title: Elucidation of Cross-Talk and Specificity of Early Response Mechanisms to Salt and PEG-Simulated Drought Stresses in Brassica napus Using Comparative Proteomic Analysis.
abstract: 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.
authors.affiliation: 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.
authors.forename: Junling
authors.initials: J
authors.lastname: Luo
authors.affiliation: 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.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Tang
authors.affiliation: Key Laboratory of Molecular Biology and Gene Engineering of Jiangxi Province, College of Life Science, Nanchang University, Nanchang, China.
authors.forename: Xiaojue
authors.initials: X
authors.lastname: Peng
authors.affiliation: 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.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Yan
authors.affiliation: 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.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Zeng
authors.affiliation: 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.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: 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.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
authors.affiliation: 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.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
mesh_terms: D029688:Brassica napus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D040901:Proteomics; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000235:genetics / Q000502:physiology*
chemical_list: D012965:Sodium Chloride