GhJAZ2 negatively regulates cotton fiber initiation by interacting with the R2R3‐MYB transcription factor GhMYB25‐like

Abstract

Jasmonic acid (JA) signaling has been well studied in Arabidopsis. Most reports focus on the role of JA in biological pathways, such as stress resistance, trichome initiation and anthocyanin accumulation. The JASMONATE ZIM-DOMAIN (JAZ) protein is one of the important repressors in the JA signaling pathway. Previous studies showed that JA functions in fiber initiation and elongation, but little is known about how JAZ genes function in fiber development. In this study, a cotton JAZ protein (GhJAZ2) containing a highly conserved TIFY motif and a C-terminal Jas domain was identified, and its function during cotton fiber development was analysed. Gene expression analysis showed that GhJAZ2 was preferentially expressed in the root, hypocotyl, flower and ovule 1 day before anthesis. Overexpression of GhJAZ2 inhibited both lint and fuzz fiber initiation, and reduced the fiber length. Yeast two-hybrid assays showed that GhJAZ2 interacted with the R2R3-MYB transcription factors GhMYB25-like and GhGL1, the bHLH transcription factor GhMYC2, the WD repeat protein GhWD40 and the unknown protein GhJI1. Among these transcription factors, previous studies showed that downregulation of GhMYB25-like leads to a fiberless phenotype in cotton seeds. Molecular and genetic evidence showed that the GhJAZ2 protein suppresses fiber initiation in the overexpressing lines by interacting with GhMYB25-like and suppressing GhMYB25-like activity. Our results suggested that GhJAZ2 functions as a primary transcription repressor during lint and fuzz fiber initiation by interacting with GhMYB25-like, GhGL1, GhMYC2, GhWD40 and GhJI1 to regulate the JA signaling pathway.

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

“…Increasingly, evidence is revealing that JA-downstream TFs mediate the specificity of JA responses. Examples include: the basic helix-loop-helix (bHLH) TF family in plant defense responses and freezing tolerance (19,(39)(40)(41)(42)(43)(44); MYB TFs in stamen development, anthocyanin biosynthesis, fiber and trichome initiation (45)(46)(47); YAB TF family in anthocyanin biosynthesis (48); APETALA2 (AP2) TFs in regulation flower time (22); and WRKY TFs in senescence (49). Different JA-responsive TFs seem to be suppressed by particular JAZ proteins, suggesting that the diversity of JA responses could result from specific JAZ-TF interactions.…”

GhJAZ2 attenuates cotton resistance to biotic stresses via the inhibition of the transcriptional activity of GhbHLH171

“…Previously, we have identified a cotton JAZ gene ( GhJAZ2 ) which is expressed in plants responsive to biotic and abiotic stresses (Xu et al ., , Zhu L et al ., ). Furthermore, it has also been identified as a negative regulator in cotton fibre initiation by suppression of GhMYB25‐like (Hu et al ., ). To elucidate the putative role of GhJAZ2 in the JA‐mediated defence to V. dahliae in cotton, we analysed the expression of GhJAZ2 in roots on V. dahliae infection and on treatment with methyl jasmonate (MeJA) and salicylic acid (SA).…”

“…To better understand the roles of GhJAZ2 in JA signalling and the immune response, transgenic cotton lines with the up‐regulation or knock‐down of the expression of GhJAZ2 were generated via overexpression and RNA interference (RNAi), respectively. We have demonstrated that GhJAZ2 is a negative regulator in the inhibition of JA‐induced seedling growth (Hu et al ., ). Moreover, in comparison with the wild‐type, less anthocyanin accumulation could be found in the cotyledon petioles of two GhJAZ2 ‐overexpressing lines (J9 and J92) with or without MeJA treatment.…”

Unraveling Cotton Fiber Development Using Fiber Mutants in the Post‐Genomic Era

“…Fuzz fibers are usually <5 mm in length and remain attached to the seeds after ginning (Zhang et al, 2007;Mauney, 2015). Currently, numerous naturally occurring cotton fiber mutants have been identified globally and characterized at the genetic, gene expression, and, more recently, genetic mapping (map-based cloning) levels (Rong et al, 2005;Hinchliffe et al, 2011;Kim et al, 2013a;Wang et al, 2014a;Naoumkina et al, 2015;Hu et al, 2016;Wan et al, 2016;Thyssen et al, 2017;Zhu et al, 2018). It is worth noting that it is difficult and often unpractical to differentiate fuzz fibers from extremely short (<6 mm) lint fibers before or after ginning.…”

“…Hu et al (2016) studied jasmonates, including jasmonic acid, and their relationship with fiber initiation using a variety of fiber mutants including n 2 and XZ142 fl. Hu et al (2016) studied jasmonates, including jasmonic acid, and their relationship with fiber initiation using a variety of fiber mutants including n 2 and XZ142 fl.…”