Tripathi Leena, Ntui Valentine Otang, Muiruri Samwel, Shah Trushar, Tripathi Jaindra Nath
International Institute of Tropical Agriculture (IITA), Nairobi, Kenya.
Commun Biol. 2025 May 7;8(1):708. doi: 10.1038/s42003-025-08093-w.
Plants deploy a sophisticated defense mechanism against pathogens through pattern recognition receptors (PRRs) and resistance (R) proteins, activating pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). E3 ubiquitin ligases, notably U-box types like PUB22 and PUB23, modulate PTI by suppressing immune responses. The role of MusaPUB22/23 in immunity against Xanthomonas vasicola pv. musacearum (Xvm), the cause of banana Xanthomonas wilt (BXW) in East Africa, was investigated by knocking out these genes in the BXW-susceptible 'Sukali Ndiizi' cultivar. The gene targets used in this study, MusaPUB22 and MusaPUB23, were identified through prior comparative transcriptomics analysis, which revealed their upregulation in susceptible versus resistant genotypes during early infection with Xvm. Gene edited plants exhibited mutations in both genes, with no significant growth penalties in most events. Several edited lines displayed complete resistance to Xvm infection, while others showed partial resistance, in contrast to the full susceptibility of wild-type controls. Resistance correlated with hydrogen peroxide accumulation and activation of key defense-related genes, indicating enhanced immune responses. This study identifies MusaPUB22/23 as susceptibility genes and provides strong evidence for their role in modulating immunity in banana. The results highlight the potential of gene editing as a promising strategy against BXW, addressing a crucial agricultural issue in East Africa while unraveling plant immunity regulation and paving the way for disease-resistant crop engineering targeting PUB genes.
植物通过模式识别受体（PRR）和抗性（R）蛋白部署了一种复杂的病原体防御机制，激活了模式触发免疫（PTI）和效应子触发免疫（ETI）。E3泛素连接酶，特别是像PUB22和PUB23这样的U-box类型，通过抑制免疫反应来调节PTI。通过在对香蕉枯萎病菌（BXW）敏感的‘Sukali Ndiizi’品种中敲除这些基因，研究了MusaPUB22/23在抵御香蕉黄单胞菌萎蔫病菌（Xanthomonas vasicola pv. musacearum，Xvm）（东非香蕉黄单胞菌枯萎病（BXW）的病原体）免疫中的作用。本研究中使用的基因靶点MusaPUB22和MusaPUB23，是通过先前的比较转录组学分析鉴定出来的，该分析揭示了它们在Xvm早期感染期间在敏感基因型与抗性基因型中的上调情况。基因编辑植物在这两个基因中都表现出突变，在大多数情况下没有明显的生长缺陷。与野生型对照的完全易感性相反，几个编辑品系对Xvm感染表现出完全抗性，而其他品系表现出部分抗性。抗性与过氧化氢积累和关键防御相关基因的激活相关，表明免疫反应增强。本研究将MusaPUB22/23鉴定为感病基因，并为它们在调节香蕉免疫中的作用提供了有力证据。研究结果突出了基因编辑作为一种对抗BXW的有前景策略的潜力，解决了东非一个关键的农业问题，同时揭示了植物免疫调节机制，并为针对PUB基因的抗病作物工程铺平了道路。
