Bna-novel-miR311-HSC70-1模块调控甘蓝型油菜响应热胁迫的机制

Mechanism research of Bna-novel-miR311-HSC70-1 module regulating heat stress response in Brassica napus L.

HSP70(heat shock protein 70)参与植物热胁迫应答,增强植物耐热性,但目前油菜中尚无miRNA调控HSP70基因的报道。本研究novel-miR311是利用高通量技术在甘蓝型油菜茎尖中筛选出的新miRNA。novel-miR311存在于油菜而不存在于拟南芥中, 5’-RACE技术证实其2个靶基因属热应激同源蛋白基因HSC70-1 (HSP70家族),在甘蓝型油菜体内被剪切。构建novel-miR311超表达载体,转化拟南芥和甘蓝型油菜,其转基因阳性苗中HSC70-1基因表达量显著下降。高温胁迫试验表明,拟南芥和甘蓝型油菜热胁迫后,其阳性苗的生长势和存活率显著低于其对应的对照。qPCR结果显示,油菜中HSC70-1基因表达量热胁迫后较热胁迫前上升。上述结果表明,油菜novel-miR311介导HSC70-1基因的剪切降低了拟南芥和甘蓝型油菜耐热性。

HSP70(heat shock protein 70)participates in the response to heat stress,and can enhance plant heat tolerance,but there have been no reports of miRNA regulating HSP70 in rapeseed.In this study,a new miRNA,named novel-miR311,was identified in the shoot tip of Brassica napus by high-throughput technology.novel-miR311 was present in Brassica napus but not in Arabidopsis,and 5'-RACE technology confirmed that its two target genes,belonged to heat stress homologous protein gene HSC70-1(HSP70 family),and could be cleavaged in Brassica napus.An overexpression vector of novel-miR311 was constructed and transformed into Arabidopsis and Brassica napus,and the expression of HSC70-1 in transgenic positive seedlings was decreased significantly.High temperature stress experiments showed that the growth potential and survival rates of Arabidopsis and Brassica napus positive seedlings were lower than those of their corresponding controls.The qPCR results showed that the expression of HSC70-1 gene in rapeseed increased after heat stress than before stress.In conclusion,the results suggest that Bna-novel-miR311 could reduce the heat resistance of Arabidopsis and Brassica napus by mediating cleavaged of HSC70-1.