AUTHOR=Nan Hong , Li Wei , Lin Yang-lei , Gao Li-zhi 

TITLE=Genome-Wide Analysis of WRKY Genes and Their Response to Salt Stress in the Wild Progenitor of Asian Cultivated Rice, Oryza rufipogon

JOURNAL=Frontiers in Genetics

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.00359

DOI=10.3389/fgene.2020.00359

ISSN=1664-8021

ABSTRACT=<p>The <italic>WRKY</italic> gene family is widespread in plants, which plays key roles in plant development and stress response. Although <italic>WRKY</italic> transcription factors have been widely characterized in many plants, a genome-wide analysis of the <italic>WRKY</italic> gene family is lacking in <italic>Oryza rufipogon</italic>. In this study, we identified 101 <italic>O. rufipogon WRKY</italic> (<italic>OrWRKY</italic>) transcription factors, which were further classified into eight subgroups. Phylogenetic analysis showed that <italic>OrWRKY</italic> transcription factors were supported by highly conserved motifs and gene structures. Chromosomal distribution of <italic>OrWRKY</italic>s indicated that most genes were dispersed on all 12 chromosomes, especially enriched on Chromosome 1. Syntenic analysis revealed that 69 (68.3%) genes were derived from either segmental (49) or tandem duplication events (20), suggesting a pivotal role of segmental duplications. We totally characterized 39 orthologous gene pairs between <italic>Oryza sativa</italic> ssp. <italic>japonica WRKY</italic> (<italic>OsjWRKY</italic>) and <italic>OrWRKY</italic> genes. We performed quantitative real-time polymerase chain reaction (qRT-PCR) experiments to validate tissue-specific and differential expression of the <italic>OrWRKY</italic>s and corresponsive expression of the <italic>OrWRKY</italic>s in response to salt stresses in leaves and roots. This study provides a new insight on the evolution of the <italic>WRKY</italic> gene family in <italic>O. rufipogon</italic> and will help further functional characterization of candidate genes toward wild rice germplasm exploration for rice genetic improvement programs.</p>