Molecular cloning and expression analysis of five GhRAXs in upland cotton (Gossypium hirsutum L.)

The formation of axillary meristems in leaf axils is a prerequisite for the development of lateral shoots, which largely contribute to plant architecture. Several transcription factor-encoding genes, including CUC3, RAX, LAS, LOF1, and ROX, have been cloned by screening for axillary meristem mutants in Arabidopsis thaliana. These genes will facilitate our understanding of the mechanisms underlying axillary meristem development. In this study, we report the cloning of five genes from cotton (Gossypium hirsutum L.) that are orthologous to A. thaliana REGULATORS OFAXILLARY MERISTEMS (RAX) and tomato Blind (Bl), and they are designated GhRAX1, 2, 3, 4, and 5. Sequence analyses indicated that all five genes shared conserved protein domains with RAX and Bl. Phylogenetic analyses of protein sequences revealed that GhRAX2/3/4 were close to RAX1, whereas GhRAX1 and GhRAX5 were close to RAX3. Expression patterns of these genes in different tissues were also analyzed using real-time PCR.