SUBCELLULAR ROOT PHENES REGULATE ROOT METABOLIC COST
Open Access
- Author:
- Sidhu, Jagdeep Singh
- Graduate Program:
- Agricultural and Environmental Plant Science (PhD)
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 28, 2023
- Committee Members:
- Erin Connolly, Major Field Member
Jonathan Lynch, Chair & Dissertation Advisor
Scott Roths, Outside Unit, Field & Minor Member
Armen Kemanian, Major Field Member
Erin Connolly, Program Head/Chair - Keywords:
- Abiotic stress tolerance
Root anatomy
Subcellular phenes
Cell size
Cell wall
Polyploidy
Root domestication syndrome
Drought
Climate change
Root metabolic cost
In silico biology - Abstract:
- Root metabolic cost plays an important role in determining plant performance and crop yields, as efficient soil exploration is essential for the effective acquisition and utilization of water and nutrients. While root anatomical phenotypes that reduce root metabolic costs are beneficial for plant improvement, subcellular phenotypes remain relatively underexplored. This dissertation investigates three subcellular phenotypes: vacuolar occupancy in relation to cell size, cortical parenchyma cell wall width (CPW), and polyploidy in relation to root metabolic cost. Using empirical and in silico approaches, we demonstrate that vacuolar occupancy in root cortical cells can reduce root metabolic cost by decreasing the volume of tissue occupied by metabolically active cytoplasmic machinery in larger and/or longer cells. We also characterize the physiology, genetics, and root/shoot pleiotropy of CPW and show that wider CPW is associated with reduced root metabolic cost and improved maize performance under suboptimal drought and nitrogen availability. Lastly, we explore how polyploidy can alter root anatomical phenotypes and shape the fitness landscape under varying edaphic conditions using wheat as a model system. We find that polyploidization is associated with reduced root tissue nitrogen and phosphorus demand, increased axial hydraulic conductance, and reduced root penetration ability. These functional changes confer an adaptive advantage for the wheat polyploids to adapt to the changing Mesopotamian agroecosystems. In conclusion, this dissertation reveals the role of subcellular phenotypes in regulating root metabolic cost and identifies novel root phenotypes for breeding crops with increased soil exploration efficiency in the face of changing climates.