LfiTCP15;2 regulates plant height of Lagerstroemia indica by influencing the growth of stem cells

Abstract

Plant height is one of the key traits affecting plant architecture, which affects the appearance and application of Lagerstroemia indica (crape myrtle) in gardens. TCP transcription factors are specific to plants and widely involved in the biological process of plant growth and development related to cell proliferation and growth, including plant height. However, the molecular mechanism by which TCP transcription factors regulate plant height development remains unclear and requires further analysis. In this study, LfiTCP15;2 was isolated from dwarf and non-dwarf progenies of crape myrtle, and the function was analyzed. Silencing of LfiTCP15;2 in non-dwarf crape myrtle inhibited internode elongation and stem cell growth, while overexpression of LfiTCP15;2 in tobacco promoted plant height, internode elongation and cell growth. To screen proteins interacting with LfiTCP15;2 and further elucidate the molecular mechanism by which LfiTCP15;2 regulates the plant height development of crape myrtle, we constructed a cDNA library of the yeast two-hybrid system using stem tips of dwarf and non-dwarf crape myrtle. The library was identified as 8.0 × 107cells/ml, with an average insert >1,000 bp in size and a 100% positive rate, providing a database for the subsequent study of the molecular regulation mechanism of the plant architecture in crape myrtle. Total of 70 proteins interacting with LfiTCP15;2 were screened in the library. LfiCHI1 and LfiCHI2 interacting with LfiTCP15;2 was proved by yeast two-hybrid assay. In conclusion, LfiTCP15;2 regulates the plant height of crape myrtle by promoting stem cell growth and internode elongation, and LfiCHI1 and LfiCHI2, which interact with LfiTCP15;2, may also be involved in this process.