Author ORCID Identifier

Document Type


Date of Award


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Bernard W. M. Wone


Desiccation tolerance was a crucial adaptation for plants during their transition to terrestrial environments. Some spike mosses, including S. lepidophylla, have evolved the remarkable ability to tolerate extreme desiccation, enabling survival in arid regions of the world. However, the regulatory basis of this trait remains unknown. This dissertation aims to unravel the genetic basis of desiccation tolerance in Selaginella lepidophylla and its potential for improving crop abiotic stress tolerance. To achieve this goal, three objectives were pursued. Objective 1 focused on determining the regulatory role of the SlbHLH transcription factor (TF) by overexpressing it in Arabidopsis thaliana to assess its impact on water-use efficiency, abiotic stress tolerance, growth, and development. Objective 2 aimed to develop a genetic transformation protocol for Selaginella species, enabling the study of regulatory genes in S. lepidophylla and other Selaginella species. Objective 3 involved identifying dehydration responsive genes from transcriptome of S. lepidophylla during dehydration, providing insights into the desiccation mechanism and potential candidate genes for improving drought tolerance in crops. Our findings as the first to functionally characterize a TF from the spike moss, S. lepidophylla, revealed that the SlbHLH TF plays a crucial regulatory role in plant growth, development, abiotic stress tolerance, and water-use efficiency. Moreover, the development of a transformation system for Selaginella moellendorffii enables the study of regulatory genes in desiccation-tolerant spike mosses, including S. lepidophylla, thereby enhancing our understanding of desiccation tolerance mechanisms. Furthermore, the identification of dehydration responsive genes associated with desiccation tolerance of S. lepidophylla provides valuable genomic resources for improving abiotic stress tolerance in crop plants. Altogether, this dissertation advances our understanding of the genetic basis of desiccation tolerance in S. lepidophylla and proposes practical approaches for enhancing crop abiotic stress tolerance. Furthermore, the development of a genetic transformation system for Selaginella and the transcriptomic analysis of S. lepidophylla provide essential tools and insights for studying desiccation tolerance mechanisms and regulatory networks, thus paving the way for future advancements in crop improvements and sustainable agriculture.

Subject Categories

Biology | Molecular Biology


Abiotic stress tolerance, Desiccation tolerance, Genetic transformation, Selaginella lepidophylla, Transcriptome

Number of Pages



University of South Dakota



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