Over-expression of , encoding a R2R3-MYB transcription factor from a high-leaf-number mutant of , increases the number of leaves in .

Ornamental foliage plants have long been cultivated for their attractive leaves. Variation in leaf traits of ornamental foliage plants is one of the goals in breeding. MYB transcription factors regulate many aspects of leaf development, and thus influence morphological traits of leaves. However, little is known about the function of MYB transcription factors in leaf development of , one of the most economically important ornamental plants in the world. In the present study, a MYB transcription factor, CcMYB24, was identified and the corresponding gene cloned from a new orchid mutant, TRIR-2, which produces more leaves than control plants. The CcMYB24 showed a higher expression level in 'TRIR-2' than in control plants, and the protein was located in the nucleus. The sequence of showed a high similarity with genes which belong to the gene family in other plants. Overexpression of resulted in a phenotype with an increased number of leaves, elevated chlorophyll content, and decreased contents of carotenoids and flavonoids in . These results provide functional evidence for the role of in promoting the production of leaves in 'TRIR-2'. Understanding the role of in will be beneficial for the molecular breeding of ornamental foliage plants.