KANADI genes and leaf enations

Randall A. Kerstetter and Jeon J. Hong

Waksman Institute, Rutgers University, Piscataway, NJ

The leaves of most plants exhibit striking differences between their adaxial (dorsal or upper) and abaxial (ventral or lower) surfaces. This sidedness of leaves represents an axis of asymmetry that corresponds to the thickness of the leaf. Cell-types within the leaf are polarized along this adaxial-abaxial axis. Loss-of-function mutations in KANAD1I (KAN1) result in the ectopic appearance of adaxial traits on the abaxial sides of leaves. The KAN1 gene product is a member of a plant-specific family of transcription factors recently dubbed the GARP domain family. Plants carrying mutations in both kan1 and a closely related gene kan2 display dramatic polarity defects that include the formation of leaf-like outgrowths on the abaxial surface of leaves. We are exploring the formation of these outgrowths or enations in order to further understand the role of KAN genes in the specification of abaxial fate.