37 + B2 + B10 + B16). The rhizospheric microbial communities were assessed using Single Strand Conformational Polymorphism (SSCP). Differences in the genetic structure of the fungal and bacterial communities were observed following treatments applied in both trials. [ABSTRACT FROM AUTHOR]

Sclerotinia sclerotiorum ist ein nekrotrophes Pflanzenpathogen mit einem breiten Wirtsspektrum und weltweit großer wirtschaftlicher Bedeutung. In der vorliegenden Studie wurde eine Reihe von Gewächshausversuchen durchgeführt, um die Ausprägung von S. sclerotiorum-Symptomen bei 30 Pflanzenarten zu bewerten, die durch zwei unterschiedliche Isolate von S. sclerotiorum verursacht wurden. Darüber hinaus wurde die Anzahl der auf den verschiedenen Testpflanzen produzierten Sklerotien bewertet. Die Ergebnisse zeigten, dass die Aggressivität des Erregers einen signifikanten Einfluss auf die Sclerotinia-Befallsstärke und die Vermehrungsrate der Sklerotien hat. Pflanzenarten, die mit einem aggressiven Isolat inokuliert wurden, zeigten stärker ausgeprägte Symptome und eine höhere Anzahl von Sklerotien als Pflanzen die mit einem weniger aggressiven Isolat inokuliert wurden. Von allen getesteten Pflanzenarten waren Aethusa cynapium (AETCY) und Leucanthemum vulgare (CHYLE) vollständig resistent gegen beide Isolate von S. sclerotiorum.

Sclerotinia stem rot, caused by the necrotrophic fungal pathogen Sclerotinia sclerotiorum, is a serious constraint to lettuce production worldwide. To understand the molecular mechanisms underlying the plant's response to S. sclerotiorum infection, next-generation sequencing was used to analyze the transcriptional alterations in lettuce post-infection in a time course of a compatible interaction. A total of 28,485, 28,777 and 29,018 unigenes were obtained at 6 hours post-inoculation (hpi), 12 hpi and 24 hpi, respectively. Among these, 4104, 4316 and 4980 genes were up-regulated while 3977, 3818 and 3802 genes were down-regulated at 6 hpi, 12 hpi and 24 hpi, respectively. Functional classification of the differentially expressed genes (DEGs) indicated that 21, 24 and 30 metabolic pathways were affected at 6 hpi, 12 hpi and 24 hpi, respectively. Some pathways were related to the plant immune response, such as 'oxidative phosphorylation', 'plant hormone signal transduction' and the 'MAPK signaling pathway'. Real time quantitative PCR (RT-qPCR) analysis of six selected DEGs further validated the RNA-seq results. In addition, some novel potential disease responsive genes, including superoxide dismutase, WRKY transcription factors, pectinesterase inhibitor and ethylene-responsive transcription factors were identified. Our results suggest that lettuce adopts multiple strategies in regulating plant immunity to S. sclerotiorum infection. Collectively, the study provides new insights in the interaction of the plant - S. sclerotiorum pathosystem and provides information for further characterization of genes involved in plant resistance against S. sclerotiorum. [ABSTRACT FROM AUTHOR]

There are three main challenges to improving sclerotinia stem rot (SSR) resistance in rapeseed (Brassica napus L.). First, breeding materials such as the backbone parents have not been extensively investigated, making the findings of previous studies difficult to directly implement. Second, SSR resistance and flowering time (FT) loci are typically linked; thus, use of these loci requires sacrifice of the rapeseed growth period. Third, the SSR resistance loci in susceptible materials are often neglected, thereby reducing the richness of resistant resources. This study was conducted to investigate the stem resistance, disease index, and FT of a doubled haploid population consisting of 151 lines constructed from the backbone parent 19514A and conventional rapeseed cultivar ZY50 within multiple environments. Quantitative trait locus (QTL) mapping revealed 13 stem resistance QTLs, 9 disease index QTLs, and 20 FT QTLs. QTL meta-analysis showed that uqA04, uqC03.1, and uqC03.2 were repeatable SSR resistance QTLs derived from different parents but not affected by the FT. Based on these three QTLs, we proposed a strategy for improving the SSR resistance of 19514A and ZY50. This study improves the understanding of the resistance to rapeseed SSR and genetic basis of FT and demonstrates that SSR resistance QTLs can be mined from parents with a minimal resistance level difference, thereby supporting the application of backbone parents in related research and resistance improvement. [ABSTRACT FROM AUTHOR]

Background: Sclerotinia sclerotiorum is a devastating fungal pathogen that poses a threat to a variety of economically important crops. Owing to the lack of highly resistant cultivars and the prolonged survival of sclerotia, effective control of Sclerotinia diseases remains challenging. RNA interference (RNAi) agents targeting essential active transcripts of genes associated with the development and virulence of pathogens are a valuable and promising disease control method., Results: Our finding suggested that a flavin adenine dinucleotide (FAD)-dependent monooxygenase gene SsMNO1 plays pivotal roles in the hyphal growth, sclerotial development, and virulence of S. sclerotiorum, rendering it a potential target for RNAi-mediated management of S. sclerotiorum. The external application of double-stranded RNA (dsRNA) targeting SsMNO1 inhibited sclerotial development in artificial media and plant tissues. Furthermore, dsRNA significantly reduced the hyphal virulence of S. sclerotiorum in host plants by interfering with SsMNO1 expression. The inhibitory activity persisted for over 1 week on the surface of Brassica napus. Artificial small interfering RNA (siRNA) targeting SsMNO1 also exhibited inhibitory effects. Transgenic Arabidopsis thaliana plants expressing SsMNO1 hairpin RNAi constructs showed increased resistance to S. sclerotiorum infection. Notably, the total RNA extracts from SsMNO1-RNAi plants also reduced the hyphal virulence in Brassica napus., Conclusions: Therefore, RNAi agents targeting SsMNO1 have dual effects on sclerotial development and hyphal virulence, rendering it an ideal target for controlling diseases caused by S. sclerotiorum. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, threatens oilseed rape (Brassica napus) crops internationally. The development of this disease is strongly controlled by the weather, which is why global climate change is likely to influence its spread and impact. Climate change may affect the pathogen directly or indirectly via the host plant. This study investigates the potential impact of climate warming on Sclerotinia stem rot severity in oilseed rape in Poland. The aim of this investigation was to assess the relationship between the direct impact (DI) and indirect impact (II) of climate change on disease severity using the 4.5 and 8.5 representative concentration pathways (RCPs). Under the RCP4.5 scenario, nearly 60% of the simulations performed for 16 regions in four periods (2020–2039, 2040–2059, 2060–2079, 2080–2099) showed reductions in disease severity in comparison to those conducted for 1986–2005, while under RCP 8.5, this reduction was generated for nearly 90% of the cases. The effect of the RCP scenario on clustering the regions according to the value of Sclerotinia stem rot severity was also investigated. The simulations revealed that, for all periods, the lowest disease severities are expected for Zachodniopomorskie and Pomorskie. The results obtained also show the superior effects of the II over the DI on Sclerotinia stem rot severity in the future. Under the RCP4.5 scenario, the rate of IIs was greater than that of DIs for 10 regions, while under RCP8.5, this relationship was registered for 16 regions. These outcomes result from the acceleration of the oilseed rape flowering period triggered by expected temperature increases. The novelty of this study lies in a detailed analysis of the relationships between the DI and II of climate change, expressed numerically, for 16 regions in Poland. The obtained results highlight the role of the indirect impact in shaping disease severity and indicate that it should be incorporated into assessment methods of climate change effects alongside the direct impact.

Three damaging soybean diseases, Sclerotinia stem rot caused by a fungus Sclerotinia sclerotiorum (Lid.) de Bary, Phytophthora root rot caused by a fungus Phytophthora sojae, and soybean cyst nematode (Heterodera glycines Ichinohe), are destructive to soybean growth and yield and cause huge economic losses. Biocontrol is an effective way to control soybean diseases with the advantage of being environmentally friendly and sustainable. To date, few reviews have reported the control of these three soybean diseases through biocontrol measures. In this review, the biological characteristics of the three pathogens and the incidence features of the three soybean diseases were first introduced. Then, biocontrol agents containing fungi and bacteria capable of controlling the three diseases, as well as their control abilities, were emphasized, followed by their mechanisms of biocontrol action. Bacillus and Streptomyces were found to possess the ability to control all three soybean diseases under greenhouse or field conditions. Finally, suggestions about screening new biocontrol species and deeply studied biocontrol molecular mechanisms are provided for further research on the biocontrol of soybean diseases. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (S. sclerotiorum) is the main disease threat of oilseed rape (Brassica napus), resulting in huge economic losses every year. SSR resistance manifests as quantitative disease resistance (QDR), and no gene with complete SSR resistance has been cloned or reported so far. Transcriptome analysis has revealed a large number of defense-related genes and response processes. However, the similarities and differences in the defense responses of different tissues are rarely reported. In this study, we analyzed the similarities and differences of different tissues in response to S. sclerotiorum at 24 h post inoculation (hpi) by using the published transcriptome data for respective leaf and stem inoculation. At 24 hpi, large differences in gene expression exist in leaf and stem, and there are more differentially expressed genes and larger expression differences in leaf. The leaf is more sensitive to S. sclerotiorum and shows a stronger response than stem. Different defense responses appear in the leaf and stem, and the biosynthesis of lignin, callose, lectin, chitinase, PGIP, and PR protein is activated in leaf. In the stem, lipid metabolism-mediated defense responses are obviously enhanced. For the common defense responses in both leaf and stem, the chain reactions resulting from signal transduction and biological process take the primary responsibility. This research will be beneficial to exploit the potential of different tissues in plant defense and find higher resistance levels of genotypic variability in different environments. Our results are significant in the identification of resistance genes and analysis of defense mechanisms. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum , is the main disease threat to oilseeds in Brassiceae, causing significant yield losses and reduction in oil content and quality. While the genetic mechanism underlying its lethal phenotype, particularly in B. juncea , remains largely unexplored. Transcriptome analysis revealed a large number of defense-related genes and response processes in B. napus and B. oleracea. However, similarities and differences in the defense responses to S. sclerotiorum on B. juncea are rarely reported. In the present study, we reported a B. juncea breeding line of H83 with high S. sclerotiorum resistance, which was used for transcriptome analysis compared to L36 with low resistance. A novel regulatory network was proposed to defend against S. sclerotiorum invasion in B. juncea. Upon infection of S. sclerotiorum , a series of were initiated within 12 h, and then defenses were activated to restrict the development and spread of S. sclerotiorum by inducing the massive synthesis of indole glucosinolates after 24 h. Twelve hub genes involved in the network were identified by the weighted gene co-expression network (WGCNA), which are involved in plant-pathogen interaction, signaling pathway genes, indole glucosinolate biosynthesis and cell wall formation. The hub genes were further validated by qRT-PCR. The research revealed a new resistant line of H83 against S. sclerotiorum and a different regulatory network in B. juncea , which would be beneficial for the future effective breeding of Sclerotinia-resistant varieties. • ●A Brassica juncea line showed high resistance to Sclerotinia sclerotiorum. • ●Induction of the indole glucosinolate biosynthesis pathway resulted in high resistance to Sclerotinia sclerotiorum. • ●Weighted gene co-expression network analysis identified 12 hub genes for resistance to Sclerotinia sclerotiorum. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, is one of the most economically devastating diseases in chickpea (Cicer arietinum L.). No complete resistance is available in chickpea to this disease, and the inheritance of partial resistance is not understood. Two hundred F7 recombinant inbred lines (RILs) derived from a cross between a partially resistant variety PBA HatTrick, and a highly susceptible variety Kyabra were characterised for their responses to SSR inoculation. Quantitative trait locus (QTL) analysis was conducted for the area under the disease progress curve (AUDPC) after RIL infection with S. sclerotiorum. Four QTLs on chromosomes, Ca4 (qSSR4-1, qSSR4-2), Ca6 (qSSR6-1) and Ca7 (qSSR7-1), individually accounted for between 4.2 and 15.8% of the total estimated phenotypic variation for the response to SSR inoculation. Candidate genes located in these QTL regions are predicted to be involved in a wide range of processes, including phenylpropanoid biosynthesis, plant-pathogen interaction, and plant hormone signal transduction. This is the first study investigating the inheritance of resistance to S. sclerotiorum in chickpea. Markers associated with the identified QTLs could be employed for marker-assisted selection in chickpea breeding. [ABSTRACT FROM AUTHOR]

【Objective】 The laboratory toxicity of 8 commonly used fungicides against canola Sclerotinia sclerotiorum in Hulun Buir, Inner Mongolia, was determined to provide theoretical basis for the precise selection and use of drugs for the prevention and control of spring canola Sclerotinia sclerotiorum in the cold and arid regions of northern China.【Methods】19 strains of Sclerotinia sclerotiorum from 6 farms in Hulun Buir were collected to test their sensitivity to 8 commonly used fungicides.【Results】 The Sclerotinia sclerotiorum samples had average EC50 values of 0.031,0.078,0.261,0.286,0.362,0.536,0.673,and 1.380 μg/mL against prochloraz,carbendazim,procymidon,tebuconazole,boscalid,dimethachlon,difenoconazole,and azoxystrobin.【Conclusions】 The canola Sclerotinia sclerotiorum in Hulun Buir,Inner Mongolia was sensitive to eight commonly used fungicides. In production, different types of fungicides should be applied alternately to prevent drug resistance. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing 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.)

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating disease of soybean. Biological control is a potential alternative to chemical fungicides for disease management, and provides broad benefits to the environment, farmers and consumers. Herein, we established a field application technique for biocontrol of Sclerotinia stem rot in soybean using wuyiencin, expanding on a previous study showing biocontrol potential. We used wuyiencin to reduce sclerotia in soybean seed, and disease incidence analysis by seed bioassay revealed an optimal wuyiencin seed soaking concentration of 12.5 μg/mL. We found that different application methods had different effects on soybean plant growth. Soybean pot experiments showed that 100 μg/mL wuyiencin was obtained a significant disease protection effect and promote soybean growth through root irrigation, and the optimal concentration for wuyiencin spraying was 100–200 μg/mL. We tested the efficacy of applying wuyiencin under field conditions, and the protection effect of 200 μg/mL wuyiencin sprayed three times was the best (64.0%), but this was slightly inferior to the protection effect of 200 μg/mL dimethachlon (77.6%).

Genetic diversity is vital for the survival of any population. If humans were all the same, a single strain of a nasty flu virus, like COVID-19, could wipe us all out! In plants, genetic diversity plays a similar role. The variation in the type and number of resistance gene(s) between individuals can cause the difference between surviving a disease or not. Studies on genetic diversity will lead to the identification of novel disease-resistance genes. Canola (Brassica napus L.) is an economically and nutritionally important oilseed worldwide. Several serious diseases, including blackleg, clubroot, sclerotinia stem rot, and verticillium stripe, threaten canola production in Canada and worldwide. Traditional methods are not enough for effective control of these diseases. Therefore, the ideal approach is to optimize and utilize the resistance genes found in different B. napus cultivars. With the advent of next-generation sequencing and the development of genomics and molecular genetics techniques, it is now possible to rapidly identify and apply resistance genes. This paper reviews current information about disease-resistance genes identified in B. napus cultivars, mapping and cloning, their importance, role and function, and their association with plant disease resistance and application in resistance breeding. The feasibility of using current resistance sources in Canadian cultivars for developing new disease-resistant cultivars is also discussed. Sustainability of a farm and an agricultural system could be maintained by breeding for disease resistance, including the resistant varieties and incorporating other integrated pest management strategies along with it. [ABSTRACT FROM AUTHOR]

Stem rot caused by Sclerotinia sclerotiorum is a serious and sometimes devastating disease of lupin ( Lupinus spp.). A total of 236 lupin accessions from across 12 Lupinus species were screened against the prevalent S. sclerotiorum isolate MBRS-1 (pathotype 76). L. angustifolius accession 21655 and L. albus var. albus accession 20589 showed immune and "near-immune" responses, respectively. Thirteen accessions of L. angustifolius , three accessions each of L. albus and L. albus var. albus , and a single accession each of L. albus var. graecus , L. mutabilis , L. palaestinus , and L. pilosus (totaling ∼4%) showed a highly resistant (HR) response. A further 19 accessions of L. angustifolius , 2 accessions each of L. albus and L. pilosus , and a single accession of L. mutabilis (totaling ∼10%) showed a resistant (R) response. The reactions of 16 (15 L. angustifolius , 1 L. digitatus ) of these 236 accessions were also compared with their reactions to a different isolate, Walkaway-3 (WW-3; pathotype 10). Against this isolate, five L. angustifolius accessions showed an HR response and four showed an R response, and the L. digitatus accession showed a moderate resistance response. Overall, isolate WW-3 caused significantly ( P < 0.05) smaller lesions than MBRS-1 across tested accessions in common. In addition, 328 plants in a "wild" naturalized field population of L. cosentinii were screened in situ in the field against isolate MBRS-1. Five (∼1.5%) of the 328 plants of wild lupin showed an immune response, 63 (∼19%) showed an HR response, and 146 (∼45%) showed an R response. We believe this is the first examination of diverse Lupinus spp. germplasm responses to a prevalent pathotype of S. sclerotiorum . Lupin genotypes exhibiting high-level resistance to Sclerotinia stem rot identified in this study can be used as parental lines for crosses in lupin breeding programs and/or directly as improved cultivars to reduce the adverse impact of this disease on lupin crops., Competing Interests: The author(s) declare no conflict of interest.

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease in soybean in many parts of the world. Sustainable control measures to combat this pathogen can be better achieved by combining different available tools. One element to control fungal diseases could be changing biological activities by adding organic matter inputs, such as biochar and compost, to the soil. Other players are arbuscular mycorrhizal fungi (AMF); bioprotective effects have already been documented for them. In the present study, we assessed the effect of organic matter inputs, such as compost alone at the application rate of 20% of the total substrate (v/v) and/or green waste biochar at the application rate of 3% (v/v) in combination with or without arbuscular mycorrhizal fungi, against Sclerotinia sclerotiorum and their effect on plant growth characteristics in soybean. Substrates including compost resulted in a lower disease severity in both, plants inoculated and non-inoculated with AMF. The AMF root colonization was highest in plants grown in the control treatment and green waste biochar substrate inoculated with Sclerotinia sclerotiorum; the lowest colonization was found in plants grown in substrates containing compost. Soil substrates, especially compost, affected shoot dry matter production in soybean plants inoculated with Sclerotinia sclerotiorum and in non-inoculated plants; compost alone was superior in treatments with and without AMF. Root morphological traits were more strongly influenced by AMF than by the substrate. Our findings suggest that compost has a positive effect in terms of soybean growth and diseases suppression, which is more pronounced than that of biochar and AMF. [ABSTRACT FROM AUTHOR]

The plant mediator is a highly conserved protein complex that interacts with transcription factors (TFs) and RNA polymerase II (RNAP II) to relay regulatory information during transcription. Plant immune response is one of the biological processes that is orchestrated by this regulatory mechanism. Brassica napus, an important oil crop, is severely attacked by a devastating disease Sclerotinia stem rot. Here, we explored broad-spectrum disease resistant roles of B. napus mediator subunit 16 (BnMED16) and its host defense mechanism against fugal pathogen Sclerotinia sclerotiorum. We found that BnMED16 expression was significantly increased by S. sclerotiorum infection, and its homologous overexpression resulted in rapid and comprehensive defense responses from the beginning to the end. This affected signal transduction with multiple channels including pathogen recognition, intracellular Ca2+ concentration, reactive oxygen species (ROS) accumulation and clearance, and activation of mitogen-activated protein kinase (MAPK) signaling cascades initially. Subsequently, pathogen-/defense-related genes and hormone-responsive pathways were highly activated, which resulted in enhanced cell wall and secretion of defense proteases. Furthermore, the biochemical analysis showed that BnMED16 interacts with BnMED25 and BnWRKY33. Additionally, BnMED25 also interacts with TFs BnMYC2, BnCOI1, and BnEIN3 of the JA/ET signal transduction pathway. Taken together, we proposed a hypothetical model that BnMED16 confers S. sclerotiorum resistance by enhancing BnMED25-mediated JA/ET defense pathways and BnWRKY33-activated defense signaling in B. napus. The BnMED16 overexpressing lines with enhanced broad-spectrum disease resistance could be useful for breeding Sclerotinia-resistant oilseed rape varieties, as well as serving as basis for further strategy development in resistance breeding.

The analysis of variance confirmed that the average sum of squares was significant for lesion length (cm). Genetic diversity as well as structure of population between genotypes of Indian mustard [Brassica juncea (L.) Czern. & Coss.] resistant to Sclerotinia stem rot [Sclerotinia selerotiorum (Lib.) de Bary] was carried out using simple sequence repeats (SSRs). A total of 114 alleles were generated via 48 polymorphic primers, with mean value of 2.38 alleles per primer. The average value of PIC and the mean gene expected heterozygosity/diversity (He) value from all the polymorphic primers were 0.43 and 0.50, respectively. All the 16 genotypes were categorized into three major clusters depending on Jaccard's dissimilarity coefficients. Evanno method for population structure revealed the presence of three populations (SP1, SP2 and SP3) at maximum ∆K. SP1 mainly comprised of resistant/highly resistant genotypes. These findings indicate the existence of ample amount of genetic variability between all the Indian mustard genotypes that could be exploited in future breeding programs to develop Sclerotinia stem rot resistant mustard cultivars.

The plant mediator is a highly conserved protein complex that interacts with transcription factors (TFs) and RNA polymerase II (RNAP II) to relay regulatory information during transcription. Plant immune response is one of the biological processes that is orchestrated by this regulatory mechanism. Brassica napu s, an important oil crop, is severely attacked by a devastating disease Sclerotinia stem rot. Here, we explored broad-spectrum disease resistant roles of B. napus mediator subunit 16 (BnMED16) and its host defense mechanism against fugal pathogen Sclerotinia sclerotiorum. We found that BnMED16 expression was significantly increased by S. sclerotiorum infection, and its homologous overexpression resulted in rapid and comprehensive defense responses from the beginning to the end. This affected signal transduction with multiple channels including pathogen recognition, intracellular Ca2+ concentration, reactive oxygen species (ROS) accumulation and clearance, and activation of mitogen-activated protein kinase (MAPK) signaling cascades initially. Subsequently, pathogen-/defense-related genes and hormone-responsive pathways were highly activated, which resulted in enhanced cell wall and secretion of defense proteases. Furthermore, the biochemical analysis showed that BnMED16 interacts with BnMED25 and BnWRKY33. Additionally, BnMED25 also interacts with TFs BnMYC2, BnCOI1, and BnEIN3 of the JA/ET signal transduction pathway. Taken together, we proposed a hypothetical model that BnMED16 confers S. sclerotiorum resistance by enhancing BnMED25-mediated JA/ET defense pathways and BnWRKY33-activated defense signaling in B. napus. The BnMED16 overexpressing lines with enhanced broad-spectrum disease resistance could be useful for breeding Sclerotinia -resistant oilseed rape varieties, as well as serving as basis for further strategy development in resistance breeding. [ABSTRACT FROM AUTHOR]

Abstract Background Sclerotinia sclerotiorum is a broad-host range necrotrophic pathogen which is the causative agent of Sclerotinia stem rot (SSR), and a major disease of soybean (Glycine max). A time course transcriptomic analysis was performed in both compatible and incompatible soybean lines to identify pathogenicity and developmental factors utilized by S. sclerotiorum to achieve pathogenic success. Results A comparison of genes expressed during early infection identified the potential importance of toxin efflux and nitrogen metabolism during the early stages of disease establishment. The later stages of infection were characterized by an apparent shift to survival structure formation. Analysis of genes highly upregulated in-planta revealed a temporal regulation of hydrolytic and detoxification enzymes, putative secreted effectors, and secondary metabolite synthesis genes. Redox regulation also appears to play a key role during the course of infection, as suggested by the high expression of genes involved in reactive oxygen species production and scavenging. Finally, distinct differences in early gene expression were noted based on the comparison of S. sclerotiorum infection of resistant and susceptible soybean lines. Conclusions Although many potential virulence factors have been noted in the S. sclerotiorum pathosystem, this study serves to highlight soybean specific processes most likely to be critical in successful infection. Functional studies of genes identified in this work are needed to confirm their importance to disease development, and may constitute valuable targets of RNAi approaches to improve resistance to SSR.

Three damaging soybean diseases, Sclerotinia stem rot caused by a fungus Sclerotinia sclerotiorum (Lid.) de Bary, Phytophthora root rot caused by a fungus Phytophthora sojae, and soybean cyst nematode (Heterodera glycines Ichinohe), are destructive to soybean growth and yield and cause huge economic losses. Biocontrol is an effective way to control soybean diseases with the advantage of being environmentally friendly and sustainable. To date, few reviews have reported the control of these three soybean diseases through biocontrol measures. In this review, the biological characteristics of the three pathogens and the incidence features of the three soybean diseases were first introduced. Then, biocontrol agents containing fungi and bacteria capable of controlling the three diseases, as well as their control abilities, were emphasized, followed by their mechanisms of biocontrol action. Bacillus and Streptomyces were found to possess the ability to control all three soybean diseases under greenhouse or field conditions. Finally, suggestions about screening new biocontrol species and deeply studied biocontrol molecular mechanisms are provided for further research on the biocontrol of soybean diseases.

MicroRNA319a (miR319a) controls cell division arrest in plant leaves by inhibiting the expression of TCP (TEOSINTE BRANCHED 1 / CYCLOIDEA / PCF) family genes. However, it is unclear whether miR319a influences infection by necrotrophic pathogens and host susceptibility. In this study, we revealed that miR319a affects plant resistance to stem rot disease caused by Sclerotinia sclerotiorum. In Brassica rapa plants infected with S. sclerotiorum , miR319a levels increased while the expression levels of several BraTCP genes significantly decreased compared with those of uninfected plants. Overexpression of BraMIR319a in B. rapa increased the susceptibility of the plants to S. sclerotiorum and aggravated stem rot disease, whereas overexpression of BraTCP4-1 promoted plant resistance. RNA sequencing data revealed a potential relationship between miR319a and pathogen-related WRKY genes. Chromatin immunoprecipitation, electrophoretic mobility shift, and reporter transaction assays showed that BraTCP4-1 could bind to the promoters of WRKY75 , WRKY70 , and WRKY33 and directly activate these pathogen-related genes. Moreover, the expression levels of WRKY75 , WRKY70 , and WRKY33 in plants overexpressing BraMIR319a decreased significantly, whereas those of plants overexpressing BraTCP4-1 increased significantly, relative to the wild type. These results suggest that miR319a and its target gene BraTCP4 control stem rot resistance through pathways of WRKY genes. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR) is a disease of soybean [ Glycine max (L.) Merr] that causes severe yield losses. We studied 185 representative soybean accessions to evaluate partial SSR resistance and sequenced these by the specific-locus amplified fragment sequencing method. In total, 22,048 single-nucleotide polymorphisms (SNPs), with minor allele frequencies (MAF) ≥5% and missing data <3%, were developed and applied to genome-wide association study of SSR responsiveness and assess linkage disequilibrium (LD) level for candidate gene selection. We identified 18 association signals related to SSR partial resistance. Among them, six overlapped the regions of previous quantitative trait loci, and twelve were novel. We identified 243 candidate genes located in the 200 kb genomic region of these peak SNPs. Based on quantitative real-time polymerase chain reaction and haplotype analysis, Glyma.03G196000 and Glyma.20G095100 , encoding pentatricopeptide repeat proteins, might be important factors in the resistance response of soybean to SSR. • Sclerotinia stem rot is a destructive disease, causing severe soybean yield losses • 18 loci associated with partial resistance to SSR were identified based on GWAS • Beneficial alleles and genes might be helpful to analyze SSR genetic resistance [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (S. sclerotiorum) is the main disease threat of oilseed rape (Brassica napus), resulting in huge economic losses every year. SSR resistance manifests as quantitative disease resistance (QDR), and no gene with complete SSR resistance has been cloned or reported so far. Transcriptome analysis has revealed a large number of defense-related genes and response processes. However, the similarities and differences in the defense responses of different tissues are rarely reported. In this study, we analyzed the similarities and differences of different tissues in response to S. sclerotiorum at 24 h post inoculation (hpi) by using the published transcriptome data for respective leaf and stem inoculation. At 24 hpi, large differences in gene expression exist in leaf and stem, and there are more differentially expressed genes and larger expression differences in leaf. The leaf is more sensitive to S. sclerotiorum and shows a stronger response than stem. Different defense responses appear in the leaf and stem, and the biosynthesis of lignin, callose, lectin, chitinase, PGIP, and PR protein is activated in leaf. In the stem, lipid metabolism-mediated defense responses are obviously enhanced. For the common defense responses in both leaf and stem, the chain reactions resulting from signal transduction and biological process take the primary responsibility. This research will be beneficial to exploit the potential of different tissues in plant defense and find higher resistance levels of genotypic variability in different environments. Our results are significant in the identification of resistance genes and analysis of defense mechanisms.

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating fungal disease in oilseed rape. Chemical control with fungicides is the primary method of controlling this disease. Metconazole is a demethylation inhibitor fungicide that has high activity against mycelial growth of phytopathogenic fungi. In this study, 119 isolates of S. sclerotiorum were collected from oilseed rape fields in different regions of Henan Province, China, in 2015 and 2016 prior to exposure to metconazole. The sensitivities of the S. sclerotiorum isolates to a range of concentrations of metconazole were determined based on mycelial growth inhibition in 90 cm Petri-dishes containing Potato dextrose Agar to which the fungicide was added. The 50% inhibition of mycelial growth (EC50) values of the S. sclerotiorum population to metconazole ranged from 0.0469 to 0.3912 µg mL− 1 and the mean EC50 value was 0.1875 ± 0.0058 µg mL− 1 (mean ± standard error). The frequency distribution range curve was unimodal with a narrow range. Spearman's rho (ρ) for the log10 of the EC50 values of 22 isolates of S. sclerotiorum between metconazole and carbendazim, dimethachlone, boscalid, fluazinam, and fludioxonil showed that there was no cross-resistance between metconazole and the other test fungicides. The results from this study provide important information for the control of Sclerotinia stem rot and sensitivity monitoring of S. sclerotiorum to metconazole in this area. [ABSTRACT FROM AUTHOR]

Cover crops and flower strips are used in agricultural fields as part of integrated pest management strategies. However, their potential as secondary hosts of soilborne pathogens such as Sclerotinia sclerotiorum in oilseed rape cultivation is not fully comprehended. In the current study, we evaluated the effect of pathogen virulence on the development of Sclerotinia stem/leaf rot and sclerotia production in 33 plant species from 11 botanical families using two S. sclerotiorum isolates. Furthermore, the effect of sclerotial size on carpogenic germination was studied. Results showed that the pathogen's virulence significantly affected the occurrence and development of Sclerotinia stem/leaf rot and the subsequent production of sclerotia. Among all plant species tested, 26 were more susceptible to the highly aggressive S . sclerotiorum isolate, which produced more and bigger sclerotia in 17 species than the less aggressive isolate. Moreover, a stronger positive correlation was found between the relative lesion length of plants inoculated with the highly aggressive isolate and the number of sclerotia produced by this isolate (Spearman's rank correlation coefficient [ r s ] = 0.572; P = 0.004). Additionally, we found that larger and heavier sclerotia produced stipes and apothecia earlier and at a greater rate than smaller ones. The heavyweight class had the highest carpogenic germination rate (82.4%), followed by the average (67.2%) and lightweight classes (59.5%). Our findings highlight the need for further investigation into the potential risks associated with cover crops, weeds, and flower strips as secondary hosts of soilborne pathogens in agricultural fields., Competing Interests: The author(s) declare no conflict of interest.

Sclerotinia stem rot is a major disease in Brassica napus that causes yield losses of 10–20% and reaching 80% in severely infected fields. SSR not only causes yield reduction but also causes low oil quality by reducing fatty acid content. There is a need to identify resistant genetic sources with functional significance for the breeding of SSR-resistant cultivars. In this study, we identified 17 QTLs involved in SSR resistance in three different seasons using SNP markers and disease lesion development after artificial inoculation. There were no common QTLs in all 3 years, but there were three QTLs that appeared in two seasons covering all seasons with a shared QTL. The QTLs identified in the 2 years were SRA9a, SRC2a and SRC3a with phenotypic effect variances of 14.75 and 11.57% for SRA9a, 7.49 and 10.38% for SRC3a and 7.73 and 6.81% for SRC2a in their 2 years, respectively. The flowering time was also found to have a negative correlation with disease resistance, i.e., early-maturing lines were more susceptible to disease. The stem width has shown a notably weak effect on disease development, causing researchers to ignore its effect. Given that flowering time is an important factor in disease resistance, we used comparative RNA-sequencing analysis of resistant and susceptible lines with consistent performance in 3 years with almost the same flowering time to identify the resistance genes directly involved in resistance within the QTL regions. Overall, there were more genes differentially expressed in resistant lines 19,970 than in susceptible lines 3936 compared to their mock-inoculated lines, demonstrating their tendency to cope with disease. We identified 36 putative candidate genes from the resistant lines that were upregulated in resistant lines compared to resistant mock and susceptible lines that might be involved in resistance to SSR.

Understanding the mode of gene action that controls seed yield and Sclerotinia stem rot resistance in Indian mustard is critical for boosting yield potential. In a line × tester mating design, ten susceptible lines and four resistant testers were used to conduct genetic analysis. The significance of general combining ability (GCA) and specific combining ability (SCA) variances revealed that both additive and non-additive gene actions were involved in the inheritance of Sclerotinia stem rot resistance and yield attributing traits. In addition to 1000-seed weight and number of primary and secondary branches/plant, the genotypes RH 1569 (line) and DRMR 2035 (tester) appeared to be the strongest general combiners for Sclerotinia stem rot resistance. RH 1657 × EC 597317 was the only cross among several that demonstrated a significant desired SCA value for Sclerotinia rot resistance. Regarding SCA effects for yield and component traits, the cross RH 1658 × EC 597328 performed best, with a non-significant but acceptable negative SCA effect for resistance. DRMR 2035, RH 1222-28, RH 1569, RH 1599-41, RH 1657, RH 1658, and EC 597328 are promising genotypes to use as parents in future heterosis breeding and for obtaining populations with high yield potential and greater resistance to Sclerotinia stem rot disease in Indian mustard, based on GCA effects of parents, per se performance, and SCA effects of hybrids. Days to 50% flowering, number of primary branches/plant, main shoot length, and 1000-seed weight all had a high genotypic coefficient of variability (GCV), broad-sense heritability (h2bs), and genetic advance as percent of the mean (GAM) values, as well as significant and desirable correlations and direct effects on seed yield. As a result, these traits have been recognized as the most critical selection criterion for Indian mustard breeding programs.

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Development of common bean cultivars with partial white mould resistance through breeding techniques has been a challenge in Brazil. As yet, lines/cultivars from breeding programmes have not been investigated for resistance; therefore, this study screened 107 lines/cultivars for their reactions to white mould in 14 preliminary trials conducted under irrigation. Thirteen resistant lines/cultivars (three of Andean origin) and six Mesoamerican cultivars (three intermediately resistant and three susceptible) were selected for further investigation. These lines/cultivars and the resistant control A195 were evaluated in six advanced trials and two straw tests to assess the effectiveness of the screening procedure. In 11 preliminary trials, screenings were performed under moderate/high or higher disease pressure. These pressures occurred in two advanced trials in which, when yields were averaged across moderate/high and high pressures, 10 Mesoamerican lines/cultivars selected for resistance yielded 14%, 23%, and 38% more than intermediately resistant cultivars, A195, and susceptible cultivars, with median disease ratings (1–9 scale) of 4.5, 5.7, 5.7, and 6.7, respectively. In the straw test, three Andean lines/cultivars (A195 included) and two susceptible cultivars in the field were among those with the highest levels of physiological resistance. Thus, field rating under high disease pressure and greenhouse rating did not correlate significantly, suggesting that field trials are critical to evaluating resistance and to identifying high‐yielding beans. Therefore, lines/cultivars from breeding programmes assessed in field trials may provide a low cost and fast way to identify high‐yielding bean cultivars with partial resistance to white mould in the subtropical southern hemisphere. [ABSTRACT FROM AUTHOR]

Sclerotinia sclerotiorum is one of the main pathogens of soybean crop, reducing crop yield potential and causing losses of up to 37%. Because it is a soil inhabitant, its management is difficult. However, the adoption of alternative methods, such as the use of antagonists, may help reduce the pathogen inoculum. Thus, the objective of this work was to select native soybean rhizobacteria and to verify the potential of in vitro antagonism against Sclerotinia sclerotiorum, as well as the effect of these isolates on the germination and vegetative development of soybean seedlings. For this, tests of inhibition and mycelial growth rate index, production of volatile compounds, production of rhizobacterial metabolites and vegetative development of soybean seedlings were conducted. With respect to antagonism, I1, U4, M6, M8 and U13 isolates were the most effective. For the production of volatile compounds by the overlapping plate method, isolates M8, M10, M9, I1, M6 and U4 had the largest reductions in pathogen mycelial growth. For the ability of isolates to produce water-soluble metabolites in culture medium, it was found that isolates I1, M3, M6 and U13 were the most effective. For the vegetative development of soybean seedlings, except for the root length, in which the isolates M8, I14, M9, I1, M6 and M10 provided the largest increases in root size, the other variables did not show significant increases when compared with the witness. In general, isolates M8, M10, M9, I1, M6 and U4 are effective in inhibiting mycelial growth of Sclerotinia sclerotiorum, produce volatile organic compounds that help control the pathogen, however, they do not show significant increases in the vegetative development of soybean seedlings. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot is a major disease in Brassica napus that causes yield losses of 10–20% and reaching 80% in severely infected fields. SSR not only causes yield reduction but also causes low oil quality by reducing fatty acid content. There is a need to identify resistant genetic sources with functional significance for the breeding of SSR-resistant cultivars. In this study, we identified 17 QTLs involved in SSR resistance in three different seasons using SNP markers and disease lesion development after artificial inoculation. There were no common QTLs in all 3 years, but there were three QTLs that appeared in two seasons covering all seasons with a shared QTL. The QTLs identified in the 2 years were SRA9a , SRC2a and SRC3a with phenotypic effect variances of 14.75 and 11.57% for SRA9a , 7.49 and 10.38% for SRC3a and 7.73 and 6.81% for SRC2a in their 2 years, respectively. The flowering time was also found to have a negative correlation with disease resistance, i.e., early-maturing lines were more susceptible to disease. The stem width has shown a notably weak effect on disease development, causing researchers to ignore its effect. Given that flowering time is an important factor in disease resistance, we used comparative RNA-sequencing analysis of resistant and susceptible lines with consistent performance in 3 years with almost the same flowering time to identify the resistance genes directly involved in resistance within the QTL regions. Overall, there were more genes differentially expressed in resistant lines 19,970 than in susceptible lines 3936 compared to their mock-inoculated lines, demonstrating their tendency to cope with disease. We identified 36 putative candidate genes from the resistant lines that were upregulated in resistant lines compared to resistant mock and susceptible lines that might be involved in resistance to SSR. [ABSTRACT FROM AUTHOR]