Project description:Bud dormancy – the repeated phase of rest that punctuates periods of growth in the life cycles of many perennial species. In temperate fruit trees, fulfillment of chilling requirement and subsequent heat requirement enable dormant buds to have uniform blooming in field. However, effects of environmental factors such as chilling underlying dormancy release and bud break has not been fully understood. Histone modification is an important epigenetic regulation system which plays an important role in gene expression in various developmental and adaptive processes. Taking advantage of next-generation sequencing, we generated epigenome and transcriptome profiling at different stages before chilling, after chilling and just before bud break in apple (Malus x domestica). We found H3K27me3 may play dominant role during chilling and the genes involved in lignin and lipid metabolic process showed histone modifications. Interestingly, the higher ratio of genes in chilling-associated network exhibited histone modifications, suggesting crucial epigenetic roles in regulating gene expressions in response to chilling during dormancy. Furthermore, H3K4me3 may play more important role during bud break and the genes related to cell wall modification/organization were strongly modified. Taken together, this study provides important insights into the chromatin-based gene regulation underlying chilling-mediated dormancy release and bud break in apple.
Project description:Bud dormancy – the repeated phase of rest that punctuates periods of growth in the life cycles of many perennial species. In temperate fruit trees, fulfillment of chilling requirement and subsequent heat requirement enable dormant buds to have uniform blooming in field. However, effects of environmental factors such as chilling underlying dormancy release and bud break has not been fully understood. Histone modification is an important epigenetic regulation system which plays an important role in gene expression in various developmental and adaptive processes. Taking advantage of next-generation sequencing, we generated epigenome and transcriptome profiling at different stages before chilling, after chilling and just before bud break in apple (Malus x domestica). We found H3K27me3 may play dominant role during chilling and the genes involved in lignin and lipid metabolic process showed histone modifications. Interestingly, the higher ratio of genes in chilling-associated network exhibited histone modifications, suggesting crucial epigenetic roles in regulating gene expressions in response to chilling during dormancy. Furthermore, H3K4me3 may play more important role during bud break and the genes related to cell wall modification/organization were strongly modified. Taken together, this study provides important insights into the chromatin-based gene regulation underlying chilling-mediated dormancy release and bud break in apple.
Project description:To better understanding the genetic and physiological changes behind the dormancy process in tree peony, we performed customized cDNA microarray to investigate gene expression profiling in tree peony M-bM-^@M-^XFeng Dan BaiM-bM-^@M-^Y buds during chilling induced dormancy release. Endo-dormant tree peony plants were exposed to 0-4M-BM-0C from 5 November to 30 December 2009 in Qingdao, Shandong, China. Buds were collected after 0 d, 6 d, 12 d, 15 d, 18 d and 24 d chilling endured. DNA microarrays were customized using Agilent eArray 5.0 program, containing spots with 14,957 gene-specific 60-mer oligonucleotides representing 14,957 non abundant ESTs obtained from 454 sequencing normalized cDNA of tree peony buds during chilling duration (TSA, 65,217). Total 3,174 significantly differentially-expressed genes (P<0.05) were observed through endo-dormancy release, and the number of up-regulated (1,611) and that of down-regulated (1,563) was almost same. Expression of differentially-expressed genes associated with GA biosynthesis and signaling, cell growth and development was confirmed by quantitative RT-PCR, which displayed similar trends pattern in expression. Transcript profiling of tree peony was measured during chilling (0-4M-BM-0C) induced dormancy release. Mixed buds, three buds for each individual, were collected after 0, 6, 12, 15, 18 (endo-dormancy release), 24 days (eco-dormancy) chilling requirement fulfilling. Three replications (3 plants/ replication) were harvested between November and December.
Project description:Correlation analysis of the expression of bud dormancy-related genes in 10 peach cultivars, with different chilling requirements for dormancy release.
Project description:Bud dormancy is a critical developmental process for perennial plant survival, and also an important physiological phase that affects the next season’s growth of temperate fruit trees. Bud dormancy is regulated by multiple genetic factors, and affected by various environmental factors, tree age and vigor. To understand molecular mechanism of bud dormancy in Japanese apricot (Prunus mume Sieb. et Zucc.), we constructed a custom oligo DNA microarray covering the Japanese apricot dormant bud ESTs referring to peach (P. persica) genome sequence. Because endodormancy release is a chilling temperature-dependent physiological event, genes showing chilling-mediated differential expression patterns are candidates to control endodormancy release. Using the microarray constructed in this study, we monitored gene expression changes of dormant vegetative buds of Japanese apricot during prolonged artificial chilling exposure. In addition, we analyzed seasonal gene expression changes. ‘Nanko’ vegetative buds collected in November, and those exposed to chilling for 40 or 60 days were used as microarray samples. Among the 58539 different unigene probes, 2345 and 1059 genes were identified as being more than two-fold up-regulated and down-regulated, respectively, following chilling exposure for 60 days (P value < 0.05). The down-regulated genes included P. mume DORMANCY-ASSOCIATED MADS-box genes, which supported the previous quantitative RT-PCR and EST analyses showing that these genes are repressed by prolonged chilling treatments. The genes encoding lipoxygenase were remarkably up-regulated by prolonged chilling. Cluster analysis suggested that the expression of the genes showing expression changes by artificial chilling exposure were coordinately regulated by seasonal changes. Our parametric analysis of gene set enrichment suggested that genes related to jasmonic acid (JA) and oxylipin biosynthesis and metabolic processes were significantly up-regulated by prolonged chilling, whereas genes related to circadian rhythm were significantly down-regulated. The results obtained from the microarray analyses were verified by quantitative RT-PCR analysis of selected genes. Taken together, this study raised the possibility that the microarray platform constructed in this study is applicable for deeper understanding of molecular network related to agronomically important bud phisiologies including dormancy release.
Project description:Bud dormancy is a critical developmental process for perennial plant survival, and also an important physiological phase that affects the next seasonM-bM-^@M-^Ys growth of temperate fruit trees. Bud dormancy is regulated by multiple genetic factors, and affected by various environmental factors, tree age and vigor. To understand molecular mechanism of bud dormancy in Japanese apricot (Prunus mume Sieb. et Zucc.), we constructed a custom oligo DNA microarray covering the Japanese apricot dormant bud ESTs referring to peach (P. persica) genome sequence. Because endodormancy release is a chilling temperature-dependent physiological event, genes showing chilling-mediated differential expression patterns are candidates to control endodormancy release. Using the microarray constructed in this study, we monitored gene expression changes of dormant vegetative buds of Japanese apricot during prolonged artificial chilling exposure. In addition, we analyzed seasonal gene expression changes. M-bM-^@M-^XNankoM-bM-^@M-^Y vegetative buds collected in November, and those exposed to chilling for 40 or 60 days were used as microarray samples. Among the 58539 different unigene probes, 2345 and 1059 genes were identified as being more than two-fold up-regulated and down-regulated, respectively, following chilling exposure for 60 days (P value < 0.05). The down-regulated genes included P. mume DORMANCY-ASSOCIATED MADS-box genes, which supported the previous quantitative RT-PCR and EST analyses showing that these genes are repressed by prolonged chilling treatments. The genes encoding lipoxygenase were remarkably up-regulated by prolonged chilling. Cluster analysis suggested that the expression of the genes showing expression changes by artificial chilling exposure were coordinately regulated by seasonal changes. Our parametric analysis of gene set enrichment suggested that genes related to jasmonic acid (JA) and oxylipin biosynthesis and metabolic processes were significantly up-regulated by prolonged chilling, whereas genes related to circadian rhythm were significantly down-regulated. The results obtained from the microarray analyses were verified by quantitative RT-PCR analysis of selected genes. Taken together, this study raised the possibility that the microarray platform constructed in this study is applicable for deeper understanding of molecular network related to agronomically important bud phisiologies including dormancy release. In this study, we used chilling exposed bud samples (0, 40, 60 days starting at November) and seasonal monthly bud samples (June to March). For the samples in dataset 1 (three different time points during chilling treatment), three technical replicates (60K M-CM-^W 3 per sample) with three biological replicates were averaged, whereas three technical replicates were averaged for the samples in dataset 2 (10 different seasonal time points)
Project description:To better understanding the genetic and physiological changes behind the dormancy process in tree peony, we performed customized cDNA microarray to investigate gene expression profiling in tree peony ‘Feng Dan Bai’ buds during chilling induced dormancy release. Endo-dormant tree peony plants were exposed to 0-4°C from 5 November to 30 December 2009 in Qingdao, Shandong, China. Buds were collected after 0 d, 6 d, 12 d, 15 d, 18 d and 24 d chilling endured. DNA microarrays were customized using Agilent eArray 5.0 program, containing spots with 14,957 gene-specific 60-mer oligonucleotides representing 14,957 non abundant ESTs obtained from 454 sequencing normalized cDNA of tree peony buds during chilling duration (TSA, 65,217). Total 3,174 significantly differentially-expressed genes (P<0.05) were observed through endo-dormancy release, and the number of up-regulated (1,611) and that of down-regulated (1,563) was almost same. Expression of differentially-expressed genes associated with GA biosynthesis and signaling, cell growth and development was confirmed by quantitative RT-PCR, which displayed similar trends pattern in expression.
Project description:Winter dormancy is an adaptative mechanism that temperate and boreal trees have developed to protect their meristems against low temperatures. In apple trees (Malus domestica), cold temperatures induce bud dormancy at the end of summer/beginning of the fall. Apple buds stay dormant during winter until they are exposed to a period of cold, after which they can resume growth (budbreak) and initiate flowering in response to warm temperatures in spring. It is well-known that small RNAs modulate temperature responses in many plant species, but however, how small RNAs are involved in genetic networks of temperature-mediated dormancy control in fruit tree species remains unclear. Here, we have made use of a recently developed ARGONAUTE (AGO)-purification technique to isolate small RNAs from apple buds. A small RNA-seq experiment resulted in the identification of small RNAs that change their pattern of expression in apple buds during dormancy.
Project description:This study investigated changes in gene expression of controlled environment chilled (4C) grape overwintering buds as they accumulated from 0 to 2000 chilling hours. Keywords: time course, chilling, endodormancy release, axillary bud, grape
Project description:This study investigated changes in gene expression of controlled environment chilled (4C) grape overwintering buds as they accumulated from 0 to 2000 chilling hours. Keywords: time course, chilling, endodormancy release, axillary bud, grape A loop design with 3 biological replicates (RNA from buds collected at 0, 500, 1000, 1500, and 2000 hr of chilling in 2002, 2004, and 2005).