Characterization of gibberellin-signalling elements during plum fruit ontogeny defines the essentiality of gibberellin in fruit development
Fruit growth is a coordinated, complex interaction of cell division, differentiation and expansion. Gibberellin (GA) involvement in the reproductive events is an important aspect of GA effects. Perennial fruit-trees such as plum (Prunus salicina L.) have distinct features that are economically important and provide opportunities to dissect specific GA mechanisms. Currently, very little is known on the molecular mechanism(s) mediating GA effects on fruit development. Determination of bioactive GA content during plum fruit ontogeny revealed that GA1 and GA4 are critical for fruit growth and development. Further, characterization of several genes involved in GA-signalling showed that their transcriptional regulation are generally GA-dependent, confirming their involvement in GA-signalling. Based on these results, a model is presented elucidating how the potential association between GA and other hormones may contribute to fruit development. PslGID1 proteins structure, Y2H and BiFC assays indicated that plum GA-receptors can form a complex with AtDELLA-repressors in a GA-dependent manner. Moreover, phenotypical-, molecular- and GA-analyses of various Arabidopsis backgrounds ectopically expressing PslGID1 sequences provide evidence on their role as active GA-signalling components that mediate GA-responsiveness. Our findings support the critical contribution of GA alone or in association with other hormones in mediating plum fruit growth and development.
KeywordsFruit development GA content GA-signalling Plum PslGID1/DELLA interaction Hormones cross-talk
We thank Dr. Stephen G. Thomas for providing gid1a-1/gid1c-1 double mutant, Dr. Stanton Gelvin for providing the EYFP vectors. We also thank the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and Early Researchers Award of the Ontario Ministry of Innovation for financial assistance. We thank Dr. Bouzayen for help with subcellular localization experiment.
- Augustí M, Almela V, Andreu I, Juan M, Zacarias L (1999) Synthetic auxin 3,5,6-TPA promotes fruit development and climacteric in Prunus persica L. Batsch. J Hortic Sci Biotech 74:556–560Google Scholar
- Dunberg A, Odén PC (1983) Gibberellins and conifers. In: Crozier A (ed) The biochemistry and physiology of gibberellins. Praeger, New York, pp 221–295Google Scholar
- Jackson DI (1968) Gibberellin in the growth of peach and apricot fruits. Aust J Biol Sci 21:209–215Google Scholar
- Nitsch JP (1970) Hormonal factors in growth and development. In: Hulme AC (ed) The biochemistry of fruits and their products. Academic Press, London, New York, pp 427–472Google Scholar
- Ross JJ, O’Neill DP, Wolbang CM, Symons GM, Reid JB (2002) Auxin-gibberellin interactions and their role in plant growth. J Plant Growth Regul 20:346–353Google Scholar
- Serrano M, Martínez-Romero D, Zuzunaga M, Riquelme F, Valero D (2007) Calcium, polyamine and gibberellin treatments to improve postharvest fruit quality. In: Dris R, Jain SM (eds) Production practices and quality assessment of food crops. Vol. 4. Postharvest treatment and technology. Kluwer Academic Publishers, Dordrecht, pp 55–68Google Scholar
- Sponsel VM, Hedden P (2004) Gibberellin biosynthesis and inactivation. In: Davies PJ (ed) Plant hormones: biosynthesis, signal transduction, action!. Kluwer Academic Publishers, Dordrecht, pp 63–94Google Scholar
- Yamaguchi I, Takahashi N (1976) Change of gibberellin and abscisic acid content during fruit development of Prunus persica. Plant Cell Physiol 17:611–614Google Scholar