Xu Zhang

Tetranychus urticae, commonly known as the two-spotted spider mite, is a highly adaptable and polyphagous arthropod in the family Tetranychidae, capable of feeding on over 1200 plant species, including strawberries (Fragaria × ananassa Duch.). The fitness and microbiota of herbivorous arthropods can vary significantly across different plant species and cultivars. In this study, we investigated the fecundity, longevity, growth rate, and microbiota composition of T. urticae reared on seven Chinese strawberry cultivars: Hongyan (HY), Yuexiu (YX), Tianshi (TS), Ningyu (NY), Xuetu (XT), Zhangjj (ZJ), and Xuelixiang (XLX). Our findings revealed significant differences among cultivars: mites reared on the XT cultivar exhibited the highest fecundity (166.56 ± 7.82 eggs), while those on XLX had the shortest pre-adult period (7.71 ± 0.13 days). Longevity was significantly extended in mites reared on XLX, XT, and NY cultivars (25.95–26.83 days). Microbiota analysis via 16S rRNA sequencing showed that Proteobacteria dominated (>89.96% abundance) across all mite groups, with Wolbachia as the predominant symbiont (89.58–99.19%). Male mites exhibited higher bacterial diversity (Shannon and Chao1 indices) than females, though Wolbachia abundance did not differ significantly between sexes or cultivars. Functional predictions highlighted roles of microbiota in biosynthesis, detoxification, and energy metabolism. These findings underscore the influence of host plant variety on T. urticae fitness and microbiota composition, suggesting potential strategies for breeding resistant strawberry cultivars and leveraging microbial interactions for pest management.

Strawberry (Fragaria × ananassa) is a globally important economic crop valued for its nutritional and commercial significance. However, its growth is frequently challenged by various biotic and abiotic stresses. To enhance strawberry root development and resilience, we engineered a Trichoderma guizhouense NJAU4742 strain to overexpress the TgSWO gene, which encodes a plant cell-wall-loosening protein known to facilitate fungal penetration and colonization. Strawberry seedlings treated with the TgSWO-overexpressing T. guizhouense NJAU4742 strain (S-OE) exhibited significant improvements in shoot and root fresh weights, root surface area, and number of root tips, showing 1.37- to 2.00-fold increases compared with the strawberry seedlings inoculated with the wild-type T. guizhouense NJAU4742 (S-WT) and 2.00- to 3.44-fold increases compared with the uninoculated strawberry seedlings (S-CK). Field-emission scanning electron microscopy (SEM) of the S-OE roots revealed denser hyphal colonization. Transcriptome analysis of S-OE showed a decrease in genes related to defense and detoxification, while genes for cell-wall growth and hormone signaling increased, shifting focus from defense to growth. Metabolomic profiling identified cysteine as a key metabolite associated with induced growth, which was further validated through exogenous cysteine application experiments. This study highlights the potential of genetically enhanced Trichoderma for improving strawberry growth and provides new insights into root–microbe interactions and metabolite-mediated plant development.

Background: Utilizating the plant endophytic microbiomes to enhance pathogen resistance in crop production is an emerging alternative method to chemical pesticides. However, research on the composition and role of microbial communities related to perennial fruit plants, such as the strawberry, is still limited. Methods: We provide a comprehensive description of the composition and diversity of fungal communities in three niches (root, stem, and leaf) of three strawberry cultivars (‘White Elves’, ‘Tokun’, and ‘Akihime’) using internal transcribed spacer (ITS) rRNA amplicon sequencing and isolation culture methods. In addition, we also evaluated the disease tolerance ability of three strawberry cultivars to Colletotrichum gloeosporioides and Alternaria alternata through pathogenicity testing. Results: ‘White Elves’ has stronger resistance to Colletotrichum gloeosporioides, and Alternaria alternata, followed by ‘Tokun’, while ‘Akihime’ has relatively weaker resistance to these pathogens. A total of 258 fungal strains were isolated from healthy strawberry plants and assigned to 34 fungal genera based on morphological and molecular characteristics analysis. Beneficial fungal genera such as Trichoderma and Talaromyces were more prevalent in ‘White Elves’, whereas common pathogenic fungi in strawberry, such as Colletotrichum, Alternaria, and Fusarium, were more prevalent in ‘Akihime’. The composition and diversity of microbial communities vary among genotypes, and resistance to pathogens may play dominant roles in determining the microbial community structure. This study’s results aid the biological control of strawberry fungal diseases and are useful for plant microbiome engineering in strawberry cultivation.

Strawberry (Fragaria × ananassa) is the most widely cultivated small berries in the world. They are not only delicious, juicy, and nutritious, but also have important economic value. However, current research on endophytic bacteria related to strawberry is limited. This work provides a comprehensive description of the composition and diversity of bacterial communities in three niches (root, stem, and leaf) of three strawberry cultivars (White Elves, Tokun, and Akihime). This study indicated that the diversity and composition of strawberry bacterial communities differ significantly between the belowground niche (roots) and aboveground compartments (stems and leaves). The bacterial diversity and richness varied between niches for all three cultivars; and it significantly decreased from root to stem to leaf. The richness and alpha diversity of Akihime bacterial community were significantly lower than that of White Elves in the stems and leaves. Beneficial bacterial genera, such as Ochrobacter, Bradyrhizobium, Sphingomonas, and Pseudolobrys, were more abundant in White Elves and Tokun than in Akihime, especially in roots and stems. The results of this study provide an important reference for discovering new species or genetic variations to improve host fitness and stress tolerance. Further research is needed to uncover the interactions between plants and endophytic bacteria, as well as the potential for extracting bioactive compounds from these bacteria.

Plant-endophytic microbes affect plant growth, development, nutrition, and resistance to pathogens. However, how endophytic microbial communities change in different strawberry plant compartments after Fusarium pathogen infection has remained elusive. In this study, 16S and internal transcribed spacer rRNA amplicon sequencing were used to systematically investigate changes in the bacterial and fungal diversity and composition in the endophytic compartments (roots, stems, and leaves) of healthy strawberries and strawberries with Fusarium wilt, respectively. The analysis of the diversity, structure, and composition of the bacterial and fungal communities revealed a strong effect of pathogen invasion on the endophytic communities. The bacterial and fungal community diversity was lower in the Fusarium-infected endophytic compartments than in the healthy samples. The relative abundance of certain bacterial and fungal genera also changed after Fusarium wilt infection. The relative abundance of the beneficial bacterial genera Bacillus, Bradyrhizobium, Methylophilus, Sphingobium, Lactobacillus, and Streptomyces, as well as fungal genera Acremonium, Penicillium, Talaromyces, and Trichoderma, were higher in the healthy samples than in the Fusarium wilt samples. The relative abundance of Fusarium in the infected samples was significantly higher than that in the healthy samples, consistent with the field observations and culture isolation results for strawberry wilt. Our findings provide a theoretical basis for the isolation, identification, and control of strawberry wilt disease.