Project description:Axillary bud outgrowth determines plant shoot architecture and is under control of endogenous hormones and a fine-tuned gene expression network. Some genes associated with shoot development are known targets of small RNAs (sRNAs). Although it is well known that sRNAs act broadly in plant development, our understanding about their roles in vegetative bud outgrowth remains limited. Moreover, the expression profiles of microRNAs (miRNAs) and their targets in axillary buds are unknown. In this study, we employed next-generation sequencing, gene expression analysis and metabolite profiling to identify sRNAs and quantify distinct hormones, respectively, in vegetative axillary buds of the tropical biofuel crop sugarcane (Saccharum spp.). Differential accumulation of abscisic acid (ABA), gibberellins (GA), and cytokinins indicates a dynamic balance of these hormones during sugarcane bud outgrowth. A number of repeat-associated siRNAs generated from distinct transposable elements and genes were highly expressed in both inactive and developing buds. RT-qPCR results revealed that specific miRNAs were differentially expressed in developing buds and some correlate negatively with the expression of their targets. Expression patterns of miR159 and its experimentally confirmed target GAMYB suggest they play roles in regulating ABA and GA-signaling pathways during bud outgrowth. Our work reveals, for the first time, differences in composition and expression profiles of small RNAs and targets between inactive and developing buds that, together with the endogenous balance of specific hormones, may be important to regulate axillary bud outgrowth in plants. Examination of small RNA populations in vegetative axillary buds of the tropical biofuel crop sugarcane (Saccharum spp.)
Project description:Axillary bud outgrowth determines plant shoot architecture and is under control of endogenous hormones and a fine-tuned gene expression network. Some genes associated with shoot development are known targets of small RNAs (sRNAs). Although it is well known that sRNAs act broadly in plant development, our understanding about their roles in vegetative bud outgrowth remains limited. Moreover, the expression profiles of microRNAs (miRNAs) and their targets in axillary buds are unknown. In this study, we employed next-generation sequencing, gene expression analysis and metabolite profiling to identify sRNAs and quantify distinct hormones, respectively, in vegetative axillary buds of the tropical biofuel crop sugarcane (Saccharum spp.). Differential accumulation of abscisic acid (ABA), gibberellins (GA), and cytokinins indicates a dynamic balance of these hormones during sugarcane bud outgrowth. A number of repeat-associated siRNAs generated from distinct transposable elements and genes were highly expressed in both inactive and developing buds. RT-qPCR results revealed that specific miRNAs were differentially expressed in developing buds and some correlate negatively with the expression of their targets. Expression patterns of miR159 and its experimentally confirmed target GAMYB suggest they play roles in regulating ABA and GA-signaling pathways during bud outgrowth. Our work reveals, for the first time, differences in composition and expression profiles of small RNAs and targets between inactive and developing buds that, together with the endogenous balance of specific hormones, may be important to regulate axillary bud outgrowth in plants.
Project description:In plant axillary bud dormancy and outgrowth are regulated by phytohormones, but it is still unknown about its molecular mechanism. We reveal that Arabidopsis axillary buds located at axil of rosette leaves show dormancy and that this is broken by the decapitation of main stem, resulting in the bud outgrowth. To investigate about the molecular mechanisms of dormancy and outgrowth, we carried out gene expression analysis during axillary shoot outgrowth in Arabidopsis wild type Columbia accession. Since axillary buds did not initiate outgrowth (dormancy) at 5 day after bolting of main stem, we used 5-day bolted plants as a control (before decapitation). Then, main stems were decapitated, and axillary shoots were collected at 24 hours after decapitation (named as growing shoot). Total RNA was prepared from either control or growing shoots and used for the microarray analysis. We carried out duplicate microarray analysis using independent plant materials.Ref):Tatematsu et al., Plant Physiol. 138: 757-766 (2005). Keywords: Expression profilling by array 4 samples were used in this experiment
Project description:In plant axillary bud dormancy and outgrowth are regulated by phytohoromones, but it is still unknown about its molecular mechanism. We reveal that Arabidopsis axillary buds located at axil of rosette leaves show dormancy and that this is broken by the decapitation of main stem, resulting in the bud outgrowth. To investigate about the molecular mechanisms of dormancy and outgrowth, we carried out gene expression analysis during axillary shoot outgrowth in Arabidopsis wild type Columbia accession. Since axillary buds did not initiate outgrowth (dormancy) at 5 day after bolting of main stem, we used 5-day bolted plants as a control (before decapitation). Then, main stems were decapitated, and axillary shoots were collected at 24 hours after decapitation (named as growing shoot). Total RNA was prepared from either control or growing shoots and used for the microarray analysis. We carried out duplicate microarray analysis using independent plant materials.Ref):Tatematsu et al., Plant Physiol. 138: 757-766 (2005). Keywords: Expression profilling by array
Project description:Aims: To determine the changes in the Arabidopsis axillary bud transcriptome in response to changes in the red light (R) to far red light (FR) ratio (R:FR). Background: The branching habit of plants is a key determinant of overall plant form and function with great relevance to modern agriculture. Shade signals transduced by phytochromes are major regulators of axillary bud outgrowth, and in turn control branching in both natural and agricultural environments. To continue our investigations into the regulation of branching by R:FR, we have developed a system using supplemental FR LEDs to tightly control the outgrowth of Arabidopsis axillary buds. Depending on the position of the bud in the rosette, outgrowth is either repressed (uppermost bud) or rapidly promoted (bud in the axil of the third leaf down) by the transition from low to high R:FR. Treatment: Two separate experiments were conducted to evaluate the effects of R:FR on transcriptome changes in the uppermost rosette bud (bud n) and the axillary bud in the axil of the third leaf from the top (bud n-2). WT Col-60000 was used as the experimental material. Plants were grown individually in 25 by 50 mm tubes and watered and fertilized optimally. Plants were grown in a split growth chamber (providing uniform temperature and PPFD but allowing for differential R:FR) with 18 h photoperiods (185 Moles m-2 s-1 PPFD provided by T12 VHO CW fluorescent lamps) and 24 C/18 C day/night temperatures. One day after sowing, the R:FR was reduced on both sides of the chamber from 3.5 to 0.08 using FR LEDs fixed in clear overhead arrays. Prior to anthesis, the plants were matched and split into two treatment groups. In experiment 1, the FR source for one of the groups was switched off at 12:00 pm on the day of anthesis, causing the R:FR to increase to 3.5. Unelongated axillary buds in the axil of the uppermost leaves (approx. 2.5 mm long) were harvested for RNA preparation from both groups (low and transiently increased R:FR) 3 h after changing the R:FR. Each treatment was composed of three biological replicates, each containing buds from about 15-18 plants. Experiment 2 was conducted exactly the same as experiment 1, except the R:FR was altered 3 days after anthesis and the unelongated axillary buds in the axils of the third leaves down (approx. 1 mm long) were harvested for RNA preparation. 12 samples (3 bud n and low R:FR, 3 bud n and high R:FR, 3 bud n-2 and low R:FR, 3 bud n-2 and high R:FR) were used in this experiment.