Molecular cloning of the GhLOM and GhROX genes associated with axillary meristem formation in cotton

Abstract

Axillary meristem (AM) is the prerequisite of shoot branch development, which then determines plant aerial architecture. Many transcription factors are known to influence AM initiation. In this study, we isolated two genes from cotton (Gossypium hirsutum L.): GhLOM and GhROX. Sequence analysis showed that GhLOM was a GRAS protein and GhROX was a bHLH transcription factor. They shared conserved protein domains with LOM and ROX, whose mutants showed the AM defect in Arabidopsis thaliana. Phylogenetic analysis of protein sequences found GhLOM in the same group as LOM-like proteins closely related to PtHAM and SlHAM, while GhROX was clustered with ROX. Expression analysis was performed by RTPCR in different plant organs and revealed that both genes predominantly accumulated in apices. The study of subcellular localization demonstrated that GhLOM and GhROX were mainly concentrated in nucleus. Transactivation assay was performed and showed that both genes were transcriptionally active.