橡胶树胶孢炭疽菌CgCntA基因功能分析

Functional Analysis of CgCntA Gene in Colletotrichum gloeosporioides from Hevea brasiliensis

胶孢炭疽菌(Colletotrichum gloeosporioides)基因组中有一个编码含Rieske和SRPBCC结构域蛋白的基因CgCntA。为了研究CgCntA的功能,利用同源重组原理构建了该基因的敲除突变体菌株,并进一步对其表型进行了分析。结果发现,CgCntA的缺失不影响胶孢炭疽菌的营养生长。在预先刺伤的叶片上,CgCntA缺失突变体的发病率及病斑大小与野生型菌株没有明显差异;而在完整无伤口的叶片上,CgCntA缺失突变体的发病率及病斑大小明显低于野生型菌株,说明CgCntA与胶孢炭疽菌侵染结构的形成有关。进一步在洋葱表皮观测胶孢炭疽菌的侵染动态情况,发现CgCntA缺失突变体不能形成活体寄生初级菌丝,而这可能就是其调控胶孢炭疽菌致病力的关键机制。本研究为橡胶树炭疽菌病害防治提供了科学依据,为橡胶安全生产进一步提供保障。

Colletotrichum gloe osporioides from Hevea brasiliensis contains the gene CgCntA which encodes a protein including Rieske and SRPBCC domains.The CgCntA knock-out mutant was constructed using the split-marker strategy and its functions were investigated.Colony growth analysis showed that CgCntA is not required for vegetative growth of C.gloeosporioides in vitro.After inoculation onto the pre-wounded Hevea leaves,the CgCntA knock-out mutant could form lesion diameter similar to that of wild type.However,when inoculated on the intact leaves,the disease incidence and the lesion diameter caused by the mutant were significantly lower than the wild type strain.Further microscope analysis revealed that the mutant could not form biotrophic primary hyphae on onion epidermis,and it might be the main cause for the virulence impair of the mutant.The study provides a scientific basis for the prevention and control of anthrax disease on rubber trees and further guarantees for the safety production of rubber.