Identification of the group IIa WRKY subfamily and the functional analysis of GhWRKY17 in upland cotton (Gossypium hirsutum L.)

Abstract

WRKY transcription factors play important roles in plant defense, stress response, leaf senescence, and plant growth and development. Previous studies have revealed the important roles of the group IIa GhWRKY genes in cotton. To comprehensively analyze the group IIa GhWRKY genes in upland cotton, we identified 15 candidate group IIa GhWRKY genes in the Gossypium hirsutum genome. The phylogenetic tree, intron-exon structure, motif prediction and Ka/Ks analyses indicated that most group IIa GhWRKY genes shared high similarity and conservation and underwent purifying selection during evolution. In addition, we detected the expression patterns of several group IIa GhWRKY genes in individual tissues as well as during leaf senescence using public RNA sequencing data and real-time quantitative PCR. To better understand the functions of group IIa GhWRKYs in cotton, GhWRKY17 (KF669857) was isolated from upland cotton, and its sequence alignment, promoter cis-acting elements and subcellular localization were characterized. Moreover, the over-expression of GhWRKY17 in Arabidopsis up-regulated the senescence-associated genes AtWRKY53, AtSAG12 and AtSAG13, enhancing the plant’s susceptibility to leaf senescence. These findings lay the foundation for further analysis and study of the functions of WRKY genes in cotton.

Characterization and functional analysis of GhWRKY42, a group IId WRKY gene, in upland cotton (Gossypium hirsutum L.)

“…The onion epidermal cells harboring the 35S- GhWRKY42 ::GFP construct emitted green fluorescence predominantly in nuclei (Fig. 3a ), whereas 35S::GFP fluorescence occurred widely throughout the cell [ 24 ].

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“…6b ). We further examined the expression level of GhWRKY42 in true leaves of CCRI74 plants at different senescence stages [ 24 ]; the results revealed that the transcript levels of GhWRKY42 gradually increased as the leaves aged (Fig. 6c ).…”

“…We collected cotyledon samples weekly at eight different developmental stages, ranging from the flattened cotyledon stage to the completely aged stage. The expression patterns of GhWRKY42 were further evaluated in true leaves of the early-aging cotton variety CCRI74 at five aging stages, as described previously [ 24 ]. Each sample included material from eight different individual plants, and we performed three repetitions for each sample.…”

WRKY genes family study reveals tissue-specific and stress-responsive TFs in wild potato species

“…been found to play important roles under abiotic stresses, such as drought 8 , heat 63 , wounding 50 , and biotic constraints, such as bacteria 59 and viruses 64 . Tissue-specificity of WRKY genes has also been highlighted in different crops, such as pepper 58 , cotton 65 and soybean 66 , elucidating their role in developmental and functional processes. Our study investigated for the first time the stress response and tissue-specificity of WRKY genes in two wild potato species.…”

Identification, Expression, and Functional Analysis of the Group IId WRKY Subfamily in Upland Cotton (Gossypium hirsutum L.)

“…Gu et al performed a genome-wide identification of WRKY genes in cotton using Gossypium hirsutum sequences from the CottonGene database ( http://www.cottongen.org ) (Zhang et al, 2015 ; Gu et al, 2018b ). Thirty-four group IId WRKY genes were identified through phylogenetic analysis (Gu et al, 2018b ). In this study, the 34 group IId WRKY genes were used for further study.…”