AUTHOR=Zhu Shousong , Fan Ruochen , Xiong Xi , Li Jianjun , Xiang Li , Hong Yuhui , Ye Yiwei , Zhang Xiaofei , Yu Xiaohui , Chen Yinhua 

TITLE=MeWRKY IIas, Subfamily Genes of WRKY Transcription Factors From Cassava, Play an Important Role in Disease Resistance

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.890555

DOI=10.3389/fpls.2022.890555

ISSN=1664-462X

ABSTRACT=<p>Cassava (<italic>Manihot esculenta</italic> Crantz) is an important tropical crop for food, fodder, and energy. Cassava bacterial blight (CBB) caused by <italic>Xanthomonas axonopodis</italic> pv. <italic>manihotis</italic> (<italic>Xam</italic>) occurs in all cassava growing regions and threatens global cassava production. WRKY transcription factor family plays the essential roles during plant growth, development, and abiotic or biotic stress. Particularly, previous studies have revealed the important role of the group IIa <italic>WRKY</italic> genes in plant disease resistance. However, a comprehensive analysis of group IIa subfamily in cassava is still missing. Here, we identified 102 <italic>WRKY</italic> members, which were classified into three groups, I, II, and III. Transient expression showed that six <italic>MeWRKY IIas</italic> were localized in the nucleus. <italic>MeWRKY IIas</italic> transcripts accumulated significantly in response to SA, JA, and <italic>Xam</italic>. Overexpression of <italic>MeWRKY27</italic> and <italic>MeWRKY33</italic> in <italic>Arabidopsis</italic> enhanced its resistance to <italic>Pst</italic> DC3000. In contrast, silencing of <italic>MeWRKY27</italic> and <italic>MeWRKY33</italic> in cassava enhanced its susceptibility to <italic>Xam</italic>. Co-expression network analysis showed that different downstream genes are regulated by different <italic>MeWRKY IIa</italic> members. The functional analysis of downstream genes will provide clues for clarifying molecular mechanism of cassava disease resistance. Collectively, our results suggest that <italic>MeWRKY IIas</italic> are regulated by SA, JA signaling, and coordinate response to <italic>Xam</italic> infection.</p>