Li Zhenyi, Long Ruicai, Zhang Tiejun, Wang Zhen, Zhang Fan, Yang Qingchuan, Kang Junmei, Sun Yan
Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
College of Animal Science and Technology, China Agriculture University, Beijing, 100193, People's Republic of China.
J Plant Res. 2017 Mar;130(2):387-396. doi: 10.1007/s10265-017-0905-9. Epub 2017 Feb 1.
Heat shock proteins (HSPs) are a ubiquitously expressed class of protective proteins that play a key role in plant response to stressful conditions. This study aimed to characterize and investigate the function of an HSP gene in alfalfa (Medicago sativa). MsHSP70, which contains a 2028-bp open reading frame, was identified through homology cloning. MsHSP70 shares high sequence identity (94.47%) with HSP70 from Medicago truncatula. Expression analysis of MsHSP70 in alfalfa organs revealed a relatively higher expression level in aerial organs such as flowers, stems and leaves than in roots. MsHSP70 was induced by heat shock, abscisic acid (ABA) and hydrogen peroxide. Transgenic Arabidopsis seedlings overexpressing MsHSP70 were hyposensitive to polyethylene glycol (PEG) and ABA treatments, suggesting that exogenous expression of MsHSP70 enhanced Arabidopsis tolerance to these stresses. Examination of physiological indexes related to drought and ABA stress demonstrated that in comparison with non-transgenic plants, T3 transgenic Arabidopsis plants had an increased proline content, higher superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. Furthermore, higher relative water content (RWC) was detected in transgenic plants compared with non-transgenic plants under drought stress. These findings clearly indicate that molecular manipulation of MsHSP70 in plants can have substantial effects on stress tolerance.
热休克蛋白（HSPs）是一类广泛表达的保护性蛋白，在植物应对胁迫条件时发挥关键作用。本研究旨在鉴定和研究紫花苜蓿（Medicago sativa）中一个热休克蛋白基因的功能。通过同源克隆鉴定出含有2028个碱基对开放阅读框的MsHSP70。MsHSP70与蒺藜苜蓿的HSP70具有较高的序列同一性（94.47%）。对MsHSP70在紫花苜蓿各器官中的表达分析表明，其在花、茎和叶等地上器官中的表达水平相对高于根。MsHSP70受热激、脱落酸（ABA）和过氧化氢诱导。过表达MsHSP70的转基因拟南芥幼苗对聚乙二醇（PEG）和ABA处理不敏感，这表明MsHSP70的外源表达增强了拟南芥对这些胁迫的耐受性。对与干旱和ABA胁迫相关的生理指标进行检测表明，与非转基因植物相比，T3代转基因拟南芥植株脯氨酸含量增加、超氧化物歧化酶（SOD）活性更高、丙二醛（MDA）含量降低。此外，在干旱胁迫下，转基因植物的相对含水量（RWC）高于非转基因植物。这些发现清楚地表明，对植物中MsHSP70进行分子操作可对胁迫耐受性产生重大影响。
