title: A Zinc Finger Protein Regulates Flowering Time and Abiotic Stress Tolerance in Chrysanthemum by Modulating Gibberellin Biosynthesis.
abstract: Flowering time and an ability to tolerate abiotic stresses are important for plant growth and development. We characterized BBX24, a zinc finger transcription factor gene, from Chrysanthemum morifolium and found it to be associated with both flowering time and stress tolerance. Transgenic lines with suppressed expression of Cm-BBX24 (Cm-BBX24-RNAi) flowered earlier than wild-type plants and showed decreased tolerance to freezing and drought stresses. Global expression analysis revealed that genes associated with both photoperiod and gibberellin (GA) biosynthesis pathways were upregulated in Cm-BBX24-RNAi lines, relative to the wild type. By contrast, genes that were upregulated in overexpressing lines (Cm-BBX24-OX), but downregulated in Cm-BBX24-RNAi lines (both relative to the wild type), included genes related to compatible solutes and carbohydrate metabolism, both of which are associated with abiotic stress. Cm-BBX24 expression was also influenced by daylength and GA4/7application. Under long days, changes in endogenous GA1, GA4, GA19, and GA20levels occurred in young leaves of transgenic lines, relative to the wild type. Regulation of flowering involves the FLOWERING TIME gene, which integrates photoperiod and GA biosynthesis pathways. We postulate that Cm-BBX24 plays a dual role, modulating both flowering time and abiotic stress tolerance in chrysanthemum, at least in part by influencing GA biosynthesis.
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Imtiaz
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Lan
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853 U.S. Department of Agriculture Robert W. Holley Center for Agriculture and Health, Ithaca, New York 14853.
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Wang
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853 U.S. Department of Agriculture Robert W. Holley Center for Agriculture and Health, Ithaca, New York 14853.
authors.forename: Zhangjun
authors.initials: Z
authors.lastname: Fei
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Hong
authors.affiliation: Department of Ornamental Horticulture, China Agricultural University, 100193 Beijing, China gaojp@cau.edu.cn.
authors.forename: Junping
authors.initials: J
authors.lastname: Gao