A rapid transcriptional activation is induced by the dormancy-breaking chemical hydrogen cyanamide in kiwifruit (Actinidia deliciosa) buds.
Budbreak in kiwifruit (Actinidia deliciosa) can be poor in locations that have warm winters with insufficient winter chilling. Kiwifruit vines are often treated with the dormancy-breaking chemical hydrogen cyanamide (HC) to increase and synchronize budbreak. This treatment also offers a tool to understand the processes involved in budbreak. A genomics approach is presented here to increase our understanding of budbreak in kiwifruit. Most genes identified following HC application appear to be associated with responses to stress, but a number of genes appear to be associated with the reactivation of growth. Three patterns of gene expression were identified: Profile 1, an HC-induced transient activation; Profile 2, an HC-induced transient activation followed by a growth-related activation; and Profile 3, HC- and growth-repressed. One group of genes that was rapidly up-regulated in response to HC was the glutathione S-transferase (GST) class of genes, which have been associated with stress and signalling. Previous budbreak studies, in three other species, also report up-regulated GST expression. Phylogenetic analysis of these GSTs showed that they clustered into two sub-clades, suggesting a strong correlation between their expression and budbreak across species.
Walton
Eric F
EF
The New Zealand Institute for Plant and Food Research Limited, Mt Albert, Auckland, New Zealand. eric.walton@otago.ac.nz
Wu
Rong-Mei
RM
Richardson
Annette C
AC
Davy
Marcus
M
Hellens
Roger P
RP
Thodey
Kate
K
Janssen
Bart J
BJ
Gleave
Andrew P
AP
Rae
Georgina M
GM
Wood
Marion
M
Schaffer
Robert J
RJ
D029042:Actinidia / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D003484:Cyanamide / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects*
D010940:Plant Proteins; D003484:Cyanamide