Genetic Relations Between ASYMMETRIC LEAVES2 And Other Polarity Genes And Molecular Mechanisms Of ASYMMETRIC LEAVES2 In Leaf Polarity Formation In Arabidopsis

The Arabidopsis ASYMMETRIC LEAVES2 (AS2) genes play important roles in specifying the adaxial identity of leaves. PHAB genes, including PHABULOSA (PHB), PHAVOLUTA (PHV) and REVOLUTA (REV), AS2 are also required for the establishment of adaxial identity. In addition, KANADI (KAN) and YABBY (YAB) act in the abaxial domain of leaves to specify the abaxial identity. Although these genes have been identified and characterized extensively, little is known about the genetic epistasis among them. To elucidate this fundarmental question, we performened single and double mutant analyse phenotypically and molecularly. We show that AS2 positively regulate REV and PHB, while do not genetically interact with the KAN genes. AS2 may promote the leaf adaxial identity via upregulating the PHAB genes and directly or by other unknown ways independently on PHAB. Our results also support a view that although REV, PHB and PHV are required for the adaxial-abaxial polarity formation, the roles that REV plays are of the primary importance.