title: Variability within a pea core collection of LEAM and HSP22, two mitochondrial seed proteins involved in stress tolerance.
abstract: LEAM, a late embryogenesis abundant protein, and HSP22, a small heat shock protein, were shown to accumulate in the mitochondria during pea (Pisum sativum L.) seed development, where they are expected to contribute to desiccation tolerance. Here, their expression was examined in seeds of 89 pea genotypes by Western blot analysis. All genotypes expressed LEAM and HSP22 in similar amounts. In contrast with HSP22, LEAM displayed different isoforms according to apparent molecular mass. Each of the 89 genotypes harboured a single LEAM isoform. Genomic and RT-PCR analysis revealed four LEAM genes differing by a small variable indel in the coding region. These variations were consistent with the apparent molecular mass of each isoform. Indels, which occurred in repeated domains, did not alter the main properties of LEAM. Structural modelling indicated that the class A α-helix structure, which allows interactions with the mitochondrial inner membrane in the dry state, was preserved in all isoforms, suggesting functionality is maintained. The overall results point out the essential character of LEAM and HSP22 in pea seeds. LEAM variability is discussed in terms of pea breeding history as well as LEA gene evolution mechanisms.
authors.affiliation: Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France.
authors.forename: Marie-Hélène
authors.identifier: http://orcid.org/0000-0001-6002-3130
authors.initials: MH
authors.lastname: Avelange-Macherel
authors.affiliation: INRA, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Payet
authors.affiliation: INRA, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France.
authors.forename: David
authors.initials: D
authors.lastname: Lalanne
authors.affiliation: INRA, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Neveu
authors.affiliation: ANU College of Medicine, Biology and Environment, Acton, 2601, Australia.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Tolleter
authors.affiliation: GEAPSI, INRA, UMR 1347 Agroécologie, centre de Dijon, F-21065, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Burstin
authors.affiliation: Université d'Angers, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France.
authors.forename: David
authors.initials: D
authors.lastname: Macherel
mesh_terms: D000595:Amino Acid Sequence; D005838:Genotype; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D018532:Pisum sativum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms; D012639:Seeds / Q000378:metabolism; D016415:Sequence Alignment; D013312:Stress, Physiological; D013696:Temperature
chemical_list: C096801:HSP22 protein, plant; D006360:Heat-Shock Proteins; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D020033:Protein Isoforms
keywords: LEA protein; gene evolution; indel; mitochondria; pea accessions; small HSP