The roles of SHORT INTERNODES/STYLISH genes, regulators of auxin homeostasis, during leaf vein development in Arabidopsis thaliana

Leaves require extensive venation systems to transport fixed carbon and water. While it is known that auxin can induce vascular differentiation, the mechanisms behind leaf veinpatterning are poorly understood. Here I have assessed the roles of SHI/STY, YUCCA, and TAA1 genes in leaf vein development. These genes have been linked to auxin biosynthesis. I have found that SHI, STY1, STY2, SRS5, YUC1, YUC2, YUC4, and TAA1 are primarily expressed at the apical, basal, and marginal domains of leaf primordia in Arabidopsis thaliana, with little expression at sites of vein formation. shi/sty mutant analyses nevertheless revealed venation phenotypes, most notably in cotyledons. In addition, some SHI/STY expression patterns shift with auxin transport inhibition and exogenous auxin application treatments. Taken altogether, I hypothesize that SHI/STY members influence leaf vein patterning through local regulation of auxin biosynthesis from the margins of leaf blades.