ABSTRACT
The DRM1/ARP gene family is increasingly exhibiting associations with stress conditions at the transcript level. Traditionally correlated with dormancy, increases in transcript levels in response to various treatments have also been reported in various species. As alternative transcript splicing is common in stress conditions, the splice variants of AtDRM1 and AtDRM2 were assessed further in this study. A previously undescribed splice variant of AtDRM1 (AtDRM1.6) is introduced in this work. In silico analyses of predicted protein sequence of all splice variants showed that all variants retain the predicted intrinsically disordered nature. Transcriptional studies of AtDRM1 and AtDRM2 in response to a wide range of abiotic, physical and hormonal treatments showed that AtDRM1.6 is differentially regulated at the transcriptional level compared with other splice variants. Promoter analyses demonstrated AtDRM1 light regulation via the upstream promoter sequence.
Subject(s)
Arabidopsis/genetics , Gene Expression Regulation, Plant , Methyltransferases/genetics , Alternative Splicing , Amino Acid Sequence , Arabidopsis/growth & development , Arabidopsis/metabolism , Gene Expression Profiling , Gene-Environment Interaction , Intrinsically Disordered Proteins/chemistry , Intrinsically Disordered Proteins/genetics , Intrinsically Disordered Proteins/metabolism , Light , Methyltransferases/chemistry , Methyltransferases/metabolism , Molecular Sequence Data , Organ Specificity , Phenotype , Promoter Regions, Genetic , Salt Tolerance/genetics , Sequence Alignment , Stress, Physiological , Transcription, GeneticABSTRACT
Intrinsically disordered proteins (IDPs) are a relatively recently defined class of proteins which, under native conditions, lack a unique tertiary structure whilst maintaining essential biological functions. Functional classification of IDPs have implicated such proteins as being involved in various physiological processes including transcription and translation regulation, signal transduction and protein modification. Actinidia DRM1 (Ade DORMANCY ASSOCIATED GENE 1), represents a robust dormancy marker whose mRNA transcript expression exhibits a strong inverse correlation with the onset of growth following periods of physiological dormancy. Bioinformatic analyses suggest that DRM1 is plant specific and highly conserved at both the nucleotide and protein levels. It is predicted to be an intrinsically disordered protein with two distinct highly conserved domains. Several Actinidia DRM1 homologues, which align into two distinct Actinidia-specific families, Type I and Type II, have been identified. No candidates for the Arabidopsis DRM1-Homologue (AtDRM2) an additional family member, has been identified in Actinidia.
Subject(s)
Actinidia/genetics , Actinidia/metabolism , Fruit , Genetic Association Studies , Plant Proteins/genetics , RNA, Messenger , Actinidia/classification , Amino Acid Sequence , Computational Biology/methods , Gene Expression Regulation, Plant , Molecular Sequence Data , Phylogeny , Plant Proteins/chemistry , Plant Proteins/metabolism , Protein Structure, Secondary , Seasons , Sequence AlignmentABSTRACT
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.
