Regulation of Crown Root Growth in Monocots

Root acclimation 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.

Monocot root systems can be categorized into embryonic and post-embryonic based on their origin. Unlike in dicots, shoot-borne crown roots and associated lateral roots form the major part of the monocot root system. Our lab is studying root development and response to water deficit in two model monocot species, Setaria viridis and Brachypodium distachyon. 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 thin sheets of soil termed GLO-Roots (Growth and Luminescence Observatory for Roots). This allows us to analyze changes in root system architecture during growth in soil over the course of weeks and to study water deficit responses under physiologically relevant conditions.

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

What we learn from Setaria and Brachypodium will be directly translatable to the bioenergy and agriculturally important crop plants, such as maize, sorghum, switchgrass and sugarcane, that are their closest relatives.