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Conference papers

ABI5 is a major regulator of late maturation in legume seeds, linking longevity, oligosaccharide accumulation and chloroplast dedifferentiation

Abstract : Abscisic acid insensitive 5 (ABI5) is a bZIP transcription factor that activates ABA- and stress-responsive genes in seeds and seedlings. Here, we will present evidence that ABI5 is also an important regulator of late maturation in legumes. Using Tnt1 insertion mutants of Medicago truncatula and EMS mutants of pea, we discovered that seed longevity is severely reduced in these two legume species. Also, in these mutants, the accumulation of raffinose oligosaccharide family (RFO) sugars that takes place at the final steps of seed maturation is impaired. Mature Mtabi5 and Psabi5 mutant seeds contain respectively 2-fold less stachyose and verbascose than in wild type seeds. MtABI5 also plays a role in the accumulation of a restricted subset of Late Embryogenesis Abundant (LEA) proteins. A proteomic analysis on the heat stable protein fraction revealed strongly reduced levels of EM1 and several D-34 LEA polypeptides. Transcriptome analysis on developing Mtabi5 mutants during seed development confirmed that the biochemical phenotypes of RFO accumulation and LEAs were also regulated at the transcriptional level. Surprisingly, this analysis also revealed a strong deregulation of transcripts encoding photosynthesis-associated nuclear genes. This result was confirmed by a transcriptome analysis of hairy roots ectopically over-expressing MtABI5. Further biochemical analysis demonstrated elevated chlorophyll and carotenoid levels in mature seeds of the Psabi5 and Mtabi5 mutants compared to wild type seeds, suggesting that in these legumes, ABI5 is involved in the dedifferentiation of chloroplasts. These results demonstrate that in legumes, ABI5 links RFO, chloroplasts and longevity. The causal relationship between these factors will be discussed.
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https://hal.inria.fr/hal-03226276
Contributor : Julia Zinsmeister Connect in order to contact the contributor
Submitted on : Friday, May 14, 2021 - 1:06:14 PM
Last modification on : Friday, May 20, 2022 - 9:04:59 AM

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Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives 4.0 International License

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  • HAL Id : hal-03226276, version 1

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Julia Zinsmeister, Emmanuel Terrasson, Benoît Ly Vu, David Lalanne, Olivier Leprince, et al.. ABI5 is a major regulator of late maturation in legume seeds, linking longevity, oligosaccharide accumulation and chloroplast dedifferentiation. Seed Longevity Workshop of the International Society for Seed Science (ISSS) 2015, International Society for Seed Science, Jul 2015, Wernigerode, Germany. ⟨hal-03226276⟩

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