title: HsfA1a upregulates melatonin biosynthesis to confer cadmium tolerance in tomato plants.
abstract: Melatonin regulates broad aspects of plant responses to various biotic and abiotic stresses, but the upstream regulation of melatonin biosynthesis by these stresses remains largely unknown. Herein, we demonstrate that transcription factor heat-shock factor A1a (HsfA1a) conferred cadmium (Cd) tolerance to tomato plants, in part through its positive role in inducing melatonin biosynthesis under Cd stress. Analysis of leaf phenotype, chlorophyll content, and photosynthetic efficiency revealed that silencing of the HsfA1a gene decreased Cd tolerance, whereas its overexpression enhanced plant tolerance to Cd. HsfA1a-silenced plants exhibited reduced melatonin levels, and HsfA1a overexpression stimulated melatonin accumulation and the expression of the melatonin biosynthetic gene caffeic acid O-methyltransferase 1 (COMT1) under Cd stress. Both an in vitro electrophoretic mobility shift assay and in vivo chromatin immunoprecipitation coupled with qPCR analysis revealed that HsfA1a binds to the COMT1 gene promoter. Meanwhile, Cd stress induced the expression of heat-shock proteins (HSPs), which was compromised in HsfA1a-silenced plants and more robustly induced in HsfA1a-overexpressing plants under Cd stress. COMT1 silencing reduced HsfA1a-induced Cd tolerance and melatonin accumulation in HsfA1a-overexpressing plants. Additionally, the HsfA1a-induced expression of HSPs was partially compromised in COMT1-silenced wild-type or HsfA1a-overexpressing plants under Cd stress. These results demonstrate that HsfA1a confers Cd tolerance by activating transcription of the COMT1 gene and inducing accumulation of melatonin that partially upregulates expression of HSPs.
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Shu-Yu
authors.initials: SY
authors.lastname: Cai
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Center of Analysis and Measurement, Zhejiang University, Hangzhou, China.
authors.forename: You-Ping
authors.initials: YP
authors.lastname: Xu
authors.affiliation: Agricultural Experiment Station, Zhejiang University, Hangzhou, China.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Qi
authors.affiliation: Zhejiang Institute of Geological Survey/Geological Research Center for Agricultural Applications, China Geological Survey, Hangzhou, China.
authors.forename: Meng-Qi
authors.initials: MQ
authors.lastname: Li
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Golam Jalal
authors.initials: GJ
authors.lastname: Ahammed
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Xia
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Shi
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Zhou
authors.affiliation: University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.|Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou, China.
authors.forename: Jing-Quan
authors.initials: JQ
authors.lastname: Yu
authors.affiliation: Department of Horticulture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Hangzhou, China.
authors.forename: Jie
authors.identifier: http://orcid.org/0000-0002-8797-7214
authors.initials: J
authors.lastname: Zhou
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D002394:Catechol O-Methyltransferase / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D002851:Chromatography, High Pressure Liquid; D004268:DNA-Binding Proteins / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D055785:Gene Knockdown Techniques; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000378:metabolism*; D008550:Melatonin / Q000096:biosynthesis*; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D013312:Stress, Physiological / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D002104:Cadmium; D002394:Catechol O-Methyltransferase; D008550:Melatonin
keywords: cadmium stress; caffeic acid O-methyltransferase 1 (COMT1); heat-shock factor A1a (HsfA1a); heat-shock proteins (HSPs); melatonin; tomato