Expression of SYMRK affects the development of arbuscular mycorrhiza in tobacco roots

SYMRK is a plant receptor-like kinase with a role in root endosymbiosis. Heterologous expression of SYMRK from non-legumes can complement the loss-of-function effects of the mutant symrk in legumes. However, it is unclear whether the development of arbuscular mycorrhiza (AM) is affected along with the enhanced expression of SYMRK . In the present study, the full-length LsSYMRK gene was cloned from Lathyrus sativus . Overexpression of LsSYMRK in tobacco roots was essential for AM development, and affected the expression of genes which are involved in the potential signaling pathway of AM. In addition, the pattern of hyphal penetration changed from radial to longitudinal when hyphae reached the root cortex. Furthermore, overexpression of LsSYMRK increased tobacco biomass in the presence of AM fungi. These results suggest that increased expression of SYMRK in roots of AM-infected tobacco can increase the colonization and biomass.