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Background: Over the course of evolution, plants have developed various sophisticated defense mechanisms to resist pests and diseases. The phytohormone abscisic acid (ABA) has an important role in the growth and development of plants and confers tolerance to selected abiotic stressors, such as drought. Previous studies have shown that ABA promotes the deposit of callose in response to piercing/sucking insect pests. The English grain aphid, Sitobion avenae Fabricius, causes huge losses in rice and is especially harmful to rice seedlings., Results: Exogenous ABA promoted growth and reduced the feeding behavior of S. avenae nymphs in rice. Our results suggested that enhanced trichome density and increased expression of related genes may be associated with rice resistance to aphids. An analysis of volatiles revealed the production of seven compounds associated with pest resistance., Conclusion: These results indicate that ABA reduces aphid feeding in rice. Our findings provide a basis for understanding ABA-mediated defense responses in rice and provide insights on more environmentally-friendly approaches to control. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

This study was conducted during 2019-2020 on the vegetative shoots of date palm Phoenix dactylifera L. cultivar 'Barhee', which were grown on MS salt media containing sodium chloride (0-25-50-100-150-200 mM) supplemented with 5% sucrose. Genetic variances were assessed using molecular markers RAPD using 8 random primers. The RAPD analysis did not result a polymorphism between the amplified bundles and the absence of genetic differences. The primer (OPE-19 and OPD-10) scored the lowest similarity rate 97%, while the genetic matching was 100% in the other primers. The morphological indicators recorded a significant and gradual decrease in the growth indicators (buds number, bud length and stem length) and a significant increase in (bud diameter and branches number) in the propagation and elongation stages. Also, the chemical growth indicators recorded an increase in the chemical content (abscisic acid and proline), the effect of Sodium chloride was negative on photosynthesis, as the chlorophyll content gradually decreased with increasing sodium chloride concentration. [ABSTRACT FROM AUTHOR]

To explore the signal transduction pathway that TaRHA2b gene is involved in regulating, yeast two-hybrid system was used to screen and identify proteins interacting with TaRHA2b. The homogenized cDNA library was constructed from the embryo of mixed barley. The decoy protein vector pGBKT7- TaRHA2b was constructed and transformed into yeast AH109 cells for self-activation detection. Candidate positive clones were screened by one to one yeast co-transfection, SD/-Leu/-Trp and SD/-Leu/- Trp/-Ade/-His medium screening and β-galactosidase chromogenic reaction. The in vitro co-transfection and GST-pull down experiments were used for further verification. The homogenized cDNA library of the barley embryos with titer of 1.2 106 cfu/ml and storage capacity of 1.1 106 was successfully constructed. The inserted fragment size was between 1000-3000 bp. The plasmids of the cDNA library were extracted and sequenced on a large scale, and 5000 plasmids were obtained. The decoy vector without self-activation function was successfully constructed. The x-gal filter paper of eighty-four hybrid clones showed strong blue color and forty-nine pieces of effective sequence information were obtained. Eight of them were selected for co-transfection verification. YTH2450 was selected for GST-pull down verification. The results showed that they were positive hybrid clones. TaRHA2b interacted with YTH2450 and other proteins. The information of above genes could be used for genetic improvement of crops, further improving the adaptability of crops to the environment. [ABSTRACT FROM AUTHOR]

Heat stress adversely affects plants growth potential. Global warming is reported to increase in the intensity, frequency, and duration of heatwaves, eventually affecting ecology, agriculture and economy. With an expected increase in average temperature by 2-3 °C over the next 30-50 years, crop production is facing a severe threat to sub-optimum growth conditions. Abscisic acid (ABA) and nitric oxide (NO) are growth regulators that are involved in the adaptation to heat stress by affecting each other and changing the adaptation process. The interaction between these molecules has been discussed in various studies in general or under stress conditions; however, regarding high temperature, their interaction has little been worked out. In the present review, the focus is shifted on the role of these molecules under heat stress emphasizing the different possible interactions between ABA and NO as both regulate stomatal closure and other molecules including hydrogen peroxide (H 2 O 2 ), hydrogen sulfide (H 2 S), antioxidants, proline, glycine betaine, calcium (Ca 2+ ) and heat shock protein (HSP). Exploring the crosstalk between ABA and NO with other molecules under heat stress will provide us with a comprehensive knowledge of plants mechanism of heat tolerance which could be useful to develop heat stress-resistant varieties., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Drought stress is one of the most immense and permanent constraints in agriculture, which leads to a massive loss of crop productivity. However, little is known about the mitigation role of exogenously applied abscisic acid (ABA) and jasmonic acid (JA) in pearl millet (Pennisetum glaucum L.) under PEG-induced drought stress. Therefore, the current study investigated the putative role of exogenous ABA and JA in improving drought stress tolerance in pearl millet. Thirteen-day-old seedlings were exposed to six different treatments as follow; control (ck), PEG-600 (20%), JA (100 μM), ABA (100 μM), PEG+JA, and PEG+ABA, and data were collected at 7 and 14 days after treatment (DAT). Results showed that PEG decreased plant growth while the oxidative damage increased due to over production of H 2 O 2 and MDA content as a result of decreased activities of the antioxidative enzymes including APX, CAT, and SOD in the leaves. However, exogenous ABA and JA positively enhanced the growth profile of seedlings by improving chlorophyll and relative water content under PEG treatment. A significant improvement was observed in the plant defense system resulting from increased activities of antioxidative enzymes due to exogenous ABA and JA under PEG. Overall, the performance of JA was found better than ABA under PEG-induced drought stress, and future investigations are needed to explore the potential effects of these phytohormones on the long-term crop management and productivity under drought stress., (© 2020 Scandinavian Plant Physiology Society.)

UV-B stress can affect plant growth at different levels, and although there is a multitude of evidence confirming the effects of UV-B radiation on plant photosynthesis, there are fewer studies using physiological assays in combination with multi-omics to investigate photosynthesis in alpine plants under stressful environments. Golden 2-like (G2-like/GLK) transcription factors (TFs) are highly conserved during evolution and may be associated with abiotic stress. In this paper, we used Handy-PEA and Imaging-PAM Maxi to detect chlorophyll fluorescence in leaves of Rhododendron chrysanthum Pall. (R. chrysanthum) after UV-B stress, and we also investigated the effect of abscisic acid (ABA) on photosynthesis in plants under stress environments. We used a combination of proteomics, widely targeted metabolomics, and transcriptomics to study the changes of photosynthesis-related substances after UV-B stress. The results showed that UV-B stress was able to impair the donor side of photosystem II (PSII), inhibit electron transfer and weaken photosynthesis, and abscisic acid was able to alleviate the damage caused by UV-B stress to the photosynthetic apparatus. Significant changes in G2-like transcription factors occurred in R. chrysanthum after UV-B stress, and differentially expressed genes localized in the Calvin cycle were strongly correlated with members of the G2-like TF family. Multi-omics assays and physiological measurements together revealed that G2-like TFs can influence photosynthesis in R. chrysanthum under UV-B stress by regulating the Calvin cycle. This paper provides insights into the study of photosynthesis in plants under stress, and is conducive to the adoption of measures to improve photosynthesis in plants under stress to increase yield. [ABSTRACT FROM AUTHOR]

The integration of abscisic acid (ABA) into a chitosan–alginate gel blend unveils crucial insights into the formation and stability of these two substances. ABA, a key phytohormone in plant growth and stress responses, is strategically targeted for controlled release within these complexes. This study investigates the design and characterization of this novel controlled-release system, showcasing the potential of alginate–chitosan gel blends in ABA delivery. Computational methods, including molecular dynamics simulations, are employed to analyze the structural effects of microencapsulation, offering valuable insights into complex behavior under varying conditions. This paper focuses on the controlled release of ABA from these complexes, highlighting its strategic importance in drug delivery systems and beyond. This controlled release enables targeted and regulated ABA delivery, with far-reaching implications for pharmaceuticals, agriculture, and plant stress response studies. While acknowledging context dependency, the paper suggests that the liberation or controlled release of ABA holds promise in applications, urging further research and experimentation to validate its utility across diverse fields. Overall, this work significantly contributes to understanding the characteristics and potential applications of chitosan–alginate complexes, marking a noteworthy advancement in the field of controlled-release systems. [ABSTRACT FROM AUTHOR]

Although the functions of basic leucine zipper (bZIP) family transcription factors in the regulation of various abiotic stresses are beginning to be unveiled, the precise roles of bZIP proteins in plants coping with submergence stress remain unclear. Here we identified a bZIP gene GmbZIP71-4 from soybean, which localized in the nucleus. The GmbZIP71-4 over-expressed tabocco line showed reduced submergence resistance due to the decreased abscisic acid (ABA) content. GO and KEGG pathway analysis based on chromatin immunoprecipitation assay sequencing (ChIP-seq) indicated that the differences expressed genes between submergence treatment and control groups were specially enriched in plant hormone signal transduction items, especially those in response to ABA. Electrophoretic mobility shift assays (EMSA) demonstrated that GmbZIP71-4 bound to the promoter of GmABF2 gene, which is consistent with the ChIP-qPCR results. GmbZIP71-4 function as a negative regulator of soybean in responding to submergence stress through manipulating ABA signaling pathway. This findings will set a solid foundation for the understanding of submergence resistance in plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. All authors read and approved the final manuscript., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Tamarix hispida is highly tolerant to salt, drought and heavy metal stress and is a potential material for the remediation of cadmium (Cd)-contaminated soil under harsh conditions. In this study, T. hispida growth and chlorophyll content decreased, whereas flavonoid and carotenoid contents increased under long-term Cd stress (25 d). The aboveground components of T. hispida were collected for RNA-seq to investigate the mechanism of Cd accumulation. GO and KEGG enrichment analyses revealed that the differentially expressed genes (DEGs) were significantly enriched in plant hormone-related pathways. Exogenous hormone treatment and determination of Cd 2+ levels showed that ethylene (ETH) and abscisic acid (ABA) antagonists regulate Cd accumulation in T. hispida. Twenty-five transcription factors were identified as upstream regulators of hormone-related pathways. ThDRE1A, which was previously identified as an important regulatory factor, was selected for further analysis. The results indicated that ThABAH2.5 and ThACCO3.1 were direct target genes of ThDRE1A. The determination of Cd 2+ , ABA, and ETH levels indicated that ThDRE1A plays an important role in Cd accumulation through the antagonistic regulation of ABA and ETH. In conclusion, these results reveal the molecular mechanism underlying Cd accumulation in plants and identify candidate genes for further research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Abscisic acid (ABA) plays an important regulatory role in plants. It is very critical to obtain the dynamic changes of ABA in situ for botanical research. Herein, coupled with paper-based analysis devices, electrochemical immunoelectrodes based on disposable stainless steels sheet were developed for ABA detection in plants in situ. The stainless steel sheets were modified with carbon cement, ferrocene-graphene oxide-multi walled carbon nanotubes nanocomposites, and ABA antibodies. The system can detect the ABA in the range of 1 nM to 100 μM, with a limit of detection of 100 pM. The ABA content in tomato leaves under high salinity was detected in situ. The trend of ABA changes was similar to the expression of SlNCED1 and SlNCED2 . Overall, this study offers an approach for in situ detection of ABA in plants, which will help to study the regulation mechanism of ABA in plants and to promote the development of precision agriculture.

Drought is a major handicap for plant growth and development. WRKY proteins comprise one of the largest families of plant transcription factors, playing important roles in plant growth and stress tolerance. In tomato (Solanum lycopersicum L.), different WRKY transcription factors differentially (positively or negatively) regulate drought tolerance, however, the role of SlWRKY6 in drought response and the associated molecular mechanisms of stress tolerance remain unclear. Here we report that SlWRKY6, a member of the WRKYII-b group, is involved in the functional aspects of drought resistance in tomato. Transcriptional activation assays show that SlWRKY6 is transcriptionally active in yeast cells, while the subcellular localization assay indicates that SlWRKY6 is localized in the nucleus. Overexpression of SlWRKY6 in tomato plants resulted in stronger antioxidant capacity and drought resistance as manifested by increased photosynthetic capacity and decreased reactive oxygen species accumulation, malondialdehyde content and relative electrolyte leakage in transgenic tomato plants compared with wild-type under drought stress. Moreover, increased abscisic acid (ABA) content and transcript abundance of ABA synthesis and signaling genes (NCED1, NCED4, PYL4, AREB1 and SnRK2.6) in the transgenic tomato plants indicated potential involvement of the ABA pathway in SlWRKY6-induced drought resistance in tomato plants. Inspection of 2-kb sequences upstream of the predicted binding sites in the promoter of SlNCED1/4 identified two copies of the core W-box (TTGACC/T) sequence in the promoter of SlNCED1/4, which correlates well with the expression of these genes in response to drought, further suggesting the involvement of ABA-dependent pathway in SlWRKY6-induced drought resistance. The study unveils a critical role of SlWRKY6, which can be useful to further reveal the drought tolerance mechanism and breeding of drought-resistant tomato varieties for sustainable vegetable production in the era of climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The rice zinc finger protein ZFP36 serves as a pivotal regulator of the hydrogen peroxide (H 2 O 2 ) signaling pathway in response to abscisic acid (ABA). Its role is crucial for integrating H 2 O 2 signals with the plant defense mechanisms against water deficit and oxidative stress. However, it remains unclear whether ZFP36 directly modulates ABA-induced H 2 O 2 signaling. This study explored the effects of oxidative post-translational modifications (OxiPTMs) on ZFP36 in rice, with an emphasis on the H 2 O 2 -induced oxidation through its cysteine (Cys) residues. We found that ZFP36 undergoes oxidative modification as a target of H 2 O 2 in the presence of ABA, specifically at Cys32. Employing quantitative detection and fluorescence assays, we observed that ZFP36 oxidation enhances the expression and activity of genes encoding protective antioxidant enzymes. Moreover, our investigation into the thioredoxin (Trx) and glutaredoxin (Grx) families revealed that OsTrxh1 facilitates the reduction of oxidized ZFP36. Genetic evidence indicates that ZFP36 positively influences rice resilience to oxidative and water stress, while OsTrxh1 exerts an opposing effect. These insights reveal a distinctive pathway for plant cells to perceive ABA-induced H 2 O 2 signaling, advance our comprehension of H 2 O 2 signaling dynamics, and ABA-related plant responses, and lay a vital groundwork for enhancing crop stress tolerance., Competing Interests: Declaration of competing interest The authors declare that they have no known financial interests or personal relationships that might influence the work reported in this paper. The authors declare no conflicts of interest., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Exogenous abscisic acid (ABA) presents a novel approach to mitigate heavy metal (HM) accumulation in plants, yet its efficacy against multiple HMs and potential enhancement methods remain underexplored. In this study, we demonstrated that the exogenous ABA application simultaneously decreased Zn, Cd and Ni accumulation by 22-25 %, 27-39 % and 60-62 %, respectively, in wild-type (WT) Arabidopsis. Conversely, ABA reduced Pb in shoots but increased its root concentration. ABA application also modulated the expression of HM uptake genes, inhibiting IRT1, NRAMP1, NRAMP4, and HMA3, and increasing ZIP1 and ZIP4 expressions. Further analysis revealed that overexpressing the ABA-importing transporter (AIT1) in plants intensified the reduction of Cd, Zn, and Ni, compared to WT. However, the inhibitory effect of exogenous ABA on Pb accumulation was mitigated in shoots with higher AIT1 expression. Furthermore, HMs-induced growth inhibition and the damage to photosynthesis were also alleviated with ABA treatment. Conclusively, AIT1's synergistic effect with ABA effectively reduces Cd, Zn and Ni accumulation, offering a synergistic approach to mitigate HM stress in plants., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Abnormal pollination from chance events or hybridization between species leads to unusual embryo development, resulting in fruit abortion. To elucidate the mechanism underlying fruit abortion, we conducted a comprehensive analysis of the transcriptome and hormone profiles in aborting fruits (AF) derived from an interspecific cross between the peach cultivar 'Huangjinmi 3' and the Prunus mume cultivar 'Jiangmei', as well as in normal-seeded fruits (NF) resulting from an intraspecific cross of 'Huangjinmi 3' with the 'Manyuanhong' peach cultivars. Growth of AF was inhibited during the exponential growth phase, with up-regulation of oxidative stress related genes and down-regulation of DNA replication and cell cycle genes. Accumulation of the tissue growth-related hormones auxin and cytokinin was reduced in AF, while levels of the growth inhibiting hormone abscisic acid (ABA) were higher compared to NF. The increased ABA concentration aligned with down-regulation of the ABA catabolism gene CYP707A2, which encodes abscisic acid 8'-hydroxylase. Correlation analysis showed ABA could explain the maximum proportion of differently expressed genes between NF and AF. We also showed that expression of KIRA1-LIKE1 (PpeKIL1), a peach ortholog of the Arabidopsis KIRA1 gene, was up-regulated in AF. PpeKIL1 promotes senescence or delays normal growth in tobacco and Arabidopsis, and its promoter activity increases with exogenous ABA treatment. Our study demonstrates a candidate mechanism where ABA induces expression of PpeKIL1, which further blocks normal fruit growth and triggers fruit abscission., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

E3 ubiquitin ligases (UBLs), as enzymes capable of specifically recognizing target proteins in the process of protein ubiquitination, play crucial roles in regulating responses to abiotic stresses such as drought, salt, and temperature. Abscisic acid (ABA), a plant endogenous hormone, is essential to regulating plant growth, development, disease resistance, and defense against abiotic stresses, and acts through a complex ABA signaling pathway. Hormone signaling transduction relies on protein regulation, and E3 ubiquitin ligases play important parts in regulating the ABA pathway. Therefore, this paper reviews the ubiquitin-proteasome-mediated protein degradation pathway, ABA-related signaling pathways, and the regulation of ABA-signaling-pathway-related genes by E3 ubiquitin ligases, aiming to provide references for further exploration of the relevant research on how plant E3 ubiquitin ligases regulate the ABA pathway.

Abscisic acid-, stress-, and ripening-induced (ASR) proteins in plants play a significant role in plant response to diverse abiotic stresses. However, the functions of ASR genes in maize remain unclear. In the present study, we identified a novel drought-induced ASR gene in maize (ZmASR1) and functionally characterized its role in mediating drought tolerance. The transcription of ZmASR1 was upregulated under drought stress and abscisic acid (ABA) treatment, and the ZmASR1 protein was observed to exhibit nuclear and cytoplasmic localization. Moreover, ZmASR1 knockout lines generated with the CRISPR-Cas9 system showed lower ROS accumulation, higher ABA content, and a higher degree of stomatal closure than wild-type plants, leading to higher drought tolerance. Transcriptome sequencing data indicated that the significantly differentially expressed genes in the drought treatment group were mainly enriched in ABA signal transduction, antioxidant defense, and photosynthetic pathway. Taken together, the findings suggest that ZmASR1 negatively regulates drought tolerance and represents a candidate gene for genetic manipulation of drought resistance in maize., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Jasmonic acid (JA) plays crucial functions in plant stress response, and the synergistic interaction between JA and abscisic acid (ABA) signaling is implicated to help plants adapt to environmental challenges, whereas the underlying molecular mechanism still needs to be revealed. Here, we report that OsJAZ10, a repressor in the JA signaling, represses rice drought tolerance via inhibition of JA and ABA biosynthesis. Function loss of OsJAZ10 markedly enhances, while overexpression of OsJAZ10 ΔJas reduces rice drought tolerance. The osjaz10 mutant is more sensitive to exogenous ABA and MeJA, and produces higher levels of ABA and JA after drought treatment, indicating OsJAZ10 represses the biosynthesis of these two hormones. Mechanistic study demonstrated that OsJAZ10 physically interacts with OsMYC2. Transient transcriptional regulation assays showed that OsMYC2 activates the expression of ABA-biosynthetic gene OsNCED2, JA-biosynthetic gene OsAOC, and drought-responsive genes OsRAB21 and OsLEA3, while OsJAZ10 prevents OsMYC2 transactivation of these genes. Further, the electrophoretic mobility shift assay (EMSA) confirmed that OsMYC2 directly binds to the promoters of OsNCED2 and OsRAB21. Electrical activity has been proposed to activate JA biosynthesis. Interestingly, OsJAZ10 inhibits the propagation of osmotic stress-elicited systemic electrical signals, indicated by the significantly increased PEG-elicited slow wave potentials (SWPs) in osjaz10 mutant, which is in accordance with the elevated JA levels. Collectively, our findings establish that OsJAZ10 functions as a negative regulator in rice drought tolerance by repressing JA and ABA biosynthesis, and reveal an important mechanism that plants integrate electrical events with hormone signaling to enhance the adaption to environmental stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The presence of the ozone hole increases the amount of UV radiation reaching a plant's surface, and UV-B radiation is an abiotic stress capable of affecting plant growth. Rhododendron chrysanthum Pall. (R. chrysanthum) grows in alpine regions, where strong UV-B radiation is present, and has been able to adapt to strong UV-B radiation over a long period of evolution. We investigated the response of R. chrysanthum leaves to UV-B radiation using widely targeted metabolomics and transcriptomics. Although phytohormones have been studied for many years in plant growth and development and adaptation to environmental stresses, this paper is innovative in terms of the species studied and the methods used. Using unique species and the latest research methods, this paper was able to add information to this topic for the species R. chrysanthum. We treated R. chrysanthum grown in a simulated alpine environment, with group M receiving no UV-B radiation and groups N and Q (externally applied abscisic acid treatment) receiving UV-B radiation for 2 days (8 h per day). The results of the MN group showed significant changes in phenolic acid accumulation and differential expression of genes related to phenolic acid synthesis in leaves of R. chrysanthum after UV-B radiation. We combined transcriptomics and metabolomics data to map the metabolic regulatory network of phenolic acids under UV-B stress in order to investigate the response of such secondary metabolites to stress. L-phenylalanine, L-tyrosine and phenylpyruvic acid contents in R. chrysanthum were significantly increased after UV-B radiation. Simultaneously, the levels of 3-hydroxyphenylacetic acid, 2-phenylethanol, anthranilate, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, α-hydroxycinnamic acid and 2-hydroxy-3-phenylpropanoic acid in this pathway were elevated in response to UV-B stress. In contrast, the study in the NQ group found that externally applied abscisic acid (ABA) in R. chrysanthum had greater tolerance to UV-B radiation, and phenolic acid accumulation under the influence of ABA also showed greater differences. The contents of 2-phenylethanol, 1-o-p-coumaroyl-β-d-glucose, 2-hydroxy-3-phenylpropanoic acid, 3-(4-hydroxyphenyl)-propionic acid and 3-o-feruloylquinic ac-id-o-glucoside were significantly elevated in R. chrysanthum after external application of ABA to protect against UV-B stress. Taken together, these studies of the three groups indicated that ABA can influence phenolic acid production to promote the response of R. chrysanthum to UV-B stress, which provided a theoretical reference for the study of its complex molecular regulatory mechanism. [ABSTRACT FROM AUTHOR]

Sapindus mukorossi has a wide distribution range, high application value, and broad developmental potential. Previous studies have mostly focused on the medicinal and economic value of soapberry; however, few studies have been conducted on its seed germination. This study measured the physiological indicators and hormone content of soapberry seeds at different germination stages and preliminarily determined that abscisic acid (ABA) and indole-3-acetic acid (IAA) are the key hormones that affect the germination of soapberry seeds. Both Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG enrichment) analyses detected hormone transduction pathways, further confirming the key role of plant hormones in the germination process of soapberry seeds. Through transcriptome analysis, we speculated that CYP707A and IPA are key genes in the ABA and IAA synthesis pathways, respectively. This study revealed the close relationship between plant hormones and soapberry seed germination and provided new ideas for further exploration of the germination mechanism of soapberry seeds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Rice flowering is a major agronomic trait, determining yield and ecological adaptability in particular regions. ABA plays an essential role in rice flowering, but the underlying molecular mechanism remains largely elusive., Objectives: In this study, we demonstrated a "SAPK8-ABF1-Ehd1/Ehd2" pathway, through which exogenous ABA represses rice flowering in a photoperiod-independent manner., Methods: We generated abf1 and sapk8 mutants using the CRISPR-Cas9 method. Using yeast two-hybrid, Pull down, BiFC and kinase assays, SAPK8 interacted and phosphorylated ABF1. ABF1 directly bound to the promoters of Ehd1 and Ehd2 using ChIP-qPCR, EMSA, and LUC transient transcriptional activity assay, and suppressed the transcription of these genes., Results: Under both long day and short day conditions, simultaneous knock-out of ABF1 and its homolog bZIP40 accelerated flowering, while SAPK8 and ABF1 over-expression lines exhibited delayed flowering and hypersensitivity to ABA-mediated flowering repression. After perceiving the ABA signal, SAPK8 physically binds to and phosphorylates ABF1 to enhance its binding to the promoters of master positive flowering regulators Ehd1 and Ehd2. Upon interacting with FIE2, ABF1 recruited PRC2 complex to deposit H3K27me3 suppressive histone modification on Ehd1 and Ehd2 to suppress these genes transcription, thereby leading to later flowering., Conclusion: Our work highlighted the biological functions of SAPK8 and ABF1 in ABA signaling, flowering control and the involvement of a PRC2-mediated epigenetic repression mechanism in the transcription regulation governed by ABF1 on ABA-mediated rice flowering repression., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Production and hosting by Elsevier B.V.)

The DELAY OF GERMINATION1-LIKE (DOGL) genes play an essential role in diverse biological processes in plants. However, their exact involvement in the response to cadmium (Cd) stress via the ABA pathway remains unclear. Here, we focused on NtDOGL4, a tobacco DOGL gene whose expression is highly induced upon exposure to Cd. Overexpression of NtDOGL4 in tobacco resulted in elevated endogenous ABA levels, reduced Cd accumulation, and increased tolerance to Cd. Moreover, NtDOGL4 overexpression led to decreased accumulation of reactive oxygen species (ROS) and improved ROS scavenging capacity under Cd stress. Further analyses revealed the direct binding of the transcription factor ABSCISIC ACID-INSENSITIVE 5 (ABI5) to the NtDOGL4 promoter, positively regulating its expression in tobacco. Notably, NtDOGL4 overexpression promoted suberin formation and deposition, while suppressing the expression of Cd transporter genes in tobacco roots, as evidenced by histochemical staining, suberin fraction determination, and qRT-PCR assays. Collectively, our results demonstrate that NtDOGL4 overexpression reduces Cd accumulation, thereby improving Cd stress tolerance through the modulation of antioxidant system, transcription of Cd transporters, and suberin deposition. Notably, the NtABI5-NtDOGL4 module functions as a positive regulator in tobacco's Cd tolerance, underscoring its potential as a molecular target for developing low-Cd crops to ensure environmental safety., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing financial interests or personal relationships that could influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The NDPK gene family is an important group of genes in plants, playing a crucial role in regulating energy metabolism, growth, and differentiation, cell signal transduction, and response to abiotic stress. However, our understanding of the NDPK gene family in Brassica napus L. remains limited. This paper systematically analyzes the NDPK gene family in B. napus, particularly focusing on the evolutionary differences within the species. In this study, sixteen, nine, and eight NDPK genes were identified in B. napus and its diploid ancestors, respectively. These genes are not only homologous but also highly similar in their chromosomal locations. Phylogenetic analysis showed that the identified NDPK proteins were divided into four clades, each containing unique motif sequences, with most NDPKs experiencing a loss of introns/exons during evolution. Collinearity analysis revealed that the NDPK genes underwent whole-genome duplication (WGD) events, resulting in duplicate copies, and most of these duplicate genes were subjected to purifying selection. Cis-acting element analysis identified in the promoters of most NDPK genes elements related to a light response, methyl jasmonate response, and abscisic acid response, especially with an increased number of abscisic acid response elements in B. napus. RNA-Seq results indicated that NDPK genes in B. napus exhibited different expression patterns across various tissues. Further analysis through qRT-PCR revealed that BnNDPK genes responded significantly to stress conditions such as salt, drought, and methyl jasmonate. This study enhances our understanding of the NDPK gene family in B. napus, providing a preliminary theoretical basis for the functional study of NDPK genes and offering some references for further revealing the phenomenon of polyploidization in plants. [ABSTRACT FROM AUTHOR]

Autophagy is a highly conserved process that plays a crucial role in adaptation of plants to stress conditions. Melatonin and abscisic acid (ABA) share an antagonistic relationship; however, both are reported to elevate autophagy individually. Here, we report that melatonin alleviates drought stress effects like wilting and stunted growth in 18-day-old plants of drought-sensitive variety of cotton (Gossypium hirsutum L.) and improves the plant growth, chlorophyll content, photosynthetic efficiency, and sugar metabolism and transport. Melatonin priming increased the endogenous melatonin content (5.02-times) but decreased the ABA (2.63-times) by reducing NCED3 expression as compared to unprimed plants under drought. Also, elevated expression of ATG8c and ATG8f correlated with higher lipidated-ATG8 levels and modulation of RAPTOR1 suggesting a higher occurrence of autophagy and regulation of plant growth in primed stressed plants. Additionally, decreased TPS63 and increased TPP22 expression could have lowered the accumulation of trehalose-6-P (T6P) in primed stressed plants thus contributing to autophagy progression. Priming also enhanced the expression of MAPK6 and RAF18, and increased the transcript/protein levels of SnRK2.6 and KIN10, which is pointing towards melatonin's beneficial effect on autophagy under drought. Despite higher ABA content, elevated TPS63 and downregulated TPP22 could have hindered autophagy induction in unprimed stressed plants. Although fluridone treatment reduced the ABA content, the expression of SnRK2.6 and KIN10 remained unaltered in fluridone-treated and untreated primed plants indicating the ABA-independent expression. These results suggest that the melatonin-mediated activation of MAPK contributes to the ABA-independent activation of SnRK2, consequently, SnRK1 and autophagy under drought., Competing Interests: Declaration of Competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Salinity is a significant abiotic stress factor affecting plant growth, consequently reducing crop yield. Abscisic acid (ABA), a well-known phytohormone, is crucial in conferring resistance to abiotic stress, thus, understanding the mechanisms underlying ABA biosynthesis is crucial. In rice (Oryza sativa L.), OsABA2, a short-chain dehydrogenase protein, has a pivotal role in modulating ABA biosynthesis and salt tolerance by undergoing phosphorylation at Ser197 through mitogen-activated protein kinase OsMPK1. However, the interaction between OsABA2 and other proteins in regulating ABA biosynthesis remains unclear. We employed OsABA2 as a bait in yeast two-hybrid screening: a basic helix-loop-helix transcription factor interacting with OsABA2, named OsbHLH110, was identified. Our results showed that firefly luciferase complementary imaging, pull-down, and co-immunoprecipitation assays validated the interaction between OsbHLH110 and OsABA2, affirming their interaction in vivo and in vitro. Moreover, the expression of OsbHLH110 significantly increases in response to salt and ABA treatments. Additionally, OsbHLH110 can directly bind to the G-box element in the OsABA2 promoter. This binding enhances luciferase activity controlled by the OsABA2 promoter, thereby increasing the expression of the OsABA2 gene and content of the OsABA2 protein, resulting in an increase in ABA content. OsABA2 enhanced the interaction between OsbHLH110 and OsABA2 promoter. This collaborative effect enhanced the regulation of ABA biosynthesis. Subsequent genetic analysis demonstrated that OsbHLH110 improved the tolerance of rice to salt stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Drought stress is a major environmental challenge that poses considerable threats to crop survival and growth. Previous research has indicated anthocyanins play a crucial role in alleviating oxidative damage, photoprotection, membrane stabilization, and water retention under drought stress. However, the presence of MYBL2 (MYELOBBLASTOSIS LIKE 2), an R3-MYB transcription factor (TF) which known to suppress anthocyanin biosynthesis. In this study, four BnMYBL2 members were cloned from Brassica napus L, and BnMYBL2-1 was overexpressed in Triticum aestivum L (No BnMYBL2 homologous gene was detected in wheat). Subsequently, the transgenic wheat lines were treated with drought, ABA and anthocyanin. Results showed that transgenic lines exhibited greater drought tolerance compared to the wild-type (WT), characterized by improved leaf water content (LWC), elevated levels of soluble sugars and chlorophyll, and increased antioxidant enzyme activity. Notably, transgenic lines also exhibited significant upregulation in abscisic acid (ABA) content, along with the transcriptional levels of key enzymes involved in ABA signalling under drought. Results also demonstrated that BnMYBL2-1 promoted the accumulation of ABA and anthocyanins in wheat. Overall, the study highlights the positive role of BnMYBL2-1 in enhancing crop drought tolerance through ABA signalling and establishes its close association with anthocyanin biosynthesis. These findings offer valuable insights for the development of drought-resistant crop varieties and enhance the understanding of the molecular mechanisms underlying plant responses to drought stress., Competing Interests: Declaration of competing interest All the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

In recent years, the use of plant hormones, such as abscisic acid (ABA) and 6-benzylaminopurine (6-BAP), has gained significant attention for their role in mitigating abiotic stresses across various plant species. These hormones have been shown to play a vital role in enhancing the ascorbate-glutathione cycle and eliciting a wide range of plant growth and biomass, photosynthetic efficiency, oxidative stress and response of antioxidants and other physiological responses. While previous research has been conducted on the individual impact of ABA and 6-BAP in metal stress resistance among various crop species, their combined effects in the context of heavy metal-stressed conditions remain underexplored. The current investigation is to assess the beneficial effects of single and combined ABA (5 and 10 μM L -1 ) and 6-BAP (5 and 10 μM L -1 ) applications in rice (Oryza sativa L.) cultivated in chromium (Cr)-contaminated soil (100 μM). Our results showed that the Cr toxicity in the soil showed a significant declined in the growth, gas exchange attributes, sugars, AsA-GSH cycle, cellular fractionation, proline metabolism in O. sativa. However, Cr toxicity significantly increased oxidative stress biomarkers, organic acids, enzymatic and non-enzymatic antioxidants including their gene expression in O. sativa seedlings. Although, the application of ABA and 6-BAP showed a significant increase in the plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased the oxidative stress, And Cr uptake. In addition, individual or combined application of ABA and 6-BAP enhanced the cellular fractionation and decreases the proline metabolism and AsA-GSH cycle in rice plants. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of heavy metal contamination in agricultural soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Abiotic stress is an adverse environmental factor that severely affects plant growth and development, and plants have developed complex regulatory mechanisms to adapt to these unfavourable conditions through long-term evolution. In recent years, many transcription factor families of genes have been identified to regulate the ability of plants to respond to abiotic stresses. Among them, the AP2/ERF (APETALA2/ethylene responsive factor) family is a large class of plant-specific proteins that regulate plant response to abiotic stresses and can also play a role in regulating plant growth and development. This paper reviews the structural features and classification of AP2/ERF transcription factors that are involved in transcriptional regulation, reciprocal proteins, downstream genes, and hormone-dependent signalling and hormone-independent signalling pathways in response to abiotic stress. The AP2/ERF transcription factors can synergise with hormone signalling to form cross-regulatory networks in response to and tolerance of abiotic stresses. Many of the AP2/ERF transcription factors activate the expression of abiotic stress-responsive genes that are dependent or independent of abscisic acid and ethylene in response to abscisic acid and ethylene. In addition, the AP2/ERF transcription factors are involved in gibberellin, auxin, brassinosteroid, and cytokinin-mediated abiotic stress responses. The study of AP2/ERF transcription factors and interacting proteins, as well as the identification of their downstream target genes, can provide us with a more comprehensive understanding of the mechanism of plant action in response to abiotic stress, which can improve plants' ability to tolerate abiotic stress and provide a more theoretical basis for increasing plant yield under abiotic stress.

Drought poses a serious challenge to sustained plant growth and crop yields in the context of global climate change. Drought tolerance in poplars and their underlying mechanisms still remain largely unknown. In this article, we investigated the overexpression of PtoMYB99 - both a drought and abscisic acid (ABA) induced gene constraining drought tolerance in poplars (as compared with wild type poplars). First, we found that PtoMYB99-OE lines exhibited increased stomatal opening and conductance, higher transpiration and photosynthetic rates, as well as reduced levels of ABA and jasmonic acid (JA). Second, PtoMYB99-OE lines accumulated more reactive oxygen species (ROS), including H 2 O 2 and O 2 - , as well as malonaldehyde (MDA), proline, and soluble sugar under osmotic stress; conversely, the activity of antioxidant enzymes (SOD, POD, and CAT), was weakened in the PtoMYB99-OE lines. Third, the expression of ABA biosynthetic genes, PtoNCED3.1 and PtoNCED3.2, as well as JA biosynthetic genes, PtoOPR3.1 and PtoOPR3.2, was significantly reduced in the PtoMYB99-OE lines under both normal conditions and osmotic stress. Based on our results, we conclude that the overexpression of PtoMYB99 compromises tolerance to osmotic stress in poplar. These findings contribute to the understanding of the role of the MYB genes in drought stress and the biosynthesis of ABA and JA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier GmbH. All rights reserved.)