Passion fruit plants alter the soil microbial community with continuous cropping and improve plant disease resistance by recruiting beneficial microorganisms.

Passion fruit (Passiflora edulis) is widely grown in tropical and subtropical regions, showing high economic and ornamental value. Microorganisms are indicators for the stability and health of the soil ecosystem, which can affect the yield and quality of passion fruit under continuous cropping. High-throughput sequencing and interactive analysis were used to analyse the variation of microbial communities in the noncultivated soil (NCS), cultivated soil (CS), and the rhizosphere soil of purple passion fruit (Passiflora edulis f. edulis ×Passiflora edulis f. flavicarpa, RP) and yellow passion fruit (Passiflora edulis f. flavicarpa, RY). An average of 98,001 high-quality fungal internal transcribed spacer (ITS) sequences, mainly from Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota and Glomeromycota, as well as an average of 71,299 high-quality bacterial 16S rRNA sequences, mainly from Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi, were obtained per sample. It was found that the continuous cropping of passion fruit increased the richness but reduced the diversity of soil fungi, while it dramatically increased the richness and diversity of soil bacteria. In addition, during the continuous cropping, grafting different scions in the same rootstock contributed to the aggregation of differential rhizosphere microbial communities. Among fungal genera, Trichoderma showed higher abundance in RY than in RP and CS, while the opposite was observed in the pathogen Fusarium. Moreover, the co-occurrence network and potential function analyses also showed that the appearance of Trichoderma was related to Fusarium and its contribution to plant metabolism was significantly greater in RY than in RP and CS. In conclusion, the rhizosphere of yellow passion fruit may be beneficial for the enrichment of disease-resistant microbes, such as Trichoderma, which may be an important factor inducing stronger resistance to stem rot. It will help to form a potential strategy for overcoming the pathogen-mediated obstacles in passion fruit and improve its yield and quality.

Occurrence and Distribution of Major Viruses Infecting Passion Fruit in Guizhou Province, China, and Molecular Characterization of Two Potyviruses.

The planting of passion fruit (Passiflora edulis) in Guizhou Province has gradually increased, and the area under cultivation ranks third in China. However, the cultivation and production of passion fruit is severely affected by viral diseases. In 2021 and 2022, we investigated the occurrence of multiple viral diseases in major cultivation areas, identified the main viruses and conducted field surveys in different growing areas of passion fruit in Guizhou Province, China. In total, 308 samples were randomly collected from 10 different passion fruit cultivation areas, and seven viral diseases were identified using electron microscopy, small RNA sequencing, and reverse-transcription polymerase chain reaction. Among them, the infection rate of Telosma mosaic virus (TeMV) was the highest (50%), followed by East Asian Passiflora virus (EAPV) (19%), and cucumber mosaic virus (CMV) (15%). The detection rates of the other four viruses were lower: Passiflora latent virus (PLV) (1%), turnip mosaic virus (TuMV) (0.6%), Passiflora virus Y (PaVY) (0.3%), and Euphorbia leaf curl virus (ELCV) (6%). In addition, high rates of mixed TeMV + CMV + EAPV infections were found in the province. Notably, 79% of EAPV-infected plants were also infected with TeMV. Finally, the molecular characteristics of the two highly detected potyviruses, TeMV and EAPV, were analyzed. To our knowledge, this study is the first systematic survey of viral diseases of passion fruit in Guizhou Province, China.

Characterization of the complete chloroplast genome of a purple passion flower variety 'Pingtang No.1' (Passiflora edulia Sims) in China and phylogenetic relationships.

Passion flower (Passiflora edulia Sims) is an important fruit that is of great economic importance. In this study, we presented the chloroplast genome of a purple passion flower variety 'Pingtang No.1' in China using BGISEQ-500 sequencing. Its chloroplast genome is 152,621 bp in size. It contains a pair of inverted repeat regions of 25,989 bp, each separating a small single copy region of 13,352 bp and a large single copy region of 85,141 bp. Totally, 111 unique genes, including 77 protein coding genes, 30 tRNAs, and 4 rRNAs, were identified and annotated in the chloroplast genome. Phylogenetic maximum likelihood analysis based on chloroplast genomes of 35 plant species, mainly from the genus Passiflora indicated that 'Pingtang No.1' and yellow passion flower 'IAPAR-123' (Passiflora edulis) cluster together. The chloroplast genome can be used for a better understanding of the evolutionary relationships of plant species of the family Passifloraceae, especially the genus Passiflora.