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GhUMC1, a blue copper-binding protein, regulates lignin synthesis and cotton immune response

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Abstract

Verticillium wilt caused by the soil-borne fungus Verticillium dahliae is a serious problem for the sustainable production of cotton. The mechanism of cotton resistance to V. dahliae is unclear, which makes it is difficult to improve cotton resistance breeding. In this study, we characterized an umecyanin-like gene GhUMC1 in cotton, which is homologous to the AtBCB gene in Arabidopsis. It is predominantly expressed in roots and responds to pathogen infection. Knock-down of GhUMC1 increases plant susceptibility to V. dahliae. Expression levels of genes in the JA and SA signaling pathways in roots were down-regulated in GhUMC1-silenced plants. The transcripts of lignin synthesis genes, such as C4H, HCT, CCoAOMT and CAD, were also decreased in GhUMC1 knock-down seedlings, as was lignin content. Interestingly, knock-down of the GhUMC1 also decreased the contents of H202 compared with the control. Our results suggest that GhUMC1 is involved in cotton resistance to V. dahliae by the regulation of the JA signaling pathway and lignin metabolism.

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... The molecular mechanisms of cotton plant defence against V. dahliae are complex. Recently, SA mediated resistance and lignin, as the major physical barriers of cell wall, were reported to play an important role in cotton plant defence against V. dahliae (Pieterse et al., 2012;Seyfferth and Tsuda, 2014;Yan and Dong, 2014;Zhu et al., 2018). In SA-related resistance, the SA signalling pathway mainly participates in Arabidopsis plant defence through some hub components, including nonexpressor of pathogenesis-related genes 1 (NPR1), NPR3/NPR4, TGAs and pathogenesis-related gene (PR) proteins (Shah, 2003;Fu et al., 2012;Moreau et al., 2012;Seyfferth and Tsuda, 2014;Yan and Dong, 2014;Ding et al., 2018). ...
... An ethylene responserelated factor GbERF1-like gene contributed to the resistance to V. dahliae through positively regulating lignin synthesisrelated genes and enhancing the lignin content (Guo et al., 2016). Interestingly, GhUMC1 was identified to be involved in cotton resistance to V. dahliae through both the SA signalling pathway and lignin synthesis (Zhu et al., 2018). Additionally, other hosts of Verticillium pathogens can increase their resistance through lignin deposition in the secondary cell wall or vascular tissue. ...
... Many reports have shown that cotton plant defence against V. dahliae involves SA and lignin molecules (Sun et al., 2014;Zhang et al., 2017;Zhu et al., 2018). In the present study, the knockdown of GhWATs promoted accumulation of SA content, activated SA pathway-related gene expression and increased lignin accumulation in xylem sections, which facilitated plant resistance to pathogens. ...
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Verticillium wilt, caused by Verticillium dahliae, seriously limits cotton production. It is difficult to control this pathogen damage mainly due to the complexity of the molecular mechanism of plant resistance to V. dahliae. Here, we identified three homologous cotton Walls Are Thin (WAT) genes, which were designated as GhWAT1, GhWAT2, and GhWAT3. The GhWATs were predominantly expressed in the roots, internodes, and hypocotyls and induced by infection with V. dahliae and treatment with indole-3-acetic acid (IAA) and salicylic acid (SA). GhWAT1-, GhWAT2-, or GhWAT3-silenced plants showed a comparable phenotype and level of resistance with control plants, but simultaneously silenced three GhWATs (GhWAT123-silenced), inhibited plant growth and increased plant resistance to V. dahliae, indicating that these genes were functionally redundant. In the GhWAT123-silenced plants, the expression of SA related genes was significantly upregulated compared with the control, resulting in an increase of SA level. Moreover, the histochemical analysis showed that xylem development was inhibited in GhWAT123-silenced plants compared with the control. However, lignin deposition increased in the xylem of the GhWAT123-silenced plants compared to the control, and there were higher expression levels of lignin synthesis- and lignifications-related genes in the GhWAT123-silenced plants. Collectively, the results showed that GhWATs in triple-silenced plants acts as negative regulators of plant resistance against V. dahliae. The potential mechanism of the WATs functioning in the plant defence can modulate the SA biosynthesis and lignin deposition in the xylem.
... Earlier it was reported that lignin metabolism plays an important role in regulating cotton defense against V. dahliae (He et al., 2018b;Li et al., 2019;Xu et al., 2011;Zhu et al., 2018). To further reveal the biochemical mechanism responsible for enhanced susceptibility of GhLOX2-silenced plants to V. dahliae infection, we checked the expression pattern of lignin metabolism related genes GhCCoAOMT1-3, GhHCT1 and lignin contents at 15 dpi. ...
... Further, expression of lignin metabolism-related genes was not changed considerably in GhLOX2-silenced plants, while these genes were highly induced in WT plants. These results were consistent with other studies where reduced expression of lignin metabolism genes corresponds to susceptibility response in cotton against V. dahliae Zhu et al., 2018). ...
Article
Verticillium wilt is a major limiting factor for sustainable production of cotton but the mechanism of controlling this disease is still poorly understood. Lipoxygenase (LOX)- derived oxylipins have been implicated in defense responses against diverse pathogens; however there is limited information about the functional characterization of LOXs in response to Verticillium dahliae infection. In this study, we report the characterization of a cotton LOX gene, GhLOX2 , which phylogenetically clustered into 13-LOX subfamily and is closely related to Arabidopsis LOX2 gene. GhLOX2 was predominantly expressed in leaves and strongly induced following V . dahliae inoculation and treatment of methyl jasmonate (MeJA). RNAi-mediated knock-down of GhLOX2 enhanced cotton susceptibility to V . dahliae and was coupled with suppression of jasmonic acid (JA)-related genes both after inoculation with the cotton defoliating strain V991 or MeJA treatment. Interestingly, lignin contents, transcripts of lignin synthesis genes and H 2 O 2 contents were also decreased in GhLOX2 -silenced plants. This study suggests that GhLOX2 is involved in defense responses against infection of V . dahliae in cotton and supports that JA is one of the major defense hormones against this pathogen.
... In Arabidopsis, BOP1/2 promotes the expression of lignin biosynthetic genes, while, BP1 represses the expression of these lignin genes 41 . Recently, mounting evidence has shown that lignin accumulation confers an increased cotton plant resistance to V. dahliae 22,[24][25][26]42 . Thus, it will be interesting to confirm biochemically and genetically whether GhBOP1 promotes the expression of lignin biosynthetic To further investigate the function of GhBOP1 in lignin accumulation, we stained cotton stems with phloroglucinol-HCl. ...
... 7a, the lignin biosynthetic genes, PAL1, C4H1, 4CL1, C3H1, CCoMT1, and CAD5, showed significantly upregulation expression in overexpression plants compared with WT stems. In contrast, in RNAi plants, all these lignin biosynthesis genes showed downregulated expression, similar to previously reported results for plants inoculated with V. dahliae22,24,25,27,42 . ...
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In the plant response to pathogen infection, many genes' expression is temporally induced, while few spatially induced expression genes have been reported. Here, we show that GhBOP1 can autonomously expand expression from restrained tissue when Gossypium hirsutum plants are attacked by Verticillium dahliae, which is considered to be spatially induced expression. Loss- and gain-of-function analyses show that GhBOP1 is a positive regulator in the modulation of plant resistance to V. dahliae. Yeast two-hybrid assays, luciferase complementation imaging and GUS reporting show that GhBOP1 interaction with GhTGA3 promotes its activation activity, regulating the expression of down-stream defence-related genes. Moreover, the induced spatial expression of GhBOP1 is accompanied by GhBP1 repression. Both antagonistically regulate the lignin biosynthesis, conferring cotton plants enhanced resistance to V. dahliae. Taken together, these results demonstrate that GhBOP1 is an economic positive regulator participating in plant defence through both the GhBOP1-GhTGA3 module and lignin accumulation.
... Verticillium highly induces laccase GhLAC15 expression, and the cell walls of overexpressing plants enhance resistance to Verticillium wilt through a defense-mediated response that enhances lignification and increases arabinose and xylose accumulation [81]. GhUMC1, a divalent copper-binding protein, is an umecyanin-like gene involved in resistance to Verticillium cotton wilt through regulation of the JA signaling pathway and lignin metabolism [82]. Walls are thin (WAT) genes regulate SA metabolism and signaling by affecting polar transport of growth hormones to further enhance plant resistance to a variety of pathogens [83]. ...
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Cotton is an important economic crop. Fusarium and Verticillium are the primary pathogenic fungi that threaten both the quality and sustainable production of cotton. As an opportunistic pathogen, Fusarium causes various human diseases, including fungal keratitis, which is the most common. Therefore, there is an urgent need to study and clarify the resistance mechanisms of cotton and humans toward Fusarium in order to mitigate, or eliminate, its harm. Herein, we first discuss the resistance and susceptibility mechanisms of cotton to Fusarium and Verticillium wilt and classify associated genes based on their functions. We then outline the characteristics and pathogenicity of Fusarium and describe the multiple roles of human neutrophils in limiting hyphal growth. Finally, we comprehensively compare the similarities and differences between animal and plant resistance to Fusarium and put forward new insights into novel strategies for cotton disease resistance breeding and treatment of Fusarium infection in humans.
... Glycine-rich proteins have been found in the cell walls of many higher plants, and they reportedly accumulate in vascular tissues; their synthesis is thought to be part of a defensive mechanism (Mousavi and Hotta, 2005). Meanwhile, 2-oxoisovalerate dehydrogenase transcription was significantly induced by water stress in drought-susceptible and drought-tolerant wheat (Li, 2012), and suppression of the cotton umecyanin-like gene GhUMC1 weakens the jasmonate signaling pathway and downregulates lignin synthesis, increasing seedling susceptibility to verticillium wilt (Zhu et al., 2018). Given these findings, these four up-regulated proteins may play an important role in pathogen resistance. ...
Article
Bacterial wilt is a serious disease of potato (Solanum tuberosum L.) caused by the soil-borne pathogenic bacterium Ralstonia solanacearum. Detecting changes in protein abundance in potato plants in response to R. solanacearum is a pivotal step in uncovering the molecular interactions of plant pathogens. In this study, using the disease-resistant cultivar ‘Zhongshu 3’, we analyzed protein expression in potato seedlings inoculated with R. solanacearum every 12 h for a total of 72 h using isobaric tags for relative and absolute quantitation-based proteomics. Our results indicate that pathogenesis-related proteins, stressrelated proteins, non-specific lipid transfer proteins, small heat shock proteins, and osmotin-like proteins were up-regulated in response to pathogen infection at different time points. The accumulation of these proteins in response to biotic stress suggests that these proteins play an important role in pathogen resistance. Our findings will provide an important basis for characterizing the role of these proteins in increasing plant resistance to pathogens and in breeding bacterial wilt-resistant plants.
... [27][28][29]46 Silencing the AtBCB gene leads to a reduction of lignin accumulation. 47 Cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) related to lignin biosynthesis and its transcriptional regulation are uncovered based on Zhong (2015). 48 LpCPC may affect the content of the soluble phenol and lignin under stress, the content of the soluble phenol and the lignin was detected in the roots and stems of transgenic Nicotiana benthamiana and wildtype. ...
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Lilium Pumilum with wide distribution is highly tolerant to salinity. The blue copper protein LpCPC (Lilium pumilum Cucumber Peeling Cupredoxin) gene was cloned from Lilium pumilum, which has the conserved regions of type I copper protein. Moreover, LpCPC has the closest relation to CPC from Actinidia chinensis using DNAMAN software and MEGA7 software. qRT-PCR indicated that LpCPC expression was higher in root and bulb of Lilium pumilum, and the expression of the LpCPC gene increased and reached the highest level at 12 h in bulbs under 20 mM NaHCO3. The transgenic yeast was more tolerant compared with the control under NaHCO3 stress. Compared with the wild type, overexpressing plants indicated a relatively lower degree of wilting. In addition, the chlorophyll content, soluble phenol content, and lignin content of overexpressing lines were higher than that of wild-type, whereas the relative conductivity of overexpressing plants was significantly lower than that of wild-type plants. Expression of essential genes including NHX1 and SOS1 in salt stress response pathways are steadily higher in overexpression tobacco than that in wild-types. Transgenic lines had much higher levels of CCR1 and CAD, which are involved in lignin production, compared with wild-type lines. The yeast two-hybrid technique was applied to screen probable interacting proteins interacting with LpCPC. Eight proteins interacted with LpCPC were screened, and five of which were demonstrated to be associated with plant salinity resistance. Overall, the role of gene LpCPC is mediating molecule responses in increasing saline-alkali stress resistance, indicating that it is an essential gene to enhance salt tolerance in Lilium pumilum. © 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.
... Stems are the central part of the plant, connected with the leaves up and the roots down, and transport important substances for long-distance cell-to-cell communication. Besides, the stem is involved in carbon storage and remobilization of plants, influencing the control of plant's carbon metabolism [1][2][3]. Therefore, understanding the regulation mechanism of stem differentiation is instrumental. The stem development is moderated by an elaborated regulation network which has been well elucidated in Arabidopsis and woody species [4,5]. ...
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The stem is an important organ in supporting plant body, transporting nutrients and communicating signals for plant growing. However, studies on the regulation of stem development in tomato are rather limited. In our study, we demonstrated that SlHB8 negatively regulated tomato stem development. SlHB8 belongs to homeo domain-leucine zipper Class III gene family transcription factors and expressed in all the organs examined including root, stem, leaves, flower, and fruit. Among these tissues, SlHB8 showed stable high expression level during tomato stem development. Overexpression of SlHB8 gene decreased stem diameter with inhibited xylem width and xylem cell layers, while loss of function of SlHB8gene increased the stem diameter and xylem width. The contents of lignin were decreased both in leaves and stems of SlHB8 overexpression plants. RNA-seq analysis on the stems of wild type and SlHB8 transgenic plants showed that the 116 DEGs (differential expressed genes) with reversible expression profiles in SlHB8-ox and SlHB8-cr plants were significantly enriched in the phenylpropanoid biosynthesis pathway and plant-pathogen pathway which were related to lignin biosynthesis and disease resistance. Meanwhile, the key genes involved in the lignin biosynthesis pathway such as SlCCR (cinnamoyl-CoA reductase), SlCYP73A14/C4H (cinnamate 4-hydroxylase), SlC3H (coumarate 3-hydroxylase) and SlCAD (cinnamoyl alcohol dehydrogenase) were down-regulated in both stem and leaves of SlHB8 overexpression plants, indicating a negative regulatory role of SlHB8 in the lignin biosynthesis and stem development.
... For instance, overexpression of GhLac1 increased the resistance of cotton against V. dahliae by promoting lignin synthesis (Hu et al. 2018). GhUMC1 was identified to involve in cotton resistance to V. dahliae through the regulation to both lignin synthesis and the SA pathway (Zhu et al. 2018). Besides, overexpression of GbERF1-like in cotton lines enhanced the resistance to V. dahliae by positive regulation of lignin synthesis (Guo et al. 2016). ...
Article
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Verticillium wilt and Fusarium wilt, caused by Verticillium dahliae and Fusarium oxysporum, respectively, severely restricted cotton production. It is difficult to control the damage due to large unknown about the interaction between plants and pathogens. Here, we reported the identification of cotton Bsr-k1, which was also designated as GhBsr-k1. The GhBsr-k1 was expressed in the root, stem and leaf. Silencing of GhBsr-k1 improved plant resistance to both V. dahliae and F. oxysporum. In the GhBsr-k1-silenced plants, the expression of phenylpropanoid metabolism related genes were significantly up-regulated comparing with the control, which resulting the increase of lignin deposition. Moreover, the expression level of PALs exhibited highly negative correlation with GhBsr-k1. Collectively, the results suggested GhBsr-k1 acted as a negative regulator during plant resistance against V. dahliae and F. oxysporum. The potential mechanisms beyond GhBsr-k1 in plant defense may related to the regulation of the transcript of lignin deposition genes (GhPAL2, GhPAL5).
... Lignin plays a critical role in cotton resistance to Verticillium dahliae: the resistant cotton varieties show a high level of lignin deposition and ligninlike phenolic polymers, (Smit and Dubery 1997) and the lignin content is positively correlated with resistance to V. dahliae (Xu et al. 2011). The GhDIR1, GbERF1-like, GhUMC1, GhWAT and GhLAC15 genes improve cotton resistance to V. dahliae via activating or strengthening lignin synthesis (Guo et al. 2016;Shi et al. 2012;Tang et al. 2019b;Zhang et al. 2019;Zhu et al. 2018). We hypothesize that lignin synthesis-related genes contributed to the cotton resistance to Fov through positively regulating lignin synthesis and enhancing the lignin content. ...
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Fusarium wilt, caused by the fungus Fusarium oxysporum Schlecht. f. sp. vasinfectum (Fov) is a destructive soil-borne cotton disease. To profile the genes and pathways responding to Fov infection, we compared transcriptomic responses before and after F. oxysporum inoculation in a highly resistant cotton cultivar, Yumian21, and a highly susceptible cultivar, Jimian11. Although the overall gene expression pattern was downregulated in both cultivars, the global gene expression in the resistant cultivar was stronger than that in the susceptible cultivar. In addition, the expressed genes of two cultivars mostly differed in “cellular process,” “single-organism process,” “metabolic process,” and “response to stimulus” functional groups in the biological process Gene Ontology category: the upregulated differentially expressed genes (DEG) were largely enriched in the resistant cultivar, while the downregulated DEGs were largely enriched in the susceptible cultivar. Phenylpropanoid biosynthesis and phenylalanine metabolism are the key metabolic pathways in cotton in response to Fov. We found that lignin plays a potential role in cotton resistance to Fov. Two coding genes, caffeic acid 3-O-methyltransferase and peroxidase2, as well as the two transcription factors MYB46 and MYB86, are possibly involved in the accumulation and synthesis of lignin. Furthermore, the result showed that the quantification of lignin could be potentially used as a selection tool to identify Fusarium wilt resistant cotton.
... MYB-related transcription factors regulate different branches of flavonoid metabolism in plants (Azuma et al. 2012). Prupe.5G114200 is annotated as umecyanin or umecyanin-like, which is plant-specific phytocyanin involved in the electron transfer activity of the copper binding (Zhu et al., 2018) and might be associated with plant defensive mechanism to metal stress (Posmyk et al., 2009). Prupe.5G114700 was annotated as mitogenactivated protein kinase 7, which is reported to be activated by environmental stress in peach and sweet cherry (Raingeaud et al. 1996). ...
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Genetic control and location of QTLs associated with phytochemical compounds and fruit quality in peach [Prunus persica (L.) Batsch] were evaluated using an F2 mapping population (ZC2) derived from cross between ‘Zin Dai’ × ‘Crimson Lady’. Antioxidant capacity, accumulation of phenolic compounds (total phenolics, flavonoids, and anthocyanins), and fruit quality traits (fruit diameter, fruit weight, fruit firmness, soluble solids concentration, titratable acidity, and ripening index) were evaluated for 2 years (2013–2014). Fourteen QTLs for phytochemical and fruit quality traits were identified in 5 LGs, with two QTL clusters (qPC.ZC_5.1_2014 and qPC.ZC_7.1) observed on LGs 5 and 7. The QTL cluster qPC.ZC_5.1_2014 was associated with antioxidant capacity, flavonoids, anthocyanin content, and SSC, while qPC.ZC_7.1 exhibited association only with flavonoids and fruit ripening index. QTL clusters associated with different fruit quality traits were observed on LGs 1 and 6. Candidate gene analyses of the QTL cluster on LG5 (qPC.ZC_5.1_2014) revealed 14 candidate genes in peach with functional annotation related to biosynthesis pathway of phytochemical compounds.
... GhDIR1 encodes a putative dirigent protein and its overexpression leads to increases in lignin content in transgenic cotton plants, which display enhanced tolerance to V. dahliae infection [38]. GhUMC1, an umecyanin-like gene in cotton, is involved in the resistance of cotton plants to V. dahliae through regulation of the JA signalling pathway and lignin metabolism [39]. ...
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Verticillium dahliae is a soil-borne hemibiotrophic fungus that can lead to plant vascular disease and significant economic loss worldwide. Its hosts include over 400 dicotyledon plant species, such as annual herbs, perennials, and woody plants. The average yield loss of cotton crop caused by Verticillium wilt is approximately 10%–35%. As the control of this disease is an urgent task for many countries, further understanding of the interaction between plants and V. dahliae is essential. Fungi can promote or inhibit plant growth, which is important; however, the most important relationship between plants and fungi is the host–pathogen relationship. Plants can become resistant to V. dahliae through diverse mechanisms such as cell wall modifications, extracellular enzymes, pattern recognition receptors, transcription factors, and salicylic acid (SA)/jasmonic acid (JA)/ethylene (ET)-related signal transduction pathways. Over the last decade, several studies on the physiological and molecular mechanisms of plant resistance to V. dahliae have been undertaken. In this review, many resistance-related genes are summarised to provide a theoretical basis for better understanding of the molecular genetic mechanisms of plant resistance to V. dahliae. Moreover, it is intended to serve as a resource for research focused on the development of genetic resistance mechanisms to combat Verticillium wilt.
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In environmental conditions, crop plants are extremely affected by multiple abiotic stresses including salinity, drought, heat, and cold, as well as several biotic stresses such as pests and pathogens. However, salinity, drought, and wilt diseases (e.g., Fusarium and Verticillium) are considered the most destructive environmental stresses to cotton plants. These cause severe growth interruption and yield loss of cotton. Since cotton crops are central contributors to total worldwide fiber production, and also important for oilseed crops, it is essential to improve stress tolerant cultivars to secure future sustainable crop production under adverse environments. Plants have evolved complex mechanisms to respond and acclimate to adverse stress conditions at both physiological and molecular levels. Recent progresses in molecular genetics have delivered new insights into the regulatory network system of plant genes, which generally includes defense of cell membranes and proteins, signaling cascades and transcriptional control, and ion uptake and transport and their relevant biochemical pathways and signal factors. In this review, we mainly summarize recent progress concerning several resistance-related genes of cotton plants in response to abiotic (salt and drought) and biotic (Fusarium and Verticillium wilt) stresses and classify them according to their molecular functions to better understand the genetic network. Moreover, this review proposes that studies of stress related genes will advance the security of cotton yield and production under a changing climate and that these genes should be incorporated in the development of cotton tolerant to salt, drought, and fungal wilt diseases (Verticillium and Fusarium).
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In environmental conditions, crop plants are extremely affected by multiple abiotic stresses including salinity, drought, heat, and cold, as well as several biotic stresses such as pests and pathogens. However, salinity, drought, and wilt diseases (e.g., Fusarium and Verticillium) are considered the most destructive environmental stresses to cotton plants. These cause severe growth interruption and yield loss of cotton. Since cotton crops are central contributors to total worldwide fiber production, and also important for oilseed crops, it is essential to improve stress tolerant cultivars to secure future sustainable crop production under adverse environments. Plants have evolved complex mechanisms to respond and acclimate to adverse stress conditions at both physiological and molecular levels. Recent progresses in molecular genetics have delivered new insights into the regulatory network system of plant genes, which generally includes defense of cell membranes and proteins, signaling cascades and transcriptional control, and ion uptake and transport and their relevant biochemical pathways and signal factors. In this review, we mainly summarize recent progress concerning several resistance-related genes of cotton plants in response to abiotic (salt and drought) and biotic (Fusarium and Verticillium wilt) stresses and classify them according to their molecular functions to better understand the genetic network. Moreover, this review proposes that studies of stress related genes will advance the security of cotton yield and production under a changing climate and that these genes should be incorporated in the development of cotton tolerant to salt, drought, and fungal wilt diseases (Verticillium and Fusarium).
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Plants evolve effective mechanisms to protect themselves against multiple stresses and employ jasmonates (JA) as vital defense signals to defend against pathogen infection. Accumulation of JA induced by signals from biotic and abiotic stresses, results in degradation of Jasmonate-ZIM-Domain (JAZ) proteins, and then de-repressed the JAZ-repressed transcription factors (such as MYC2) to activate defense responses and developmental processes. Here, we characterized a JAZ family protein, GhJAZ2, from cotton (Gossypium hirsutum) which was induced by methyl jasmonate (MeJA) and inoculation of Verticillium dahliae. Over-expression of GhJAZ2 in cotton impairs the sensitivity to JA, decreases the expression level of JA-response genes (GhPDF1.2 and GhVSP) and enhances the susceptibility to V. dahliae and insect herbivory. Yeast two-hybrid and BiFC assays showed that GhJAZ2 may be involved in regulation of cotton disease resistance by interacting with more disease response proteins, like pathogenesis-related protein GhPR10, dirigent-like protein GhD2, NBS-LRR disease resistant protein GhR1, and a basic helix-loop-helix transcription factor GhbHLH171. Unlike MYC2, over-expression of GhbHLH171 in cotton activates the JA synthesis and signaling pathway, and improves plant tolerance to fungus V. dahliae. Molecular and genetic evidences showed that GhJAZ2 could interact with GhbHLH171 and inhibit its transcriptional activity, as a result, restrain the JA-mediated defense response. This study provides new insights into the molecular mechanisms of GhJAZ2 in the regulation of cotton defense response. This article is protected by copyright. All rights reserved.