TaWRKY13-A Serves as a Mediator of Jasmonic Acid-Related Leaf Senescence by Modulating Jasmonic Acid Biosynthesis

Abstract

Leaf senescence is crucial for crop yield and quality. Transcriptional regulation is a key step for integrating various senescence-related signals into the nucleus. However, few regulators of senescence implicating transcriptional events have been functionally characterized in wheat. Based on our RNA-seq data, we identified a WRKY transcription factor, TaWRKY13-A, that predominately expresses at senescent stages. By using the virus-induced gene silencing (VIGS) method, we manifested impaired transcription of TaWRKY13-A leading to a delayed leaf senescence phenotype in wheat. Moreover, the overexpression (OE) of TaWRKY13-A accelerated the onset of leaf senescence under both natural growth condition and darkness in Brachypodium distachyon and Arabidopsis thaliana. Furthermore, by physiological and molecular investigations, we verified that TaWRKY13-A participates in the regulation of leaf senescence via jasmonic acid (JA) pathway. The expression of JA biosynthetic genes, including AtLOX6, was altered in TaWRKY13-A-overexpressing Arabidopsis. We also demonstrated that TaWRKY13-A can interact with the promoter of AtLOX6 and TaLOX6 by using the electrophoretic mobility shift assay (EMSA) and luciferase reporter system. Consistently, we detected a higher JA level in TaWRKY13-A-overexpressing lines than that in Col-0. Moreover, our data suggested that TaWRKY13-A is partially functional conserved with AtWRKY53 in age-dependent leaf senescence. Collectively, this study manifests TaWRKY13-A as a positive regulator of JA-related leaf senescence, which could be a new clue for molecular breeding in wheat.

Evaluation of aphid resistance on different rose cultivars and transcriptome analysis in response to aphid infestation

“…However, although the JA level was transiently increased at the early stages of aphid feeding on an aphid-resistant sorghum cultivar, exogenous application of JA promoted improved aphid feeding and colonization [ 43 ], which indicated a dichotomous role of JA in aphid resistance. Interestingly, the expression levels of LOX genes, which catalyze the first committed step of JA biosynthesis, are generally regulated by WRKY TFs [ 44 , 45 ], which were up-regulated by aphid infestation in this study (Fig. 5 ; Table 4 ).…”

Transcriptome Analysis of Early Senescence in the Post-Anthesis Flag Leaf of Wheat (Triticum aestivum L.)

“…In the past 20 years, WRKY TFs have been broadly investigated in plants, and they were extensively proven to be involved in numerous physiological processes, including leaf senescence. For example, WRKY14 , WRKY2 , WRKY53 , WRKY13, WRKY40 , and WRKY42 are putative SAGs, as their close homologs are positive regulators of JA- and ET-mediated signaling [ 23 , 24 , 25 , 68 ]. Likewise, in the present study, these genes were upregulated as the flag leaf senesced.…”

“…EIN3 (a key transcription factor in the ethylene signaling pathway) and ORE1/NAC2 accelerate chlorosis during ethylene-mediated leaf senescence by directly activating chlorophyll catabolic genes in Arabidopsis [ 22 ]. TaWRKY13-A , TaWRKY40-D, and TaWRKY42-B have also been reported to be involved in the regulation of leaf senescence and related to the JA or ABA pathway [ 23 , 24 , 25 ]. In conclusion, NAC and WRKY transcription factors seem to be inextricably linked with plant hormones, such as ABA, JA, and ethylene, and play crucial roles in senescence.…”

New Advances in the Regulation of Leaf Senescence by Classical and Peptide Hormones

“…Several factors involve in regulation of leaf senescence through modulating JA biosynthesis. TaWRKY13-A and TaWRKY42-B facilitate the onset and progression of leaf senescence by promoting the expression of LOX genes, which consequently induces accumulation of JA content in wheat (Zhao et al, 2020 ; Qiao et al, 2021 ). miR139 indirectly controls JA biosynthesis via changing TCPs activity, thus overexpression of miR139 delays leaf senescence (Schommer et al, 2008 ).…”