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Pan-genome analysis of Caragana reveals genomic mechanisms of drought adaptation of leguminous shrubs to arid environments

delete2026-08-01
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OA
AI
J
Jiaxing Song
J
Jie An
H
Houyin Xia
W
Wanjiang Li
J
Jingdian Hu
Q
Qian Li
C
Chenjian Li
X
Xiaoxia Shen
程红 (Hong Cheng)
Y
Yi Zhou
T
Tianming Hu
P
Peizhi Yang *
DOI:10.1186/s13059-026-04230-8delete
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Abstract

Abstract

En 中文
Perennial leguminous shrubs of the genus Caragana play key roles in arid and semi-arid ecosystems, contributing to ecological restoration, nitrogen fixation, and bioenergy production. However, the genomic basis underlying their adaptation to arid environments remains insufficiently understood. Here, we generate chromosome-scale genome assemblies for 14 representative Caragana species, including a near telomere-to-telomere assembly of Caragana korshinskii (NMCN13). Using these genomes, we construct a graph-based pan-genome and identify extensive genomic variation, including 801,351 structural variants and 104,404 presence-absence variations. Comparative analyses identify clade-specific gene family expansions enriched in stress-related pathways, particularly secondary metabolism. We further identify two candidate drought-responsive genes, CkoERF1 and CkoWAKL, whose functions are supported by heterologous overexpression in Arabidopsis thaliana and alfalfa, demonstrating enhanced drought-response phenotypes. Transposable element analyses indicate that variation in LTR retrotransposon abundance contributes to genome size diversity across species. Notably, we find that some key symbiosis-related genes, for example, NIN, DMI1, DMI2, and NSP1, are conserved across all species, suggesting a stable genetic basis for nitrogen fixation. This study provides high-quality genomic resources and a comprehensive pan-genomic framework for Caragana. Our findings offer new insights into genome evolution, environmental adaptation, and drought tolerance mechanisms, and establish a foundation for future functional genomics and breeding efforts in leguminous shrubs.
Keywords:
Pan-genome
Caragana
Arid adaptation
Structural variants
Drought stress

Journal

G
Genome Biology
IF:
9.4
Papers:
6.3K
Citations:
7.3W

Organization

C
College of Grassland Science
Scholars:
127
Papers: 40
Citations: 0
S
school of agriculture
Scholars:
97
Papers: 140
Citations: 2
C
College of Grassland Agriculture
Scholars:
55
Papers: 16
Citations: 0
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