PbSRT1 and PbSRT2 regulate pear growth and ripening yet displaying a species-specific regulation in comparison to other Rosaceae spp. (July 2021)

• Record Type: Journal Article
• Authors: Vall-llaura, Núria; Torres, Rosario; Lindo-García, Violeta; Muñoz, Paula; Munné-Bosch, Sergi; Larrigaudière, Christian; Teixidó, Neus; Giné-Bordonaba, Jordi
• Is Part Of: Plant science. Volume 308(2021)
• Publication Date: 2021-07
• Subjects: Apple -- Ethylene -- Epigenetic regulation -- Hormonal cross-talk -- Nectarine -- Sugars; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2021.110925
• Languages: English
• ISSNs: 0168-9452

Abstract

Graphical abstract: Highlights: Phylogenetic analysis differentiated stone and pome fruit sirtuin protein sequences. Differential inter and intra species (apple, pear and nectarine) gene expression profile of SRTs. PbSRT1 is negatively correlated with the pear hormones ABA, IAA, GA1 and zeatin. PbSRT2 is associated to the ripening process in an ethylene-independent manner. Sugar accumulation during pear ripening may be mediated by PbSRT2 . Abstract: Epigenetic regulation is crucial to ensure a coordinated control of the different events that occur during fruit development and ripening. Sirtuins are NAD + -dependent histone deacetylases involved in the regulation of gene expression of many biological processes. However, their implications in the Rosaceae family remains unexplored. Accordingly, in this work, we demonstrated the phylogenetic divergence of both sirtuins among Rosaceae species. We then characterized the expression pattern of both SRT1 and SRT2 in selected pome and stone fruit species. Both SRT1 and SRT2 significantly changed during the fruit development and ripening of apple, nectarine and pear fruit, displaying a different expression profile. Such differences could explain in part their different ripening behaviour. To further unravel the role of sirtuins on the fruit development and ripening processes, a deeper analysis was performed using pear as a fruit model. In pear, PbSRT1 gene expression levels were negatively correlated with specific hormones (i.e. abscisic acid, indole-3-acetic acid, gibberellin A1 and zeatin) during the first phases of fruit development. PbSRT2 seemed to directly mediate pear ripening in an ethylene-independent manner. This hypothesis was further reinforced by treating the fruit with the ethylene inhibitor 1-methylcyclopropene (1-MCP). Instead, enhanced PbSRT2 along pear growth/ripening positively correlated with the accumulation of major sugars (R 2 > 0.94), reinforcing the idea that sugar metabolism may be a target of epigenetic modifications during fruit ripening. Overall, the results from this study point out, for the first time, the importance that sirtuins have in the regulation of fruit growth and ripening of pear fruit by likely regulating hormonal and sugar metabolism.