Dataset Information

Change in Auxin and Cytokinin Levels Coincides with Altered Expression of Branching Genes during Axillary Bud Outgrowth in Chrysanthemum.

ABSTRACT: In the production and breeding of Chrysanthemum sp., shoot branching is an important quality aspect as the outgrowth of axillary buds determines the final plant shape. Bud outgrowth is mainly controlled by apical dominance and the crosstalk between the plant hormones auxin, cytokinin and strigolactone. In this work the hormonal and genetic regulation of axillary bud outgrowth was studied in two differently branching cut flower Chrysanthemum morifolium (Ramat) genotypes. C17 is a split-type which forms an inflorescence meristem after a certain vegetative period, while C18 remains vegetative under long day conditions. Plant growth of both genotypes was monitored during 5 subsequent weeks starting one week before flower initiation occurred in C17. Axillary bud outgrowth was measured weekly and samples of shoot apex, stem and axillary buds were taken during the first two weeks. We combined auxin and cytokinin measurements by UPLC-MS/MS with RT-qPCR expression analysis of genes involved in shoot branching regulation pathways in chrysanthemum. These included bud development genes (CmBRC1, CmDRM1, CmSTM, CmLsL), auxin pathway genes (CmPIN1, CmTIR3, CmTIR1, CmAXR1, CmAXR6, CmAXR2, CmIAA16, CmIAA12), cytokinin pathway genes (CmIPT3, CmHK3, CmRR1) and strigolactone genes (CmMAX1 and CmMAX2). Genotype C17 showed a release from apical dominance after floral transition coinciding with decreased auxin and increased cytokinin levels in the subapical axillary buds. As opposed to C17, C18 maintained strong apical dominance with vegetative growth throughout the experiment. Here high auxin levels and decreasing cytokinin levels in axillary buds and stem were measured. A differential expression of several branching genes accompanied the different hormonal change and bud outgrowth in C17 and C18. This was clear for the strigolactone biosynthesis gene CmMAX1, the transcription factor CmBRC1 and the dormancy associated gene CmDRM1, that all showed a decreased expression in C17 at floral transition and an increased expression in C18 with continuous vegetative growth. These results offer a case study for Chrysanthemum, showing an altered cytokinin to auxin balance and differential gene expression between vegetative growth with apical dominance and transition to generative growth with loss of apical dominance and axillary bud outgrowth. This suggests a conservation of several aspects of the hormonal and genetical regulation of bud outgrowth in Chrysanthemum. Furthermore, 15 previously uncharacterised genes in chrysanthemum, were described in this study. Of those genes involved in axillary bud outgrowth we identified CmDRM1, CmBRC1 and CmMAX1 as having an altered expression preceding axillary bud outgrowth, which could be useful as markers for bud activity.

SUBMITTER: Dierck R

PROVIDER: S-EPMC4996534 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Change in Auxin and Cytokinin Levels Coincides with Altered Expression of Branching Genes during Axillary Bud Outgrowth in Chrysanthemum.

Dierck Robrecht R De Keyser Ellen E De Riek Jan J Dhooghe Emmy E Van Huylenbroeck Johan J Prinsen Els E Van Der Straeten Dominique D

PloS one 20160824 8

In the production and breeding of Chrysanthemum sp., shoot branching is an important quality aspect as the outgrowth of axillary buds determines the final plant shape. Bud outgrowth is mainly controlled by apical dominance and the crosstalk between the plant hormones auxin, cytokinin and strigolactone. In this work the hormonal and genetic regulation of axillary bud outgrowth was studied in two differently branching cut flower Chrysanthemum morifolium (Ramat) genotypes. C17 is a split-type which ...[more]

PMID: 27557329

Similar Datasets

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.

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 24oC/18oC 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.

Dataset Information

Change in Auxin and Cytokinin Levels Coincides with Altered Expression of Branching Genes during Axillary Bud Outgrowth in Chrysanthemum.

Publications

Change in Auxin and Cytokinin Levels Coincides with Altered Expression of Branching Genes during Axillary Bud Outgrowth in Chrysanthemum.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets