Colin Turnbull

Plasticity of bud outgrowth varies at cauline and rosette nodes in Arabidopsis thaliana

Publisher: Oxford University Press (OUP)

Date: 17-12-2021

DOI: 10.1093/PLPHYS/KIAB586

Abstract: Shoot branching is a complex mechanism in which secondary shoots grow from buds that are initiated from meristems established in leaf axils. The model plant Arabidopsis (Arabidopsis thaliana) has a rosette leaf growth pattern in the vegetative stage. After flowering initiation, the main stem elongates with the top leaf primordia developing into cauline leaves. Meristems in Arabidopsis initiate in the axils of rosette or cauline leaves, giving rise to rosette or cauline buds, respectively. Plasticity in the process of shoot branching is regulated by resource and nutrient availability as well as by plant hormones. However, few studies have attempted to test whether cauline and rosette branching are subject to the same plasticity. Here, we addressed this question by phenotyping cauline and rosette branching in three Arabidopsis ecotypes and several Arabidopsis mutants with varied shoot architectures. Our results showed no negative correlation between cauline and rosette branch numbers in Arabidopsis, demonstrating that there is no tradeoff between cauline and rosette bud outgrowth. Through investigation of the altered branching pattern of flowering pathway mutants and Arabidopsis ecotypes grown in various photoperiods and light regimes, we further elucidated that the number of cauline branches is closely related to flowering time. The number of rosette branches has an enormous plasticity compared with cauline branches and is influenced by genetic background, flowering time, light intensity, and temperature. Our data reveal different levels of plasticity in the regulation of branching at rosette and cauline nodes, and promote a framework for future branching analyses.

Different plasticity of bud outgrowth at cauline and rosette nodes in Arabidopsis thaliana

Publisher: Cold Spring Harbor Laboratory

Date: 27-09-2021

DOI: 10.1101/2021.09.26.461886

Abstract: Shoot branching is a complex mechanism in which secondary shoots grow from buds that are initiated from meristems established in leaf axils. The model plant Arabidopsis thaliana has a rosette leaf growth pattern in the vegetative stage. After flowering initiation, the main stem starts to elongate with the top leaf primordia developing into cauline leaves. Meristems in arabidopsis are initiated in the axils of rosette or cauline leaves, giving rise to rosette or cauline buds, respectively. Plasticity in the process of shoot branching is regulated by resource and nutrient availability as well as by plant hormones. However, few studies have attempted to test whether cauline and rosette branching are subject to the same plasticity. Here, we addressed this question by phenotyping cauline and rosette branching in three arabidopsis ecotypes and several arabidopsis mutants with varied shoot architectures. Our results show that there is no negative correlation between cauline and rosette branch numbers in arabidopsis, demonstrating that there is no trade-off between cauline and rosette bud outgrowth. Through investigation of the altered branching pattern of flowering pathway mutants and arabidopsis ecotypes grown in various photoperiods and light regimes, we further elucidated that the number of cauline branches is closely related to flowering time. The number or rosette branches has an enormous plasticity compared with cauline branches and is influenced by genetic background, flowering time, light intensity and temperature. Our data reveal different plasticity in the regulation of branching at rosette and cauline nodes and promote a framework for future branching analyses. Different plasticity of branching at cauline and rosette nodes of arabidopsis is revealed through detailed correlative analyses of branching under varied genetic and environmental contexts.

Feedback Regulation of Xylem Cytokinin Content Is Conserved in Pea and Arabidopsis

Publisher: Oxford University Press (OUP)

Date: 02-02-2007

DOI: 10.1104/PP.106.093708

Regulation of Carotenoid Composition and Shoot Branching inArabidopsisby a Chromatin Modifying Histone Methyltransferase, SDG8

Publisher: Oxford University Press (OUP)

Date: 2009

DOI: 10.1105/TPC.108.063131

Abstract: Carotenoid pigments are critical for plant survival, and carotenoid composition is tuned to the developmental stage, tissue, and to environmental stimuli. We report the cloning of the CAROTENOID CHLOROPLAST REGULATORY1 (CCR1) gene. The ccr1 mutant has increased shoot branching and altered carotenoid composition, namely, reduced lutein in leaves and accumulation of cis-carotenes in dark-grown seedlings. The CCR1 gene was previously isolated as EARLY FLOWERING IN SHORT DAYS and encodes a histone methyltransferase (SET DOMAIN GROUP 8) that methylates histone H3 on Lys 4 and/or 36 (H3K4 and H3K36). ccr1 plants show reduced trimethyl-H3K4 and increased dimethyl-H3K4 surrounding the CAROTENOID ISOMERASE (CRTISO) translation start site, which correlates with low levels of CRTISO mRNA. Microarrays of ccr1 revealed the downregulation of 85 genes, including CRTISO and genes associated with signaling and development, and upregulation of just 28 genes. The reduction in CRTISO transcript abundance explains the altered carotenoid profile. The changes in shoot branching are additive with more axillary branching mutants, but the altered carotenoid profile may partially affect shoot branching, potentially by perturbed biosynthesis of the carotenoid substrates of strigolactones. These results are consistent with SDG8 regulating shoot meristem activity and carotenoid biosynthesis by modifying the chromatin surrounding key genes, including CRTISO. Thus, the level of lutein, the most abundant carotenoid in higher plants that is critical for photosynthesis and photoprotection, appears to be regulated by a chromatin modifying enzyme in Arabidopsis thaliana.

The University Of Edinburgh

Location: United Kingdom of Great Britain and Northern Ireland

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University Of Cambridge

Location: United Kingdom of Great Britain and Northern Ireland

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Imperial College London

Location: United Kingdom of Great Britain and Northern Ireland

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Discovery Projects - Grant ID: DP0452148

Start Date: 2004

End Date: 12-2006

Amount: $240,000.00

Funder: Australian Research Council