628 / 2019-04-26 09:37:44

Dissecting the mechanisms underlying branch angle control in plants

Branch angle; SCARECROW; SCR-LIKE 23; LZY1; TAC1; Cell type expression.

Growth and Development > Growth and Development

Branch angle is an important morphological trait affecting plant architecture, disease resistance, and yields. The Arabidopsis thaliana mutant scarecrow (scr) showed an enlarged branch angle, which can be recovered when SCARECROW-LIKE 23 (SCL23), the closest paralog to SCR, is also mutated. A previous microarray analysis suggested that both AtLAZY1/LAZY1-LIKE1 (LZY1) and Tiller Angle Control 1 (TAC1), which have opposite effects on branch angle, were significantly downregulated in scr mutant. We infer that SCR and SCL23 control branch angle through regulation of LZY1 or TAC1 expression in a tissue specific manner. To test this hypothesis, we examined the expression pattern of SCR and SCL23 using promoter::GUS reporter-constructs, and found that SCR and SCL23 were expressed in different cell types at the branch site. By qRT-PCR analyses, we showed that the expression of LZY1 and TAC1 was altered at the branch sites in the scr and scl23/scr mutants. We have introduced LZY1 or TAC1 promoter::GUS reporter into the scr, scl23, scl23/scr, and wild type background, and which allows us to determine their expression at the cell type level. Anatomic features at the branch sites in these mutants will also be examined. Finally, we will seek other genes regulating branch angle through comparative transcriptomics. These results will deepen our understanding of the mechanisms underlying branch angle control in plants.