Biology subjects

Song, B.-H.

Publications and source records attributed to Song, B.-H..

3 recordsLinked to original sources

bioRxiv2026

Phenolic Chemical Defense Contributes to Resistance against Multiple Soybean Cyst Nematode Populations in Wild Soybean

Soybean cyst nematode (Heterodera glycines, SCN) is one of the most damaging pathogens of soybean worldwide. Virulence diversity among SCN populations and reliance on a limited number of resistance sources present major challenges for durable SCN management. Here, we investigated a wild soybean (Glycine soja) genotype (WsR), that is resistant to two SCN populations, race 2 (HG type 1.2.5.7) and race 5 (HG type 2.5.7), and compared its transcriptional and metabolic responses with those of the susceptible genotype (WsS). WsR exhibited a substantially stronger defense-associated transcriptional response to both SCN populations, including preferential induction of genes associated with Ca2+/calmodulin and salicylic acid signaling. Integration of transcriptomic and time-resolved metabolomic analyses revealed convergence on phenolic metabolism, with enhanced accumulation of phenolic acids, flavonoids, and isoflavonoids in resistant WsR. Genes involved in phenolic biosynthesis and modification were also preferentially induced in WsR, linking transcriptional reprogramming with the observed metabolic response. Importantly, two resistance-associated phenolic compounds, 4-hydroxybenzaldehyde and 2,3-dihydroxybenzoic acid, directly increased mortality of SCN second-stage juveniles from both populations in a concentration-dependent manner. By connecting resistance-associated transcriptional responses and metabolic reprogramming with direct activity of specific phenolic compounds against SCN, our study provides functional evidence linking phenolic metabolism to chemical defense against SCN. Together, these findings identify enhanced phenolic chemical defense as a major component of resistance to multiple SCN populations in wild soybean and highlight wild soybean as a valuable source of molecular and biochemical diversity for SCN resistance.

plant biology↗

bioRxiv2026

A chromosome-scale reference genome and single-nucleus root atlas reveal the cellular and molecular basis of coastal adaptation in sand bean (Strophostyles helvola)

Plants adapted to saline coastal habitats provide valuable systems for understanding how natural selection reshapes stress-response programs, yet the cellular and molecular basis of this adaptation remains poorly resolved. Here, we generated a chromosome-scale reference genome and a single-nucleus transcriptomic atlas of roots from sand bean (Strophostyles helvola), a wild legume represented by salt-tolerant Beach and salt-sensitive Inland ecotypes. The atlas comprised 87,901 nuclei assigned to 25 transcriptional clusters representing 16 major root cell types. Salt exposure elicited cell-type-specific transcriptional responses that differed between Beach and Inland roots. Beach roots preferentially maintained respiration-, energy metabolism-, and protein-homeostasis-associated functions, whereas Inland roots showed stronger induction of canonical abiotic-stress, ABA, water-deficit, hypoxia, and oxidative-stress programs. Integrating baseline ecotype differences with salt-responsive expression revealed that many genes induced by salt in Inland roots were already expressed at higher levels in untreated Beach roots. This baseline-enriched configuration comprised a broadly distributed regulatory backbone, including ERF-family transcription factors and RING-type E3 ubiquitin ligases, together with cell-type-associated modules involving ion and water transport at the root-soil interface, redox and dehydration protection in outer-root tissues, endodermal barrier-associated genes, and vascular regulatory candidates. These findings support a model in which Beach salt tolerance is associated not with entirely distinct stress-response pathways, but with the pre-existing and spatially organized deployment of conserved protective programs that remain responsive to salt exposure. Our study establishes genomic and cellular resources for sand beans and provides a framework for investigating how natural variation in the regulation and cellular organization of conserved pathways contributes to environmental stress tolerance.

plant biology↗

bioRxiv2022

Genetic basis and selection of glyceollin induction in wild soybean

O_LIGlyceollins, a family of phytoalexin induced in legume species, play essential roles in responding to environmental stresses and in human health. However, little is known about the genetic basis and selection of glyceollin induction. C_LIO_LIWe employed a metabolite-based genome-wide association (mGWA) approach to identify candidate genes involved in glyceollin induction from genetically diverse and understudied wild soybeans subjected to soybean cyst nematode stress. C_LIO_LIEight SNPs on chromosomes 3, 9, 13, 15, and 20 showed significant association with glyceollin induction. Six genes close to one of the significant SNPs (ss715603454) on chromosome 9 fell into two clusters, and they encode enzymes in the glycosyltransferase class within the phenylpropanoid pathway. Transcription factors (TFs) genes, such as MYB and WRKY were also found within the linkage disequilibrium of the significant SNPs on chromosome 9. Epistasis and a strong selection signal were detected on the four significant SNPs on chromosome 9. C_LIO_LIGene clusters and transcription factors may play important roles in regulating glyceollin induction in wild soybeans. Additionally, as major evolutionary factors, epistatic interactions and selection may influence glyceollin variation in natural populations. C_LI

plant biology↗