PpTCP18 is upregulated by lncRNA5 and controls branch number in peach (Prunus persica) through positive feedback regulation of strigolactone biosynthesis

Abstract

Branch number is an important agronomic trait in peach (Prunus persica) trees because plant architecture affects fruit yield and quality. Although breeders can select varieties with different tree architecture, the biological mechanisms underlying architecture remain largely unclear. In this study, a pillar peach (‘Zhaoshouhong’) and a standard peach (‘Okubo’) were compared. ‘Zhaoshouhong’ was found to have significantly fewer secondary branches than ‘Okubo’. Treatment with the synthetic strigolactone (SL) GR24 decreased branch number. Transcriptome analysis indicated that PpTCP18 (a homologous gene of Arabidopsis thaliana BRC1) expression was negatively correlated with strigolactone synthesis gene expression, indicating that PpTCP18 may play an important role in peach branching. Yeast one-hybrid, electrophoretic mobility shift, dual-luciferase assays and PpTCP18-knockdown in peach leaf buds indicated that PpTCP18 could increase expression of PpLBO1, PpMAX1, and PpMAX4. Furthermore, transgenic Arabidopsis plants overexpressing PpTCP18 clearly exhibited reduced primary rosette-leaf branches. Moreover, lncRNA sequencing and transient expression analysis revealed that lncRNA5 targeted PpTCP18, significantly increasing PpTCP18 expression. These results provide insights into the mRNA and lncRNA network in the peach SL signaling pathway and indicate that PpTCP18, a transcription factor downstream of SL signaling, is involved in positive feedback regulation of SL biosynthesis. This role of PpTCP18 may represent a novel mechanism in peach branching regulation. Our study improves current understanding of the mechanisms underlying peach branching and provides theoretical support for genetic improvement of peach tree architecture.

Acknowledgements

We thank Anita K. Snyder for copyediting the manuscript. This work was supported by the National Key Research and Development Program of China (2019YFD1000100), the Henan Province Outstanding Foreign Scholar Program (GZS2020007), the Modern Agricultural Industry Technology Systems Project of Henan Province (HARS-22-09-G1), the Special Fund of Henan Province for Agro-scientific Research in the Public Interest (No. 201300110500), the Youth Fund of Henan Province (No. 30602313), and the Innovation Fund of Henan Agricultural University (No. 30500873).

Author contributions

Conceptualization: B.T. and J.F.; methodology development: Q.W.; bioinformatic data analyses: H.Z. and X.L.; experimental validation: L.Y., and Y.H.; formal analysis: J.C., W.W., and L.L.Z.; investigation: Q.W.; resources: X.Z., X.Y., and J.L.; data curation: X.W.; writing – original draft preparation: X.W.; writing – review and editing: B.T.; visualization: B.T.; supervision: J.F.; project administration: B.T. and J.F.; funding acquisition: X.W., B.T., and J.F. All authors have read and agreed to the published version of the manuscript.

Data availability

All data needed to evaluate the conclusions stated in this paper are present in the paper and/or the supplementary materials.

Conflict of interest

The authors declare that they have no conflicts of interest related to this work.

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