Journal of Genetics and Genomics

Review

Regulation of root-to-shoot ratio in plant resource allocation by external and internal cues

Qing Li, Yi Tong, et al.

doi: 10.1016/j.jgg.2026.07.010

Abstract (30) PDF (3)

Abstract:
Plants dynamically adjust their root-to-shoot ratio (R:S) in fluctuating environments, a response often interpreted as adaptive resource allocation, although other explanations have also been proposed. Despite ongoing debates surrounding optimal partitioning theory, the active-regulation framework remains valuable for understanding R:S regulation, which is significant for improving plant resource use efficiency and thus fitness and productivity. This review synthesizes multi-scale advances, from physiology to molecular mechanisms, to outline the regulatory networks associated with coordinated root–shoot growth. We examine how major environmental factors such as light, temperature, osmotic stress, nitrogen, and phosphorus regulate R:S through distinct pathways, highlighting the photoreceptor-mediated carbon-nitrogen allocation, organ-specific thermomorphogenic responses, and the multi-layered osmotic stress networks. For nutrient regulation, we emphasize the OsWRI1a–RNR10–DNR1 module for tissue-specific R:S nitrogen response and the PHR1-centered phosphate starvation response network. We also summarize how endogenous hormones (auxin, cytokinin, abscisic acid, and strigolactone) and signaling hubs like TOR kinase regulate R:S. Finally, we discuss current challenges and future directions for a system-level understanding of R:S regulation and its targeted manipulation.

Original Research

Prdm15 deficiency perturbs hematopoietic stem and progenitor cell homeostasis

Qiwen Dong, Weiwei Xiao, et al.

doi: 10.1016/j.jgg.2026.07.009

Abstract (29) PDF (0)

Abstract:
The maintenance of homeostasis in hematopoietic stem and progenitor cells (HSPCs) is essential for the proper development of the entire hematopoietic system. However, the mechanisms underlying this regulatory equilibrium remain elusive. Here, we report that Prdm15 deficiency in HSPCs induces the accumulation of immature hematopoietic stem cells in mice. A series of transplantation assays shows that these cells display impaired reconstitution capacity and competitive fitness, which are associated with abnormal differentiation trajectories and transcriptional alterations identified by single-cell RNA sequencing. Mechanistically, integrated multi-omics analyses including ATAC-seq and CUT&Tag sequencing of HSPCs indicate that Prdm15 deficiency induces significant transcriptional and epigenetic alterations, particularly affecting the methyltransferase KMT2C and altering H3K4me1 and H3K27ac modifications at the promoters of hematopoietic developmental genes. Collectively, our findings establish PRDM15 as a critical epigenetic regulator of HSPCs, offering valuable insights into the molecular mechanisms underlying hematopoietic homeostasis.

Original Research

LRRC71 stabilizes SEPT4 protein to ensure sperm annulus integrity and male fertility

Jinmei Cheng, Yu Wang, et al.

doi: 10.1016/j.jgg.2026.07.008

Abstract (16) PDF (0)

Abstract:
The structural integrity of the sperm flagellum is essential for male fertility, and its impairment is associated with reduced sperm motility. The sperm annulus is a septin-based fibrous ring that demarcates the midpiece and the principal piece. Notably, defects in sperm annulus formation frequently co-occur with abnormalities in flagellar structure; however, the underlying molecular mechanisms remain poorly understood. Herein, we identify an evolutionarily conserved leucine-rich repeat-containing protein, LRRC71, and show that its deficiency results in spermatozoa with a shortened mitochondrial sheath and a defective annulus, ultimately leading to male infertility. Further analysis reveals that LRRC71 deficiency leads to reduced sperm motility and decreased ATP levels following capacitation, effects that are potentially driven by a metabolic shift from oxidative phosphorylation to glycolysis. In addition, the protein levels of SEPT4, SEPT5, and SEPT7 are significantly reduced in Lrrc71-null spermatids. Mechanistically, LRRC71 directly binds SEPT4 via its N-terminal domain, thereby stabilizing the sperm annulus. Furthermore, the exogenous expression of SEPT4 rescues both motility and annulus defects in Lrrc71-null spermatozoa, confirming this functional hierarchy. Collectively, our findings demonstrate that LRRC71 serves as a central hub stabilizing sperm annulus integrity, providing insights into the pathogenic mechanisms underlying infertility associated with downregulation of LRRC71 in humans.

Original Research

Shaker potassium channel OsKAT1 regulates root K⁺ uptake and lodging resistance in rice under low K⁺ stress

Wenxuan Yu, Jun Fu, et al.

doi: 10.1016/j.jgg.2026.07.007

Abstract (26) PDF (0)

Abstract:
Widespread potassium (K) deficiency in paddy soils, coupled with the low potassium use efficiency (KUE) of rice, has driven research on genetically improving KUE for sustainable rice production. Breeding high-KUE rice cultivars requires thorough understanding of root K⁺ uptake molecular mechanisms mediated by specific K⁺ channels and transporters. Here, we characterize the Shaker-type K⁺ channel OsKAT1 in rice. Disruption of OsKAT1 impairs root K⁺ uptake, resulting in reduced K⁺ accumulation and severe growth retardation under low-K⁺ stress. Conversely, overexpression of OsKAT1 enhances root K⁺ acquisition and promotes rice growth. Notably, OsKAT1-overexpressing lines exhibit increased culm diameter and improved bending resistance, thereby enhancing lodging tolerance. OsKAT1 overexpression also significantly increases grain size and weight under both K⁺-sufficient and low-K⁺ conditions. Natural variation at the OsKAT1 locus correlates with differential gene expression among haplotypes, with Hap 2 and Hap 3 conferring superior tolerance to low-K⁺ stress. Additionally, our results suggest that the expression pattern and physiological function of OsKAT1 may be cultivar-dependent. Collectively, these findings establish OsKAT1 as a key integrator of low-K⁺ adaptation, lodging resistance, and yield enhancement in rice, offering a promising genetic target for breeding rice varieties with improved KUE and yield potential.

Large-scale low-coverage whole-genome sequencing reveals the genetic architecture of wool and growth traits in fine-wool sheep

Jianxin Shi, Changchun Lin, et al.

doi: 10.1016/j.jgg.2026.07.006

Abstract (24) PDF (0)

Abstract:
Breeding sheep with superior growth performance and wool quality is essential for the sustainability of the fine-wool sheep industry. In this study, we perform low-coverage whole-genome sequencing (lcWGS) on 3842 individuals from 5 sheep breeds (4 fine-wool and 1 semi-fine wool) and generate a large genomic dataset. By comparing these breeds with coarse-wool sheep, we characterize the genomic landscape and selection signatures of fine-wool sheep. We identify several known functional genes associated with hair follicle development and skin morphology, including EGFR, KRT74, EDAR, EREG, and GLI2. Furthermore, GWAS of 19 traits identifies 156 candidate genes significantly associated with growth and wool characteristics, including LCORL for body size, EGFR for clean wool yield, and PRDM1 for fiber diameter. Notably, EGFR is detected in both GWAS and selection signature analyses, indicating its important role in phenotype formation and historical selection. Overall, our findings reveal the genetic basis of growth and wool traits in fine-wool and semi-fine wool sheep, highlight EGFR, LCORL, and PRDM1 as candidate genes, and provide valuable genomic resources and candidate markers for future functional validation and molecular breeding.

Incomplete penetrance in neurogenetic disorders: current insights and emerging perspectives

Jiao-Jiao Xu, Dian-Fu Chen, et al.

doi: 10.1016/j.jgg.2026.07.005

Abstract (43) PDF (0)

Abstract:
Neurogenetic disorders have been recognized clinically for decades, and advances in clinical and genetic studies have identified more than 1700 monogenic causes of neurological diseases. Various types of mutations, including missense, truncating, and repeat expansions, have been reported in patients with neurogenetic disorders. It is now recognized that incomplete penetrance is common, with some individuals carrying disease-causing mutations remaining clinically unaffected. However, there is currently no comprehensive conceptual framework to categorize or explain these observations. Here, we review and integrate decades of evidence on incomplete penetrance in neurogenetic disorders to clarify its biological and mechanistic bases. Accordingly, four major themes are identified, encompassing genetic modifiers, epigenetic modifications, mosaicism, and environmental factors. These factors may act independently or interactively to influence pathogenic burden and functional network balance, ultimately determining whether a pathogenic mutation manifests clinically. Based on these insights, we highlight emerging perspectives and propose future research to fill gaps in our understanding. A deeper understanding of incomplete penetrance will be essential for generating genetic insights to support more effective genetic counseling, therapeutic interventions, and disease prevention in neurogenetic disorders.