Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Barcelona, Spain.
Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr Bohr-Gasse 3, Vienna 1030, Austria.
J Exp Bot. 2021 Mar 29;72(7):2727-2740. doi: 10.1093/jxb/eraa610.
Bacterial wilt caused by the soil-borne pathogen Ralstonia solancearum is economically devastating, with no effective methods to fight the disease. This pathogen invades plants through their roots and colonizes their xylem, clogging the vasculature and causing rapid wilting. Key to preventing colonization are the early defense responses triggered in the host's root upon infection, which remain mostly unknown. Here, we have taken advantage of a high-throughput in vitro infection system to screen natural variability associated with the root growth inhibition phenotype caused by R. solanacearum in Arabidopsis during the first hours of infection. To analyze the genetic determinants of this trait, we have performed a genome-wide association study, identifying allelic variation at several loci related to cytokinin metabolism, including genes responsible for biosynthesis and degradation of cytokinin. Further, our data clearly demonstrate that cytokinin signaling is induced early during the infection process and cytokinin contributes to immunity against R. solanacearum. This study highlights a new role for cytokinin in root immunity, paving the way for future research that will help in understanding the mechanisms underpinning root defenses.
由土壤病原菌青枯雷尔氏菌引起的细菌性萎蔫病对经济具有毁灭性影响，目前尚无有效的防治方法。该病原体通过植物根系入侵，并在木质部定殖，堵塞维管束，导致植物迅速萎蔫。防止定殖的关键是宿主根系在感染早期触发的早期防御反应，但这些反应在很大程度上仍不清楚。在这里，我们利用高通量的体外感染系统，筛选了拟南芥在感染早期几小时内被青枯雷尔氏菌感染时根系生长抑制表型相关的自然变异。为了分析该性状的遗传决定因素，我们进行了全基因组关联研究，鉴定了与细胞分裂素代谢相关的几个位点的等位变异，包括负责细胞分裂素生物合成和降解的基因。此外，我们的数据清楚地表明，细胞分裂素信号在感染过程的早期被诱导，细胞分裂素有助于对青枯雷尔氏菌的免疫。这项研究强调了细胞分裂素在根免疫中的新作用，为未来的研究铺平了道路，有助于理解根防御的机制。
