小麦干热风抗性鉴定及热胁迫相关基因TaHSPs的表达分析

为鉴定黄淮麦区小麦品种干热风抗性以及不同抗性品种热激蛋白(TaHSPs)基因的表达差异,以98个小麦品种为试验材料,于花后10~20d进行人工模拟干热风处理,通过测定小麦不同生长时期的叶绿素含量、收获后的千粒重与籽粒品质,评价不同品种干热风抗性;对筛选出的干热风抗性不同的品种在出苗15d进行热胁迫处理,通过荧光定量PCR测定热胁迫0~4.5h内TaHSPs基因表达量的变化。结果表明,干热风处理后,供试小麦品种旗叶的叶绿素含量均降低,高抗干热风品种降幅较小,热敏感型品种降幅较大;供试小麦品种的千粒重均降低。山农23号等3个品种达到高、中抗干热风等级,且抗性比较稳定,师栾02-1为热敏感型品种。干热风处理后籽粒蛋白质含量升高,总淀粉含量降低,抗干热风小麦品种总淀粉相对含量降幅较小。不同小麦品种幼苗在热胁迫0~4.5h期间,TaHSPs基因表达量均为抛物线趋势,抗干热风品种在热胁迫1h时TaHSP16.9基因表达上调幅度大于热敏感型品种。对于TaHSP17.8基因,抗干热风品种在热胁迫期间,上调表达反应时间均早于热敏感型品种;在热胁迫0.5h时,山农23号、周麦18与泰山9818三个抗干热风品种基因表达均上调至590倍以上,而师栾02-1与济南17号的上调幅度在300倍以下。对于TaHSP23.6基因,山农23号的上调表达峰值远高于其他品种。对于TaHSP26.6基因,热敏感型品种在热胁迫后期的上调倍数高于抗干热风品种,师栾02-1与济南17号两个热敏感型品种在热胁迫4.5h时上调幅度均在4 000倍以上,而抗干热风品种山农23号、周麦18与泰山9818上调幅度均在3 000倍以下。

Identification of Dry-Hot Wind Resistance of Wheat Cultivars and Gene Expression Analysis of TaHSPs Related to Heat Stress

This study aims to identify dry-hot wind resistance of wheat cultivars and analyze expression of heat shock protein genes(TaHSPs) related to heat stress in resistant and susceptible wheat cultivars.Ninety-eight wheat cultivars were used as materials and treated with simulating dry-hot wind from 10 to 20 days after anthesis.Chlorophyll content,grain quality and thousand-kernel weight were tested,and the effects of dry-hot wind resistance of wheat cultivars were studied.The expression of TaHSPs in 15-day-old seedling of resistant and susceptible wheat cultivars,which were subjected to continuous heat stress at 38 ℃ for 4.5 h,was tested by real-time quantitative PCR.The results showed that the chlorophyll content in flag leaf of wheat cultivars decreased gradually during the treatment of dry-hot wind and decreased much more in susceptible wheat cultivars than in resistant cultivars.Thousand-kernel weight of all cultivars was reduced after dry-hot wind treatment and some cultivars which were identified showed the same resistance to dry-hot wind in two-year replications,such as Shannong 23 showed steady resistance to dry-hot wind,whereas Shiluan 02-1 was sensitive to dry-hot wind in 2-year replications.Protein content was significantly increased while the starch content was significantly decreased.Besides,the percentage of decreased starch content of wheat cultivars with high adversity resistance index (AI) was lower than those with low AI.Expression analysis of TaHSPs genes showed, TaHSP16.9, TaHSP17.7, TaHSP23.6 and TaHSP26.6 in wheat seedling were highly expressed and the expression trends of TaHSPs were first increasing and then decreasing during heat stress at 38 ℃.In addition,the gene expression patterns of TaHSPs were different between resistant and susceptible wheat cultivars under heat stress at 1 h.For TaHSP16.9,the up-regulated extent of gene expression in resistant wheat cultivars was greater than that in susceptible wheat cultivars.For TaHSP17.8,the up-regulated times of gene expression in resistant wheat cultivars was higher than that in susceptible wheat cultivars under heat stress at 0.5 h.The up-regulated times of gene expression level in Shannong 23 with heat tolerance was higher than 590,whereas the expression level in Shiluan 02-1 with heat sensitivity only reached 300.For TaHSP23.6,the peak of Shannong 23 with heat tolerance was four times higher than those in other cultivars.For TaHSP26.6,the up-regulated times of gene expression in susceptible wheat cultivars were higher than resistant wheat cultivars under heat stress at 4.5 h.The up-regulated times of TaHSP26.6 in heat susceptible cultivars were higher than 4 000,whereas that in heat tolerant cultivars only reached 3 000.