Crown Root Regulation in Response to Drought in Setaria and Brachypodium

Root adaptation to environmental signals is essential for plant survival. Though they are hidden from view during growth in soil, conditions encountered by the roots determine the size, shape and developmental rate of the entire plant.

Our lab is studying root development and response to stress in two model monocot plants, Setaria viridis and Brachypodium distachyon. In these plants, as well as other monocots such as maize, sorghum and switchgrass, crown roots comprise 90% of the root biomass under well-watered conditions.  Both species demonstrate great sensitivity to water availability by inhibiting the growth of crown roots in low water conditions, and responding to rewatering by rapid growth of new crown roots.  We have made transgenic luciferase-expressing plants that can be imaged in our GLO-Roots system.  This allows us to analyze changes in root system architecture during growth in soil over the course of weeks.

We have also performed a quantitative trait locus (QTL) analysis using the progeny from a cross between Setaria viridis and its domesticated relative Setaria italica, which does not regulate its crown root growth as severely in response to water deficit. This has identified QTLs for crown root growth in both watered and drought conditions.

We are analyzing data from RNAseq performed on root crowns of Setaria viridis grown in watered or drought conditions to look for genes differentially expressed during crown root suppression.

We are also screening NMU-mutagenized Setaria viridis seeds to look for plants that no longer inhibit crown root growth in drought conditions.