不同盐浓度胁迫下冬小麦幼苗光合特性及转录组分析

Photosynthetic characteristics and transcriptome analysis of winter wheat seedlings under different salt concentration stress

光合作用是小麦(Triticum aestivum)生长发育的基础,盐胁迫影响小麦的光合作用,进而限制小麦的产量。为了揭示小麦光合作用过程中的耐盐生理与分子机理,挖掘与小麦光合作用相关的耐盐基因,本研究以冬小麦品种‘德抗961’(耐盐)和‘师栾02-1’(不耐盐)为供试材料,进行苗期盐胁迫处理,对不同盐浓度梯度下小麦幼苗生理指标与转录组数据进行了比对与分析。结果表明,盐胁迫下小麦净光合速率(P_(n))、蒸腾速率(T_(r))、胞间二氧化碳浓度(C_(i))和气孔导度(G_(s))均受到不同程度的影响,但耐盐品种‘德抗961’的变化幅度小于不耐盐品种‘师栾02-1’。根据转录组数据筛选了盐胁迫下12个与光合特性有关的差异表达基因,分别分布在甘油脂质代谢、MAPK信号通路、植物信号转导、黄酮类生物合成等代谢途径,并进行了实时荧光定量(qRT-PCR)验证,结果表明筛选出来的12个差异基因的表达情况与转录组测序结果吻合,其具体功能有待进一步验证。研究结果不仅有助于进一步揭示小麦耐盐机理,同时也为小麦耐盐遗传改良提供了新的候选基因。

Photosynthesis is the basis of wheat(Triticum aestivum)growth and development.Salt stress has negative effects on wheat yield through affecting wheat photosynthesis.In order to reveal the physiology and molecular mechanism of salt tolerance in wheat photosynthesis,and explore the genes related to salt tolerance and photosynthesis,the winter wheat varieties‘Dekang 961'(salt tolerance)and‘Shiluan 02-1'(salt sensitive)were used in this study.The physiological indexes and RNA-seq data were analyzed in the wheat seedlings that treated with different gradients of salt stress.It showed that the net photosynthetic rate(P_(n)),transpiration rate(T_(r)),intercellular carbon dioxide concentration(C_(i))and stomatal conductivity(G_(s))were affected by salt stress to varying degrees.But the effect of salt stress on‘Dekang 961'was weaker than‘Shiluan 02-1'.Based on the RNA-seq data,12 salt stress related genes were identified to respond to photosynthesis probably,which participate in glycerid metabolism,MAPK signaling,plant signal transduction,flavonoid biosynthesis,etc.The q RT-PCR results also verified that the expression level of the 12 identified photosynthesis relative genes was consistent with the RNA-seq data.However,their functions needed to be studied in the future.This study revealed the mechanism of wheat salt tolerance,also provided new candidate genes for the genetic improvement of salt tolerance in wheat.