2种虾脊兰属(Calanthe R.Br.)植物热胁迫相关基因表达模式分析

The Analysis of Expression Patterns of Heat Stress-related Genes in Two Species of Calanthe R.Br.

虾脊兰属(Calanthe R.Br.)植物物种多样性丰富,但在全球变暖的环境影响下,极端高温天气频繁出现,加剧了非生物胁迫对该属物种生存和繁殖的危害。本研究以兰科(Orchidaceae Juss.)6种虾脊兰属植物作为研究对象,通过高温半致死生理实验初步确定不同虾脊兰属植物的耐热性,并挑选耐热型银带虾脊兰(Calanthe argenteostriata C.Z.Tang&S.J.Cheng)和热敏感型三棱虾脊兰(C.tricarinata Lindl.)进行转录组测序,以筛选热胁迫相关基因,并分析其表达差异及功能。同时利用实时荧光定量PCR技术检测其基因在不同温度下的表达模式,分析相关基因与耐热性的关系。结果表明:(1)6种虾脊兰属植物的耐热性由弱至强排序:三棱虾脊兰<钩距虾脊兰<三褶虾脊兰<西南虾脊兰<中华虾脊兰<银带虾脊兰。(2)在耐热型银带虾脊兰和热敏感型三棱虾脊兰中鉴定到响应热胁迫的基因家族包括HSP、HSF、LEA、XTH、TIL。(3)三棱虾脊兰耐热相关基因表达的上限温度为30℃,超过该温度则对三棱虾脊兰造成伤害;银带虾脊兰9个耐热相关的差异基因在40℃下依然保持较高的表达量,可能因此获得了对高温胁迫较高的耐受性。本研究从分子水平上探究虾脊兰属植物对高温的响应,为筛选耐热性关键基因及培育耐热性较强的园林植物提供重要的线索,对现代园林育种具有重要的指导意义和应用价值。

The species diversity of Calanthe R.Br.is rich.However,under the influence of global warming,extreme high temperature weather frequently occurs,which exacerbates the harm of abiotic stress on the survival and reproduction of Calanthe.In this study,six species of Calanthe were analyzed for heat tolerance via applying means of high-temperature semi-lethal physiological experiments.Calanthe argenteostriata C.Z.Tang&S.J.Cheng and C.tricarinata Lindl.,which were identified to be heat tolerant or sensitive,respectively,were used for transcriptome sequencing and identification of differentially-expressed genes(DEGs)under heat stress treatment conditions.In addition,their transcriptional profiles at different temperatures were detected by real-time fluorescent quantitative PCR technology.The research results were included:(1)The heat tolerance of six species of Calanthe is ranked from weak to strong:C.tricarinata Lindl.,C.graciliflora Hayata,C.triplicata(Willem.)Ames,C.herbacea Lindl.,C.sinica Z.H.Tsi,C.argenteostriata C.Z.Tang&S.J.Cheng.(2)Gene families responsible to heat stress were identified,including HSP,HSF,LEA,XTH,TIL.(3)In C.tricarinata Lindl.,the up-regulated expression threshold of DEGs was 30℃,and the temperature over 30℃might cause heat damage.In C.argenteostriata C.Z.Tang&S.J.Cheng,nine DEGs were highly expressed at 40℃,possibly resulting in an improvement of tolerance to heat stress.This study explored the response of Calanthe to heat stress at the molecular level,provided important clues for identifying key genes of heat tolerance and cultivating garden heat tolerant plants,which might provide reference in modern garden breeding.