Molecular genetic analysis of DRO1 genes in soybean

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Under drought conditions, a strong and deep root system provides advantages for exploring and exploiting moisture in deeper soil layers where water is still sufficient. In rice, the Deeper Rooting 1 (OsDRO1) gene has been identified, characterized and proven functional in drought avoidance. OsDRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip, which causes roots to grow asymmetrically and to bend downward in response to gravity. Higher expression of OsDRO1 increased root growth angle, which made roots grow in a more downward direction and led to yield improvement under drought conditions. In soybean, different GmDRO1 homologs were found. Those are potential candidates for genetic and functional characterizations. We established the phylogenetic relationship of GmDRO1 genes with other plant species, determined the chromosomal locations of GmDRO1 genes and paralogs, the expression pattern, and their structural variants. The main objective of this study is to investigate the roles of GmDRO1 genes in soybean root system architecture. Soybean transgenic hairy roots were used to investigate the influence of DRO1 genes on the soybean root growth angle. Results obtained in this study did not support the hypothesis of gene enhancing deep root growth angle by GmDRO1 homologs in soybean.