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Balla, Jozef; Blažková, Jarmila; Reinöhl, Vilém; Procházka, Stanislav

doi:10.1023/a:1021215728096

Cited by 14 publications

(2 citation statements)

References 30 publications

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“…In pea shoots, endogenous active GA and auxin levels are well associated ( O’Neill and Ross, 2002 ; Hedden and Thomas, 2012 ; Supplemental Figure 2, C and 2D ). As reported previously ( Balla et al, 2002 ; Liu et al, 2011a ), endogenous auxin levels increased in released buds over time and this is independent of auxin level changes in local internodes ( Figure 1C ). This could be due to enhanced sugars in buds promoting local auxin biosynthesis and export from the buds after decapitation ( Sairanen et al, 2012 ; Mason et al, 2014 ; Barbier et al, 2015 ).…”

Section: Discussionsupporting

confidence: 88%

Auxin-independent effects of apical dominance induce changes in phytohormones correlated with bud outgrowth

et al. 2023

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The inhibition of shoot branching by the growing shoot tip of plants, termed apical dominance, was originally thought to be mediated by auxin. Recently the importance of the shoot tip sink strength during apical dominance has re-emerged with recent studies highlighting roles for sugars in promoting branching. This raises many unanswered questions on the relative roles of auxin and sugars in apical dominance. Here we show that auxin depletion after decapitation is not always the initial trigger of rapid cytokinin increases in buds that are instead correlated with enhanced sugars. Auxin may also act through strigolactones which have been shown to suppress branching after decapitation, but here we show that strigolactones do not have a significant effect on initial bud outgrowth after decapitation. We report here that when sucrose or cytokinin is abundant, strigolactones are less inhibitory during the bud release stage compared to during later stages and that strigolactone treatment rapidly inhibits cytokinin accumulation in pea (Pisum sativum) axillary buds of intact plants. After initial bud release, we find an important role of gibberellin in promoting sustained bud growth downstream of auxin. We are therefore able to suggest a model of apical dominance that integrates auxin, sucrose, strigolactones, cytokinins and gibberellins and describes differences in signalling across stages of bud release to sustained growth.

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Section: Discussionsupporting

confidence: 88%

Auxin-independent effects of apical dominance induce changes in phytohormones correlated with bud outgrowth

et al. 2023

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“…In pea, inhibition of auxin export specifically from the bud reduced bud outgrowth (Chabikwa et al, 2019). In this work, although NPA had no effect on bud outgrowth when directly smeared onto axillary buds of intact transgenic trees, NPA applied to the decapitated stumps could retard the branch outgrowth of the nearest bud to a moderate degree, indicating auxin export from buds was involved in the bud mobilization and the sustained outgrowth of axillary shoots (Balla et al, 2002). Auxin export from the axillary bud is regarded as not essential to trigger initiation of bud growth but is important for sustained bud outgrowth (Barbier et al, 2019;Chabikwa et al, 2019), in accordance with that after NPA treatment, the elongation of wild-type and transgenic lateral branches was almost the same (Fig.…”

Section: Discussionmentioning

confidence: 55%

Overexpression of SHORT-ROOT2 transcription factor enhances the outgrowth of mature axillary buds in poplar trees

Yang

et al. 2022

Journal of Experimental Botany

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SHORT-ROOT (SHR) transcription factors play important roles in asymmetric cell division and radial patterning of Arabidopsis root. In hybrid poplar (P. tremula × P. alba clone INRA 717-1B4), PtaSHR2 was preferentially expressed in axillary buds (AXBs) and transcriptionally upregulated during AXB maturation and activation. Overexpression of SHR2 (PtSHR2OE) induced an enhanced outgrowth of AXBs below the bud maturation point with a simultaneous transition of an active shoot apex into an arrested terminal bud. The larger and more mature AXBs of PtSHR2OE trees revealed altered expression levels of genes involved in axillary meristem initiation and bud activation as well as a higher ratio of cytokinin to auxin. With the aim to elucidate the underlying mechanism of PtSHR2OE-induced high branching, subsequent molecular and biochemical studies showed that compared to wild-type trees, decapitation induced a quicker bud outburst in PtSHR2OE trees, which could be fully inhibited by exogenous application of auxin or cytokinin biosynthesis inhibitor, but not by N-1-naphthylphthalamic acid. Our results indicated that overexpression of PtSHR2B disturbed the internal hormonal balance in AXBs by interfering with the basipetal transport of auxin, rather than causing auxin biosynthesis deficiency or auxin insensitivity, thereby releasing mature AXBs from the apical dominance and promoting their outgrowth.

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Changes in Concentrations of Cytokinins (CKs) in Root and Axillary Bud Tissue of Miniature Rose Suggest that Local CK Biosynthesis and Zeatin-Type CKs Play Important Roles in Axillary Bud Growth

Bredmose¹,

Kristiansen²,

Nørbæk³

et al. 2005

J Plant Growth Regul

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Untitled

Cited by 14 publications

References 30 publications

Auxin-independent effects of apical dominance induce changes in phytohormones correlated with bud outgrowth

Auxin-independent effects of apical dominance induce changes in phytohormones correlated with bud outgrowth

Overexpression of SHORT-ROOT2 transcription factor enhances the outgrowth of mature axillary buds in poplar trees

Changes in Concentrations of Cytokinins (CKs) in Root and Axillary Bud Tissue of Miniature Rose Suggest that Local CK Biosynthesis and Zeatin-Type CKs Play Important Roles in Axillary Bud Growth

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