Comparative transcriptome analysis suggests convergent evolution of desiccation tolerance in Selaginella species

Abstract

Background Desiccation tolerant Selaginella species evolved to survive extreme environmental conditions. Studies to determine the mechanisms involved in the acquisition of desiccation tolerance (DT) have focused on only a few Selaginella species. Due to the large diversity in morphology and the wide range of responses to desiccation within the genus, the understanding of the molecular basis of DT in Selaginella species is still limited. Results Here we present a reference transcriptome for the desiccation tolerant species S. sellowii and the desiccation sensitive species S. denticulata. The analysis also included transcriptome data for the well-studied S. lepidophylla (desiccation tolerant), in order to identify DT mechanisms that are independent of morphological adaptations. We used a comparative approach to discriminate between DT responses and the common water loss response in Selaginella species. Predicted proteomes show strong homology, but most of the desiccation responsive genes differ between species. Despite such differences, functional analysis revealed that tolerant species with different morphologies employ similar mechanisms to survive desiccation. Significant functions involved in DT and shared by both tolerant species included induction of antioxidant systems, amino acid and secondary metabolism, whereas species-specific responses included cell wall modification and carbohydrate metabolism. Conclusions Reference transcriptomes generated in this work represent a valuable resource to study Selaginella biology and plant evolution in relation to DT. Our results provide evidence of convergent evolution of S. sellowii and S. lepidophylla due to the different gene sets that underwent selection to acquire DT

Convergent evolution of desiccation tolerance in grasses

“…Desiccation tolerance is likely an ancestral adaptation in plants that evolved during terrestrialization, subsequently formed the basis of seed pathways, and was later rewired again in vegetative tissues 5,25,42,50 . While previous studies have found surprisingly little overlap in gene expression across desiccation tolerant plants 51,52 , our data suggest that the repeated evolution of specific genetic, biochemical, and physiological traits required for anhydrobiosis, are highly convergent and build on more broadly conserved water deficit responses.…”

Systems biology of resurrection plants

“…The transcriptome of the third DT representative of Selaginella , S. sellowii , was compared with the desiccation tolerant S. lepidophylla and the desiccation sensitive S. denticulata [ 112 ]. S. lepidophylla and S. sellowii were selected since both manifest VDT but have different morphologies, thus providing the opportunity to identify common DT strategies that are independent of morphological adaptations.…”

Data Baru dari Marga Selaginella

“…Beberapa spesies Selaginella ini telah mengembangkan toleransi kekeringan (DT) yaitu sifat tertentu yang memungkinkan mereka bertahan dalam waktu yang sangat lama pada kondisi kering. Toleransi terhadap pengeringan, dianggap sebagai kemampuan untuk pulih dari kehilangan air di protoplasma, dan tersebar dalam struktur reproduksi (seperti biji dan serbuk sari) tetapi jarang terjadi pada jaringan vegetatif tumbuhan cheophyta (Alejo-Jacuinde et al, 2020).…”