ABI5 Is a Regulator of Seed Maturation and Longevity in Legumes

• Published in: The Plant cell Vol. 28; no. 11; pp. 2735 - 2754
• Main Authors: Zinsmeister, Julia, Lalanne, David, Terrasson, Emmanuel, Chatelain, Emilie, Vandecasteele, Céline, Vu, Benoit Ly, Dubois-Laurent, Cécile, Geoffriau, Emmanuel, Le Signor, Christine, Dalmais, Marion, Gutbrod, Katharina, Dörmann, Peter, Gallardo, Karine, Bendahmane, Abdelhafid, Buitink, Julia, Leprince, Olivier
• Format: Journal Article
• Language: English
• Published: England American Society of Plant Biologists 01.11.2016; American Society of Plant Biologists (ASPB)
• Subjects: Carotenoids - metabolism; Chlorophyll - metabolism; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; Life Sciences; Medicago truncatula; Medicago truncatula - genetics; Medicago truncatula - metabolism; Medicago truncatula - physiology; Pisum sativum; Pisum sativum - genetics; Pisum sativum - metabolism; Pisum sativum - physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Seeds - genetics; Seeds - metabolism; Seeds - physiology; Transcription Factors - genetics; Transcription Factors - metabolism; medicago-truncatula seed; transciption factor; late embryogenesis; drought stress tolerance; arabidopsis-thaliana; desiccation tolerance; heat-stable proteome; green-seed; gene expression
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.16.00470

The preservation of our genetic resources and production of high-quality seeds depends on their ability to remain viable and vigorous during storage. In a quantitative trait locus analysis on seed longevity in Medicago truncatula, we identified the bZIP transcription factor ABSCISIC ACID INSENSITIVE5 (ABI5). Characterization of Mt-abi5 insertion mutant seeds revealed that both the acquisition of longevity and dormancy were severely impaired. Using transcriptomes of developing Mt-abi5 seeds, we created a gene coexpression network and revealed ABI5 as a regulator of gene modules with functions related to raffinose family oligosaccharide (RFO) metabolism, late embryogenesis abundant (LEA) proteins, and photosynthesis-associated nuclear genes (PhANGs). Lower RFO contents in Mt-abi5 seeds were linked to the regulation of SEED IMBIBITION PROTEIN1. Proteomic analysis confirmed that a set of LEA polypeptides was reduced in mature Mt-abi5 seeds, whereas the absence of repression of PhANG in mature Mt-abi5 seeds was accompanied by chlorophyll and carotenoid retention. This resulted in a stress response in Mt-abi5 seeds, evident from an increase in a-tocopherol and upregulation of genes related to programmed cell death and protein folding. Characterization of abi5 mutants in a second legume species, pea (Pisum sativum), confirmed a role for ABI5 in the regulation of longevity, seed degreening, and RFO accumulation, identifying ABI5 as a prominent regulator of late seed maturation in legumes.