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Made available in DSpace on 2020-12-10T20:10:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-23 Conseil Regional des Pays de la Loire Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Directorate for Biological Sciences FP7 Food, Agriculture and Fisheries, Biotechnology Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) National Science Foundation European Regional Development Fund Angers Loire Metropole Region Pays de la Loire During the later stages of seed maturation, two key adaptive traits are acquired that contribute to seed lifespan and dispersal, longevity and dormancy. The seed-specific heat shock transcription factor A9 is an important hub gene in the transcriptional network of late seed maturation. Here, we demonstrate that HSFA9 plays a role in thermotolerance rather than in ex situ seed conservation. Storage ofhsfa9seeds ofMedicago truncatulaand Arabidopsis had comparable lifespan at moderate storage relative humidity (RH), whereas at high RH,hsfa9seeds lost their viability much faster than wild type seeds. Furthermore, we show that inM.truncatula, Mthsfa9seeds acquired more dormancy during late maturation than wild type. Transient expression of MtHSFA9in hairy roots and transcriptome analysis of Mthsfa9Tnt1 insertion mutants identified a deregulation of genes involved in ABA biosynthesis, catabolism and signalling. Consistent with these results,Mthsfa9seeds exhibited increased ABA levels and higher sensitivity to ABA. These data suggest that in legumes,HSFA9acts as a negative regulator of the depth of seed dormancy during seed development via the modulation of hormonal balance. Univ Angers, Inst Agro, SFR 4207 QuaSaV, IRHS,UMR1345,INRAE, F-49071 Beaucouze, France Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, Botucatu, SP, Brazil Ctr Res Agr Genom CRAG, Barcelona, Spain Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, Botucatu, SP, Brazil CAPES: 001 Directorate for Biological Sciences: 703285 FP7 Food, Agriculture and Fisheries, Biotechnology: FP7-609398 FAPESP: 17/50211-9 National Science Foundation: 703285

Made available in DSpace on 2018-11-26T17:54:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01. Added 1 bitstream(s) on 2019-10-09T18:27:39Z : No. of bitstreams: 1 S2317-15372018000200185.pdf: 712556 bytes, checksum: 73d75532f5b6d539fb9e74f5c06c15ce (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Region-des-Pays-de-la-Loire, Objectif vegetal, France Long-term survival during dry storage or longevity is a pre-requisite to avoid deterioration, leading to loss of vigor. Longevity is routinely evaluated by the ability to germinate after storage. It increases progressively during seed maturation, after the acquisition of desiccation tolerance. However, the capacity to germinate represents only a part of the success of crop establishment. How seed maturation affects the resistance of several traits, as vigor, associated with seedling establishment, against detenoration was evaluated dunng seed filling and post-abscission phase of soybean BRS 284 seeds. Three newphenological stages between 7.1 and 7.2 (7.1.1, 7.1.2 and 7.1.3) were introduced to capture the rapid increase in seed longevity. Germination speed started to be affected at 7-14 days after storage depending on the stages. The delay on germination increased with maturation from 7.1.3 to dry mature seeds. The time to 50% loss of elongation capacity of both organs during storage was similar to that of loss of germination. Also, it increased steadily dunng seed maturation after mass matunty and harvest matunty stages, highlighting the importance of the late phase of seed maturation for building seed vigor. Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod & Melhoramento Vegetal, BR-18610307 Botucatu, SP, Brazil Univ Angers, SFR QUASAV 4207, Inst Rech Hort & Semences, Agrocampus Ouest,INRA, F-49071 Beaucouze, France Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod & Melhoramento Vegetal, BR-18610307 Botucatu, SP, Brazil

Made available in DSpace on 2018-11-26T17:49:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01. Added 1 bitstream(s) on 2019-10-09T18:27:25Z : No. of bitstreams: 1 S0100-67622017000400211.pdf: 3550446 bytes, checksum: ec84449ab028d0f2ced339061cea8e82 (MD5) The aim of this study was to evaluate DNA integrity and to identify ultrastructural changes in the primary root of Peltophorum dubium seeds subjected to drying, since these changes may reflect the germination capacity. Seeds were germinated and were dehydrated when reached 1 mm in length of the primary root, until reaching different moisture contents, being then rehydrated and evaluated in relation to survival. After this procedure, different points of interest (control, 20% and 10% moisture content) were selected to evaluate DNA and cell ultrastructure integrity in order to detect possible cellular changes in primary roots after dehydration. When dried down to 32% moisture, there was no influence on the growth resumption of the germinated seeds, but when they were dehydrated to 20% moisture, the survival was reduced to 67%, reaching nullity in the survival with drying to 8% moisture. By the evaluation of ultrastructural changes in root cells, it was observed that drying to approximately 20% moisture content marked the onset of damages by desiccation, both physiologically and ultrastructurally. Drying to levels close to 10% moisture content was not only responsible for total disorganization and rupture of membranes, but also promoted intracellular collapse. Loss of genomic DNA integrity was observed during drying. Univ Fed Lavras, Engn Florestal, Lavras, MG, Brazil Univ Wageningen, Dept Fisiol Plantas, Wageningen, Netherlands Univ Fed Lavras, Dept Ciencias Florestais, Lavras, MG, Brazil Univ Estadual Paulista, Dept Prod Vegetal, Botucatu, SP, Brazil Univ Estadual Paulista, Dept Prod Vegetal, Botucatu, SP, Brazil

Made available in DSpace on 2018-11-26T15:44:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-12 Seed longevity, defined as the ability to remain alive during storage, is an important agronomic factor. Poor longevity negatively impacts seedling establishment and consequently crop yield. This is particularly problematic for soybean as seeds have a short lifespan. While the economic importance of soybean has fueled a large number of transcriptome studies during embryogenesis and seed filling, the mechanisms regulating seed longevity during late maturation remain poorly understood. Here, a detailed physiological and molecular characterization of late seed maturation was performed in soybean to obtain a comprehensive overview of the regulatory genes that are potentially involved in longevity. Longevity appeared at physiological maturity at the end of seed filling before maturation drying and progressively doubled until the seeds reached the dry state. The increase in longevity was associated with the expression of genes encoding protective chaperones such as heat shock proteins and the repression of nuclear and chloroplast genes involved in a range of chloroplast activities, including photosynthesis. An increase in the raffinose family oligosaccharides (RFO)/sucrose ratio together with changes in RFO metabolism genes was also associated with longevity. A gene co-expression network analysis revealed 27 transcription factors whose expression profiles were highly correlated with longevity. Eight of them were previously identified in the longevity network of Medicago truncatula, including homologues of ERF110, HSF6AB, NFXL1 and members of the DREB2 family. The network also contained several transcription factors associated with auxin and developmental cell fate during flowering, organ growth and differentiation. A transcriptional transition occurred concomitant with seed chlorophyll loss and detachment from the mother plant, suggesting the activation of a post-abscission program. This transition was enriched with AP2/EREBP and WRKY transcription factors and genes associated with growth, germination and post-transcriptional processes, suggesting that this program prepares the seed for the dry quiescent state and germination. Univ Estadual Paulista, Fac Ciencias Agron, Botucatu, SP, Brazil Univ Angers, SFR QUASAV, Agrocampus Ouest, Inst Rech Hort & Semences,INRA, Beaucouze, France Univ Estadual Paulista, Fac Ciencias Agron, Botucatu, SP, Brazil