02658naa a2200301 a 450000100080000000500110000800800410001902400280006010000230008824501630011126000090027452017050028365000110198865000150199965000110201465000200202565300250204565300230207065300460209370000170213970000180215670000220217470000260219670000190222270000270224170000180226877300700228620983562018-11-08       2018    bl uuuu     u00u1 u    #d7 a10.1093/jxb/erx4512DOI1 aFALAVGNA, V. da S.  aEvolutionary diversification of galactinol synthases in Rosaceaebadaptive roles of galactinol and raffinose during apple bud dormancy.h[electronic resource]  c2018  aGalactinol synthase (GolS) is a key enzyme in the biosynthetic pathway of raffinose family oligosaccharides (RFOs), which play roles in carbon storage, signal transduction, and osmoprotection. The present work assessed the evolutionary history of GolS genes across the Rosaceae using several bioinformatic tools. Apple (Malus × domestica) GolS genes were transcriptionally characterized during bud dormancy, in parallel with galactinol and raffinose measurements. Additionally, MdGolS2, a candidate to regulate seasonal galactinol and RFO content during apple bud ormancy, was functionally characterized in Arabidopsis. Evolutionary analyses revealed that whole genome duplications have driven GolS gene evolution and diversification in Rosaceae speciation. The strong purifying selection identified in duplicated GolS genes suggests that differential gene expression might define gene function better than protein structure. Interestingly, MdGolS2 was differentially expressed during bud dormancy, concomitantly with the highest galactinol and raffinose levels. One of the intrinsic adaptive features of bud dormancy is limited availability of free water; therefore, we generated transgenic Arabidopsis plants expressing MdGolS2. They showed higher galactinol and raffinose contents and increased tolerance to water deficit. Our results suggest that MdGolS2 is the major GolS responsible for RFO accumulation during apple dormancy, and these carbohydrates help to protect dormant buds against limited water supply. Keywords: Apple, bud dormancy, galactinol synthase, Malus × domestica, raffinose family oligosaccharides, tolerance to water deficit, transgenic expression, whole-genome duplication.  aApples  aDormência  aMaçã  aMalus Domestica  aDormência das gemas  aGalactinol sintase  aOligossacarídeos da família da rafinose1 aPORTO, D. D.1 aMIOTTO, Y. E.1 aSANTOS, H. P. dos1 aOLIVEIRA, P. R. D. de1 aPINHEIRO, M M.1 aGIANCARLO PASQUALI, G.1 aREVERS, L. F.  tJournal of Experimental Botanygv. 69, n. 5, p. 1247- 1259, 2018.