马铃薯StBI-1基因鉴定及其抗疫霉菌的功能探索

Identification of Solanum tuberosum StBI-1 Gene and Exploration of Its Function in Resistance to Ph ytophthora

Baxinhibitor1(BI-1)是真核生物中高度保守的细胞死亡调节因子,在植物响应生物与非生物胁迫中扮演重要角色。为探究BI-1是否参与马铃薯响应疫霉菌侵染的免疫应答,首先以拟南芥AtBI-1蛋白序列为模板在马铃薯蛋白数据库中进行BLAST检索。通过比对分析及构建系统进化树,鉴定到与AtBI-1相似度为77.22%的马铃薯蛋白NP_001305552.1,将编码该蛋白的马铃薯基因命名为StBI-1;蛋白结构预测分析表明,StBI-1包含7个跨膜域和Baxinhibitor-1-like家族结构域。利用实时定量PCR分析StBI-1基因在马铃薯响应致病疫霉菌侵染过程中的表达模式,并借助农杆菌介导的烟草瞬时表达体系初步探索StBI-1抗疫霉菌的生物学功能。结果显示,StBI-1响应致病疫霉菌侵染而诱导上调表达,尤其是在侵染后期。同时,过表达StBI-1可显著增强本氏烟草对寄生疫霉菌和致病疫霉菌的抗性。综合以上结果,本研究对马铃薯BI-1基因进行鉴定分析及克隆,并初步揭示StBI-1抗疫霉菌的生物学功能,为挖掘马铃薯抗晚疫病新型基因资源及深入解析其抗病分子机理奠定了理论基础。

Bax inhibitor 1(BI-1)is a regulator in evolutionarily conserved cell death in eukaryotes,and plays an important role in response to biotic and abiotic stress in plants.To investigate whether BI-1 is involved in the immune response of Solanum tuberosum to Ph yto phthora infection,we used the protein sequence of AtBI-1 as a query to process a BLAST search in the S.tuberosum protein database.Through sequence alignment and phylogenetic tree construction,one protein(NP_001305552.1)was identified to be 77.22%similarity to AtBI-1 in S.tuberosum,and the gene encoding this protein was termed StBI-1.Functional domain prediction analysis indicated that StBI-1 contains seven transmem-brane domains and a Bax inhibitor-l-like family domain.The quantitative real-time PCR(qRT-PCR)was used to analyze the expression pattern of StBI-1 gene in S.tuberosum upon infection with Phyto-phthora infestans.Agrobacterium-mediated transient expression system was used in Nicotiana bentha m iana,to preliminarily explore the biological function of StBI-resistance to Ph ytophthora.The results showed that the expression of StBI-1 was induced upon P.infestans infection,especially at the late stage of infection.Simultaneously,overexpression of StBI-1 could significantly enhance N.benthamiana resistance to both P.parasitica and P.infestans.Taken together,S.tuberosum BI-1 gene was identified and cloned,and its biological function in resistance to Phytophthora was implied.This study provides a theoretical foundation for exploring novel genetic resources of S.tuberosum in resistance to potato late blight disease and for further investigation on the molecular mechanism of plant resistance mediated by StBI-1.