谷瘟菌生理小种致病力鉴定及遗传转化体系建立

Differentiating the pathogenicity of millet blast races and establishing a stable genetic transformation system

谷瘟病是目前造成谷子产量和品质损失最严重的病害,且在不同生态区域具有致病性分化,因此分离不同谷瘟病生理小种,探索不同生理小种对谷子育成品种的侵染性,建立谷瘟病菌遗传转化体系,对谷瘟病致病机制研究、谷子品种资源抗病性鉴定、不同谷子品种生产区域布局、谷瘟病精确防治以提高谷子产量和品质具有重要意义.本研究利用6个谷子主产区的谷瘟小种,进行离体培养和产孢实验,对孢子形态进行了精细观察.并且用这些生理小种对具有代表性的谷子品种进行了苗期离体接菌实验,鉴定了谷瘟生理小种与宿主间的互作关系.结果表明,不同的谷瘟生理小种对不同品种的致病性存在差异,海南采集到的HN-1和三亚两个菌株致病力较强,不同生理小种侵染的谷子品种不一致.rDNA-IGS序列、稻瘟同源Avr基因分子鉴定结果表明这些生理小种间存在遗传差异.本研究所用不同谷子种质资源材料对不同的生理小种表现出抗性差异,且其中一些材料苗期和成株期抗性表现截然相反,说明谷子瘟病抗性资源可能携带不同小种专化抗性、广谱抗性、苗期抗性与成株期抗性位点,为不同地区选育抗谷瘟病新品种,提高谷子产量和品质提供了理论依据.筛选出一个致病力强的谷瘟真菌海南-1(HN-1),用这个小种对17个谷子育成品种或中间材料开展田间成株期接种实验,鉴定出黄金苗、豫谷1、朝谷58,创278-14B为高抗品种,Ci846,SK325为高感品种,为后续分离抗病基因打下了坚实的基础.同时创建了谷瘟病病原真菌的遗传转化体系,并成功转化HN-1小种,获得具有GFP,mCherry荧光的HN-1GFP/mCherry生理小种,为进一步研究谷瘟致病基因的功能提供了有力的支持.

The fungal pathogen Magnaporthe causes blast disease and destroys millet,rice,and wheat crops worldwide,which threatens global food production.Blast disease has spread in the main millet-producing area of China and is pathogenically differentiated in different ecological regions.Therefore,a study on the pathogenicity of millet blast races,the resistance spectrum of millet cultivars in the adult stage,and establishing a genetic transformation system for the blast fungus is of great significance for distributing local millet resources,controlling blast,and improving the yield and quality of millet.Herein,we collected blast races from six regions nationwide,isolated them from single spores,and successfully induced extensive conidial spores in tomato plants.Furthermore,we conducted artificial in-vitro inoculation experiments with different millet varieties to evaluate their resistance spectra at the seedling stage and lay a solid foundation to isolate disease-resistant genes.The results showed that the pathogenicity of the strains to different varieties was divergent;however,the virulence of the races from Hainan Province was significantly stronger than that from other regions.Thus,the HN-1 strain with the highest infectivity was inoculated into 17 different adult-stage cultivars in the field.Consequently,four cultivars with adult-plant resistance were screened out.We established a stable genetic transformation system in the HN-1 background to provide a technical foundation for future studies on millet blast virulent proteins.