title: Exogenous γ-Aminobutyric Acid Improves the Structure and Function of Photosystem II in Muskmelon Seedlings Exposed to Salinity-Alkalinity Stress.
abstract: Gamma-aminobutyric acid (GABA) is important in plant responses to environmental stresses. We wished to clarify the role of GABA in maintenance of photosynthesis in muskmelon seedlings (Cucumis melo L., cv. Yipintianxia) during saline-alkaline stress. To this end, we assessed the effect of GABA on the structure and function of the photosynthetic apparatus in muskmelon seedlings grown under saline-alkaline stress. These stresses in combination reduced net photosynthetic rate, gas-exchange, and inhibited photosystem II (PSII) electron transport as measured by the JIP-test. They also reduced the activity of chloroplast ATPases and disrupted the internal lamellar system of the thylakoids. Exogenous GABA alleviated the stress-induced reduction of net photosynthesis, the activity of chloroplast ATPases, and overcame some of the damaging effects of stress on the chloroplast structure. Based on interpretation of the JIP-test, we conclude that exogenous GABA alleviated stress-related damage on the acceptor side of PSII. It also restored energy distribution, the reaction center status, and enhanced the ability of PSII to repair reaction centers in stressed seedlings. GABA may play a crucial role in protecting the chloroplast structure and function of PSII against the deleterious effects of salinity-alkalinity stress.
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Xiang
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Lipan
authors.initials: L
authors.lastname: Hu
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Weinan
authors.initials: W
authors.lastname: Xu
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Ai
authors.initials: A
authors.lastname: Zhen
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Horticulture, Northwest Agricultural & Forest University, Yangling, 712100 China.|Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Shaanxi, Yangling, 712100, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Hu
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D002734:Chlorophyll / Q000737:chemistry; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D028463:Cucumis melo / Q000187:drug effects / Q000378:metabolism*; D005470:Fluorometry; D010788:Photosynthesis / Q000187:drug effects; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D012492:Salts / Q000494:pharmacology*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D012492:Salts; D002734:Chlorophyll; D005680:gamma-Aminobutyric Acid; D000251:Adenosine Triphosphatases