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

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.

Jujube witches’ broom phytoplasmas inhibit ZjBRC1-mediated abscisic acid metabolism to induce shoot proliferation

“…These results confirmed the possibility that the bushy appearance of SJP1/2 was partially caused by repressing ZjBRC1 -controlled ABA accumulation in the buds. It was noticed that there was a large discrepancy in leaf area between plants, which might account for differences in branch numbers [ 38 ].…”

Lessons from a century of apical dominance research

“…BRC1 is also a key integrator of light quality, in particular the response to plant density and to changes to the ratio of red to far-red (R:FR) wavelengths of light ( Finlayson et al , 2010 ; González-Grandío et al , 2013 ). Reduced shoot branching is part of the shade avoidance response which commonly also includes increased plant height and early flowering time ( Casal, 2012 ; Fichtner et al , 2022 ). In sorghum and Arabidopsis, it was shown that high planting density and a low R:FR ratio results in high TB1/BRC1 expression and reduced shoot branching/tillering ( Kebrom et al , 2006 ; Aguilar-Martínez et al , 2007 ; Finlayson et al , 2010 ; González-Grandío et al , 2013 ).…”

Strigolactones and Shoot Branching: What Is the Real Hormone and How Does It Work?

“…2022 ). Since any variation in the rosette leaf number impacts the rosette branch number in highly branched arabidopsis genotypes ( Fichtner et al. 2022 ), it needs to be determined if wild-type rootstocks can reduce rosette branching in clamt mutant scions when branching is measured as rosette branches per rosette leaf as seen in lbo ( Brewer et al.…”

“…This should be a focus of future research, including potential roles in integrating reproductive strategy, as it has been shown that the reproductive strategy, circadian clock and flowering time affect branching ( Beveridge et al. 2003 , Fichtner et al. 2022 , F. Wang et al.…”