State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, 7300070, China.
College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China.
Sci Rep. 2021 Dec 6;11(1):23434. doi: 10.1038/s41598-021-02707-z.
Winter rapeseed (Brassica rapa L.) is a major oilseed crop in Northern China, where its production was severely affected by chilling and freezing stress. However, not much is known about the role of differentially accumulated proteins (DAPs) during the chilling and freezing stress. In this study, isobaric tag for relative and absolute quantification (iTRAQ) technology was performed to identify DAPs under freezing stress. To explore the molecular mechanisms of cold stress tolerance at the cellular and protein levels, the morphological and physiological differences in the shoot apical meristem (SAM) of two winter rapeseed varieties, Longyou 7 (cold-tolerant) and Lenox (cold-sensitive), were explored in field-grown plants. Compared to Lenox, Longyou 7 had a lower SAM height and higher collar diameter. The level of malondialdehyde (MDA) and indole-3-acetic acid (IAA) content was also decreased. Simultaneously, the soluble sugars (SS) content, superoxide dismutase (SOD) activity, peroxidase (POD) activity, soluble protein (SP) content, and collar diameter were increased in Longyou 7 as compared to Lenox. A total of 6330 proteins were identified. Among this, 98, 107, 183 and 111 DAPs were expressed in L7 CK/Le CK, L7 d/Le d, Le d/Le CK and L7 d/L7 CK, respectively. Quantitative real-time PCR (RT-qPCR) analysis of the coding genes for seventeen randomly selected DAPs was performed for validation. These DAPs were identified based on gene ontology enrichment analysis, which revealed that glutathione transferase activity, carbohydrate-binding, glutathione binding, metabolic process, and IAA response were closely associated with the cold stress response. In addition, some cold-induced proteins, such as glutathione S-transferase phi 2(GSTF2), might play an essential role during cold acclimation in the SAM of Brassica rapa. The present study provides valuable information on the involvement of DAPs during cold stress responses in Brassica rapa L, and hence could be used for breeding experiments.
冬季油菜（Brassica rapa L.）是中国北方的主要油料作物，其生产受到低温和冷冻胁迫的严重影响。然而，对于低温和冷冻胁迫过程中差异表达蛋白（DAP）的作用知之甚少。在这项研究中，采用同位素相对和绝对定量（iTRAQ）技术鉴定了冷冻胁迫下的 DAP。为了从细胞和蛋白质水平探索冷胁迫耐受的分子机制，在田间生长的植物中研究了两个冬季油菜品种龙游 7（耐寒）和 Lenox（耐寒）的茎尖分生组织（SAM）的形态和生理差异。与 Lenox 相比，龙游 7 的 SAM 高度较低，颈圈直径较高。丙二醛（MDA）和吲哚-3-乙酸（IAA）含量也降低。同时，与 Lenox 相比，龙游 7 的可溶性糖（SS）含量、超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性、可溶性蛋白（SP）含量和颈圈直径增加。共鉴定出 6330 种蛋白质。其中，L7 CK/Le CK、L7 d/Le d、Le d/Le CK 和 L7 d/L7 CK 中分别表达了 98、107、183 和 111 个 DAP。对 17 个随机选择的 DAP 的编码基因进行了定量实时 PCR（RT-qPCR）分析以验证。这些 DAP 基于基因本体富集分析进行鉴定，结果表明谷胱甘肽转移酶活性、碳水化合物结合、谷胱甘肽结合、代谢过程和 IAA 反应与冷胁迫反应密切相关。此外，一些冷诱导蛋白，如谷胱甘肽 S-转移酶 phi 2（GSTF2），可能在 Brassica rapa 的 SAM 中冷驯化过程中发挥重要作用。本研究为 Brassica rapa L 冷胁迫响应过程中 DAP 的参与提供了有价值的信息，可为育种实验提供参考。
