Comparative pan-genomics reveals pervasive lineage-specific innovations and improves inference of cross-species synteny in cereals.
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Journal Article↗
Biomedical subjects
Shichao Sun
Publications and source records attributed to Shichao Sun.
Scaling up orphan crop research: genebank genetics highlight geographic structure in cultivated cowpea from 10 617 global accessions.
Vigna unguiculata (L.) Walp. is a dryland legume crop, providing essential food and nutritional security for millions of people across the semi-arid tropics, in Africa, Asia and Latin America. However, as a typical 'orphan crop', cowpea has long remained underrepresented in global genomic research to support crop improvement. Here, we conducted the largest genetic diversity analysis of cowpea to date, comprising 10 617 accessions sourced from seven international collections. Using genotyping-by-sequencing, we characterised the global patterns of genetic diversity, assessed redundancy within and across collections, and examined the geographic structure of the cowpea global allele pool. Our results revealed nine distinct genetic groups with clear geographic associations and fine-scale population differentiation, reflecting dispersal history, regional adaptation and the influence of modern breeding. Duplication across collections was detected, highlighting the need for improved curation and integration of germplasm resources. Landraces from sub-Saharan Africa do not fully capture the genetic diversity present in several other geographic regions, indicating the existence of abundant and untapped genetic resources worldwide. These findings not only provide insights into the genetic structure and evolutionary history of cowpea but also offer a valuable foundation for harnessing global germplasm diversity to enhance breeding potential and accelerate crop improvement.
Vigna↗
Insights into salt adaptation from comparative genomics of Scirpus mariqueter and a related freshwater species.
The evolutionary mechanisms underlying ecological divergence between closely related species remain a central question in biology. Scirpus mariqueter is a coastal halophyte thriving in the saline intertidal zone and exhibits marked adaptive differences compared to its freshwater relative Bolboschoenus planiculmis. However, the genomic and physiological bases of its salt tolerance remain poorly understood. We generated high-quality genome assemblies for both species and investigated the anatomical and physiological innovations underpinning S. mariqueter's adaptation to extreme environments. Morphological analyses revealed that S. mariqueter evolved specialized traits-including denser leaf palisade tissues, enhanced stem aerenchyma, and compact root cortices-synergistically limiting salt intrusion. Using chromosome-level genomes, we identified lineage-specific expansions in S. mariqueter of gene families critical for salinity tolerance, including those regulating carbohydrate metabolism, photosynthetic fidelity, and reactive oxygen species (ROS) detoxification. Strikingly, germin-like protein (GLP) and wound-induced protein (WIP) families contain tandem repeats mediating ROS scavenging and cell wall integrity, underwent adaptive expansion, paralleling anatomical innovations. Physiological profiling under salt stress confirmed S. mariqueter's unique capacity to maintain photosynthetic activity and carbohydrate production, directly linking genomic adaptations to functional resilience. This study reveals an adaptive strategy whereby structural modifications, diversification of stress-responsive gene families, and metabolic stability collectively enable S. mariqueter to thrive in saline ecosystems.
Salt Tolerance↗