Xiao-Ping Zhang

Ectomycorrhizal fungi (EMF) colonize roots to establish symbiotic associations with plants. Sporocarps of the EMF Tuber spp. are considered as a delicacy in numerous countries and is a kind of EMF of great economic and social importance. Elucidating host responses to Tuber colonization would facilitate the exploration of symbiotic interactions and contribute to truffle cultivation. Tuber indicum and T. panzhihuanense, two primary commercial truffle species in China, were selected to colonize Pinus armandii and Carya illinoinensis in a two-and-a-half-year symbiosis experiment. Host performances, including growth, nutrient uptake, and physiological characteristics, were dynamically monitored. The molecular response of host leaf to Tuber symbiosis was further analyzed using RNA-seq. Tuber indicum and T. panzhihuanense exhibited superior colonization of P. armandii compared to that of C. illinoinensis. Both Tuber species enhanced the performance of the two hosts by increasing their height, stem circumference, and biomass. Phosphorus levels and activities of peroxidase and catalase in hosts were observed to increase during Tuber symbiosis. The results confirmed that Tuber colonization led to significant alterations in leaf transcriptomic profiles of the two trees. Tuber indicum and T. panzhihuanense both elicited defense-related regulation in host leaves, such as secondary metabolism, cell wall biogenesis, plant hormone signal transduction, and plant-pathogen interaction, with distinct patterns in P. armandii and C. illinoinensis. Our study provides an evaluation of host performance during truffle symbiosis and highlights the diverse patterns of Tuber-induced systematic defense regulation in hosts, offering insights into the specific symbiotic traits of Tuber-host pairs.

Dictyophora indusiata cultivation is severely impeded by premature hyphal regression. This study elucidates the spatiotemporal dynamics of mycelial regression and associated microbial succession in both substrate and soil matrices across progressive regression stages (CK: normal growth; S1: initial recession; S2: advanced recession; S3: complete recession). Microscopic analysis revealed preferential mycelial regression in the substrate, preceding soil regression by 1–2 stages. High-throughput sequencing demonstrated significant fungal community restructuring, characterized by a sharp decline in Phallus abundance (substrate: 99.7% → 7.0%; soil: 78.3% → 5.5%) and concomitant explosive proliferation of Trichoderma (substrate: 0% → 45.2%; soil: 0.1% → 55.3%). Soil fungal communities exhibited a higher richness (Chao1, p < 0.05) and stability, attributed to functional redundancy (e.g., Aspergillus, Conocybe) and physical protection by organic–mineral complexes. Conversely, substrate bacterial diversity dominated, driven by organic matter availability (e.g., the Burkholderia–Caballeronia–Paraburkholderia complex surged to 59%) and optimized porosity. Niche analysis confirmed intensified competition in post-regression soil (niche differentiation) versus substrate niche contraction under Trichoderma dominance. Critically, Trichoderma overgrowing was mechanistically linked to (1) nutrient competition via activated hydrolases (e.g., Chit42) and (2) pathogenic activity (e.g., T. koningii causing rot). We propose ecological control strategies: application of antagonistic Bacillus subtilis (reducing Trichoderma by 63%), substrate C/N ratio modulation via soybean meal amendment, and Sphingomonas–biochar soil remediation. This work provides the first integrated microbial niche model for D. indusiata regression, establishing a foundation for sustainable cultivation.

Non-volatile organic acids (NVOAs) are essential to the flavor profile of Baijiu. However, the low levels and diversity of NVOAs in Baijiu make their isolation, annotation, and quantification challenging. In this study, a well-established pipeline combining chemical derivatization, isotope labeling, and high-resolution mass spectrometry with a three-tier annotation process was used to quantify NVOAs in three typical flavor types of Baijiu with high coverage and confidence. The results revealed the annotation of 56, 145, and 1277 NVOAs in Baijiu at tier 1, tier 2, and tier 3 levels, respectively. Among them, a total of 166 high-confidence NVOAs were first reported in Baijiu. Furthermore, multivariate statistical analyses indicated that abundant NVOAs could potentially be used as biomarkers to distinguish between different flavor types of Baijiu. This study provides a powerful tool for the qualification and quantification of NVOAs in Baijiu. The results will greatly expand the understanding of NVOAs in Baijiu.

Pathogenic invasion of Trichoderma pleuroticola profoundly altered microflora in the Auricularia cornea crop production system, impacting diversity and composition in both artificial bed-log and fruiting bodies. A more complex ecological network between the diseased and healthy bodies. Researchers still have poor knowledge about how the important agricultural relationship between the composition of the microbiome of the artificial bed-log and the fruiting bodies is infected by the pathogenic invasive microbes T. pleuroticola, but this knowledge is crucial if we want to use or improve it. Here, we investigated 8 groups (48 biological samples) across 5 growth stages of the A. cornea production system using metagenomic technology. Diseased and healthy fruiting bodies exhibited distinct microbial compositions, while core members in artificial bed-logs remained stable. Core microbiota analysis highlighted Pseudomonas and Pandoraea bacterial genera, as well as Sarocladium, Cephalotrichum, Aspergillus, and Mortierella fungal genera as biomarker species after the bodies were treated with the pathogenic invasive microbes T. pleuroticola. In diseased bodies, these core members upregulated pathways including polymyxin resistance, L-arginine degradation II, superpathway of L-arginine and L-ornithine degradation, glucose degradation (oxidative), glucose and glucose-1-phosphate degradation, promoting fruit spoilage. Our data confirm that T. pleuroticola plays an important role in the early stages of disease development in the A. cornea crop generation system. The exposed volatile core microbiome may play an important role in accelerating T. pleuroticola-induced decay of fruiting bodies.

Auricularia cornea is a widely prized basidiomycetous mushroom with culinary and medicine value, which is cultivated artificially on a large scale in China. However, little attention has been paid to the differences in metabolic profiles under different pH growth conditions. In the present study, weakly acidic and weakly alkaline artificial substrates were developed and used for the cultivation of A. cornea, and the metabolic profiles of its fruiting bodies were determined using UPLC-MS/MS. The results show that the weakly alkaline substrate environment promoted mycelial growth, increased body surface area, and improved yield and transformation efficiency, but attenuated metabolite accumulation by A. cornea. A total of 412 different metabolites were identified in negative and positive ion mode, of which 99 had significantly different amounts and covered 51 metabolic pathways. Principal component analysis (PCA) and orthogonal patrial least squares discriminant analysis (OPLA-DA) showed clear separation between two treatments, indicating different metabolic profiles. The different metabolites mainly included seven chemical categories, including amino acids and derivatives, nucleotides and derivatives, phenolic acids, organic acids, lipids, flavonoids, and alkaloids. This study revealed the biological significance of these metabolites, which could be useful for further unexplored compounds and possible biological functions of A. cornea.