title: Physiological and proteomic analysis of salinity tolerance in Puccinellia tenuiflora.
abstract: Soil salinity poses a serious threat to agriculture productivity throughout the world. Studying mechanisms of salinity tolerance in halophytic plants will provide valuable information for engineering plants for enhanced salt tolerance. Monocotyledonous Puccinellia tenuiflora is a halophytic species that widely distributed in the saline-alkali soil of the Songnen plain in northeastern China. Here we investigate the molecular mechanisms underlying moderate salt tolerance of P. tenuiflora using a combined physiological and proteomic approach. The changes in biomass, inorganic ion content, osmolytes, photosynthesis, defense-related enzyme activities, and metabolites in the course of salt treatment were analyzed in the leaves. Comparative proteomic analysis revealed 107 identities (representing 93 unique proteins) differentially expressed in P. tenuiflora leaves under saline conditions. These proteins were mainly involved in photosynthesis, stress and defense, carbohydrate and energy metabolism, protein metabolism, signaling, membrane, and transport. Our results showed that reduction of photosynthesis under salt treatment was attributed to the down-regulation of the light-harvesting complex (LHC) and Calvin cycle enzymes. Selective uptake of inorganic ions, high K(+)/Na(+) ratio, Ca(2+) concentration changes, and an accumulation of osmolytes contributed to ion balance and osmotic adjustment in leaf cells. Importantly, P. tenuiflora plants developed diverse reactive oxygen species (ROS) scavenging mechanisms in their leaves to cope with moderate salinity, including enhancement of the photorespiration pathway and thermal dissipation, synthesis of the low-molecular-weight antioxidant α-tocopherol, and an accumulation of compatible solutes. This study provides important information toward improving salt tolerance of cereals.
authors: Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field, Ministry of Education, Harbin 150040, China.
authors: Juanjuan
authors: J
authors: Yu
authors: Sixue
authors: S
authors: Chen
authors: Qi
authors: Q
authors: Zhao
authors: Tai
authors: T
authors: Wang
authors: Chuanping
authors: C
authors: Yang
authors: Carolyn
authors: C
authors: Diaz
authors: Guorong
authors: G
authors: Sun
authors: Shaojun
authors: S
authors: Dai
mesh_terms: D000704:Analysis of Variance; D002681:China; D015180:Electrophoresis, Gel, Two-Dimensional; D016166:Free Radical Scavengers; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D006109:Poaceae / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D020543:Proteome / Q000187:drug effects / Q000378:metabolism*; D040901:Proteomics; D054712:Salinity; D055049:Salt Tolerance / Q000502:physiology*; D055051:Salt-Tolerant Plants; D036226:Seedlings / Q000737:chemistry / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D024502:alpha-Tocopherol / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D010940:Plant Proteins; D020543:Proteome; D012965:Sodium Chloride; D012964:Sodium; D024502:alpha-Tocopherol; D011188:Potassium