College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095 Jiangsu, P.R. China.
College of Biology and Food Science, Chongqing Three Gorges University, Chongqing 404000, P.R. China.
J Exp Bot. 2022 Jun 2;73(11):3787-3806. doi: 10.1093/jxb/erac099.
MADS-box genes play well-documented roles in plant development, but relatively little is known regarding their involvement in defence responses. In this study, pre-treatment of peach (Prunus persica) fruit with β-aminobutyric acid (BABA) activated resistance against Rhizopus stolonifer, leading to a significant delay in the symptomatic appearance of disease. This was associated with an integrated defence response that included a H2O2 burst, ABA accumulation, and callose deposition. cDNA library screening identified nucleus-localized MADS2 as an interacting partner with NPR1, and this was further confirmed by yeast two-hybrid, luciferase complementation imaging, and co-immunoprecipitation assays. The DNA-binding activity of NPR1 conferred by the NPR1-MADS2 complex was required for the transcription of SA-dependent pathogenesis-related (PR) and ABA-inducible CalS genes in order to gain the BABA-induced resistance, in which MAPK1-induced post-translational modification of MADS2 was also involved. In accordance with this, overexpression of PpMADS2 in Arabidopsis potentiated the transcription of a group of PR genes and conferred fungal resistance in the transgenic plants. Conversely, Arabidopsis mads2-knockout lines showed high sensitivity to the fungal pathogen. Our results indicate that MADS2 positively participates in BABA-elicited defence in peach through a combination of SA-dependent NPR1 activation and ABA signaling-induced callose accumulation, and that this defence is also related to the post-translational modification of MADS2 by MAPK1 for signal amplification.
MADS 框基因在植物发育中发挥着有充分记录的作用，但关于它们在防御反应中的参与相对知之甚少。在这项研究中，用 β-氨基丁酸（BABA）预处理桃（Prunus persica）果实可激活对根霉（Rhizopus stolonifer）的抗性，导致疾病症状明显延迟出现。这与包括 H2O2 爆发、ABA 积累和几丁质沉积在内的综合防御反应有关。cDNA 文库筛选鉴定出定位于细胞核的 MADS2 作为与 NPR1 相互作用的伙伴，酵母双杂交、荧光素酶互补成像和共免疫沉淀实验进一步证实了这一点。NPR1-MADS2 复合物赋予 NPR1 的 DNA 结合活性对于获得 BABA 诱导的抗性是必需的，其中 MAPK1 诱导的 MADS2 的翻译后修饰也参与其中。与此一致的是，在拟南芥中过表达 PpMADS2 增强了一组 PR 基因的转录，并赋予转基因植物对真菌的抗性。相反，拟南芥 mads2 敲除系对真菌病原体表现出高度敏感性。我们的结果表明，MADS2 通过依赖 SA 的 NPR1 激活和 ABA 信号诱导的几丁质积累的组合，积极参与了桃中 BABA 诱导的防御，并且这种防御也与 MAPK1 对 MADS2 的翻译后修饰有关，用于信号放大。
