[Objective] This study’s objective was to investigate the diversity of intestinal microorganisms in adult Vespa velutina (Asian hornet) killed by natural causes. This study investigates the composition of intestinal fungi and bacteria and predicts the pathogenic pathogen in adult Vespa velutina (Asian hornet). [Methods] We determined the ITS1 sequence of fungi and the V3–V4 variant region of 16S rRNA of bacteria using Illumina MiSeq technology. Operational taxonomic units (OTU) of gut symbiotic microorganisms were quantified, and the resulting data were subjected to analysis of species abundance, composition, and alpha diversity. OTU function was predicted using PICRUSt2/FUNGuild. In addition, cultured microorganisms from the gut microbiota of adult Vespa velutina were isolated and identified. A number of 3610 (fungi) and 8373 (bacteria) were identified via cluster analysis. A total of 13 strains, 51 classes, 126 orders, 285 families, and 586 genera were identified for fungi and 44 strains, 113 classes, 319 orders, 662 families, and 1394 genera were identified for bacteria. E. shigella, Herbaspirillum, and Aaaia were the most abundant classes of bacteria, and Fusarium, Mortierella, and Starmerella were the most abundant classes of fungi. In addition, 16 community genera of fungi and 11 of bacteria were outlined as core taxa. Species diversity and richness for the gut fungal and bacterial communities with VN were found to be higher than those with VA. Furthermore, bacterial species diversity and richness were found to be higher than those of fungi in VA and VN. Functional analysis revealed that Vespa velutina gut bacteria exhibited 20 functions, while fungi were classified into three types of nutrient modes. Cultivable bacteria were obtained from two phyla and two classes, but no fungi could be cultivated. [Conclusion] Variations in the species diversity and abundance of both fungi and bacteria in the gut were observed between the VA and the VN. The involvement of bacteria in the death of adult Vespa velutina was found to be significant. In addition, VA1 (the self-named strain) may be a pathogenic bacterium derived from the gut of the VA that exhibits virulence.

Eucalypt species are among the most important for timber production worldwide. Eucalyptus cloeziana is increasingly culticated due to its desirable structural properties. Leaf blight is one of the ...

Buzura suppressaria Guenee (Lepidoptera: Geometridae) is a defoliator that seriously harms eucalyptus trees in South China. Buzura suppressaria nuclear polyhedrosis virus (BsNPV) is a baculovirus that infects B. suppressaria with high specificity and efficiency. Transcriptomes of B. suppressaria were sequenced before and after BsNPV infection using an Illumina-based platform to probe for differentially expressed genes (DEGs) of B. suppressaria after viral infection. On average, ∼57.4 million high-quality clean reads were generated and assembled de novo into 69,761 unigenes. The NCBI nonredundant protein, Swiss-Prot, Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene ontology (GO), and Cluster of Orthologous Groups databases were used to annotate unigenes through NCBI BLAST; 33,575 unigenes (48.1%) were then mapped to at least one of these databases, and 4,366 unigenes (6.3%) were mapped to all databases. Differential expression analysis showed that 25,212 unigenes were upregulated and 22,880 unigenes were downregulated in at least one pairwise comparison. Control versus 48 h had more DEGs than other two pairwise comparisons in either the GO or KEGG database, because the number of regulated gene would increase as BsNPV infected more tissues and would decrease as more tissues were disabled. To ascertain B. suppressaria immune response to BsNPV infection, DEGs were annotated to the GO and KEGG databases. In total, 89 GO categories are related to immune response and 1,007 DEGs are annotated to these GO categories. Furthermore, 7 downregulated DEGs and 37 upregulated were obtained simultaneously in all three groups. These DEGs were considered to possess a central role throughout viral infection.

Eucalypt GL-9 (Eucalyptus grandis × Eucalyptus urophylla) is one of the most widely grown genotypes of Eucalyptus in China. Each year, leaf blight causes serious economic losses in the eucalyptus industry in the south of China. In December 2019, a leaf blight disease was found to be widespread on eucalyptus GL-9 in Hechi in Guangxi, China (25°22'17"N, 108°15'32"E). Symptomatic lesions were usually brown at the early stage of infection and then turned off-white at the late stage. They had a large number of black round pycnidia randomly dispersed on the surface. Most of the lesions initially started from the leaf tip and then gradually expanded to the base of the leaf. Three randomly sampled leaves were washed using sterile water. Next, small pieces of tissue (5×10 mm) were removed from the margins of the lesions, surface disinfected with 75% ethanol for 1 min and 0.1% HgCl2 for 3 min, and then washed three times with sterile water. The tissues were placed on potato dextrose agar (PDA) and incubated at 28°C for 5 days to observe the fungus morphological characteristics. The hyphae on the PDA were milky yellow, and the PDA was light yellow when viewed from the bottom, with few aerial hyphae. The colonies had petal-like edges. In the later stage, hyphae in the center of the colonies turned brown. Three representative isolate (EC7, EC8, EC10) were selected for further study. Their conidia were olive-shaped, spindle-shaped, or obliquely globose, 8.80-11.93 μm in length (10.35 μm in average), 4.69-7.33 μm in width (6.06 μm in average) (n=100 in each isolate), with a conical apiculus and a hyaline basal appendage that was tubular, smooth, and thin-walled. For molecular identification, their genomic DNA was extracted using a Genomic DNA Kit (Tiangen, China). The internal transcribed spacer (ITS) region of rDNA and β-tubulin (TUB) genes were amplified using ITS5/ITS4 and βt2a/βt2b primer sets, respectively (White et al. 1990). BLASTn searches showed that the ITS and TUB sequences had the highest identity with Apoharknessia eucalyptorum strains, with 100% (586/586 in EC7 and EC8, 590/590 in EC10) identity for ITS (KY979752.1) and 99% (502/505 in EC7, 506/508 in EC8 and 504/507 in EC10) identity for TUB (KY979919.1) of ex-type CBS 142519. The ITS and TUB sequences of three isolates were submitted to GenBank (EC7: OM060439 and OM103586, EC8: OM679378 and OM715153, EC10: OM679377 and OM715152). A maximum likelihood phylogenetic tree was constructed by combining the two sequenced loci in MEGA7. Three isolates clustered in the A. eucalyptorum clade with 92% bootstrap support. Thus, based on morphological (Crous et al. 2017; Garrett et al. 2018) and molecular characteristics, the pathogen was identified as A. eucalyptorum. In a pathogenicity test, twenty healthy GL-9 seedlings were collected, and were divided into four groups. Seedlings from groups 1-3 were used to inoculate three isolates respectively, and seedlings from another group were sprayed distilled water as control. Before test, leaves were washed with sterile water, surface disinfected with 75% ethanol, and then rinsed with sterile water. After drying, an inoculation needle was used to make tiny wounds near the leaf margin on each leaf. Next, conidia solution (1×107 conidia/ml) and sterile water were sprayed to leaves in different groups and moistened with airtight bags. After 3 days, airtight bags were moved. Lesions appeared on all the pathogen-inoculated leaves, whereas only the inoculation point turned brown on the control leaves. The pathogenicity test was repeated three times and the same results were obtained. Fungi were re-isolated from symptomatic leaves and identified as A. eucalyptorum following the same methodologies used for the initial identification. To our knowledge, this is the first report of A. eucalyptorum causing leaf blight on E. grandis × E. urophylla in China. This study expands the understanding of the pathogen of leaf blight on E. grandis × E. urophylla. More research is needed to develop effective strategies to manage this disease.

Eucalyptus citriodora is a wood and oil dual-purpose tree with strong growth adaptability and high ornamental value. Recent years, it has been widely planted in Guangxi in China. In Nov. 2021, bran...

Aniseed (Illicium verum) is a woody spice tree that has been grown in China for a long time. Anthracnose is an important disease of aniseed, which can cause severe leaf drop. In Sep. 2020, severe a...