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Summary Water scarcity, resulting from climate change, poses a significant threat to ecosystems.Syntrichia ruralis, a dryland desiccation‐tolerant moss, provides valuable insights into survival of water‐limited conditions.We sequenced the genome ofS. ruralis, conducted transcriptomic analyses, and performed comparative genomic and transcriptomic analyses with existing genomes and transcriptomes, including with the close relativeS. caninervis. We took a genetic approach to characterize the role of anS. ruralistranscription factor, identified in transcriptomic analyses, inArabidopsis thaliana.The genome was assembled into 12 chromosomes encompassing 21 169 protein‐coding genes. Comparative analysis revealed copy number and transcript abundance differences in known desiccation‐associated gene families, and highlighted genome‐level variation among species that may reflect adaptation to different habitats. A significant number of abscisic acid (ABA)‐responsive genes were found to be negatively regulated by a MYB transcription factor (MYB55) that was upstream of theS. ruralisortholog of ABA‐insensitive 3 (ABI3). We determined that this conserved MYB transcription factor, uncharacterized inArabidopsis, acts as a negative regulator of an ABA‐dependent stress response inArabidopsis.The new genomic resources from this emerging model moss offer novel insights into how plants regulate their responses to water deprivation.
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The architecture of resilience: a genome assembly of Myrothamnus flabellifolia sheds light on desiccation tolerance and sex determination
Summary Myrothamnus flabellifoliais a dioecious resurrection plant endemic to southern Africa that has become an important model for understanding desiccation tolerance. Despite its ecological and medicinal significance, genomic and transcriptomic resources for the species are limited.We generated a chromosome‐level, haplotype‐resolved reference genome assembly and annotation forM. flabellifoliaand conducted transcriptomic profiling across a natural dehydration–rehydration time course in the field. Genome architecture and sex determination were characterized, and co‐expression network andcis‐regulatory element (CRE) enrichment analyses were used to investigate dynamic responses to desiccation.The 1.28‐Gb genome exhibits unusually consistent chromatin architecture with unique chromosome organization across highly divergent haplotypes. We identified an XY sexual system with a small sex‐determining region on Chromosome 8. Transcriptomic responses varied with dehydration severity, pointing to early suppression of growth, progressive activation of protective mechanisms, and subsequent return to homeostasis upon rehydration. Late embryogenesis abundant and early light‐induced protein transcripts were dynamically regulated and showed enrichment of abscisic acid and stress‐responsive CREs pointing toward conserved responses.Together, this study provides foundational resources for understanding the genomic architecture and reproductive biology ofM. flabellifoliaand offers new insights into the mechanisms of desiccation tolerance.
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- Award ID(s):
- 2239530
- PAR ID:
- 10662904
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- New Phytologist
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 249
- Issue:
- 2
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- 1063 to 1084
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/nph.70700
