Project description:Microarray analysis revealed specific alterations in gene expression in dormancy breaking buds induced by pruning (P), hydrogen cyanamide (HC), pruning plus hydrogen cyanamide (PHC) after 24 h of treatment. PHC treatment altered the expression of the largest number of genes and rapid accumulation of a sublethal level of reactive oxygen species and reactive nitrogen species subsequently induces cell wall loosening and expansion for bud sprouting
Project description:Perennial plants, like fruit trees grown in temperate regions, are characterized by bud dormancy, a rest state that protects the bud from cold during winter. At the same time, these plants have developed a requirement for winter chill for correct flowering. However, winters are becoming increasingly warm in temperate regions, resulting in dramatic effects on the flowering output and therefore crop yield. A compound that successfully compensates for missing winter chill is hydrogen cyanamide, which has been used to synchronize and advance flowering time in a range of commercially important fruit crops. Hydrogen cyanamide also represents a unique tool for researchers to study controlled endodormancy release. Here, we treated dormant sweet cherry flower buds with hydrogen cyanamide, sampling flower buds at different time points after treatment. RNAseq revealed more than 6,000 hydrogen cyanamide-responsive genes. In accordance with these results, hydrogen cyanamide treatment increased the levels of jasmonoyl-isoleucine (JA-Ile) and the cytokinins trans-zeatin riboside (tZR), dihydrozeatin (DZ) and dihydrozeatin riboside (DZR). Furthermore, hydrogen cyanamide affected the expression of antioxidant- and cell wall loosening-associated transcripts. These results suggest a complex mechanism of action for hydrogen cyanamide-induced endodormancy release, including key roles for JA-Ile, zeatin-type cytokinins and hydrogen cyanide.
Project description:Hydrogen cyanamide (HC) is an agrochemical compound frequently used to break bud dormancy in grapevine grown under mild winter conditions all over the world. The present study was carried out to get a better understanding of the molecular mechanism associated with HC to release bud dormancy in grapevine using RNA-seq based transcriptomic and tandem mass tag (TMT) based proteomic analysis.
Project description:Dormancy of buds is a critical developmental process that allows plants to survive extreme seasonal variations in climate. Dormancy transition in leaf buds of Japanese pear leading cultivar M-bM-^@M-^XKosuiM-bM-^@M-^Y were investigated using 10 K cDNA microarray. Leaf buds collected on October (early endodormancy) and February (breaking stage) were used to monitor the changes in the transcriptome. Over 1000 genes were differentially expressed (p value < 0.05 and 2 fold change) when the early endodormant stage and breaking one were compared to each other. Functional classification revealed that the majority of genes were involved in response to abiotic/biotic stimulus and stress, signal transduction, and transcription. Among them, 76 and 22 genes were significantly (over 10 fold change) highly expressed in early endodormant stage and breaking stage, respectively, this result suggests that even in the endodormant stage, gene expression in the buds is high. Among them, several transcriptional factors were included. The quantitative real-time PCR analysis showed that at least three of their seasonal changes during endodormancy transition phases were similar to two DAM (dormancy-associated MADS box) genes isolated from Japanese pear, suggesting that they might be novel candidate genes associated to dormancy. The gene expression profiles between dormant and released leaf bud were compared.
Project description:Dormancy of buds is a critical developmental process that allows plants to survive extreme seasonal variations in climate. Dormancy transition in leaf buds of Japanese pear leading cultivar ‘Kosui’ were investigated using 10 K cDNA microarray. Leaf buds collected on October (early endodormancy) and February (breaking stage) were used to monitor the changes in the transcriptome. Over 1000 genes were differentially expressed (p value < 0.05 and 2 fold change) when the early endodormant stage and breaking one were compared to each other. Functional classification revealed that the majority of genes were involved in response to abiotic/biotic stimulus and stress, signal transduction, and transcription. Among them, 76 and 22 genes were significantly (over 10 fold change) highly expressed in early endodormant stage and breaking stage, respectively, this result suggests that even in the endodormant stage, gene expression in the buds is high. Among them, several transcriptional factors were included. The quantitative real-time PCR analysis showed that at least three of their seasonal changes during endodormancy transition phases were similar to two DAM (dormancy-associated MADS box) genes isolated from Japanese pear, suggesting that they might be novel candidate genes associated to dormancy.
Project description:A grape-bud-oriented genomic platform was produced for a large-scale comparative analysis of bud responses to two stimuli of grape-bud dormancy release, hydrogen cyanamide (HC) and heat shock (HS). The results suggested considerable similarity in bud response to the stimuli, both in the repertoire of responding genes and in the temporary nature of the transcriptome reprogramming. Nevertheless, the bud response to HC was slower, more condensed and stronger, as reflected by a higher number of regulated genes and a higher intensity of regulation compared to the response to HS. To facilitate large-scale comparative analysis of early changes in the bud transcriptome by cDNA microarray, HC and HS were applied to canes collected from three vineyards, located in different regions, in three different years. This experimental scheme resulted in two true biological replicates for each treatment, differing in both timing and location, and loop design of technical replicates within time series. Consistent with our previous studies, both application of 5% Dormex (HC) and incubation for 1 h in 50oC water (HS) resulted in increased bud-break rates compared to respective controls. Bud break of HS-treated and HC-treated buds started 10 to 12 days after treatment. Three weeks after treatment, HS-treated buds exhibited 100% bud break while HC-treated buds had reached 80% bud break. The control showed significantly lower levels of bud break during this period. Bud material was collected from control, HC- and HS-treated cuttings at six time points (3, 6, 12, 24, 48 and 96 h) after the treatments and used to prepare total RNA samples.
Project description:A grape-bud-oriented genomic platform was produced for a large-scale comparative analysis of bud responses to two stimuli of grape-bud dormancy release, hydrogen cyanamide (HC) and heat shock (HS). The results suggested considerable similarity in bud response to the stimuli, both in the repertoire of responding genes and in the temporary nature of the transcriptome reprogramming. Nevertheless, the bud response to HC was slower, more condensed and stronger, as reflected by a higher number of regulated genes and a higher intensity of regulation compared to the response to HS.
Project description:To determine how dormancy breaking agent, hydrogen cyanamide (HC) advances bud break in peach (Prunus persica), this research compared the transcriptome of buds of low-chill ‘TropicBeauty’ peach trees treated with 1% (v/v) HC and that of non-treated trees at 3 and 7 days after treatment (DAT), respectively, using RNA sequencing analysis. The peak of total bud break occurred 6 weeks earlier in the HC treated trees (at 32 DAT) than the non-treated trees (at 74 DAT). There were 1312 and 1095 differentially expressed genes (DEGs) at 3 and 7 DAT, respectively. At 3 DAT, DEGs related to oxidative stress, including response to hypoxia, lipid oxidation, and reactive oxygen species (ROS) metabolic process, were up regulated in HC-treated buds. Additionally, DEGs encoding enzymes for ROS scavenging and pentose phosphate pathway were up regulated at 3 DAT but were not differently expressed at 7 DAT, indicating a temporary demand for defense mechanisms against HC-triggered oxidative stress. Up regulation of DEGs for cell division and development at 7 DAT, which were down regulated at 3 DAT, suggests cell activity was initially suppressed but enhanced within 7 days following the treatment. At 7 DAT, DEGs related to cell wall degradation and modification were up-regulated, possibly responsible for the burst of buds. The results of this study strongly suggest that HC induces transient oxidative stress shortly after application leading to the release of bud dormancy and, subsequently, causes an increase in cell activity and cell wall loosening, thereby accelerating bud break in peach.
Project description:We carried out the transcriptome analysis to explore expression profiles differences and identify the key genes involved in pear seed dormancy release, by comparing callery pear (Pyrus calleryana Decne) seeds at three different stages of cold stratification