School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 201101, China.
Plant Cell Physiol. 2021 Mar 25;62(1):28-42. doi: 10.1093/pcp/pcaa121.
A novel late embryogenesis abundant (LEA) gene, MsLEA-D34, was cloned from alfalfa (Medicago sativa L.). Its function and gene regulatory pathways were studied via overexpression (OE) and RNA interference (RNAi) of the gene in Arabidopsis and in hairy roots of alfalfa, as well as via analyzing key genes related to MsLEA-D34 during developmental phases in alfalfa. The results showed that MsLEA-D34 was a typical intrinsically disordered protein with a high capability for protein protection. Overexpression of MsLEA-D34 increased plant tolerance to osmotic and salt stresses, and caused Arabidopsis early flowering under drought and well-watered conditions. Overexpressing MsLEA-D34 induced up-regulation of FLOWERING LOCUS T (FT) and GIGANTEA (GI) at the flowering phase of Arabidopsis and hairy roots of alfalfa, but only FT was down-regulated in MsLEA-D34-RNAi lines. A positive effect of MsLEA-D34 on FT accumulation was demonstrated in alfalfa hairy roots. An ABA-responsive element (ABRE)-binding transcription factor (MsABF2), a novel transcription factor cloned from alfalfa, directly bound to the RY element in the MsLEA-D34 promoter and activated MsLEA-D34 expression. The above results indicate that MsLEA-D34 can regulate abiotic stress response in plants and influence flowering time of Arabidopsis.
从紫花苜蓿（Medicago sativa L.）中克隆了一个新的晚期胚胎丰富（LEA）基因 MsLEA-D34。通过在拟南芥和紫花苜蓿毛状根中过表达（OE）和 RNA 干扰（RNAi）该基因，以及在紫花苜蓿发育阶段分析与 MsLEA-D34 相关的关键基因，研究了其功能和基因调控途径。结果表明，MsLEA-D34 是一种典型的无规卷曲蛋白，具有很高的蛋白质保护能力。过表达 MsLEA-D34 提高了植物对渗透胁迫和盐胁迫的耐受性，并导致拟南芥在干旱和充分浇水条件下提前开花。过表达 MsLEA-D34 在拟南芥和紫花苜蓿毛状根的开花期诱导 FT 和 GI 的上调，但仅在 MsLEA-D34-RNAi 系中下调 FT。在紫花苜蓿毛状根中证明了 MsLEA-D34 对 FT 积累的正向影响。从紫花苜蓿克隆的一个新的转录因子 ABA 响应元件（ABRE）结合转录因子（MsABF2）直接结合到 MsLEA-D34 启动子中的 RY 元件上，并激活 MsLEA-D34 的表达。上述结果表明，MsLEA-D34 可以调节植物的非生物胁迫反应，并影响拟南芥的开花时间。
