Putative WRKYs associated with regulation of fruit ripening revealed by detailed expression analysis of the WRKY gene family in pepper

Abstract

WRKY transcription factors play important roles in plant development and stress responses. Here, global expression patterns of pepper CaWRKYs in various tissues as well as response to environmental stresses and plant hormones were systematically analyzed, with an emphasis on fruit ripening. The results showed that most CaWRKYs were expressed in at least two of the tissues tested. Group I, a subfamily of the entire CaWRKY gene family, had a higher expression level in vegetative tissues, whereas groups IIa and III showed relatively lower expression levels. Comparative analysis showed that the constitutively highly expressed WRKY genes were conserved in tomato and pepper, suggesting potential functional similarities. Among the identified 61 CaWRKYs, almost 60% were expressed during pepper fruit maturation, and the group I genes were in higher proportion during the ripening process, indicating an as-yet unknown function of group I in the fruit maturation process. Further analysis suggested that many CaWRKYs expressed during fruit ripening were also regulated by abiotic stresses or plant hormones, indicating that these CaWRKYs play roles in the stress-related signaling pathways during fruit ripening. This study provides new insights to the current research on CaWRKY and contributes to our knowledge about the global regulatory network in pepper fruit ripening.

Genome-wide analysis of WRKY gene family in the sesame genome and identification of the WRKY genes involved in responses to abiotic stresses

“…Six of these genes (SiWRKY16, SiWRKY21, SiWRKY22, SiWRKY29, SiWRKY39, and SiWRKY58) were highly expressed in all sesame tissues. Highly expressed WRKY genes usually play important roles in plant development [45]. Therefore, we concluded that the 15 highly expressed SiWRKY genes might be important regulatory factors in sesame development, although further studies are required to verify the function of these genes.…”

Natural variations in the MYB transcription factor MYB31 determine the evolution of extremely pungent peppers

“…Large‐scale QTL identification and genome‐wide association study (GWAS) strategies have been previously adopted to detect QTLs or genes associated with the control of variations in CAPD content among inter‐ and intraspecific varieties, and the detected QTLs varied among the populations used for analysis (Blum et al ., ; Ben‐Chaim et al ., ; Ogawa et al ., ; Nimmakayala et al ., ; Han et al ., ). Although the functions of AT3 , Kas , CoMT , AMT and CaMYB31 are related to CAPD biosynthesis (Stewart et al ., ; Abraham‐Juarez et al ., ; Gururaj et al ., ; Arce‐Rodríguez & Ochoa‐Alejo, ), only a few CAPD content‐related QTLs have been cloned and functionally verified based on fine mapping (Cheng et al ., ; Lee et al ., ; Nimmakayala et al ., ; Han et al ., ). Recently, recombinant inbred lines (RILs) and F 2 plants derived from a cross between the nonpungent C. annuum accession ‘YCM334’ and the pungent C. annuum cultivar ‘Tean’ were used to identify the nonpungency locus Pun3 on chromosome 7 (Han et al ., ).…”

TaWRKY51 promotes lateral root formation through negative regulation of ethylene biosynthesis in wheat (Triticum aestivum L.)

“…The WRKY TFs are known to play critical roles in biotic and abiotic stress responses, such as pathogen infection (Liu et al, 2005;Mao et al, 2011;Chen et al, 2013;Dey et al, 2014), high salt (Niu et al, 2012;Liang et al, 2017), drought stress (Luo et al, 2013;Sun et al, 2015;Li et al, 2017), oxidative stress , nutrient stress (Chen et al, 2009;Su et al, 2015;Dai et al, 2016) and high temperature (Cai et al, 2015;He et al, 2016). In addition to their important role in stress responses, WRKYs are also involved in a wide range of plant growth and development processes, such as seed dormancy and germination (Luo et al, 2005;Zhang et al, 2011;Ding et al, 2014), seed size (Gu et al, 2017), fruit maturation (Cheng et al, 2016;Ye et al, 2017) and senescence (Besseau et al, 2012;Meng et al, 2013). Recently, an increasing number of data indicate that some WRKY genes are responsive to phytohormones such as abscisic acid (ABA) and gibberellic acid (GA), thereby regulating plant growth and development .…”