Systems Analysis of Embolism Resiliency in Grasses for Biofuel Production Under Marginal Environments
EMSL Project ID
60873
Abstract
Production of grass lignocellulosic biomass for biorefining can be significantly diminished by periods of acute high temperature known as heat waves. High temperature disrupts folding of proteins leading to perturbation of key biosynthetic and signaling processes. Although plants can reduce their body temperature through transpiration of water from leaf surface, this mechanism becomes defunct if the soil moisture is low. Under these conditions transpiration generates excessively negative pressure in the xylem leading to formation of air-vapour cavities, also known as embolism. Simply put, the xylem dries out. Once formed, emboli can spread to the neighboring water-filled xylem cells through specialized, porous areas in the cell wall known as pits. A pit lacks a secondary cell wall, and serves to conduct water between neighboring xylem cells. Emboli restrict water flow making xylem defunct even after water becomes available. Therefore, reduction of embolism spread is an essential drought resilience mechanism. Ultrastructural data on hundreds of plant species suggests that pit morphology plays an important role in reducing the embolism spread: generally speaking, smaller pits with thicker pit membrane are typical for plants adapted to arid climates whereas large pits with thin pit membrane are found in plants adapted to mesic climates. We hypothesize that grass biomass production in marginal environments can be increased by reducing the propensity for embolism by engineering smaller pits. Testing this hypothesis was not previously possible because analysis of xylem cavitation is technically challenging. In the previous EMSL project we found that X-Ray computed microtomography (Micro-CT) and Advanced Photon Source (APS) imaging enable quantification of xylem cavitation. In this project we would like to use these imaging techniques to reveal the pit morphotypes and their underlying genetic networks responsible for preventing or reducing embolism in vascular bundles of bioenergy grasses. We will achieve this goal through two specific aims. In Aim#1 we will identify the genetic network responsible for pit morphology and determine the impact of drought on this network using tissue-specific transcriptomics pipeline and RNA-seq facilities available at EMSL and JGI, and live cell imaging. In Aim#3 we will determine functions of genes responsible for pit development and role of pit size in embolism formation and spread using reverse genetics, light microscopy, electron microscopy, and Micro-CT at EMSL APS imaging. The outcomes of this project will identify genes that reduce embolism by controlling pit morphology. This information will enable engineering grass varieties with superior heat and drought resiliency and higher biomass yields in marginal environments.
Project Details
Project type
FICUS Research
Start Date
2023-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members