小麦耐热性的生理遗传研究进展

Progresses in Research of Physiological and Genetic Mechanisms of Wheat Heat Tolerance

小麦是中国第二大口粮作物,其产量直接关系人民的生活水平,所以高产和稳产一直是中国小麦的首要育种目标。小麦起源于温带,属喜凉作物,生长季节内的高温对生长发育会产生不利影响,使其产量下降,品质变劣。由于耐热性是复杂的数量遗传性状,其机制的解析一直是生物学研究难点,也是研究热点。为了解析小麦耐热的生理遗传学及分子生物学基础,国内外研究人员通过正向遗传学方法,构建遗传分离群体,以冠层温度、灌浆持续时间、细胞膜稳定性和叶绿素含量等生理学参数,以及穗粒数和千粒重热感指数为指标,在小麦不同染色体上定位了多个耐热相关的QTL位点。同时利用反向遗传学方法,特别是通过转录组、蛋白组和表观遗传组等组学方法鉴定了大量的高温胁迫响应的基因、mi RNA及长片段非编码RNA,并通过转基因等手段证明了部分候选基因在小麦抵御高温胁迫中的重要作用。另外,虽然植物中高温受体至今尚未发现,但是钙离子信号通道以及ABA和SA等激素在高温信号传导中的作用也逐渐引起人们的关注。文中主要综述了现阶段高温对小麦产量品质及生理性状的影响、小麦耐热相关QTL的定位,以及小麦响应高温胁迫的转录组、蛋白组和表观遗传组的研究进展;提出应针对小麦种质资源进行系统的耐热性评价,筛选优异等位基因、解析其分子遗传机理,通过创新再利用,为选育适合中国气候条件的耐热小麦品种提供新材料,实现品种耐热性与丰产性的统一。

Wheat(Triticum aestivum) is a second largest staple crop in China, which closely related to the improvement of people's living standards, and high and stable yield is the most important target in wheat breeding program. Nowadays, heat stress has become one of the limiting factors for wheat production, because wheat is a chimonophilous crop, and very sensitive to heat stress especially at productive stage, which would cause decrease in both wheat quantity and quality. Recently, to analyze the physiological, genetic and molecular basis of heat tolerance in wheat, researchers have developed diverse segregation populations with different heat sensitivities, and mapped dozens of heat-tolerant QTLs on wheat chromosomes in terms of canopy temperature, grain filling duration, membrane stability and chlorophyll content, as well as heat sensitivity index of grain number and thousand kernel weight. In addition, transcriptome, proteome, and epigenome analyses have been applied to identify heat responsive genes, mi RNAs and long non-coding RNAs, and some of which have been proved to contribute to the heat tolerance in wheat. Although receptors of heat signal is not yet identified, calcium ion channel and phytohormone e.g. ABA and SA exhibited a crucial role in signal transduction. In this paper, the progresses in research of heat-tolerance related QTL mapping, transcriptome, proteome and epigenome profiling and heat-responsive gene identification were summarized, and proposed that it is necessary to perform systematical evaluation of wheat germplasm, screening of allelic variation and analysis of underlying molecular mechanism for further utilization in wheat breeding program to develop wheat cultivars with high and stable yield in China.