title: ARABIDOPSIS THALIANA HOMEOBOX25 uncovers a role for Gibberellins in seed longevity.
abstract: Seed longevity is crucial for agriculture and plant genetic diversity, but it is limited by cellular damage during storage. Seeds are protected against aging by cellular defenses and by structures such as the seed coat. We have screened an activation-tagging mutant collection of Arabidopsis (Arabidopsis thaliana) and selected four dominant mutants with improved seed longevity (isl1-1D to isl4-1D) under both natural and accelerated aging conditions. In the isl1-1D mutant, characterized in this work, overexpression of the transcription factor ARABIDOPSIS THALIANA HOMEOBOX25 (ATHB25; At5g65410) increases the expression of GIBBERELLIC ACID3-OXIDASE2, encoding a gibberellin (GA) biosynthetic enzyme, and the levels of GA1 and GA4 are higher (3.2- and 1.4-fold, respectively) in the mutant than in the wild type. The morphological and seed longevity phenotypes of the athb25-1D mutant were recapitulated in transgenic plants with moderate (4- to 6-fold) overexpression of ATHB25. Simultaneous knockdown of ATHB25, ATHB22, and ATHB31 expression decreases seed longevity, as does loss of ATHB25 and ATHB22 function in a double mutant line. Seeds from wild-type plants treated with GA and from a quintuple DELLA mutant (with constitutive GA signaling) are more tolerant to aging, providing additional evidence for a role of GA in seed longevity. A correlation was observed in several genotypes between seed longevity and mucilage formation at the seed surface, suggesting that GA may act by reinforcing the seed coat. This mechanism was supported by the observation of a maternal effect in reciprocal crosses between the wild type and the athb25-1D mutant.
authors: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain.
authors: Eduardo
authors: E
authors: Bueso
authors: Jesús
authors: J
authors: Muñoz-Bertomeu
authors: Francisco
authors: F
authors: Campos
authors: Veronique
authors: V
authors: Brunaud
authors: Liliam
authors: L
authors: Martínez
authors: Enric
authors: E
authors: Sayas
authors: Patricia
authors: P
authors: Ballester
authors: Lynne
authors: L
authors: Yenush
authors: Ramón
authors: R
authors: Serrano
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005838:Genotype; D018525:Germination / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D059372:Nucleotide Motifs / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D062087:Plant Mucilage / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D012639:Seeds / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D013194:Staining and Labeling; D014230:Triazoles / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; D062087:Plant Mucilage; D014230:Triazoles; C053370:paclobutrazol