Bacillus velezensis csuftb-96, an efficient and promising biocontrol agent for managing Diplodia shoot blight caused by Diplodia sapinea.

Investigation on the promotion mechanism for the enzymatic saccharification of Pinus massoniana by polyol-based deep eutectic solvents pretreatment

Aluminum addition alters bacterial community structure in rhizospheric soil and root endosphere of Pinus massoniana forests

In-situ lignin modification in acid-alkaline combinational pretreatment on masson pine for efficient biomass saccharification

Characterization of the aquaporin gene family in Pinus massoniana and functional analysis of PmNIP2;1 involved in high-temperature and drought stress.

PmVNS2 promotes secondary cell wall formation and enhances xylem development in transgenic poplar. Secondary cell wall deposition is essential for wood formation in trees, and NAC-domain transcription factors are widely involved in transcriptional networks associated with this process. Here, we identified PmVNS2, a VND-subfamily NAC gene from Pinus massoniana. PmVNS2 encodes a conserved NAC-domain protein and shows preferential expression in developing xylem. Heterologous expression of PmVNS2 in Populus davidiana × P. bolleana resulted in enhanced plant growth and secondary xylem development, accompanied by increased secondary cell wall thickening. Molecular analyses showed that PmVNS2 overexpression was associated with altered expression of genes related to lignin and cellulose biosynthesis. In addition, several downstream transcriptional regulators involved in secondary wall formation were affected, while some hemicellulose-related genes exhibited reduced expression. Together, these findings suggest that PmVNS2 may participate in transcriptional regulation associated with secondary cell wall formation and contribute to wood development-related processes in conifer species.

Seed endophytic microbiota are crucial for plant early development and stress resistance. Pinus massoniana is a key ecological and economic tree species in China, yet it is severely threatened by pine wilt disease (PWD). However, the community composition of P. massoniana seed endophytic microbiota and the persistent symbiosis formed via vertical transmission in seeds remain unclear. We analyzed the endophytic bacterial and fungal microbiota of P. massoniana seeds from four geographic regions using high-throughput 16S rRNA and ITS sequencing to characterize community structure, diversity, and functional potential, providing a basis for endophytic microbiota-based strategies to enhance resistance to PWD. Results showed that both alpha and beta diversity analyses indicated that seed endophytic microbial communities of P. massoniana differed among regions. Bacterial communities were dominated by Pseudomonadota (phylum), Gammaproteobacteria (class), and the genera Klebsiella, norank_f_Pectobacteriaceae, and Lactobacillus. Fungal communities were primarily composed of Ascomycota and Basidiomycota (phylum), Sordariomycetes (class), and the genera Rosellinia, Aspergillus, and Coniophora. Correlation network analysis revealed that fungal networks were characterized by a higher proportion of positive correlations, whereas bacterial networks were more complex. Notably, several genera detected in seeds, including Pseudomonas, Bacillus, and Trichoderma, have also been reported in mature P. massoniana tissues, indicating a potential for putative vertical transmission from mother plants. Functional prediction further suggested that these taxa were enriched in pathways related to terpenoid and polyketide metabolism and saprotrophic functions, which have been implicated in PWD resistance and have been previously reported to exert nematode-suppressive or plant growth-promoting effects. Overall, this study elucidates the community structure and ecological characteristics of seed endophytic microbiota in P. massoniana and identifies potentially beneficial microbial taxa, providing potential support for the future utilization of P. massoniana endophytic microbiota in PWD research.

Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, is a globally destructive threat to coniferous forests, causing severe ecological and economic losses. Conventional resistance breeding is critically hampered by long life cycles of trees and field evaluation challenges. To address these limitations, we developed a three-tier biotechnology pipeline with a dual-output goal (generating both resistant germplasm and mechanistic insights) designed to bridge the in vitro–field gap. This strategy is founded upon the resolution of a longstanding pathogenesis debate, which established aseptic PWNs as a standardized research tool. The pipeline integrates high-throughput in vitro cellular screening (Tier 1), whole-plant validation via organogenesis (Tier 2), and scaled production coupled with mechanistic investigation through somatic embryogenesis (Tier 3). Tier 1 enables rapid phenotypic screening, Tier 2 validates resistance in whole plants, and Tier 3 facilitates mass production and in-depth study. It operates as a closed-loop, knowledge-driven system, simultaneously accelerating PWN-resistant germplasm development and empowering molecular mechanism discovery. Validated across Pinus massoniana and P. densiflora, this work provides a concrete, community-usable model system that directly addresses a core methodological bottleneck in forest pathology. This strategy effectively bridges the in vitro–field gap, offering a replicable model for perennial crop breeding and contributing to resilient forest management.

Damping-off disease, primarily caused by Fusarium oxysporum, poses a significant challenge to the cultivation of Masson pine (Pinus massoniana) seedlings. Although Trichoderma koningiopsis improves damping-off disease resistance in Masson pine by regulating the rhizosphere microbial community, the underlying mechanisms remain unknown. Metabolomic analysis showed that T. koningiopsis altered Masson pine root exudates, especially plant organic acids such as capric acid (CA), lauric acid (LA) and pelargonic acid (PA). Co-culturing rhizosphere microbes with 0.1 mM CA, LA, PA and a combination of the three (1:1:1, CDNs1) significantly inhibited F. oxysporum and promoted the growth of rhizosphere biocontrol strains (Trichoderma, Penicillium and Bacillus), with CDNs1 exerting a superior effect. Amplicon sequencing and RT-qPCR showed that CDNs1 significantly altered the microbial community composition in the rhizosphere, especially inhibited the growth of Fusarium and enriched beneficial microbes (Trichoderma and Penicillium). CDNs1 effectively decreased the incidence and severity index of damping-off disease in Masson pine seedlings by 73.33% and 41.67%, respectively. Mechanistically, CDNs1 enhanced resistance to damping-off disease by modulating plant hormones, oxidative stress defences and the photosynthesis pathway. Collectively, this study provides insight into the mechanism by which T. koningiopsis enhances damping-off disease resistance by regulating the rhizosphere microbial community.

Engineered bacterium Pseudomonas abietaniphila BHJ04-BLG4 controls pine wilt disease via nematocidal activity and induction of host systemic resistance.

Thinning improves timber yield and structure in Pinus Massoniana plantations: a 35-year experiment

This study investigates the impact of wildfires on the diversity and types of soil microbial functions within Karst forest ecosystems, and examines their relationship with soil nutrients. In particular, we focus on the Quercus fabri broadleaf and Pinus massoniana coniferous forests within areas affected by wildfires in Qiannan, located in the Karst area of Guizhou, Southwestern China. Analysis of soil microbial functional types associated with soil nutrients and their effects was performed using microbial amplicon sequencing technology. Significant differences in the functional diversity of soil bacteria and soil fungi associated with relevant soil nutrients were observed between the Q. fabri broadleaf and P. massoniana coniferous forests in the study area. After fire, the functional diversity of bacteria in both forest types increased significantly, resulting in a convergence in bacterial functional types. Fire enhanced the functional diversity of fungi in the P. massoniana forest; however, had no discernible effect on the Q. fabri forest. In addition, fire altered the types and abundance of microbial functions associated with soil nutrients, exerting a greater impact on bacterial functional types. The results also revealed that fire enhanced the abundance of TOC- and TP-related microbial functional types in both forest types, while reducing TK-related functional types. TN-related functional types increased in the Q. fabri forest but decreased in the P. massoniana forest. At the bacterial level, fire increased TOC-, TN-, and TP-related functional types in both forest types; however, reduced TK-related types. In fungal communities, fire increased TP-related functional groups in the Q. fabri forest while reducing TOC-, TN-, and TK-related groups. In contrast, in the P. massoniana forest, fire increased TOC- and TP-related groups but decreased TN- and TK-related groups. The research findings provide a scientific basis for the restoration and management of the post-fire forest ecosystems in Karst areas.

Changes of soil microbial community in Pinus massoniana forest plantation after conversion

Depolymerizing lignin to produce high-value chemicals has garnered increasing attention. Given the complex structure of real lignin, the cracking efficiency of β-O-4 linkages and the selectivity of depolymerization products are significantly lower than those of lignin model compounds. Meanwhile, the relationship between the structure of lignin and the β-O-4 linkage cracking was ignored. In this work, to well address the issue, three real lignins (corncob lignin (CL), pinus massoniana lignin (PML), and eucalyptus lignin (EL)) were employed to discuss the impacts of special ether bonds in lignin on the β-O-4 linkage cracking in the no-additional-hydrogen catalytic system mediated by a CoNi2@BTC catalyst. The lignin depolymerization results showed that the ether bonding structure in the lignin significantly impacted the cracking of β-O-4 linkages and selectivity of the final products, resulting in a great difference among their intermediates. Notably, the methoxy groups in the real lignin greatly inhibited the further hydrogenation of phenolic compounds, resulting in the accumulation of abundant methoxy-substituted phenolic compounds and a low yield of cycloalkanes (12.37% to 14.06%). To deeply discuss the β-O-4 linkage cracking in the lignin depolymerization, degradation experiments with coexisting ether bond compounds were performed, and the activation energy was employed to quantitatively evaluate the impacts of other ether bonds on the β-O-4 linkage cracking. The results revealed that multiple ether bonds (α-O-4, 4-O-5, and methoxy group) significantly increased the activation energy (from 236% to 373%) of β-O-4 linkages, resulting in the evident decline in the β-O-4 model compound. In addition, the degradation of the methoxy-substituted β-O-4 model compound (GG) demonstrated that the methoxy-substituted aromatic ring products were resistant to further hydrogenation, resulting in the accumulation of methoxy-substituted aromatic ring products in the depolymerization of real lignin. All the findings will provide a novel perspective for the targeted high-value utilization of real lignin in chemical production.

Ectomycorrhizal fungi form symbiotic relationships with a wide range of terrestrial plants, acquiring carbohydrates for themselves and promoting nutrient uptake in their host plants. However, some ectomycorrhizal fungi cannot effectively obtain the thiamine necessary for growth from their host or synthesize it themselves. Ectomycorrhizal fungi can recruit hypha-associated microorganisms, which play a vital role in promoting nutrient absorption and ectomycorrhizal root formation, ultimately colonizing within fruiting bodies to form a unique bacterial microbiota. In this study, nontargeted metabolomics and whole-genome sequencing were employed to investigate the colonization characteristics of the hyphae-associated bacterium Bacillus altitudinis B4 on the mycelial surface of ectomycorrhizal fungus Suillus clintonianus, as well as the synergistic promotion of thiamine synthesis and absorption by B. altitudinis B4 and the fungal mycelium, respectively. The results suggested that S. clintonianus first secreted ureidosuccinic acid and pregnenolone, recruiting the hyphae-associated bacterium B. altitudinis B4 to the mycelial surface. Subsequently, the ureidosuccinic acid secreted by S. clintonianus further stimulated B. altitudinis B4 to enhance thiamine production by increasing its biomass and upregulating the expression of related functional genes. Finally, S. clintonianus absorbed the thiamine secreted by the B. altitudinis B4, promoting fungal growth and increasing the colonization rate in association with Pinus massoniana. This study elucidates the thiamine acquisition mechanisms of ectomycorrhizal fungi, highlighting the critical role of bacterial partners in fungal nutrition and host-fungal interactions.

Long-term effects of resin tapping on growth and modelling of mature Masson pine (Pinus massoniana).

Tree species mixing has been widely recognized as an effective silvicultural strategy for enhancing both stand productivity and biodiversity. Nevertheless, its effects on branch radial growth and the underlying physiological mechanisms remain inadequately understood. In this study, we measured branch ring widths and 22 functional traits of pure and mixed plantations of Pinus massoniana Lamb. and Castanopsis hystrix Hook. f. & Thomson ex A. DC. to investigate the effects of species mixing on branch radial growth, to assess potential variations between even- and uneven-aged forest mixtures, and to elucidate the underlying physiological mechanisms. Our results demonstrated that tree species mixing generally promoted branch radial growth, as indicated by the basal area increment for both studied species. The effect of species mixing on branch radial growth was not significantly different between even- and uneven-aged mixtures for C. hystrix; however, it diminished with increasing age of P. massoniana. Our findings indicated that the radial branch growth of P. massoniana was related to larger tracheid radial diameter and higher hydraulic conductance. In contrast, increased branch radial growth of C. hystrix was more related to higher specific leaf area and thinner leaves in mixed plantations, which potentially improved the light capture efficiency and leaf carbon turnover rate. Our results also indicated that tree species mixture is an effective strategy for enhancing branch growth. The positive mixing effect could diminish as P. massoniana reaches an over-mature age in the mixed-species stand, implying that species mixing practices during the early stages of stand development provide more benefit. The findings provide valuable insights for formulating reasonable forest management strategies and improving the understanding of the eco-physiology of species mixing effects on tree growth.

Pines (Pinus L.) are widely cultivated for their rich resin content and ease of wood processing. However, pines are constantly threatened by pine wood nematode (PWN; Bursaphelenchus xylophilus), causing a large number of pine forests to wilt and die. Pinus massoniana and P. thunbergii are both major host species for PWN. Previous studies have found that P. thunbergii is more sensitive to PWN than P. massoniana. It is particularly important to understand the differential sensitivity mechanisms against PWN among pine species in order to ensure their balanced growth and protect their diversity. Therefore, this study analyzed and identified the main differential metabolic pathway between P. massoniana and P. thunbergii through metabolomics. We compared the disease phenotypes of P. massoniana and P. thunbergii inoculated with PWN. And we further analyzed metabolome data to screen the different resistance pathways in the two pine species. As a result, the pentose phosphate pathway, in which d-gluconate was the key difference substance, was prominent in the resistance difference of P. massoniana and P. thunbergii. The levels of G6DPH, NADPH and organic acids in P. massoniana were significantly higher than those in P. thunbergii to better maintain redox balance. The content of these substances in P. thunbergii increased after treatment with exogenous d-gluconic acid, and its ability to resist nematodes was comparable to that of P. massoniana. Moreover, d-gluconic acid was demonstrated by scanning electron microscopy to restore the damage of pine cells. This discovery indicated that activating the pentose phosphate pathway could increase the ability of pine trees to defend against nematodes, which not only enhances the understanding of pine resistance, but also promotes breeding research on pine trees and provides a novel perspective for the development of new insecticidal substances. © 2025 Society of Chemical Industry.

Cumulative droughts and legacy effects decreased long-term growth resilience in Pinus massoniana in the middle Dabie Mountains

Induced resistance to pine wilt disease in Pinus massoniana by the endophytic engineered bacterium Pseudomonas koreensis BM06-P60