|Authors: ||M.L. Badenes, A. Lloret, G. Ríos|
|Keywords: ||dormancy, DAM, SAP, sorbitol, hydric stress, gene expression|
Perennial plants in temperate climates remain in a non-growing latent state during the cold period of winter, to ensure optimal protection against low temperatures and drought.
The dormancy period is induced by low temperatures, but also dormancy release results from quantitative and cumulative perception of chilling.
This trait is highly genotype-dependent, and an important limiting factor for production in a climate change scenario.
Peach has been widely used for studying seasonal dormancy in adult tissues at physiological and molecular level, as a model for other perennial plants from temperate climates.
Molecular studies of buds from cultivars that differed in chilling requirements are needed to study correlation between bud characteristics during dormancy with genetic chilling requirements, physiology status and transcriptomic studies of genes linked to dormancy release.
This study reviews the different genes identified whose expression correlates with the dormancy status of buds.
Studies of DORMANCY-ASSOCIATED MADS-box (DAM) whose expression is upregulated during dormancy are presented.
Also, PpSAP1 gene coding for a stress associate protein (SAP) with two zinc-finger domains correlates its expression in dormant buds with dormancy release. PpSAP1 is repressed in flower buds after dormancy release, but hydric stresses induce its expression, similarly to other SAP genes in plants.
The constitutive expression of PpSAP1 in plum increases its tolerance to water stress.
Sorbitol is the primary photosynthetic product and the major phloem-translocated form of carbon in the Rosaceae. PpeS6PDH encodes a sorbitol-6-phosphate dehydrogenase involved in sorbitol synthesis that is expressed in dormant flower buds concomitantly with sorbitol accumulation. PpeS6PDH gene expression is affected by cold and water deficit stress suggesting a role of this gene in protection of buds against abiotic stresses, particularly chilling and desiccation.
Understanding the molecular mechanisms involved in dormancy release will become crucial to manage tree crop production under warmer conditions.
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