Integrated proteomic, transcriptomic, and metabolomic profiling reveals that the gibberellin-abscisic acid hub runs flower development in the Chinese orchid Cymbidium sinense

Abstract

The seasonal flowering Chinese Cymbidium produce an axillary floral meristem and require a dormancy period during cold conditions for flower development. However, the bud activation mechanism remains elusive. This study evaluates the multi-omics across six stages of flower development, along with functional analysis of core genes to decipher the innate mechanism of floral bud initiation and outgrowth in the Chinese orchid Cymbidium sinense. Transcriptome and proteome analyses identified 10 modules with essential roles in floral bud dormancy and activation. Gene clusters in the early stages of flower development were mainly related to flowering time regulation and meristem determination, while the late stages were correlated with hormone signaling pathways. The metabolome identified 69 potential hormones in which gibberellin (GA) and abscisic acid (ABA) were the main regulatory hubs, and GA4 and GA53 exhibited a reciprocal loop. Extraneous GA application caused rapid elongation of flower buds and promoted the expression of flower development genes. Contrarily, exogenous ABA application extended the dormancy process and ABA inhibitors induced dormancy release. Moreover, CsAPETALA1 ( CsAP1 ) was identified as the potential target of ABA for floral bud activation. Transformation of CsAP1 in Arabidopsis and its transient overexpression in C. sinense protoplasts not only affected flowering time and floral organ morphogenesis in Arabidopsis but also orchestrated the expression of flowering and hormone regulatory genes. The presence of ABA response elements in the CsAP1 promoter, rapid downregulation of CsAP1 after exogenous ABA application, and the activation of the floral bud after ABA inhibitor treatment suggest that ABA can control bud outgrowth through CsAP1.

Acknowledgements

We are thankful to funding agencies for funding and anonymous reviewers for valuable comments. This research was funded by grants from the National Natural Science Foundation of China (31872151, 31672184), the Guangzhou Science and Technology Project (201707010307), the Innovation Team of Modern Agriculture Industry Technology System in Guangdong Province (2021KJ121), and the Guangdong Academy of Agricultural Sciences Discipline Team Construction Project (202127TD, BZ202006, R2020PY-JX018).

Author contributions

S.A., C.L., F.Y., and G.Z. designed the experiments. C.L., J.G., and Y.W. performed the experiments. S.A., C.L., Q.X., and J.J. analyzed the data. S.A., C.L., and F.Y. wrote the manuscript. All authors read and approved of its contents.

Data availability

The original contributions presented in the study are publicly available. The supplementary data are provided along with the manuscript as supplementary tables and supplementary figures. The transcriptome sequencing clean data have been uploaded to the database of the BIG Data Center (http://gsa.big.ac.cn/index.jsp) under accession number PRJCA025438. Proteome data are available via ProteomeXchange with identifier PXD051591.

Conflict of interest

The authors declare that there was no conflict of interest.

Supplementary data

Supplementary data are available at Horticulture Research online.

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