Xiong Junbo, Sun Yan, Yang Qingchuan, Tian Hong, Zhang Heshan, Liu Yang, Chen Mingxin
Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Institute of Animal and Veterinary Science, Hubei Academy of Agricultural Science, Yaoyuan 1, Hongshan, Wuhan, Hubei 430017 China.
Institute of Grassland Science, China Agricultural University, 2 West Road, Yuan Ming Yuan, Beijing, 100193 China.
Proteome Sci. 2017 Oct 30;15:19. doi: 10.1186/s12953-017-0127-z. eCollection 2017.
Alfalfa () is the most extensively cultivated forage legume in the world, and salinity stress is the most problematic environmental factors limiting alfalfa production. To evaluate alfalfa tissue variations in response to salt stress, comparative physiological and proteomic analyses were made of salt responses in the roots and shoots of the alfalfa.
A two-dimensional gel electrophoresis (2-DE)-based proteomic technique was employed to identify the differentially abundant proteins (DAPs) from salt-treated alfalfa roots and shoots of the salt tolerance cultivars Zhongmu No 1 cultivar, which was subjected to a range of salt stress concentrations for 9 days. In parallel, REL, MAD and HO contents, and the activities of antioxidant enzymes of shoots and roots were determinand.
Twenty-seven spots in the shoots and 36 spots in the roots that exhibited showed significant abundance variations were identified by MALDI-TOF-TOF MS. These DAPs are mainly involved in the biological processes of photosynthesis, stress and defense, carbohydrate and energy metabolism, second metabolism, protein metabolism, transcriptional regulation, cell wall and cytoskeleton metabolism, ion transpor, signal transduction. In parallel, physiological data were correlated well with our proteomic results. It is worth emphasizing that some novel salt-responsive proteins were identified, such as CP12, pathogenesis-related protein 2, harvest-induced protein, isoliquiritigenin 2'-O-methyltransferase. qRT-PCR was used to study the gene expression levels of the four above-mentioned proteins; four patterns are consistent with those of induced protein.
The primary mechanisms underlying the ability of alfalfa seedlings to tolerate salt stress were photosynthesis, detoxifying and antioxidant, secondary metabolism, and ion transport. And it also suggests that the different tissues responded to salt-stress in different ways.
紫花苜蓿是世界上种植最广泛的豆科牧草，盐胁迫是限制紫花苜蓿生产的最严重环境因素。为了评估紫花苜蓿组织对盐胁迫的响应差异，对紫花苜蓿的根和地上部进行了盐胁迫响应的比较生理和蛋白质组学分析。
采用基于二维凝胶电泳（2-DE）的蛋白质组学技术，从耐盐品种中苜一号经一系列盐胁迫浓度处理9天的紫花苜蓿根和地上部中鉴定差异丰度蛋白（DAPs）。同时，测定地上部和根的相对电导率（REL）、丙二醛（MAD）和过氧化氢（HO）含量以及抗氧化酶活性。
通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-TOF MS）鉴定出地上部27个和根部36个显示出显著丰度变化的蛋白点。这些DAPs主要参与光合作用、胁迫与防御、碳水化合物与能量代谢、次生代谢、蛋白质代谢、转录调控、细胞壁与细胞骨架代谢、离子转运、信号转导等生物学过程。同时，生理数据与蛋白质组学结果相关性良好。值得强调的是，鉴定出了一些新的盐响应蛋白，如CP12、病程相关蛋白2、收获诱导蛋白、异甘草素2'-O-甲基转移酶。采用实时荧光定量PCR（qRT-PCR）研究上述4种蛋白的基因表达水平；4种模式与诱导蛋白一致。
紫花苜蓿幼苗耐盐胁迫的主要机制是光合作用、解毒与抗氧化、次生代谢和离子转运。这也表明不同组织对盐胁迫的响应方式不同。
