title: GASA5, a regulator of flowering time and stem growth in Arabidopsis thaliana.
abstract: Flowering is a critical event in the life cycle of plants and is regulated by a combination of endogenous controls and environmental cues. In the present work, we provide clear genetic evidence that GASA5, a GASA family gene in Arabidopsis (Arabidopsis thaliana), is involved in controlling flowering time and stem growth. GASA5 expression was present in all tissues of Arabidopsis plants, as detected by RT-PCR, and robust GUS staining was observed in the shoot apex of 8-day-old seedlings and inflorescence meristems during reproductive development. Phenotypic analysis showed that a GASA5 null mutant (gasa5-1) flowered earlier than wild type with a faster stem growth rate under both long-day (LD) and short-day (SD) photoperiods. In contrast, transgenic plants overexpressing GASA5 demonstrated delayed flowering, with a slower stem growth rate compared to wild-type plants. However, neither the GASA5 null mutants nor the GASA5 overexpressing plants revealed obvious differences in flowering time upon treatment with gibberellic acid (GA(3)), indicating that GASA5 is involved in gibberellin (GA)-promoted flowering. GAI (GA INSENSITIVE), one of the five DELLAs in Arabidopsis, was more highly expressed in GASA5-overexpressing plants, but it was lower in gasa5-1. Further transcript profiling analysis suggested that GASA5 delayed flowering by enhancing FLOWERING LOCUS C (FLC) expression and repressing the expression of key flowering-time genes, FLOWERING LOCUS T (FT) and LEAFY (LFY). Our results suggest that GASA5 is a negative regulator of GA-induced flowering and stem growth.
authors.affiliation: Guangdong Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631, Guangdong, People's Republic of China.
authors.forename: Shengchun
authors.initials: S
authors.lastname: Zhang
authors.forename: Chengwei
authors.initials: C
authors.lastname: Yang
authors.forename: Jianzong
authors.initials: J
authors.lastname: Peng
authors.forename: Shulan
authors.initials: S
authors.lastname: Sun
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D035264:Flowers / Q000235:genetics* / Q000254:growth & development; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010937:Plant Growth Regulators / Q000494:pharmacology; D018547:Plant Stems / Q000235:genetics* / Q000254:growth & development; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; C542544:GASA5 protein, Arabidopsis; D005875:Gibberellins; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D005966:Glucuronidase