AUTHOR=Zhou Qinqin , Jayawardhane Kethmi N. , Strelkov Stephen E. , Hwang Sheau-Fang , Chen Guanqun 

TITLE=Identification of Arabidopsis Phospholipase A Mutants With Increased Susceptibility to Plasmodiophora brassicae

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.799142

DOI=10.3389/fpls.2022.799142

ISSN=1664-462X

ABSTRACT=<p>Clubroot, caused by the obligate parasite <italic>Plasmodiophora brassicae</italic>, is one of the most devastating diseases of canola (<italic>Brassica napus</italic>) in Canada. The identification of novel genes that contribute to clubroot resistance is important for the sustainable management of clubroot, as these genes may be used in the development of resistant canola cultivars. Phospholipase As (PLAs) play important roles in plant defense signaling and stress tolerance, and thus are attractive targets for crop breeding. However, since canola is an allopolyploid and has multiple copies of each <italic>PLA</italic> gene, it is time-consuming to test the functions of <italic>PLAs</italic> directly in this crop. In contrast, the model plant <italic>Arabidopsis thaliana</italic> has a simpler genetic background and only one copy of each <italic>PLA</italic>. Therefore, it would be reasonable and faster to validate the potential utility of <italic>PLA</italic> genes in <italic>Arabidopsis</italic> first. In this study, we identified seven homozygous <italic>atpla</italic> knockout/knockdown mutants of <italic>Arabidopsis</italic>, and tested their performance following inoculation with <italic>P. brassicae</italic>. Four mutants (<italic>pla<sub>1</sub>-ii</italic>α, <italic>pla<sub>1</sub>-i</italic>γ<italic>3</italic>, <italic>pla<sub>1</sub>-iii</italic>, <italic>ppla-iii</italic>β, <italic>ppla-iii</italic>δ) developed more severe clubroot than the wild-type, suggesting increased susceptibility to <italic>P. brassicae</italic>. The homologs of these <italic>Arabidopsis PLAs</italic> (<italic>AtPLAs</italic>) in <italic>B. napus</italic> (<italic>BnPLAs</italic>) were identified through Blast searches and phylogenic analysis. Expression of the <italic>BnPLAs</italic> was subsequently examined in transcriptomic datasets generated from canola infected by <italic>P. brassicae</italic>, and promising candidates for further characterization identified.</p>