Genome-Wide Identification of the WUSCHEL-Related Homeobox (WOX) Gene Family in Three Cymbidium Species and Expression Patterns in C. goeringii

Abstract

Numerous members of the WOX gene family play pivotal roles during the processes of growth and development in many plants, as has been demonstrated. Cymbidium goeringii, Cymbidium ensifolium, and Cymbidium sinense are ornamental plants with a fascinating floral morphology that are economically important in China. However, there is limited knowledge about the members of the WOX gene family and their functions in these three Cymbidium species. Hence, the WOX genes in three Cymbidium species were identified on the ground of the genomes data of C. goeringii, C. ensifolium, and C. sinense in this study. These identified WOX genes were further studied for their physicochemical properties, evolutionary relationship, gene structure, protein structure, and cis-acting elements of promoters, as well as the expression pattern of the WOX genes in different tissues of C. goeringii. The findings revealed that eight WOX genes in C. goeringii, twelve WOX genes in C. ensifolium, and nine WOX genes were identified. These WOX genes were further subdivided into WUS, ancient, and intermediate clades. The length of the coding region ranged from 149 to 335 aa, and it was predicted that all WOX genes would be located on the cell nucleus. The promoter cis-acting elements primarily comprised stress response, phytohormone response, plant growth and development, and transcription factor elements. Furthermore, both the transcriptomic data and RT-qPCR analysis showed that most WOX genes may be involved in multiple developmental stages of C. goeringii. To sum up, these results may serve as a theoretical foundation for further study of the function analysis of WOX genes in orchids.