Diallo A, Wonni I, Sicard A, Blondin L, Gagnevin L, Vernière C, Szurek B, Hutin M
INERA, Institut de l'Environnement et de Recherches Agricoles du Burkina Faso, Laboratoire de Phytopathologie, Bobo-Dioulasso, Burkina Faso.
PHIM Plant Health Institute, Université de Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France.
Rice (N Y). 2023 Jul 31;16(1):33. doi: 10.1186/s12284-023-00648-x.
Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat for food security in many rice growing countries including Burkina Faso, where the disease was first reported in the 1980's. In line with the intensification of rice cultivation in West-Africa, BLB incidence has been rising for the last 15 years. West-African strains of Xoo differ from their Asian counterparts as they (i) are genetically distant, (ii) belong to new races and, (iii) contain reduced repertoires of Transcription Activator Like (TAL) effector genes. In order to investigate the evolutionary dynamics of Xoo populations in Burkina Faso, 177 strains were collected from 2003 to 2018 in three regions where BLB is occurring. Multilocus VNTR Analysis (MLVA-14) targeting 10 polymorphic loci discriminated 24 haplotypes and showed that Xoo populations were structured according to their geographical localization and year of collection. Considering their major role in Xoo pathogenicity, we assessed the TAL effector repertoires of the 177 strains upon RFLP-based profiling. Surprisingly, an important diversity was revealed with up to eight different RFLP patterns. Finally, comparing neutral vs. tal effector gene diversity allowed to suggest scenarios underlying the evolutionary dynamics of Xoo populations in Burkina Faso, which is key to rationally guide the deployment of durably resistant rice varieties against BLB in the country.
由稻黄单胞菌稻致病变种（Xoo）引起的水稻白叶枯病，对包括布基纳法索在内的许多水稻种植国家的粮食安全构成重大威胁，布基纳法索于20世纪80年代首次报道了该病。随着西非水稻种植的集约化，在过去15年里，白叶枯病的发病率一直在上升。西非的Xoo菌株与其亚洲菌株不同，因为它们（i）在基因上距离较远，（ii）属于新的小种，并且（iii）转录激活因子样（TAL）效应子基因的库有所减少。为了研究布基纳法索Xoo种群的进化动态，在2003年至2018年期间，从三个发生白叶枯病的地区收集了177个菌株。针对10个多态性位点的多位点可变数目串联重复序列分析（MLVA - 14）区分出24种单倍型，并表明Xoo种群根据其地理定位和收集年份进行了结构化。考虑到它们在Xoo致病性中的主要作用，我们基于限制性片段长度多态性（RFLP）分析评估了这177个菌株的TAL效应子库。令人惊讶的是，发现了重要的多样性，多达八种不同的RFLP模式。最后，比较中性基因与TAL效应子基因的多样性，有助于推测布基纳法索Xoo种群进化动态的潜在情景，这对于合理指导该国持久抗白叶枯病水稻品种的部署至关重要。
