Comprehensive analyses of the citrus WRKY gene family involved in the metabolism of fruit sugars and organic acids
Mingfei Zhang, Wen Lu, Xinxia Yang, Li Qin, Xingyu Lin, Kexin Liu, Chunmei Yin, Bo Xiong, Ling Liao, Guochao Sun, Siya He, Jiaxian He, Xun Wang, Zhihui Wang
Abstract
Sugars and organic acids are the main factors determining the flavor of citrus fruit. The WRKY transcription factor family plays a vital role in plant growth and development. However, there are still few studies about the regulation of citrus WRKY transcription factors (CsWRKYs) on sugars and organic acids in citrus fruit. In this work, a genome-wide analysis of CsWRKY s was carried out in the citrus genome, and a total of 81 CsWRKY s were identified, which contained conserved WRKY motifs. Cis -regulatory element analysis revealed that most of the CsWRKY promoters contained several kinds of hormone-responsive and abiotic-responsive cis -elements. Furthermore, gene expression analysis and fruit quality determination showed that multiple CsWRKY s were closely linked to fruit sugars and organic acids with the development of citrus fruit. Notably, transcriptome co-expression network analysis further indicated that three CsWRKY s, namely, CsWRKY3 , CsWRKY47 , and CsWRKY46 , co-expressed with multiple genes involved in various pathways, such as Pyruvate metabolism and Citrate cycle. These CsWRKYs may participate in the metabolism of fruit sugars and organic acids by regulating carbohydrate metabolism genes in citrus fruit. These findings provide comprehensive knowledge of the CsWRKY family on the regulation of fruit quality.