Comparative transcriptomic analysis of Chinese cabbage’s defense responses to Alternaria brassicae

This is the authors' abstract. We don't add key points for this paper.

• BrERF109 is identified as a key positive regulator in Chinese cabbage against Alternaria brassicae infection. • BrERF109 activates the expression of BrIGMT4 by binding to its promoter. • BrERF109 increases plants’ defense against Alternaria brassicae by inducing indolic glucosinolates accumulation. Black spot is a fungus disease elicited by Alternaria brassicae infection and causes devastating damage to Chinese cabbage. We explored the molecular mechanisms of Chinese cabbage's defense responses to A. brassicae infection by comparative transcriptomic analysis. Notably, we found that the expression of BrERF109 was induced by A. brassicae infection. Silencing of BrERF109 by an optimized VIGS assay in Chinese cabbage reduced disease resistance, whereas BrERF109 -overexpression in Arabidopsis enhanced disease resistance. Furthermore, silencing of BrERF109 in Chinese cabbage repressed the expression of indolic glucosinolates genes thus significantly lowered the indolic glucosinolates levels, while BrERF109 -overexpression in Arabidopsis induced indolic glucosinolates accumulation. BrERF109 could directly bind the promoter of BrIGMT4 , thereby promoting the indolic glucosinolates accumulation and actively defending against A. brassicae . Our study uncovered the BrERF109- BrIGMT4 regulatory module in Chinese cabbage's defense responses to A. brassicae infection, as well as providing valuable dataset to further explore plants- A. brassicae interactions.