Identification and Functional Validation of Auxin-Responsive Tabzip Genes from Wheat Leaves in Arabidopsis.

Leaves are an essential and unique organ of plants, and many studies have proved that auxin has significant impacts on the architecture of leaves, thus the manipulation of the three-dimensional structure of a leaf could provide potential strategies for crop yields. In this study, 32 basic leucine zipper transcription factors (bZIP TFs) which responded to 50 μM of indole-acetic acid (IAA) were identified in wheat leaves by transcriptome analysis. Phylogenetic analysis indicated that the 32 auxin-responsive were classified into eight groups with possible different functions. Phenotypic analysis demonstrated that knocking out the homologous gene of the most down-regulated auxin-responsive in Arabidopsis () decreased its sensitivity to 1 and 50 μM IAA, while the complementary lines recovered its sensitivity to auxin as a wild type (Wassilewskija), suggesting that the down-regulated was a negative factor in the auxin-signaling pathway. These results demonstrated that the auxin-responsive genes might have various and vital functions in the architecture of a wheat leaf under auxin response.