Luo Junling, Tang Shaohua, Peng Xiaojue, Yan Xiaohong, Zeng Xinhua, Li Jun, Li Xiaofei, Wu Gang
Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of People's Republic of China, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China.
Key Laboratory of Molecular Biology and Gene Engineering of Jiangxi Province, College of Life Science, Nanchang University, Nanchang, China.
PLoS One. 2015 Oct 8;10(10):e0138974. doi: 10.1371/journal.pone.0138974. eCollection 2015.
To understand the cross-talk and specificity of the early responses of plants to salt and drought, we performed physiological and proteome analyses of Brassica napus seedlings pretreated with 245 mM NaCl or 25% polyethylene glycol (PEG) 6000 under identical osmotic pressure (-1.0 MPa). Significant decreases in water content and photosynthetic rate and excessive accumulation of compatible osmolytes and oxidative damage were observed in response to both stresses. Unexpectedly, the drought response was more severe than the salt response. We further identified 45 common differentially expressed proteins (DEPs), 143 salt-specific DEPs and 160 drought-specific DEPs by isobaric tags for relative and absolute quantitation (iTRAQ) analysis. The proteome quantitative data were then confirmed by multiple reaction monitoring (MRM). The differences in the proteomic profiles between drought-treated and salt-treated seedlings exceeded the similarities in the early stress responses. Signal perception and transduction, transport and membrane trafficking, and photosynthesis-related proteins were enriched as part of the molecular cross-talk and specificity mechanism in the early responses to the two abiotic stresses. The Ca2+ signaling, G protein-related signaling, 14-3-3 signaling pathway and phosphorylation cascades were the common signal transduction pathways shared by both salt and drought stress responses; however, the proteins with executive functions varied. These results indicate functional specialization of family proteins in response to different stresses, i.e., CDPK21, TPR, and CTR1 specific to phosphorylation cascades under early salt stress, whereas STN7 and BSL were specific to phosphorylation cascades under early drought stress. Only the calcium-binding EF-hand family protein and ZKT were clearly identified as signaling proteins that acted as cross-talk nodes for salt and drought signaling pathways. Our study provides new clues and insights for developing strategies to improve the tolerance of crops to complex, multiple environmental stresses.
为了解植物对盐和干旱早期反应的相互作用及特异性，我们对在相同渗透压（-1.0 MPa）下用245 mM NaCl或25%聚乙二醇（PEG）6000预处理的甘蓝型油菜幼苗进行了生理和蛋白质组分析。在两种胁迫下均观察到水分含量和光合速率显著降低，相容性渗透溶质过度积累以及氧化损伤。出乎意料的是，干旱反应比盐反应更严重。我们通过相对和绝对定量的等压标签（iTRAQ）分析进一步鉴定了45种常见的差异表达蛋白（DEP）、143种盐特异性DEP和160种干旱特异性DEP。然后通过多反应监测（MRM）确认蛋白质组定量数据。干旱处理和盐处理幼苗之间蛋白质组图谱的差异超过了早期胁迫反应中的相似性。信号感知与转导、运输与膜 trafficking以及光合作用相关蛋白作为对两种非生物胁迫早期反应中分子相互作用和特异性机制的一部分而富集。Ca2+信号传导、G蛋白相关信号传导、14-3-3信号通路和磷酸化级联是盐和干旱胁迫反应共有的常见信号转导通路；然而，具有执行功能的蛋白质有所不同。这些结果表明家族蛋白在响应不同胁迫时的功能特化，即早期盐胁迫下CDPK21、TPR和CTR1对磷酸化级联具有特异性作用，而早期干旱胁迫下STN7和BSL对磷酸化级联具有特异性作用。只有钙结合EF手型家族蛋白和ZKT被明确鉴定为作为盐和干旱信号通路相互作用节点的信号蛋白。我们的研究为制定提高作物对复杂多重环境胁迫耐受性的策略提供了新的线索和见解。
