In:
Journal of Experimental Botany, Oxford University Press (OUP), Vol. 72, No. 13 ( 2021-06-22), p. 4822-4838
Abstract:
Shoot branching is an important factor that influences the architecture of apple trees and cytokinin is known to promote axillary bud outgrowth. The cultivar ‘Fuji’, which is grown on ~75% of the apple-producing area in China, exhibits poor natural branching. The TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) family genes BRANCHED1/2 (BRC1/2) are involved in integrating diverse factors that function locally to inhibit shoot branching; however, the molecular mechanism underlying the cytokinin-mediated promotion of branching that involves the repression of BRC1/2 remains unclear. In this study, we found that apple WUSCHEL2 (MdWUS2), which interacts with the co-repressor TOPLESS-RELATED9 (MdTPR9), is activated by cytokinin and regulates branching by inhibiting the activity of MdTCP12 (a BRC2 homolog). Overexpressing MdWUS2 in Arabidopsis or Nicotiana benthamiana resulted in enhanced branching. Overexpression of MdTCP12 inhibited axillary bud outgrowth in Arabidopsis, indicating that it contributes to the regulation of branching. In addition, we found that MdWUS2 interacted with MdTCP12 in vivo and in vitro and suppressed the ability of MdTCP12 to activate the transcription of its target gene, HOMEOBOX PROTEIN 53b (MdHB53b). Our results therefore suggest that MdWUS2 is involved in the cytokinin-mediated inhibition of MdTCP12 that controls bud outgrowth, and hence provide new insights into the regulation of shoot branching by cytokinin.
Type of Medium:
Online Resource
ISSN:
0022-0957
,
1460-2431
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2021
detail.hit.zdb_id:
1466717-4
SSG:
12
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