MAX1, a regulator of the flavonoid pathway, controls vegetative axillary bud outgrowth in Arabidopsis.
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ABSTRACT:
SUBMITTER: Lazar G
PROVIDER: S-EPMC1324789 | biostudies-literature |
REPOSITORIES: biostudies-literature
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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.
2012-11-21 | GSE42415 | GEO
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.
2012-11-21 | E-GEOD-42415 | biostudies-arrayexpress
Project description:Axillary meristems (AMs) are secondary shoot meristems whose outgrowth determines plant architecture. In rice, AMs form tillers, and tillering mutants reveal an interplay between transcription factors and the phytohormones auxin and strigolactone as some factors that underpin this developmental process. Previous studies showed that knockdown of the transcription factor gene RFL reduced tillering and caused a very large decrease in panicle branching. Here, the relationship between RFL, AM initiation, and outgrowth was examined. We show that RFL promotes AM specification through its effects on LAX1 and CUC genes, as their expression was modulated on RFL knockdown, on induction of RFL:GR fusion protein, and by a repressive RFL-EAR fusion protein. Further, we report reduced expression of auxin transporter genes OsPIN1 and OsPIN3 in the culm of RFL knockdown transgenic plants. Additionally, subtle change in the spatial pattern of IR4 DR5:GFP auxin reporter was observed, which hints at compromised auxin transport on RFL knockdown. The relationship between RFL, strigolactone signalling, and bud outgrowth was studied by transcript analyses and by the tillering phenotype of transgenic plants knocked down for both RFL and D3. These data suggest indirect RFL-strigolactone links that may affect tillering. Further, we show expression modulation of the auxin transporter gene OsPIN3 upon RFL:GR protein induction and by the repressive RFL-EAR protein. These modified forms of RFL had only indirect effects on OsPIN1. Together, we have found that RFL regulates the LAX1 and CUC genes during AM specification, and positively influences the outgrowth of AMs though its effects on auxin transport.
| S-EPMC4986878 | biostudies-literature
Project description:Melatonin plays an important role in plant resistance to biotic and abiotic stresses. However, whether melatonin is involved in the regulation of plant architecture, such as the formation of axillary bud outgrowth or tillering, in rice remains unknown. Here, we found that different concentrations of melatonin influenced axillary bud outgrowth in rice, and moderate melatonin concentrations also alleviated the inhibition of axillary bud outgrowth in the presence of high concentrations of basic amino acids lysine and arginine. Furthermore, transcriptome analysis demonstrated that genes involved in nitrogen metabolism and phytohormone signal transduction pathways may affect axillary bud outgrowth, which is regulated by melatonin. We determined that the differentially expressed genes glutamine synthetase OsGS2 and amino acid transporter OsAAP14, which are involved in nitrogen metabolism and are regulated by melatonin and basic amino acids, were the key regulators of axillary bud outgrowth in rice. In addition, we validated the functions of OsGS2 and OsAAP14 using rice transgenic plants with altered axillary bud outgrowth and tillers. Taken together, these results suggest that melatonin mediates axillary bud outgrowth by improving nitrogen assimilation and transport in rice.
| S-EPMC9326366 | biostudies-literature
Project description:BACKGROUND:Axillary buds allow the production of either vegetative or reproductive shoots, which display a plastic developmental potential of the plant to suit the prevailing environmental changes. Strawberry represents one of many plant species which displays horizontal above-ground growth of shoot development for asexual reproduction. Two distinct runner growth patterns exist in different strawberry species: one is called sympodial type such as Fragaria vesca, and the other one is called monopodial type such as Fragaria pentaphylla. Despite the runner growth morphology of these strawberry species have been well known, the mechanisms that determine the distinct patterns have rarely been reported. RESULTS:In this study, we used Fragaria vesca Hawaii-4 and Fragaria pentaphylla as model species, and captured the initiated dormant bud and non-dormant bud as materials to compare their transcriptome profiles and phytohormone content. Comparisons revealed that relatively higher auxin activity is present in the dormant bud and relatively higher cytokinin activity is in the non-dormant bud. Decapitation and pharmacological experiments on dormant buds showed that the reduction of auxin accumulation triggers the regeneration of vegetative shoots in dormant buds, and exogenous cytokinin application triggers cell fate turnover and generation of reproductive shoots. CONCLUSION:Here, we uncover a mechanism by which auxin and cytokinin coordinate the dormancy and outgrowth of axillary bud in strawberry runner. Our results suggest a contrasting behavior of auxin and cytokinin in control of axillary bud development, facilitating a preliminary understanding of shoot architecture formation in strawberry.
| S-EPMC6884756 | biostudies-literature
Project description:Background and aims:Branching is an important mechanism of plant shape establishment and the direct consequence of axillary bud outgrowth. Recently, hydrogen peroxide (H2O2) metabolism, known to be involved in plant growth and development, has been proposed to contribute to axillary bud outgrowth. However, the involvement of H2O2 in this process remains unclear.Methods:We analysed the content of H2O2 during bud outgrowth and characterized its catabolism, both at the transcriptional level and in terms of its enzymatic activities, using RT-qPCR and spectrophotometric methods, respectively. In addition, we used in vitro culture to characterize the effects of H2O2 application and the reduced glutathione (GSH) synthesis inhibitor l-buthionine sulfoximine (BSO) on bud outgrowth in relation to known molecular markers involved in this process.Key results:Quiescent buds displayed a high content of H2O2 that declined when bud outgrowth was initiated, as the consequence of an increase in the scavenging activity that is associated with glutathione pathways (ascorbate-glutathione cycle and glutathione biosynthesis); catalase did not appear to be implicated. Modification of bud redox state after the application of H2O2 or BSO prevented axillary bud outgrowth by repressing organogenesis and newly formed axis elongation. Hydrogen peroxide also repressed bud outgrowth-associated marker gene expression.Conclusions:These results show that high levels of H2O2 in buds that are in a quiescent state prevents bud outgrowth. Induction of ascorbate-glutathione pathway scavenging activities results in a strong decrease in H2O2 content in buds, which finally allows bud outgrowth.
| S-EPMC7596375 | biostudies-literature
Project description:Axillary bud outgrowth, a key factor in ratoon rice yield formation, is regulated by several phytohormone signals. The regulatory mechanism of key genes underlying ratoon buds in response to phytohormones in ratoon rice has been less reported. In this study, GR24 (a strigolactone analogue) was used to analyze the ratooning characteristics in rice cultivar Huanghuazhan (HHZ). Results show that the elongation of the axillary buds in the first seasonal rice was significantly inhibited and the ratoon rate was reduced at most by up to 40% with GR24 treatment. Compared with the control, a significant reduction in the content of auxin and cytokinin in the second bud from the upper spike could be detected after GR24 treatment, especially 3 days after treatment. Transcriptome analysis suggested that there were at least 742 and 2877 differentially expressed genes (DEGs) within 6 h of GR24 treatment and 12 h of GR24 treatment, respectively. Further bioinformatics analysis revealed that GR24 treatment had a significant effect on the homeostasis and signal transduction of cytokinin and auxin. It is noteworthy that the gene expression levels of OsCKX1, OsCKX2, OsGH3.6, and OsGH3.8, which are involved in cytokinin or auxin metabolism, were enhanced by the 12 h GR24 treatment. Taken overall, this study showed the gene regulatory network of auxin and cytokinin homeostasis to be regulated by strigolactone in the axillary bud outgrowth of ratoon rice, which highlights the importance of these biological pathways in the regulation of axillary bud outgrowth in ratoon rice and would provide theoretical support for the molecular breeding of ratoon rice.
| S-EPMC10975295 | biostudies-literature
Project description:KEY MESSAGE:Tulip vegetative reproduction. Tulips reproduce asexually by the outgrowth of their axillary meristems located in the axil of each bulb scale. The number of axillary meristems in one bulb is low, and not all of them grow out during the yearly growth cycle of the bulb. Since the degree of axillary bud outgrowth in tulip determines the success of their vegetative propagation, this study aimed at understanding the mechanism controlling the differential axillary bud activity. We used a combined physiological and "bottom-up" molecular approach to shed light on this process and found that first two inner located buds do not seem to experience dormancy during the growth cycle, while mid-located buds enter dormancy by the end of the growing season. Dormancy was assessed by weight increase and TgTB1 expression levels, a conserved TCP transcription factor and well-known master integrator of environmental and endogenous signals influencing axillary meristem outgrowth in plants. We showed that TgTB1 expression in tulip bulbs can be modulated by sucrose, cytokinin and strigolactone, just as it has been reported for other species. However, the limited growth of mid-located buds, even when their TgTB1 expression is downregulated, points at other factors, probably physical, inhibiting their growth. We conclude that the time of axillary bud initiation determines the degree of dormancy and the sink strength of the bud. Thus, development, apical dominance, sink strength, hormonal cross-talk, expression of TgTB1 and other possibly physical but unidentified players, all converge to determine the growth capacity of tulip axillary buds.
| S-EPMC5940712 | biostudies-literature
Project description:Shoot branching is an important agronomic trait that directly determines plant architecture and affects crop productivity. To promote crop yield and quality, axillary branches need to be manually removed during cucumber production for fresh market and thus are undesirable. Auxin is well known as the primary signal imposing for apical dominance and acts as a repressor for lateral bud outgrowth indirectly. The TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) family gene BRANCHED1 (BRC1) has been shown to be the central integrator for multiple environmental and developmental factors that functions locally to inhibit shoot branching. However, the direct molecular link between auxin and BRC1 remains elusive. Here we find that cucumber BRANCHED1 (CsBRC1) is expressed in axillary buds and displays a higher expression level in cultivated cucumber than in its wild ancestor. Knockdown of CsBRC1 by RNAi leads to increased bud outgrowth and reduced auxin accumulation in buds. We further show that CsBRC1 directly binds to the auxin efflux carrier PIN-FORMED (CsPIN3) and negatively regulates its expression in vitro and in vivo. Elevated expression of CsPIN3 driven by the CsBRC1 promoter results in highly branched cucumber with decreased auxin levels in lateral buds. Therefore, our data suggest that CsBRC1 inhibits lateral bud outgrowth by direct suppression of CsPIN3 functioning and thus auxin accumulation in axillary buds in cucumber, providing a strategy to breed for cultivars with varying degrees of shoot branching grown in different cucumber production systems.
| S-EPMC6708385 | biostudies-literature
Project description:Axillary bud outgrowth determines shoot architecture and is under the control of endogenous hormones and a fine-tuned gene-expression network, which probably includes 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 within axillary buds are largely unknown. Here, we employed sRNA next-generation sequencing as well as computational and gene-expression analysis to identify and quantify sRNAs and their targets in vegetative axillary buds of the biofuel crop sugarcane (Saccharum spp.). Computational analysis allowed the identification of 26 conserved miRNA families and two putative novel miRNAs, as well as a number of trans-acting small interfering RNAs. sRNAs associated with transposable elements and protein-encoding genes were similarly represented in both inactive and developing bud libraries. Conversely, sequencing and quantitative reverse transcription-PCR results revealed that specific miRNAs were differentially expressed in developing buds, and some correlated negatively with the expression of their targets at specific stages of axillary bud development. For instance, the expression patterns of miR159 and its target GAMYB suggested that they may play roles in regulating abscisic acid-signalling pathways during sugarcane bud outgrowth. Our work reveals, for the first time, differences in the composition and expression profiles of diverse sRNAs and targets between inactive and developing vegetative buds that, together with the endogenous balance of specific hormones, may be important in regulating axillary bud outgrowth.
| S-EPMC3654421 | biostudies-literature