Abstract:Lectin plays an important role in defense signaling in plants, but its function in plant growth and development is not well known. Previously, we cloned a rice (Oryza sativa L.) gene OsJAC1 encoding a mannose-binding jacalin-related lectin, and found that OsJAC1 was jasmonic acid (JA) inducible. Here we cloned the promoter of OsJAC1, and GUS activity was detected in young roots, coleoptiles, sheaths, leaves, nodes of stems, stems, rachises, pistils, stamens and lemmas of OsJAC1::GUS transgenic rice, suggesting that OsJAC1 is a constitutive expression gene in rice. Moreover, OsJAC1-overexpressed (Ubi::OsJAC1) rice showed dwarfism with shorter coleptiles resulting from the failure of cell elongation of coleoptiles. In addition, compared with coleoptiles of wild-type plants, those of OsJAC1 overexpression rice were more sensitive to JA treatment. These data revealed that, besides its roles in defense response, lectin plays an important role in rice growth and development.