title: The Tomato Hoffman's Anthocyaninless Gene Encodes a bHLH Transcription Factor Involved in Anthocyanin Biosynthesis That Is Developmentally Regulated and Induced by Low Temperatures.
abstract: Anthocyanin pigments play many roles in plants, including providing protection against biotic and abiotic stresses. Many of the genes that mediate anthocyanin accumulation have been identified through studies of flowers and fruits; however, the mechanisms of genes involved in anthocyanin regulation in seedlings under low-temperature stimulus are less well understood. Genetic characterization of a tomato inbred line, FMTT271, which showed no anthocyanin pigmentation, revealed a mutation in a bHLH transcription factor (TF) gene, which corresponds to the ah (Hoffman's anthocyaninless) locus, and so the gene in FMTT271 at that locus was named ah. Overexpression of the wild type allele of AH in FMTT271 resulted in greater anthocyanin accumulation and increased expression of several genes in the anthocyanin biosynthetic pathway. The expression of AH and anthocyanin accumulation in seedlings was shown to be developmentally regulated and induced by low-temperature stress. Additionally, transcriptome analyses of hypocotyls and leaves from the near-isogenic lines seedlings revealed that AH not only influences the expression of anthocyanin biosynthetic genes, but also genes associated with responses to abiotic stress. Furthermore, the ah mutation was shown to cause accumulation of reactive oxidative species and the constitutive activation of defense responses under cold conditions. These results suggest that AH regulates anthocyanin biosynthesis, thereby playing a protective role, and that this function is particularly important in young seedlings that are particularly vulnerable to abiotic stresses.
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Zhengkun
authors.initials: Z
authors.lastname: Qiu
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Jianchang
authors.initials: J
authors.lastname: Gao
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Guo
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Zejun
authors.initials: Z
authors.lastname: Huang
authors.affiliation: The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Yongchen
authors.initials: Y
authors.lastname: Du
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D001947:Breeding; D003080:Cold Temperature; D018506:Gene Expression Regulation, Plant; D056426:Genetic Loci / Q000235:genetics; D005838:Genotype; D018546:Hypocotyl / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism* / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D051792:Basic Helix-Loop-Helix Proteins; D010940:Plant Proteins; D017382:Reactive Oxygen Species