Postdoctoral Fellowship: PRFB: Studying a Local Species to Prepare for a Global Crisis: Unfurling Mechanisms of Desiccation Tolerance from the Resurrection Fern Pleopeltis

Carmo, Olivia Maria Silva, Houston TX

Investigators

Abstract

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2024. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Olivia Maria Silva Carmo is “Studying a local species to prepare for a global crisis: unfurling mechanisms of desiccation tolerance from the resurrection fern Pleopeltis polypodioides". The host institution for the fellowship is the Baylor College of Medicine and the sponsoring scientist is Dr. Steven Boeynaems. The current climate crisis will bring an increase in droughts which will test the resiliency of ecosystems, agricultural systems, and human societies on a global scale. Fortunately, some extremophiles are already prepared for this new climate reality: desiccation-tolerant organisms can survive extreme dry spells—losing most of their internal water in dry conditions and “reviving” upon rehydration. Understanding the mechanisms of desiccation tolerance could harbor major biotechnological breakthroughs, for example, the dry storage of sensitive biologicals like RNA vaccines allowing for their distribution to remote areas without ultra-cold storage, or the genetic information sufficient to engineer more drought-tolerant crops and improve food security. The underlying mechanisms of desiccation tolerance, particularly how genetic material is protected, is still poorly understood. This project focuses on characterizing how genetic material is protected and reorganized over the course of dehydration and rehydration using the resurrection fern, Pleopeltis polypodioides (hereafter Pleopeltis). This resurrection fern is an ideal model system for desiccation tolerance as it can lose up to 97% of its relative water weight while maintaining viability and it can rehydrate in as little as three hours. Even when cut from the plant, Pleopeltis fronds can de/rehydrate, allowing the study of desiccation tolerance in the field and lab. Broader impacts include establishing Pleopeltis as a viable model of desiccation tolerance for future studies, spreading awareness of desiccation tolerance using Pleopeltis as a mascot of desiccation tolerance in the classroom, and establishing an open access Pleopeltis Database from which all datasets resulting from this project can be accessed. Training objectives include acquiring skills in plant physiology, genomics, and development and maintenance of online database resources. While the proteins and metabolites that facilitate desiccation tolerance have been characterized in some organisms, the processes by which nucleic acids are protected and reorganized during desiccation and rehydration remain enigmatic. The goal of this project is to fill this knowledge gap, using the desiccation tolerant fern Pleopeltis as a model species. Specific aims include: 1a) sequencing and annotating the Pleopeltis genome using well established long read sequencing and annotation tools, 1b) determining how the Pleopeltis genome architecture, including intrachromosomal contacts, accessible chromatin, and associations with other intranuclear bodies, change as a function of hydration status using chromatin conformation capture (Hi-C), ATAC-seq, and electron microscopy respectively; 2) determining how Pleopeltis transcript, metabolite, and protein profiles are rewired over the course of de/rehydration; and 3) translating these findings to a heterologous system, focusing on proteins that may facilitate nucleic acid stabilization, to identify sequence determinants of desiccation tolerance-conferring proteins. All data will be open access and hosted in appropriate repositories: sequencing data in NCBI Short Read Archive (https://www.ncbi.nlm.nih.gov/sra), mass spectrometry data in MetabolomeXchange (http://www.metabolomexchange.org/site/) and the proteomics database PRIDE (https://www.ebi.ac.uk/pride/), electron microscopy in EMPIAR (https://www.ebi.ac.uk/empiar/), and all other data and metadata will be uploaded to Zenodo (https://zenodo.org/). An accessible and interactive Pleopeltis Database browser will integrate all datasets produced in this research and serve as a catalyst for the desiccation tolerance field. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.