Insights into the functional role of tomato TM6 as a transcriptional regulator of flower development

Abstract

Flower development is a crucial step towards the completion of the plant life cycle. Physiological processes and gene regulatory mechanisms underlying flower formation have been extensively characterized, and the implication of MADS-box transcription factors as primary regulators of flower morphology has been widely described, mainly due to the analysis of loss-of-function mutants in model species. Nevertheless, detailed characterization of allele variation in several MADS-box homologous genes from crop species remains undescribed. Here, we have characterized a tomato mutant with aberrant flower development. Mutant plants exhibit changes in petal cell identity, as well as homeotic transformations of stamens into carpelloid structures, which in most cases result in succulent organs. Molecular analysis proved that a loss-of-function mutation in the TOMATO MADS-BOX 6 (TM6) gene is responsible for this mutant phenotype. Furthermore, as a result of the loss of function of TM6, misregulation of the transcription and mRNA processing of other MADS-box genes involved in reproductive development has been detected. Our findings demonstrate that TM6 is a key player in the complex regulatory network of MADS-box genes controlling flower development and also provide a novel mutant that may be useful for generating male sterile lines in tomatoes.

Acknowledgements

This research was supported by research grants PID2019-110833RB-C31 and P20_00324 funded by the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) and the Spanish regional government of Junta de Andalucía (2014-2020 FEDER-Andalusia Operational Program), respectively. The authors would like to thank Campus de Excelencia Internacional Agroalimentario (CeiA3) for providing research facilities.

Author Contributions

R.L. and J.C. conceived and designed the research. R.F., C.C., and R.L. performed research experiments and data analysis. A.O.-A., F.J.Y.-L., and T.A. contributed new reagents or analytical tools. R.F., R.L., F.J.Y.-L., and J.C. wrote and edited the manuscript. All authors read and approved the manuscript.

Data Availability

The DNA-seq and RNA-seq data from this article can be found at the Sequence Read Archive (SRA; https://www.ncbi.nlm.nih.gov/sra/) under BioProject accession numbers PRJNA1015112 and PRJNA1015144, respectively.

Conflict of Interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary Data

Supplementary data are available at Horticulture Research online.

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