title: Regulation of loquat fruit low temperature response and lignification involves interaction of heat shock factors and genes associated with lignin biosynthesis.
abstract: Transcriptional regulatory mechanisms underlying lignin metabolism have been widely studied in model plants and woody trees, as well as fruit, such as loquat (Eriobotrya japonica). Unlike the well-known NAC, MYB and AP2/ERF transcription factors, the roles of heat shock factors (HSFs) in lignin regulation have been rarely reported. Two treatments (heat treatment, HT; low temperature conditioning, LTC) were applied to alleviate low temperature-induced lignification in loquat fruit. Gene expression analysis indicated that EjHSF1 transcript abundance, in parallel with heat shock protein genes (EjHsp), was induced by HT, while expression of EjHSF3 was repressed by LTC. Using dual-luciferase assays, EjHSF1 and EjHSF3 trans-activated the promoters of EjHsp genes and lignin biosynthesis-related genes, respectively. Thus, two distinct regulatory mechanisms of EjHSF transcription factors in chilling injury-induced fruit lignification are proposed: EjHSF1 transcriptionally regulated EjHsp genes are involved in chilling tolerance, while EjHSF3 transcriptionally regulated lignin biosynthesis. Furthermore, the relations between EjHSF3 and previously characterized fruit lignification regulators, including EjAP2-1, EjMYB1 and EjMYB2, were also investigated. Yeast-two hybrid (Y2H) and biomolecular fluorescence complementation (BiFC) assays demonstrated protein-protein interaction between EjHSF3 and EjAP2-1. Thus, the involvement of EjHSF3 in fruit lignification is via both lignin biosynthetic genes and the regulator, EjAP2-1.
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Jiao-Ke
authors.initials: JK
authors.lastname: Zeng
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Xian
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Hang
authors.initials: H
authors.lastname: Ge
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Xue-Ren
authors.initials: XR
authors.lastname: Yin
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.|The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
authors.forename: Kun-Song
authors.initials: KS
authors.lastname: Chen
mesh_terms: D003080:Cold Temperature; D031983:Eriobotrya / Q000235:genetics / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D000076249:Heat Shock Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008031:Lignin / Q000096:biosynthesis*
chemical_list: D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D008031:Lignin
keywords: Chilling injury; HSF-AP2 complex; flesh lignification; heat shock factor; heat shock protein; heat treatment