title: Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin.
abstract: Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism.
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Shi
authors.affiliation: Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Ye
authors.affiliation: Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Dun-Xian
authors.initials: DX
authors.lastname: Tan
authors.affiliation: Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
authors.affiliation: Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China zhulongch@wbgcas.cn ryliu@sibs.ac.cn hengzhang@gmail.com.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China zhulongch@wbgcas.cn ryliu@sibs.ac.cn hengzhang@gmail.com.
authors.forename: Renyi
authors.initials: R
authors.lastname: Liu
authors.affiliation: Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China zhulongch@wbgcas.cn ryliu@sibs.ac.cn hengzhang@gmail.com.
authors.forename: Zhulong
authors.initials: Z
authors.lastname: Chan
mesh_terms: D000222:Adaptation, Physiological; D003080:Cold Temperature; D031744:Cynodon / Q000187:drug effects / Q000502:physiology*; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D008550:Melatonin / Q000378:metabolism* / Q000494:pharmacology*; D055442:Metabolome; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D013312:Stress, Physiological; D059467:Transcriptome
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D008550:Melatonin
keywords: Abiotic stress; antioxidant; bermudagrass; melatonin; metabolites; reactive oxygen species; transcriptomic.