AUTHOR=Xiong Xian-Peng , Sun Shi-Chao , Zhang Xin-Yu , Li Yan-Jun , Liu Feng , Zhu Qian-Hao , Xue Fei , Sun Jie 

TITLE=GhWRKY70D13 Regulates Resistance to Verticillium dahliae in Cotton Through the Ethylene and Jasmonic Acid Signaling Pathways

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00069

DOI=10.3389/fpls.2020.00069

ISSN=1664-462X

ABSTRACT=<p><italic>Verticillium</italic> wilt caused by <italic>Verticillium dahliae</italic> is a destructive cotton disease causing severe yield and quality losses worldwide. WRKY transcription factors play important roles in plant defense against pathogen infection. However, little has been reported on the functions of WRKYs in cotton's resistance to <italic>V. dahliae</italic>. Here, we identified 5, 5, and 10 <italic>WRKY70</italic> genes in <italic>Gossypium arboreum</italic>, <italic>Gossypium raimondii</italic>, and <italic>Gossypium hirsutum</italic>, respectively, and investigated the expression profiles of all <italic>GhWRKY70</italic> genes in various cotton tissues and in response to hormone treatment or <italic>V. dahliae</italic> infection. Reverse transcription-quantitative PCR analysis showed that <italic>GhWRKY70D13</italic> was expressed higher in roots and stems than in other tissues, and up-regulated after <italic>V. dahliae</italic> inoculation. Knock-down of <italic>GhWRKY70D13</italic> improved resistance to <italic>V. dahliae</italic> in both resistant and susceptible cotton cultivars. Comparative analysis of transcriptomes generated from wild-type and stable RNAi (RNA interference) plant with down-regulated <italic>GhWRKY70D13</italic> showed that genes involved in ethylene (ET) and jasmonic acid (JA) biosynthesis and signaling were significantly upregulated in the <italic>GhWRKY70D13</italic> RNAi plants. Consistently, the contents of 1-aminocyclopropane-1-carboxylic (ACC), JA, and JA-isoleucine levels were significantly higher in the <italic>GhWRKY70D13</italic> RNAi plants than in wild-type. Following <italic>V. dahliae</italic> infection, the levels of ACC and JA decreased in the <italic>GhWRKY70D13</italic> RNAi plants but still significantly higher (for ACC) than that in wild-type or at the same level (for JA) as in non-infected wild-type plants. Collectively, our results suggested that <italic>GhWRKY70D13</italic> negatively regulates cotton's resistance to <italic>V. dahliae</italic> mainly through its effect on ET and JA biosynthesis and signaling pathways.</p>