title: Relationship between endodormancy, FLOWERING LOCUS T and cell cycle genes in Vitis vinifera.
abstract: In grapevines, the increased expression of VvFT , genes involved in the photoperiodic control of seasonal growth ( VvAP1, VvAIL2 ) and cell cycle genes ( VvCDKA, VvCDKB2, VvCYCA1, VvCYCB, VvCYCD3.2 ) in the shoot apex relative to the latent bud, suggests a high mitotic activity of the apex which could prevent them to enter into endodormancy. Additionally, the up-regulation of these genes by the dormancy-breaking compound hydrogen cyanamide (H 2 CN 2 ) strongly suggests that VvFT plays a key role in regulating transcriptionally cell cycle genes. At the end of the growing season, short-day (SD) photoperiod induces the transition of latent grapevine buds (Vitis vinifera L) from paradormancy (PD) to endodormancy (ED), which allows them to survive the cold temperatures of winter. Meanwhile, the shoot apex gradually decreases its growth without entering into ED, and as a result of the fall of temperatures at the beginning of autumn, dies. To understand developmental differences and contrasting responses to environmental cues between both organs, the expression of cell cycle genes, and of genes involved in photoperiodic control of seasonal growth in trees, such as FLOWERING LOCUS T (FT), APETALA1 (AP1) and AINTEGUMENTA-like (AIL) was analyzed at the shoot apex and latent buds of vines during the transition from PD to ED. After shift to SD photoperiod, increased expression of cell cycle genes in the shoot apex suggests a high mitotic activity in this organ which could prevent them from entering into ED. Additionally, the increased expression of VvFT, VvAP1and VvAIL2 in the shoot apex, and the up-regulation of VvFT, VvAP1and cell cycle genes VvCDKA, VvCDKB2, VvCYCA.1, by the dormancy-breaking compound hydrogen cyanamide (H2CN2), strongly suggests that VvFT plays a key role in regulating transcriptionally cell cycle genes, giving thus, more support to the model for photoperiodic control of seasonal growth in trees. Furthermore, downregulation of VvFT by the SD photoperiod detected in leaves and buds of grapevines highlights the importance of VvFT in the induction of growth cessation and in ED development, probably by regulating the expression of cell cycle genes.
authors.affiliation: Facultad de Ciencias, Laboratorio de Bioquímica Vegetal, Universidad de Chile, Casilla 653, Santiago, Chile.|Programa Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Universidad de Chile, Santiago, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Vergara
authors.affiliation: Facultad de Ciencias, Laboratorio de Bioquímica Vegetal, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Ximena
authors.initials: X
authors.lastname: Noriega
authors.affiliation: Facultad de Ciencias, Laboratorio de Bioquímica Vegetal, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Francisca
authors.initials: F
authors.lastname: Parada
authors.affiliation: Centro de Ciencias e Tecnologías Agropecuarias, Universidade Estadual do Norte Fluminense, Avda Alberto Lamego 2000, Campos Dos Goytacazes, RJ, Brazil.
authors.forename: Débora
authors.initials: D
authors.lastname: Dantas
authors.affiliation: Facultad de Ciencias, Laboratorio de Bioquímica Vegetal, Universidad de Chile, Casilla 653, Santiago, Chile. frperez@uchile.cl.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Pérez
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology; D002940:Circadian Rhythm; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017440:Photoperiod; D057445:Plant Dormancy / Q000235:genetics*; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012621:Seasons; D027843:Vitis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D018797:Cell Cycle Proteins
keywords: Apex; Buds; Dormancy; Grapevines