Aspergillus fumigatus is the primary pathogen causing aspergillosis. Recent molecular population genetic studies have demonstrated that A. fumigatus exhibits high local genetic diversity, with evidence for limited differentiation among geographic populations. However, research on the impacts of geomorphological factors on shaping the population genetic diversity patterns of this species remains scarce. In this study, large-scale sampling and in-depth population genetic analysis were performed on soil-derived A. fumigatus from Guizhou Province, a representative karst landscape in southern China. This area is dominated by plateaus and mountains (accounting for 92.5% of the total area) and represents a classic example of conical karst landscapes. A total of 206 A. fumigatus strains were isolated from 9 sampling sites across Guizhou. Genetic diversity, genetic differentiation, and population structure of these strains were analyzed based on short tandem repeats (STRs) at 9 loci. The results revealed that A. fumigatus in the karst region of Guizhou harbors abundant novel alleles and genotypes, with high genetic diversity. Gene flow among geographical populations was infrequent, and significant genetic differentiation was detected between 30 of the 36 pairs of geographical populations where mountain ranges played a very important role, with the overall regional genetic differentiation reaching PhiPT = 0.061 (p = 0.001). Furthermore, the Guizhou populations showed significant differences from those reported in other regions worldwide. Surprisingly, only one of the 206 (0.49%) A. fumigatus isolates from this region exhibited resistance to the two medical triazoles commonly used for treating aspergillosis, and this resistance frequency was far lower than those reported in previous studies from other regions. We discuss the implications of our results for evolution and environmental antifungal resistance management in this important human fungal pathogen.

Background: Root-knot nematodes (RKNs) are destructive parasites affecting both agricultural and natural plants. Fagopyrum tataricum, a phenolic-rich edible and medicinal plant, has antidiabetic, anti-inflammatory, and anticancer properties, yet the impact of RKN infection on its rhizosphere microbiome remains unclear. Methods: We employed full-length 16S rRNA gene sequencing (FL16S) to profile bacterial communities in the rhizosphere of healthy and RKN-infected F. tataricum plants. Results: FL16S classified 78.41% of operational taxonomic units (OTUs) at the genus level and 69.18% at the species level. Healthy plants showed higher richness, diversity, and evenness, while principal co-ordinate analysis (PCoA) and PERMANOVA indicated significant RKN-associated shifts in community composition. Dominant phyla included Bacteroidota, Proteobacteria, Patescibacteria, Verrucomicrobiota, Actinobacteriota, Acidobacteriota, and Chloroflexi, with Abditibacteriota enriched in healthy and Acidobacteriota in diseased rhizospheres. At the OTU level, 66 differentially abundant taxa were identified, including nine hub OTUs in healthy plants, suggesting keystone roles in network stability. Network analyses revealed reduced diversity, interactions, and altered intra- and inter-phylum dynamics under RKN infection. Conclusions: These findings provide insight into rhizosphere microbial responses to RKN parasitism in F. tataricum and identify potential microbial biomarkers and biocontrol targets, supporting microbiome-based management strategies.

Rubber tree powdery mildew caused by Erysiphe quercicola is the most widespread and destructive foliar disease in China’s rubber-growing regions. This disease frequently occurs in severe epidemics during winter–spring each year, delaying rubber tapping by 1–2 months and causing substantial yield losses, and has become a critical bottleneck for stable natural-rubber production. Xishuangbanna is China’s core planting region for natural rubber and a typical representative of mountainous rubber plantations in Yunnan. More than two-thirds of local rubber plantations are located on mountain slopes steeper than 15°. However, the population-genetic background of E. quercicola in this region remains poorly understood. A total of 188 samples of rubber powdery mildew were recovered from nine sampling sites belonging to three geographic populations (Mengla, Menghai, Jinghong). Ten SSR loci were used to analyse the genetic diversity, genetic differentiation and population structure of the tested samples. The results revealed that E. quercicola in Xishuangbanna rubber plantations exhibited high overall genetic diversity. Most samples possessed unique genotypes even at a fine spatial scale, and the Mengla population showed higher genetic diversity than the other populations. Analysis of molecular variance (AMOVA) revealed that the genetic variation of E. quercicola in Xishuangbanna was predominantly partitioned within sampling-site subpopulations. Significant pairwise genetic differentiation was detected among the three geographic populations, although all pairwise ΦPT values were less than 0.1, indicating a pattern of significant yet limited genetic differentiation at fine geographic scales. PCoA and STRUCTURE analyses further confirmed obvious population genetic structure in this region. The results of this study provide a theoretical basis for the epidemic monitoring of rubber powdery mildew in the Xishuangbanna rubber plantation area.

Aspergillus fumigatus is the primary pathogen causing aspergillosis. Recent molecular population genetic studies have demonstrated that A. fumigatus exhibits high local genetic diversity and with evidence for limited differentiation among geographic populations. However, research on the impacts of geomorphological factors on shaping the population diversity patterns of this species remains scarce. In this study, large-scale sampling and in-depth population genetic analysis were performed on soil-derived A. fumigatus from Guizhou Province, a representative karst landscape in southern China. This area is dominated by plateaus and mountains (accounting for 92.5% of the total area) and rep-resents a classic example of conical karst landscapes. A total of 206 A. fumigatus strains were isolated from 9 sampling sites across Guizhou. Genetic diversity, genetic differen-tiation, and population structure of these strains were analyzed based on 9 loci short tandem repeats (STRs). The results revealed that A. fumigatus in the karst region of Guizhou harbors abundant novel alleles and genotypes, with high genetic diversity. Gene flow among geographical populations was infrequent, and significant genetic differentiation was detected between multiple pairs of geographical populations, with the overall regional genetic differentiation reaching PhiPT = 0.061. Furthermore, the Guizhou populations showed significant differences from those reported in other regions world-wide. Surprisingly, only one of the 206 (0.49%) A. fumigatus isolates from this region exhibited resistance to the two medical triazoles commonly used for treating aspergillosis, and this resistance frequency was far lower than those reported in previous studies from other regions.

Aspergillus fumigatus is the predominant pathogenic fungus responsible for aspergillosis. In recent years, the global detection rate of azole-resistant A. fumigatus (ARAF) has continuously increased, and the extensive application of agricultural azole fungicides has been recognized as a crucial driving factor for the emergence and spread of resistance mutations in environmental A. fumigatus. Previous investigations conducted by our research team in karst vegetable fields of Guizhou Province revealed that the resistance rate of local A. fumigatus was only 0.49%, which was markedly lower than those reported in most previous studies in China and outside of China. To supplement the prevalence data of azole resistance across different habitats in this region, a total of 191 environmental A. fumigatus strains were isolated from nine tea plantations across Guizhou. In this study, two clinically prevalent azole drugs, itraconazole and voriconazole, were used for antifungal susceptibility testing, and the triazole target gene cyp51A of all isolates was sequenced and analyzed. Antifungal susceptibility results demonstrated that the MIC ranges of the tea plantation A. fumigatus population were 0.015–0.5 μg/ml for itraconazole and 0.031–0.25 μg/ml for voriconazole, with no evidence of triazole resistance. Genetic analysis identified ten different gene mutations among 29 isolates, all of which were classified as non-resistance-associated mutations. Among these mutations, four were synonymous mutations, including 267G→A, 540G→A, 1074A→G, and 1362T→C, while six were non-synonymous mutations, including 137T→A, 514A→G, 743A→C, 744T→A, 765C→G, and 1279G→A. These non-synonymous mutations resulted in five amino acid substitutions in 25 strains, namely F46Y, M172V, N248T/K, D255E, and E427K. The N248T/K mutation exhibited the highest mutational frequency of 0.1309 (25/191) and was distributed across all sampling sites. Correlation analyses indicated that no significant correlations were observed between all detected variant loci and MICs of isolates to itraconazole and voriconazole. Phylogenetic analysis revealed that the six sequence types of cyp51A in Guizhou tea plantations were broadly intermixed with those from other parts of China and outside of China. We discussed the implications of these results in the management of ARAF.

Aspergillus fumigatus is the predominant pathogenic fungus responsible for aspergillosis. In recent years, the global detection rate of azole-resistant A. fumigatus has continuously increased, and the extensive application of agricultural azole fungicides has been recognized as a crucial driving factor for the emergence and spread of resistance mutations in environmental A. fumigatus. Previous investigations conducted by our research team in karst vegetable fields of Guizhou Province revealed that the triazole resistance rate of local A. fumigatus was only 0.49%, which was markedly lower than those reported in most previous studies in China and outside of China. To supplement the prevalence data of azole resistance across different habitats in this region, a total of 191 environmental A. fumigatus strains were isolated from nine tea plantations across Guizhou. In this study, two clinically prevalent azole drugs, itraconazole and voriconazole, were used for antifungal susceptibility testing, and the triazole target gene cyp51A of all isolates was sequenced and analyzed. Antifungal susceptibility results demonstrated that the MIC ranges of the tea plantation A. fumigatus population were 0.015–0.5 μg/mL for itraconazole and 0.031–0.25 μg/mL for voriconazole, with no evidence of triazole resistance. Genetic analysis identified ten different gene mutations among 29 isolates, all of which were classified as non-resistance-associated mutations. Among these mutations, four were synonymous mutations, including 267G→A, 540G→A, 1074A→G, and 1362T→C, while six were non-synonymous mutations, including 137T→A, 514A→G, 743A→C, 744T→A, 765C→G, and 1279G→A. These non-synonymous mutations resulted in five amino acid substitutions in 25 strains, namely F46Y, M172V, N248T/K, D255E, and E427K. The N248T/K mutation exhibited the highest mutational frequency of 0.1309 (25/191) and was distributed across all nine sampling sites. Correlation analyses indicated that no significant correlations were observed between all detected variant loci and MICs of isolates to itraconazole and voriconazole. Phylogenetic analysis revealed that the six sequence types of cyp51A in Guizhou tea plantations were broadly intermixed with those from other parts of China and outside of China. We discussed the implications of these results in the management of antifungal resistance.