RNAi-mediated repression of dormancy-related genes results in evergrowing apple trees.

Autor: Wu R; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand., Cooney J; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Ruakura Campus, Hamilton 3214, New Zealand., Tomes S; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand., Rebstock R; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand., Karunairetnam S; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand., Allan AC; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand.; School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand., Macknight RC; Department of Biochemistry, University of Otago, Dunedin 9016, New Zealand., Varkonyi-Gasic E; The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Mt Albert Research Centre, Sandringham, Auckland 1025, New Zealand.
Jazyk: angličtina
Zdroj: Tree physiology [Tree Physiol] 2021 Aug 11; Vol. 41 (8), pp. 1510-1523.
DOI: 10.1093/treephys/tpab007
Abstrakt: DORMANCY-ASSOCIATED MADS-box (DAM) and SHORT VEGETATIVE PHASE (SVP) genes have been implicated in the regulation of winter dormancy in perennials. Ectopic expression of apple (Malus × domestica Borkh. 'Royal Gala') DAM and SVP genes delays budbreak and constrains lateral shoot outgrowth. In this study, we used RNA interference (RNAi) to simultaneously target all apple DAM and SVP genes in order to study their role and mode of action in the regulation of bud dormancy, budbreak and flowering. A synthetic construct carrying a hairpin fragment assembled from sequences specific to coding regions of three DAM and two SVP genes was used to generate transgenic lines. Reduced expression of DAM/SVP genes resulted in delayed leaf senescence and abscission in autumn, failure to enter bud dormancy in winter and continual growth of new leaves regardless of the season for over 3 years. Precocious flowering but normal flower morphology, fertility and fruit development were observed. The non-dormant phenotype was associated with modified phytohormone composition. The content of gibberellins (GAs) and jasmonates (JAs) was significantly increased in terminal buds of RNAi lines compared with wildtype plants, accompanied by elevated expression of the key GA biosynthesis pathway gene GIBBERELLIN 20 OXIDASE-2 (MdGA20ox-2) along with the FLOWERING LOCUS T gene MdFT2. The key mediator of plasmodesmatal closure, MdCALLOSE SYNTHASE 1 (MdCALS1), was repressed in RNAi lines. This study provides functional evidence for the role of DAM/SVP genes in vegetative phenology of apple and paves the way for production of low-chill varieties suitable for growth in warming climates.
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Databáze: MEDLINE
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