title: MtPM25 is an atypical hydrophobic late embryogenesis-abundant protein that dissociates cold and desiccation-aggregated proteins.
abstract: Late embryogenesis-abundant (LEA) proteins are one of the components involved in desiccation tolerance (DT) by maintaining cellular structures in the dry state. Among them, MtPM25, a member of the group 5 is specifically associated with DT in Medicago truncatula seeds. Its function is unknown and its classification as a LEA protein remains elusive. Here, evidence is provided that MtPM25 is a hydrophobic, intrinsically disordered protein that shares the characteristics of canonical LEA proteins. Screening protective activities by testing various substrates against freezing, heating and drying indicates that MtPM25 is unable to protect membranes but able to prevent aggregation of proteins during stress. Prevention of aggregation was also found for the water soluble proteome of desiccation-sensitive radicles. This inhibition was significantly higher than that of MtEM6, one of the most hydrophilic LEA protein associated with DT. Moreover, when added after the stress treatment, MtPM25 is able to rapidly dissolve aggregates in a non-specific manner. Sorption isotherms show that when it is unstructured, MtPM25 absorbs up to threefold more water than MtEM6. MtPM25 is likely to act as a protective molecule during drying and plays an additional role as a repair mechanism compared with other LEA proteins.
authors.affiliation: Université d'Angers, INRA, Agrocampus-Ouest, UMR1191 Physiologie Moléculaire des Semences, 16 Bd Lavoisier, F-49045 Angers, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Boucher
authors.forename: Julia
authors.initials: J
authors.lastname: Buitink
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Lin
authors.forename: Julie
authors.initials: J
authors.lastname: Boudet
authors.forename: Folkert A
authors.initials: FA
authors.lastname: Hoekstra
authors.forename: Michaela
authors.initials: M
authors.lastname: Hundertmark
authors.forename: Denis
authors.initials: D
authors.lastname: Renard
authors.forename: Olivier
authors.initials: O
authors.lastname: Leprince
mesh_terms: D002950:Citrate (si)-Synthase / Q000378:metabolism; D003080:Cold Temperature; D003890:Desiccation; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D046913:Medicago truncatula / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000378:metabolism; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; C066246:late embryogenesis abundant protein, plant; D014867:Water; D007770:L-Lactate Dehydrogenase; D002950:Citrate (si)-Synthase