AUTHOR=Yang Li , Zhao Chuanji , Bai Zetao , Yang Lingli , Schranz M. Eric , Liu Shengyi , Bouwmeester Klaas 

TITLE=Comparative transcriptome analysis of compatible and incompatible Brassica napus—Xanthomonas campestris interactions

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.960874

DOI=10.3389/fpls.2022.960874

ISSN=1664-462X

ABSTRACT=<p>Black rot caused by the vascular pathogenic bacterium <italic>Xanthomonas campestris</italic> pv. <italic>campestris</italic> (<italic>Xcc</italic>) is widespread in Brassicaceae plants and an infectious disease that causes large yield losses in oil seed rape (<italic>Brassica napus</italic> L.). Improvement of resistance through breeding is a crucial strategy to prevent black rot disease in <italic>B. napus</italic>, but presently hampered by insufficient understanding of <italic>Xcc-</italic>Brassica interactions. This study compares two EMS-mutagenized <italic>B. napus</italic> lines that show contrasting resistance levels to their susceptible progenitor. Patterns of differential gene expression between these <italic>B. napus</italic> lines were evaluated at three time points post inoculation by comparative RNA-seq analysis. In line with the observed disease phenotypes, the susceptible line ZS9m<italic>Xcc</italic>S-1 displayed a steady amount of differentially expressed genes (DEGs) at different time points of infection, whereas the resistant line ZS9m<italic>Xcc</italic>R-1 displayed a gradual increase in DEGs throughout the course of infection. Weighted gene co-expression network analysis (WGCNA) pinpointed multiple defense-related hub genes with potential central roles in immunity, including the cell surface receptor genes <italic>CRK11</italic> and <italic>BIR1</italic>, and the associated downstream regulatory genes <italic>WRKY11</italic> and <italic>PBL30</italic>. KEGG analysis of DEGs belonging to two distinct co-expression modules revealed enriched pathways associated with defense, including Ca<sup>2+</sup>-signaling, receptor-mediated immunity, and phytohormone balance. Taken together, our comparative transcriptome analysis provides new avenues to unravel the mechanisms underlying black rot resistance in <italic>B. napus</italic>.</p>