Overexpression of ACL 1 （abaxially curled leaf 1） Increased Bulliform Cells and Induced Abaxial Curling of Leaf Blades in Rice

Understanding the genetic mechanism underlying rice leaf-shape development is crucial for optimizing rice configuration and achieving high yields; however, little is known about leaf abaxial curling. We isolated a rice transferred DNA （T-DNA） insertion mutant, BY240, which exhibited an abaxial leaf curling phenotype that co-segregated with the inserted T-DNA. The T-DNA was inserted in the promoter of a novel gene, ACL1 （Abaxially Curled Leaf 1）, and led to overexpression of this gene in BY240. Overexpression of ACL1 in wild-type rice also resulted in abaxial leaf curling. ACL1 encodes a protein of 116 amino acids with no known conserved functional domains. Overexpression of ACL2, the only homolog of ACL1 in rice, also induced abaxial leaf curling. RT-PCR analysis revealed high expressions of ACLs in leaf sheaths and leaf blades, suggesting a role for these genes in leaf development. In situ hybridization revealed non-tissue-specific expression of the ACLs in the shoot apical meristem, leaf primordium, and you