Genome-wide analysis of R2R3-MYB transcription factors in poplar and functional validation of PagMYB147 in defense against Melampsora magnusiana.

MAIN CONCLUSION: Transcription of PagMYB147 was induced in poplar infected by Melampsora magnusiana, and a decline in its expression levels increases the host's susceptibility, whereas its overexpression promotes resistance to rust disease. Poplars are valuable tree species with diverse industrial and silvicultural applications. The R2R3-MYB subfamily of transcription factors plays a crucial role in response to biotic stresses. However, the functional studies on poplar R2R3-MYB genes in resistance to leaf rust disease are still insufficient. We identified 191 putative R2R3-MYB genes in the Populus trichocarpa genome. A phylogenetic analysis grouped poplar R2R3-MYBs and Arabidopsis R2R3-MYBs into 33 subgroups. We detected 12 tandem duplication events and 148 segmental duplication events, with the latter likely being the main contributor to the expansion of poplar R2R3-MYB genes. The promoter regions of these genes contained numerous cis-acting regulatory elements associated with response to stress and phytohormones. Analyses of RNA-Seq data identified a multiple R2R3-MYB genes response to Melampsora magnusiana (Mmag). Among them, PagMYB147 was significantly up-regulated under Mmag inoculation, salicylic acid (SA) and methyl jasmonate (MeJA) treatment, and its encoded product was primarily localized to the cell nucleus. Silencing of PagMYB147 exacerbated the severity of Mmag infection, likely because of decreased reactive oxygen species (ROS) production and phenylalanine ammonia-lyase (PAL) enzyme activity, and up-regulation of genes related to ROS scavenging and down-regulation of genes related to PAL, SA and JA signaling pathway. In contrast, plants overexpressing PagMYB147 showed the opposite ROS accumulation, PAL enzyme activity, SA and JA-related gene expressions, and improved Mmag resistance. Our findings suggest that PagMYB147 acts as a positive regulatory factor, affecting resistance in poplar to Mmag by its involvement in the regulation of ROS homeostasis, SA and JA signaling pathway.

The Long-Distance Transport of Jasmonates in Salt-Treated Pea Plants and Involvement of Lipid Transfer Proteins in the Process.

The adaption of plants to stressful environments depends on long-distance responses in plant organs, which themselves are remote from sites of perception of external stimuli. Jasmonic acid (JA) and its derivatives are known to be involved in plants' adaptation to salinity. However, to our knowledge, the transport of JAs from roots to shoots has not been studied in relation to the responses of shoots to root salt treatment. We detected a salt-induced increase in the content of JAs in the roots, xylem sap, and leaves of pea plants related to changes in transpiration. Similarities between the localization of JA and lipid transfer proteins (LTPs) around vascular tissues were detected with immunohistochemistry, while immunoblotting revealed the presence of LTPs in the xylem sap of pea plants and its increase with salinity. Furthermore, we compared the effects of exogenous MeJA and salt treatment on the accumulation of JAs in leaves and their impact on transpiration. Our results indicate that salt-induced changes in JA concentrations in roots and xylem sap are the source of accumulation of these hormones in leaves leading to associated changes in transpiration. Furthermore, they suggest the possible involvement of LTPs in the loading/unloading of JAs into/from the xylem and its xylem transport.

Lipids and Lipid-Mediated Signaling in Plant-Pathogen Interactions.

Plant lipids are essential cell constituents with many structural, storage, signaling, and defensive functions. During plant-pathogen interactions, lipids play parts in both the preexisting passive defense mechanisms and the pathogen-induced immune responses at the local and systemic levels. They interact with various components of the plant immune network and can modulate plant defense both positively and negatively. Under biotic stress, lipid signaling is mostly associated with oxygenated natural products derived from unsaturated fatty acids, known as oxylipins; among these, jasmonic acid has been of great interest as a specific mediator of plant defense against necrotrophic pathogens. Although numerous studies have documented the contribution of oxylipins and other lipid-derived species in plant immunity, their specific roles in plant-pathogen interactions and their involvement in the signaling network require further elucidation. This review presents the most relevant and recent studies on lipids and lipid-derived signaling molecules involved in plant-pathogen interactions, with the aim of providing a deeper insight into the mechanisms underpinning lipid-mediated regulation of the plant immune system.

Genome-Wide Identification of Sorghum Paclobutrazol-Resistance Gene Family and Functional Characterization of SbPRE4 in Response to Aphid Stress.

Sorghum (Sorghum bicolor), the fifth most important cereal crop globally, serves as a staple food, animal feed, and a bioenergy source. Paclobutrazol-Resistance (PRE) genes play a pivotal role in the response to environmental stress, yet the understanding of their involvement in pest resistance remains limited. In the present study, a total of seven SbPRE genes were found within the sorghum BTx623 genome. Subsequently, their genomic location was studied, and they were distributed on four chromosomes. An analysis of cis-acting elements in SbPRE promoters revealed that various elements were associated with hormones and stress responses. Expression pattern analysis showed differentially tissue-specific expression profiles among SbPRE genes. The expression of some SbPRE genes can be induced by abiotic stress and aphid treatments. Furthermore, through phytohormones and transgenic analyses, we demonstrated that SbPRE4 improves sorghum resistance to aphids by accumulating jasmonic acids (JAs) in transgenic Arabidopsis, giving insights into the molecular and biological function of atypical basic helix-loop-helix (bHLH) transcription factors in sorghum pest resistance.

Genome-Wide Analysis of the SRPP/REF Gene Family in Taraxacum kok-saghyz Provides Insights into Its Expression Patterns in Response to Ethylene and Methyl Jasmonate Treatments.

Taraxacum kok-saghyz (TKS) is a model plant and a potential rubber-producing crop for the study of natural rubber (NR) biosynthesis. The precise analysis of the NR biosynthesis mechanism is an important theoretical basis for improving rubber yield. The small rubber particle protein (SRPP) and rubber elongation factor (REF) are located in the membrane of rubber particles and play crucial roles in rubber biosynthesis. However, the specific functions of the SRPP/REF gene family in the rubber biosynthesis mechanism have not been fully resolved. In this study, we performed a genome-wide identification of the 10 TkSRPP and 2 TkREF genes' family members of Russian dandelion and a comprehensive investigation on the evolution of the ethylene/methyl jasmonate-induced expression of the SRPP/REF gene family in TKS. Based on phylogenetic analysis, 12 TkSRPP/REFs proteins were divided into five subclades. Our study revealed one functional domain and 10 motifs in these proteins. The SRPP/REF protein sequences all contain typical REF structural domains and belong to the same superfamily. Members of this family are most closely related to the orthologous species T. mongolicum and share the same distribution pattern of SRPP/REF genes in T. mongolicum and L. sativa, both of which belong to the family Asteraceae. Collinearity analysis showed that segmental duplication events played a key role in the expansion of the TkSRPP/REFs gene family. The expression levels of most TkSRPP/REF members were significantly increased in different tissues of T. kok-saghyz after induction with ethylene and methyl jasmonate. These results will provide a theoretical basis for the selection of candidate genes for the molecular breeding of T. kok-saghyz and the precise resolution of the mechanism of natural rubber production.

A Genome-Wide Analysis of the Jasmonic Acid Biosynthesis Gene Families in Peanut Reveals Their Crucial Roles in Growth and Abiotic Stresses.

Abiotic stress is a limiting factor in peanut production. Peanut is an important oil crop and cash crop in China. Peanut yield is vulnerable to abiotic stress due to its seeds grown underground. Jasmonic acid (JA) is essential for plant growth and defense against adversity stresses. However, the regulation and mechanism of the jasmonic acid biosynthesis pathway on peanut defense against abiotic stresses are still limitedly understood. In this study, a total of 64 genes encoding key enzymes of JA biosynthesis were identified and classified into lipoxygenases (AhLOXs), alleno oxide synthases (AhAOSs), allene oxide cyclases (AhAOCs), and 12-oxo-phytodienoic acid reductases (AhOPRs) according to gene structure, conserved motif, and phylogenetic feature. A cis-regulatory element analysis indicated that some of the genes contained stress responsive and hormone responsive elements. In addition to proteins involved in JA biosynthesis and signaling, they also interacted with proteins involved in lipid biosynthesis and stress response. Sixteen putative Ah-miRNAs were identified from four families targeting 35 key genes of JA biosynthesis. A tissue expression pattern analysis revealed that AhLOX2 was the highest expressed in leaf tissues, and AhLOX32 was the highest expressed in shoot, root, and nodule tissues. AhLOX16, AhOPR1, and AhOPR3 were up-regulated under drought stress. AhLOX16, AhAOS3, AhOPR1, and AhAOC4 had elevated transcript levels in response to cold stress. AhLOX5, AhLOX16, AhAOC3, AhOPR1, and AhOPR3 were up-regulated for expression under salt stress. Our study could provide a reference for the study of the abiotic stress resistance mechanism in peanut.

BcWRKY1 confers Botrytis cinerea susceptibility via inhibiting JA biosynthesis.

WRKYs play important roles in plant stress resistance. However, the role of WRKYs in non-heading Chinese cabbage (Brassica campestris ssp. chinensis) against Botrytis cinerea (B. cinerea) remains poorly understood. Herein, the expression of BcWRKY1 was induced by B. cinerea. Further, the role of BcWRKY1 in B. cinerea infection was identified. Silencing of BcWRKY1 in non-heading Chinese cabbage enhanced plant resistance to B. cinerea. After B. cinerea inoculation, BcWRKY1-silencing plants exhibited lower reactive oxygen species (ROS) content, higher jasmonic acid (JA) content, and the expression level of JA biosynthesis genes, BcOPR3, BcLOX3-1 and BcLOX3-2 were upregulated. Overexpression of BcWRKY1 in Arabidopsis exhibited a complementary phenotype. By directly targeting W-boxes in the promoter of BcLOX3-2, BcWRKY1 inhibited the transcription of this gene. In addition, 13 candidate interacting proteins of BcWRKY1 were identified by yeast two-hybrid (Y2H) screening, and the interaction between BcWRKY1 and BcCaM6 weakened the inhibition of BcLOX3-2. In summary, our findings suggest that BcWRKY1 interacts with BcCaM6 to negatively regulate disease resistance.

Methyl jasmonate-induced bHLH42 mediates tissue-specific accumulation of anthocyanins via regulating flavonoid metabolism-related pathways in Caitai.

Anthocyanin is a type of plant secondary metabolite beneficial to human health. The anthocyanin content of vegetable and fruit crops signifies their nutritional quality. However, the molecular mechanism of anthocyanin accumulation, especially tissue-specific accumulation, in Caitai, as well as in other Brassica rapa varieties, remains elusive. In the present study, taking advantage of three kinds of Caitai cultivars with diverse colour traits between leaves and stems, we conducted a comparative transcriptome analysis and identified the molecular pathway of anthocyanin biosynthesis in Caitai leaves and stems, respectively. Our further investigations demonstrate that bHLH42, which is robustly induced by MeJA, closely correlates with tissue-specific accumulation of anthocyanins in Caitai; bHLH42 upregulates the expression of flavonoid/anthocyanin biosynthetic pathway genes to activate anthocyanin biosynthesis pathway, importantly, overexpression of bHLH42 significantly improves the anthocyanin content of Caitai. Our analysis convincingly suggests that bHLH42 induced by jasmonic acid signalling plays a crucial role in tissue-specific accumulation of anthocyanins in Caitai.

Less Frequently Used Growth Regulators in Plant Tissue Culture.

Plant growth regulators are routinely added to in vitro culture media to foster the growth and differentiation of the cells, tissues, and organs. However, while the literature on usage of the more common auxins, cytokinins, gibberellins, abscisic acid, and ethylene is vast, other compounds that also have shown a growth-regulating activity have not been studied as frequently. Such substances are also capable of modulating the responses of plant cells and tissues in vitro by regulating their growth, differentiation, and regeneration competence, but also by enhancing their responses toward biotic and abiotic stress agents and improving the production of secondary metabolites of interest. This chapter will discuss the in vitro effects of several of such less frequently added plant growth regulators, including brassinosteroids (BRS), strigolactones (SLs), phytosulfokines (PSKs), methyl jasmonate, salicylic acid (SA), sodium nitroprusside (SNP), hydrogen sulfite, various plant growth retardants and inhibitors (e.g., ancymidol, uniconazole, flurprimidol, paclobutrazol), and polyamines.

New insights into azelaic acid-induced resistance against Alternaria Solani in tomato plants.

BACKGROUND: The effect of azelaic acid (Aza) on the response of tomato plants to Alternaria solani was investigated in this study. After being treated with Aza, tomato plants were infected with A. solani, and their antioxidant, biochemical, and molecular responses were analyzed. RESULTS: The results demonstrated that H2O2 and MDA accumulation increased in control plants after pathogen infection. Aza-treated plants exhibited a remarkable rise in peroxidase (POD) and catalase (CAT) activities during the initial stages of A. solani infection. Gene expression analysis revealed that both Aza treatment and pathogen infection altered the expression patterns of the SlNPR1, SlERF2, SlPR1, and SlPDF1.2 genes. The expression of SlPDF1.2, a marker gene for the jasmonic acid/ethylene (JA/ET) signaling pathway, showed a remarkable increase of 4.2-fold upon pathogen infection. In contrast, for the SlNPR1, a key gene in salicylic acid (SA) pathway, this increased expression was recorded with a delay at 96 hpi. Also, the phytohormone analysis showed significantly increased SA accumulation in plant tissues with disease development. It was also revealed that tissue accumulation of JA in Aza-treated plants was increased following pathogen infection, while it was not increased in plants without pathogen inoculation. CONCLUSION: The results suggest that the resistance induced by Aza is mainly a result of modulations in both SA and JA pathways following complex antioxidant and molecular defense responses in tomato plants during A. solani infection. These findings provide novel information regarding inducing mechanisms of azelaic acid which would add to the current body of knowledge of SAR induction in plants as result of Aza application.

The development of yellow lupin anthers depends on the relationship between jasmonic acid and indole-3-acetic acid.

The main purpose of this study was to demonstrate that the course of anther development, including post-meiotic maturation, dehiscence and senescence, is ensured by the interdependencies between jasmonic acid (JA) and indole-3-acetic acid (IAA) in yellow lupin (Lupinus luteus L.). The concentration of JA peaked during anther dehiscence when IAA level was low, whereas the inverse relationship was specific to anther senescence. Cellular and tissue localization of JA and IAA, in conjunction with broad expression profile for genes involved in biosynthesis, signalling, response, and homeostasis under different conditions, allowed to complete and define the role of studied phytohormones during late anther development, as well as predict events triggered by them. The development/degeneration of septum and anther wall cells, dehydration of epidermis, and rupture of stomium may involve JA signalling, while the formation of secondary thickening in endothecial cell walls is rather JA independent. The IAA is involved in programmed cell death (PCD)-associated processes during anther senescence but does not exclude its participation in the anther dehiscence processes, mainly related to cell disintegration and degeneration. A detailed understanding of these multistage processes, especially at the level of phytohormonal interplay, can contribute to the effective control of male fertility, potentially revolutionizing the breeding of L. luteus.

Neddylation inhibition prevents acetaminophen-induced liver damage by enhancing the anabolic cardiolipin pathway.

Drug-induced liver injury (DILI) is a significant cause of acute liver failure (ALF) and liver transplantation in the Western world. Acetaminophen (APAP) overdose is a main contributor of DILI, leading to hepatocyte cell death through necrosis. Here, we identified that neddylation, an essential post-translational modification involved in the mitochondria function, was upregulated in liver biopsies from patients with APAP-induced liver injury (AILI) and in mice treated with an APAP overdose. MLN4924, an inhibitor of the neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8)-activating enzyme (NAE-1), ameliorated necrosis and boosted liver regeneration in AILI. To understand how neddylation interferes in AILI, whole-body biotinylated NEDD8 (bioNEDD8) and ubiquitin (bioUB) transgenic mice were investigated under APAP overdose with and without MLN4924. The cytidine diphosphate diacylglycerol (CDP-DAG) synthase TAM41, responsible for producing cardiolipin essential for mitochondrial activity, was found modulated under AILI and restored its levels by inhibiting neddylation. Understanding this ubiquitin-like crosstalk in AILI is essential for developing promising targeted inhibitors for DILI treatment.

Genome-wide Characterization of Small Secreted Peptides in Nicotiana tabacum and Functional Assessment of NtLTP25 in Plant Immunity.

Small secreted peptides (SSPs), serving as signaling molecules for intercellular communication, play significant regulatory roles in plant growth, development, pathogen immunity, and responses to abiotic stress. Despite several SSPs, such as PIP, PSK, and PSY having been identified to participate in plant immunity, the majority of SSPs remain understudied, necessitating the exploration and identification of SSPs regulating plant immunity from vast genomic resources. Here we systematically characterized 756 putative SSPs across the genome of Nicotiana tabacum. 173 SSPs were further annotated as established SSPs, such as nsLTP, CAPE, and CEP. Furthermore, we detected the expression of 484 putative SSP genes in five tissues, with 83 SSPs displaying tissue-specific expression. Transcriptomic analysis of tobacco roots under plant defense hormones revealed that 46 SSPs exhibited specific responsiveness to salicylic acid (SA), and such response was antagonistically regulated by methyl jasmonate. It's worth noting that among these 46 SSPs, 16 members belong to nsLTP family, and one of them, NtLTP25, was discovered to enhance tobacco's resistance against Phytophthora nicotianae. Overexpression of NtLTP25 in tobacco enhanced the expression of ICS1, subsequently stimulating the biosynthesis of SA and the expression of NPR1 and pathogenesis-related genes. Concurrently, NtLTP25 overexpression activated genes associated with ROS scavenging, consequently mitigating the accumulation of ROS during the subsequent phases of pathogenesis. These discoveries indicate that these 46 SSPs, especially the 16 nsLTPs, might have a vital role in governing plant immunity that relies on SA signaling. This offers a valuable source for pinpointing SSPs involved in regulating plant immunity.

Heat stress reprograms herbivory-induced defense responses in potato plants.

Climate change is predicted to increase the occurrence of extreme weather events such as heatwaves, which may thereby impact the outcome of plant-herbivore interactions. While elevated temperature is known to directly affect herbivore growth, it remains largely unclear if it indirectly influences herbivore performance by affecting the host plant they feed on. In this study, we investigated how transient exposure to high temperature influences plant herbivory-induced defenses at the transcript and metabolic level. To this end, we studied the interaction between potato (Solanum tuberosum) plants and the larvae of the potato tuber moth (Phthorimaea operculella) under different temperature regimes. We found that P. operculella larvae grew heavier on leaves co-stressed by high temperature and insect herbivory than on leaves pre-stressed by herbivory alone. We also observed that high temperature treatments altered phylotranscriptomic patterns upon herbivory, which changed from an evolutionary hourglass pattern, in which transcriptomic responses at early and late time points after elicitation are more variable than the ones in the middle, to a vase pattern. Specifically, transcripts of many herbivory-induced genes in the early and late defense stage were suppressed by HT treatment, whereas those in the intermediate stage peaked earlier. Additionally, we observed that high temperature impaired the induction of jasmonates and defense compounds upon herbivory. Moreover, using jasmonate-reduced (JA-reduced, irAOC) and -elevated (JA-Ile-elevated, irCYP94B3s) potato plants, we showed that high temperature suppresses JA signaling mediated plant-induced defense to herbivore attack. Thus, our study provides evidences on how temperature reprograms plant-induced defense to herbivores.

Comparative transcriptomics analysis of tolerant and sensitive genotypes reveals genes involved in the response to cold stress in bitter gourd (Momordica charantia L.).

Bitter gourd is an economically important horticultural crop for its edible and medicinal value. However, the regulatory mechanisms of bitter gourd in response to cold stress are still poorly elucidated. In this study, phytohormone determination and comparative transcriptome analyses in XY (cold-tolerant) and QF (cold-sensitive) after low temperature treatment were conducted. Under cold stress, the endogenous contents of abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA) in XY were significantly increased at 24 h after treatment (HAT), indicating that ABA, JA and SA might function in regulating cold resistance. RNA-seq results revealed that more differentially expressed genes were identified at 6 HAT in QF and 24 HAT in XY, respectively. KEGG analysis suggested that the plant hormone signal transduction pathway was significantly enriched in both genotypes at all the time points. In addition, transcription factors showing different expression patterns between XY and QF were identified, including CBF3, ERF2, NAC90, WRKY51 and WRKY70. Weighted gene co-expression network analysis suggested MARK1, ERF17, UGT74E2, GH3.1 and PPR as hub genes. These results will deepen the understanding of molecular mechanism of bitter gourd in response to cold stress and the identified genes may help to facilitate the genetic improvement of cold-resistant cultivars.

The CRL3KCTD10 ubiquitin ligase-USP18 axis coordinately regulates cystine uptake and ferroptosis by modulating SLC7A11.

SLC7A11 is a cystine transporter and ferroptosis inhibitor. How the stability of SLC7A11 is coordinately regulated in response to environmental cystine by which E3 ligase and deubiquitylase (DUB) remains elusive. Here, we report that neddylation inhibitor MLN4924 increases cystine uptake by causing SLC7A11 accumulation, via inactivating Cullin-RING ligase-3 (CRL-3). We identified KCTD10 as the substrate-recognizing subunit of CRL-3 for SLC7A11 ubiquitylation, and USP18 as SLC7A11 deubiquitylase. Upon cystine deprivation, the protein levels of KCTD10 or USP18 are decreased or increased, respectively, contributing to SLC7A11 accumulation. By destabilizing or stabilizing SLC7A11, KCTD10, or USP18 inversely regulates the cystine uptake and ferroptosis. Biologically, MLN4924 combination with SLC7A11 inhibitor Imidazole Ketone Erastin (IKE) enhanced suppression of tumor growth. In human breast tumor tissues, SLC7A11 levels were negatively or positively correlated with KCTD10 or USP18, respectively. Collectively, our study defines how SLC7A11 and ferroptosis is coordinately regulated by the CRL3KCTD10/E3-USP18/DUB axis, and provides a sound rationale of drug combination to enhance anticancer efficacy.

Arabidopsis Transcriptomics Reveals the Role of Lipoxygenase2 (AtLOX2) in Wound-Induced Responses.

In wounded Arabidopsis thaliana leaves, four 13S-lipoxygenases (AtLOX2, AtLOX3, AtLOX4, AtLOX6) act in a hierarchical manner to contribute to the jasmonate burst. This leads to defense responses with LOX2 playing an important role in plant resistance against caterpillar herb-ivory. In this study, we sought to characterize the impact of AtLOX2 on wound-induced phytohormonal and transcriptional responses to foliar mechanical damage using wildtype (WT) and lox2 mutant plants. Compared with WT, the lox2 mutant had higher constitutive levels of the phytohormone salicylic acid (SA) and enhanced expression of SA-responsive genes. This suggests that AtLOX2 may be involved in the biosynthesis of jasmonates that are involved in the antagonism of SA biosynthesis. As expected, the jasmonate burst in response to wounding was dampened in lox2 plants. Generally, 1 h after wounding, genes linked to jasmonate biosynthesis, jasmonate signaling attenuation and abscisic acid-responsive genes, which are primarily involved in wound sealing and healing, were differentially regulated between WT and lox2 mutants. Twelve h after wounding, WT plants showed stronger expression of genes associated with plant protection against insect herbivory. This study highlights the dynamic nature of jasmonate-responsive gene expression and the contribution of AtLOX2 to this pathway and plant resistance against insects.

Eicosapentaenoic acid: New insights into an oomycete-driven elicitor to enhance grapevine immunity.

The widespread use of pesticides in agriculture remains a matter of major concern, prompting a critical need for alternative and sustainable practices. To address this, the use of lipid-derived molecules as elicitors to induce defence responses in grapevine plants was accessed. A Plasmopara viticola fatty acid (FA), eicosapentaenoic acid (EPA) naturally present in oomycetes, but absent in plants, was applied by foliar spraying to the leaves of the susceptible grapevine cultivar (Vitis vinifera cv. Trincadeira), while a host lipid derived phytohormone, jasmonic acid (JA) was used as a molecule known to trigger host defence. Their potential as defence triggers was assessed by analysing the expression of a set of genes related to grapevine defence and evaluating the FA modulation upon elicitation. JA prompted grapevine immunity, altering lipid metabolism and up-regulating the expression of several defence genes. EPA also induced a myriad of responses to the levels typically observed in tolerant plants. Its application activated the transcription of defence gene's regulators, pathogen-related genes and genes involved in phytoalexins biosynthesis. Moreover, EPA application resulted in the alteration of the leaf FA profile, likely by impacting biosynthetic, unsaturation and turnover processes. Although both molecules were able to trigger grapevine defence mechanisms, EPA induced a more robust and prolonged response. This finding establishes EPA as a promising elicitor for an effectively managing grapevine downy mildew diseases.

Coronatine-treated seedlings increase the tolerance of cotton to low-temperature stress.

Coronatine, an analog of Jasmonic acid (JA), has been shown to enhance crop tolerance to abiotic stresses, including chilling stress. However, the underlying molecular mechanism remains largely unknown. In this study, we investigated the effect of Coronatine on cotton seedlings under low temperature using transcriptomic and metabolomics analysis. Twelve cDNA libraries from cotton seedlings were constructed, and pairwise comparisons revealed a total of 48,322 differentially expressed genes (DEGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified the involvement of these unigenes in various metabolic pathways, including Starch and sucrose metabolism, Sesquiterpenoid and triterpenoid biosynthesis, Phenylpropanoid biosynthesis, alpha-Linolenic acid metabolism, ABC transporters, and Plant hormone signal transduction. Additionally, substantial accumulations of jasmonates (JAs), abscisic acid and major cell wall metabolites were observed. Transcriptome analysis revealed differential expression of regulatory genes, and qRT-PCR analysis confirmed the expression patterns of 9 selected genes. Co-expression analysis showed that the JA-responsive genes might form a network module with ABA biosynthesis genes or cell wall biosynthesis genes, suggesting the existence of a COR-JA-cellulose and COR-JA-ABA-cellulose regulatory pathway in cotton seedlings. Collectively, our findings uncover new insights into the molecular basis of coronatine--associated cold tolerance in cotton seedlings.

Apple SINA11-JAZ2 module is involved in jasmonate signaling response.

The E3 ubiquitin ligase MdSINA11 targets the jasmonate ZIM domain protein MdJAZ2 for ubiquitination and degradation through the 26S proteasome pathway, thereby initiating jasmonate signaling and jasmonic acid-triggered anthocyanin biosynthesis in apple.