Convergent evolution of desiccation tolerance in grasses

Desiccation tolerance has evolved repeatedly in plants as an adaptation to survive extreme environments. Plants use similar biophysical and cellular mechanisms to survive life without water, but convergence at the molecular, gene, and regulatory levels remains to be tested. Here, we explore the evolutionary mechanisms underlying the recurrent evolution of desiccation tolerance across grasses. We present genomes of three resurrection grasses native Sub-Saharan Africa. We leveraged comparative genomic and transcriptomic approaches to identify patterns of convergence and divergence across these species. We observed substantial overlap in gene duplication and expression associated with desiccation, and syntenic genes of shared origin are activated across species, indicative of parallel evolution. In other cases, similar metabolic pathways are induced, but using different gene sets, pointing towards phenotypic convergence. Species-specific mechanisms supplement these shared core mechanisms, ..., These data were used to identify core mechanisms of desiccation tolerance shared across grasses. We subjected replicated sets of the resurrection grasses Oropetiuum capense, Tripogon minimus, and Microchloa caffra to a controlled dehydration-rehydration timecourse. Tissues were collected at six comparable timepoints (four during drying and two during recovery) for each of the three species. Plants were sampled at targeted hydration states including from well-watered, partially dehydrated, fully desiccated, and 24 and 48 hours post rehydration. The hydration status of tissues was validated by measuring relative water content. Gene expression data (RNAseq) was generated by extracting total RNA using Spectrum Plant Total RNA kit according to the manufacturer's instructions. Total RNA was then cleaned to remove impurities and contaminants using Zymo Clean & Concentrator kit. RNAseq libraries were constructed by Novagene following a standard polyA+ enrichment strategy and sequenced on an..., , # Convergent evolution of desiccation tolerance in grasses

Here, we provide physiological metadata, annotation information, and other useful intermediate files from our analyses.

## Description of the data and file structure

These data are organized in directories. In the parent directory, we provide physiological data in the file *3_grasses_timecourse_metadata.csv*. Plants were sampled at targeted hydration states during the process of dehydration, including well watered (WW), partially dehydrated (D1, D2, and D3), fully desiccated (D4), and rehydrated (R1 and R2). We validated the physiological status of tissues by measuring relative water content (RWC) and photosynthetic efficiency (Fv/Fm), and these data are summarized in the *3_grasses_timecourse_metadata.csv* file. The parent directory also contains a matrix of all the syntenic orthologs for each study species in the file *Syntenic_orthogroups.tsv*. We used the MCScan toolkit (v1.1) implemented in python [] using the chromoso...