AUTHOR=Yang Kankan , Zhou Geng , Chen Chen , Liu Xiaohong , Wei Lin , Zhu Feiying , Liang Zhihuai , Chen Huiming 

TITLE=Joint metabolomic and transcriptomic analysis identify unique phenolic acid and flavonoid compounds associated with resistance to fusarium wilt in cucumber (Cucumis sativus L.)

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1447860

DOI=10.3389/fpls.2024.1447860

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p>Fusarium wilt (FW) caused by <italic>Fusarium oxysporum</italic> f. sp. <italic>cucumerinum (Foc)</italic> is a destructive soil-borne disease in cucumber (<italic>Cucumis sativus</italic>. L). However, there remains limited knowledge on the molecular mechanisms underlying FW resistance-mediated defense responses in cucumber.</p></sec><sec><title>Methods</title><p>In this study, metabolome and transcriptome profiling were carried out for two FW resistant (NR) and susceptible (NS), near isogenic lines (NILs) before and after <italic>Foc</italic> inoculation. NILs have shown consistent and stable resistance in multiple resistance tests conducted in the greenhouse and in the laboratory. A widely targeted metabolomic analysis identified differentially accumulated metabolites (DAMs) with significantly greater NR accumulation in response to <italic>Foc</italic> infection, including many phenolic acid and flavonoid compounds from the flavonoid biosynthesis pathway.</p></sec><sec><title>Results</title><p>Transcriptome analysis identified differentially expressed genes (DEGs) between the NILs upon <italic>Foc</italic> inoculation including genes for secondary metabolite biosynthesis and transcription factor genes regulating the flavonoid biosynthesis pathway. Joint analysis of the metabolomic and transcriptomic data identified DAMs and DEGs closely associated with the biosynthesis of phenolic acid and flavonoid DAMs. The association of these compounds with NR-conferred FW resistance was exemplified by <italic>in vivo</italic> assays. These assays found two phenolic acid compounds, bis (2-ethylhexyl) phthalate and diisooctyl phthalate, as well as the flavonoid compound gallocatechin 3-O-gallate to have significant inhibitory effects on <italic>Foc</italic> growth. The antifungal effects of these three compounds represent a novel finding.</p></sec><sec><title>Discussion</title><p>Therefore, phenolic acids and flavonoids play important roles in NR mediated FW resistance breeding in cucumber.</p></sec>