Genome-Wide Analysis of the Banana WRKY Transcription Factor Gene Family Closely Related to Fruit Ripening and Stress.

Caihong Jia,Jihong Liu,Jingyi Wang,Juhua Liu,Jianbin Zhang,Biyu Xu,Zhuo Wang,Hongxia Miao,Zhiqiang Jin

doi:10.3390/plants11050662

Abstract

WRKY transcription factors (TFs) play an important role in plant responses to biotic and abiotic stress as well as in plant growth and development. In the present study, bioinformatics methods were used to identify members of the WRKY transcription factor family in the Musa acuminata (DH-Pahang) genome (version 2). A total of 164 MaWRKYs were identified and phylogenetic analysis showed that MaWRKYs could be categorized into three subfamilies. Overall, the 162 MaWRKYs were distributed on 11 chromosomes, and 2 genes were not located on the chromosome. There were 31 collinear genes from segmental duplication and 7 pairs of genes from tandem duplication. RNA-sequencing was used to analyze the expression profiles of MaWRKYs in different fruit development, ripening stages, under various abiotic and biotic stressors. Most of the MaWRKYs showed a variety of expression patterns in the banana fruit development and ripening stages. Some MaWRKYs responded to abiotic stress, such as low temperature, drought, and salt stress. Most differentially expressed MaWRKYs were downregulated during banana’s response to Foc TR4 infection, which plays an important role in physiological regulation to stress. Our findings indicate that MaWRKY21 directly binds to the W-box of the MaICS promoter to decrease MaICS transcription and then reduce the enzyme activity. These studies have improved our understanding of the molecular basis for the development and stress resistance of an important banana variety.

Highlights

WRKY transcription factors (TFs) are one of the largest families in plants and form integral parts of signaling webs that modulate many plant processes [1]
To analyze the evolutionary relationships among MaWRKYs, 164 MaWRKY proteins were aligned with AtWRKY proteins from Arabidopsis and OsWRKY proteins from rice, and an unrooted phylogenetic tree was constructed by MEGA7
We identified 164 MaWRKYs based on version 2 of the M. acuminata genome and 162

Summary

Introduction

WRKY transcription factors (TFs) are one of the largest families in plants and form integral parts of signaling webs that modulate many plant processes [1]. There are one or two conserved domains with a length of 60 amino acid residues in the amino acid sequence of WRKY transcription factors, which includes an N-terminal DNA binding motif and a. Plant WRKY transcription factors can be divided into three categories: the first family contains two WRKY domains and two zinc finger structures with. The amino acid sequence of the zinc finger motif is CX4–5 CX22–23 HXH (C is cysteine, X is any amino acid, X4–5 is any 4–5 amino acid, X22–23 is any 22–23 amino acid, and H is histidine) or CX7 CX23 HXC (X7 is any 7 amino acid and X23 is any 23 amino acid). With the completion of plant genome sequencing, more and more WRKY gene families have been identified at the whole genome level, such as in apple [4], lily [5], Ricinus communis [6], carrot [7], and cotton [8]

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Conclusion