Investigating the mechanobiology of root hair growth in Arabidopsis thaliana

Abstract:
Root hairs are tubular outgrowths of epidermal cells (trichoblasts) in the maturation zone of the root. They help absorb water and mineral nutrients while also anchoring the growth of the root tip. Root hairs navigate through soil pores and can help penetrate compacted soils, but how root hair morphogenesis under differing mechanical conditions is enabled by cell wall dynamics is poorly understood.

To address this knowledge gap, we varied the stiffness of growth media for Arabidopsis seedlings by adjusting agar concentrations. We found that seedling roots showed shorter and fewer root hairs with increasing media stiffness. We also observed decreased turgor pressure, abnormal epidermal cell patterning, altered microtubule organization, and increased wall thickness with more transverse cellulose organization as media stiffness increased. We also investigated how xyloglucan, a hemicellulose that is abundant in the primary cell walls of eudicots, influences root hair growth. Xyloglucan-deficient root hairs are shorter than wild type, but mechanisms underlying this phenotype remain elusive. We found that cell walls are thicker, and turgor pressure and growth rates are lower, in xyloglucan-deficient root hairs, potentially explaining their reduced growth. Lastly, we developed a protocol to perform live cell imaging of root hairs using macrofluidic chambers that allows the study of root and root hair growth under controlled chemomechanical conditions, and will show data for calcium dynamics in actively growing root hairs. One long term goal of this research is to be able to engineer crops that can grow in harder soil conditions

About the Speaker:
My name is Vyankatesh (Venky) Zambare, and I am a fifth-year Ph.D. student in the Plant Biology program. I hail from central India and earned my Integrated M.Tech in Biotechnology from the School of Biotechnology and Bioinformatics, D Y Patil University, Navi Mumbai. I gained undergraduate research experience in various research projects related to microbiology, molecular biology, genetics, and structural bioinformatics. For my master's dissertation at the Indian Institute of Science Education and Research, I explored the role of heat shock proteins in the mitochondrial membranes for macromolecule transport in plants. This experience bolstered my interest in plant functional genomics and molecular and cell biology. Currently, in the Anderson lab, I study how mechanical changes in the growth environment affect root hair morphogenesis and the role of specific cell wall components in root hair mechanobiology.

Contact

  Charles Anderson
  cta3@psu.edu