title: Comparative photosynthetic and metabolic analyses reveal mechanism of improved cold stress tolerance in bermudagrass by exogenous melatonin.
abstract: Melatonin (N-acetyl-5-methoxytryptamine) has been reported to participate in plant development and abiotic stress responses. The main objective of this study was to investigate the role of melatonin in the cold-sensitive (S) and the cold-tolerant (T) bermudagrass genotypes' response to cold stress. The genotypes were treated with 100 μM melatonin and exposed to 4 °C temperature for 3 days. In both genotypes, cold stress increased the endogenous melatonin levels, and more prominently in T than S. Physiological responses indicated that exogenous melatonin triggered antioxidant activities in both genotypes, while it alleviated cell damage in the T genotype response to cold stress. Melatonin treatment under cold stress increased fluorescence curve levels for both genotypes, and higher in T than S genotypes. In both genotypes, the alterations in photosynthetic fluorescence parameters after melatonin treatment highlighted the participation of melatonin in improving photosystem response to cold stress, particularly for the cold-tolerant genotype. The metabolic analyses revealed the alterations of 44 cold-responsive metabolites in the two genotypes, mainly including carbohydrates, organic acids and amino acids. After exogenous melatonin treatment under cold condition, there was high accumulation of metabolites in the cold-tolerant regimes than their cold-sensitive counterparts. Collectively, the present study revealed differential modulations of melatonin between the cold-sensitive and the cold-tolerant genotypes in response to cold stress. This was mainly by impacting antioxidant system, photosystem II, as well as metabolic homeostasis.
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
authors.forename: Jibiao
authors.initials: J
authors.lastname: Fan
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
authors.forename: Erick
authors.initials: E
authors.lastname: Amombo
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
authors.forename: Ao
authors.initials: A
authors.lastname: Liu
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
authors.forename: Margaret Mukami
authors.initials: MM
authors.lastname: Gitau
authors.affiliation: Plant Breeding Division Bangladesh Agricultural Research Institute (BARI) Joydebpur, Gazipur 1701, Bangladesh.
authors.forename: A B M
authors.initials: ABM
authors.lastname: Khaldun
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China. Electronic address: chenliang1034@126.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China. Electronic address: jfu@wbgcas.cn.
authors.forename: Jinmin
authors.initials: J
authors.lastname: Fu
mesh_terms: D058639:Cold-Shock Response / Q000187:drug effects* / Q000235:genetics; D031744:Cynodon / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D008550:Melatonin / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects* / Q000235:genetics
chemical_list: D008550:Melatonin
keywords: Bermudagrass; Cold stress; Genotype; Melatonin; Metabolism; Photosystem II