AUTHOR=Shao An , Xu Xiao , Amombo Erick , Wang Wei , Fan Shugao , Yin Yanling , Li Xiaoning , Wang Guangyang , Wang Hongli , Fu Jinmin 

TITLE=CdWRKY2 transcription factor modulates salt oversensitivity in bermudagrass [Cynodon dactylon (L.) Pers.]

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1164534

DOI=10.3389/fpls.2023.1164534

ISSN=1664-462X

ABSTRACT=<p>Common bermudagrass [<italic>Cynodon dactylon</italic> (L.) Pers.] has higher utilization potential on saline soil due to its high yield potential and excellent stress tolerance. However, key functional genes have not been well studied partly due to its hard transformation. Here, bermudagrass “Wrangler” successfully overexpressing <italic>CdWRKY2</italic> exhibited significantly enhanced salt and ABA sensitivity with severe inhibition of shoot and root growth compared to the transgenic negative line. The reduced auxin accumulation and higher ABA sensitivity of the lateral roots (LR) under salt stress were observed in <italic>CdWRKY2</italic> overexpression <italic>Arabidopsis</italic> lines. IAA application could rescue or partially rescue the salt hypersensitivity of root growth inhibition in <italic>CdWRKY2</italic>-overexpressing <italic>Arabidopsis</italic> and bermudagrass, respectively. Subsequent experiments in <italic>Arabidopsis</italic> indicated that CdWRKY2 could directly bind to the promoter region of <italic>AtWRKY46</italic> and downregulated its expression to further upregulate the expression of ABA and auxin pathway-related genes. Moreover, <italic>CdWRKY2</italic> overexpression in <italic>mapk3</italic> background <italic>Arabidopsis</italic> could partly rescue the salt-inhibited LR growth caused by <italic>CdWRKY2</italic> overexpression<italic>.</italic> These results indicated that CdWRKY2 could negatively regulate LR growth under salt stress <italic>via</italic> the regulation of ABA signaling and auxin homeostasis, which partly rely on AtMAPK3 function. CdWRKY2 and its homologue genes could also be useful targets for genetic engineering of salinity-tolerance plants.</p>