摘要
过高的环境温度对植物造成热胁迫和热损伤,影响植物的生长、发育,以及种子的寿命。以白菜型油菜耐热品种庆元本地油菜和不耐热品种绍兴矮大秆油菜新收获种子为材料,研究了不同温度处理对油菜种子活力以及基因组DNA甲基化水平和状态的影响。结果表明,种子经37℃和4℃处理2h,发芽率和活力指数与对照差异不显著;经70℃处理2h后,耐热和不耐热品种种子发芽率和活力指数均明显降低,37℃热诱导后再进行70℃热胁迫处理,发芽率和活力指数均高于直接70℃处理的种子,表明热诱导可以显著提高种子的耐热性。甲基化MSAP分析结果表明,种子热胁迫过程中基因组DNA甲基化水平降低,同时有甲基化和去甲基化现象发生,并以去甲基化现象为主。相关性分析结果显示种子发芽势、发芽率、下胚轴长和活力指数与双链DNA内部发生甲基化的条带数呈负相关,而与双链DNA外部发生甲基化的条带数呈正相关。更为重要的是耐热与不耐热性材料在热胁迫中表现完全相反的甲基化变异模式,耐热品种去甲基化的条带数多于不耐热品种,但甲基化的条带数目则相反,显示DNA甲基化与种子耐热性有重要关系。在热胁迫过程中,种子可能通过DNA甲基化变化调控相关基因的表达来应对高温胁迫。
High temperature or heat stress,causes thermal damage to plants,and affects plant growth,development,as well as seed longevity.By using a seed heat tolerant genotype Qingyuanbendiyoucai and a seed heat susceptive genotype Shaoxingaidaganyoucai,this study aimed at investigation of the effect of different temperature treaments on seed vigor and DNA methylation of these two landraces of Brassica rapa L.The result showed that the seed germination percentage and the vigor index present no significant difference from those of CK under 37°C and 4°C,the seed vigor declined significantly under 70°C of heat stress,and heat acclimation in 37°C for 2 h effectively enhanced seed thermo-tolerance.The results of MSAP analysis showed that the level of global DNA methylation decreased under 70°C of heat stress,both DNA methylation and demethylation were detected,and more DNA demethylation bands were recorded.Seed germinating potential,germination percentage,hypocotyl length,vigor index were significantly negatively correlatied with number of bands of full-methylated（both bands） at the internal cytosine,but positively correlated with the the number of bands of full-methylated（both bands） at the external cytosine.Most importantly,opposite patterns of DNA methylation were discovered in heat tolerant and susceptive seeds under 70°C heat stress,more bands of DNA demethylation were detected in the heat tolerant seeds,but more bands of DNA methylation were detected in the heat susceptive seeds,which suggested that DNA methylation and demethylation play an important role in seed heat tolerance,epigenetic regulation of gene expression by DNA methylation is important for plant to cope with heat stress.
出处
《作物学报》
CAS
CSCD
北大核心
2011年第9期1597-1604,共8页
Acta Agronomica Sinica
基金
国家"十一五"科技支撑计划项目(2009BADA8B01)
国家自然科学基金项目(30800693)资助
