Cloning of a Zoysia ZjLsL and its overexpression to induce axillary meristem initiation and tiller formation in Arabidopsis and bentgrass

Zoysia grass and creeping bentgrass are important turf grasses used in parks, gardens and playing fields. Development of grasses with increased tiller formation will enhance their commercial cultivation. To investigate the regulatory mechanism of tiller formation, we cloned the Zoysia japonica Lateral suppressor-like (ZjLsL) gene. The Lateral suppressor (Ls) gene encodes a transcriptional regulator belonging to the plant-specific GRAS protein family of putative transcription factors, and regulates axillary meristem initiation. A full-length DNA of the ZjLsL gene was isolated by 5'/3' DNA walking. Phylogenetic analysis showed that ZjLsL is closely related to Ls genes. Southern blot analysis revealed that zoysia grass has two copies of the ZjLsL gene. ZjLsL expression was detected in all organs of zoysia grass but was most highly expressed in culms. Overexpression of ZjLsL in creeping bentgrass and Arabidopsis plants promoted axillary bud formation. These results suggest that ZjLsL plays an important role in axillary meristem initiation and tiller formation.