Amylase is an indispensable hydrolase in insect growth and development. Its varied enzymatic parameters cause insects to have strong stress resistance. Amylase gene replication is a very common phenomenon in insects, and different copies of amylase genes enable changes in its location and function. In addition, the classification, structure, and interaction between insect amylase inhibitors and amylases have also invoked the attention of researchers. Some plant-derived amylase inhibitors have inhibitory activities against insect amylases and even mammalian amylases. In recent years, an increasing number of studies have clarified the effects of pesticides on the amylase activity of target and non-target pests, which provides a theoretical basis for exploring safe and efficient pesticides, while the exact lethal mechanisms and safety in field applications remain unclear. Here, we summarize the most recent advances in insect amylase studies, including its sequence and characteristics and the regulation of amylase inhibitors (α-AIs). Importantly, the application of amylases as the nanocide trigger, RNAi, or other kinds of pesticide targets will be discussed. A comprehensive foundation will be provided for applying insect amylases to the development of new-generation insect management tools and improving the specificity, stability, and safety of pesticides.

Pear black spot disease, caused by Alternaria alternata, is a devastating disease in pears and leads to enormous economic losses worldwide. In this investigation, we isolated a Streptomyces odonnellii SZF-179 from the rhizosphere soil of pear plants in China. Indoor confrontation experiments results showed that both SZF-179 and its aseptic filtrate had excellent inhibitory effects against A. alternata. Afterwards, the main antifungal compound of SZF-179 was identified as polyene, with thermal and pH stability in the environment. A microscopic examination of A. alternata mycelium showed severe morphological abnormalities caused by SZF-179. Protective studies showed that SZF-179 fermentation broth could significantly reduce the diameter of the necrotic lesions on pear leaves by 42.25%. Furthermore, the potential of fermentation broth as a foliar treatment to control black leaf spot was also evaluated. Disease indexes of ‘Hosui’ and ‘Wonwhang’ pear plants treated with SZF-179 fermentation broth were lower than that of control plants. Overall, SZF-179 is expected to be developed into a safe and broad-spectrum biocontrol agent. No studies to date have evaluated the utility of S. odonnellii for the control of pear black spot disease; our study fills this research gap. Collectively, our findings provide new insights that will aid the control of pear black spot disease, as well as future studies of S. odonnellii strains.

Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom.

The quality of fresh tea leaves is crucial to the final product, and maintaining microbial stability in tea plantations is essential for optimal plant growth. Unique microbial communities play a critical role in shaping tea flavor and enhancing plant resilience against biotic stressors. Tea production is frequently challenged by pests and diseases, which can compromise both yield and quality. While biotic stress generally has detrimental effects on plants, it also activates defense metabolic pathways, leading to shifts in microbial communities. Microbial biocontrol agents (MBCAs), including entomopathogenic and antagonistic microorganisms, present a promising alternative to synthetic pesticides for mitigating these stresses. In addition to controlling pests and diseases, MBCAs can influence the composition of tea plant microbial communities, potentially enhancing plant health and resilience. However, despite significant advances in laboratory research, the field-level impacts of MBCAs on tea plant microecology remain insufficiently explored. This review provides insights into the interactions among tea plants, insects, and microorganisms, offering strategies to improve pest and disease management in tea plantations.

Venom proteins act in the immunological interactions between parasitoids and their host insects. The effect of venom proteins on host immunity is not fully understood in pupal parasitoids. We identified the functions of a venom protein, calreticulin (PvCRT), in the pupal ectoparasitoid Pachycrepoideus vindemiae. Here, we report that PvCRT features a signal peptide and two conserved “calreticulin” domains. Multiple sequence alignments show that PvCRT shares 83.54% amino acid identity with CRT from both Pteromalus puparum and Nasonia vitripennis, which infers a close relationship among these three species. Using qPCR analysis, we found a lower expression level of PvCRT (0.27-fold) in the venom apparatus compared to the corresponding carcass. Immunohistochemical localization revealed that PvCRT was ubiquitously expressed in venom gland. The expression of the PvCRT gene in Drosophila transgenic lines via the UAS/Gal4 binary expression system reduced the self-encapsulation phenotype of tu(1)Sz¹ mutants. Additionally, studies on humoral immunity indicate that PvCRT does not affect the antimicrobial immune responses of the host. This work on an ectoparasitoid will increase our understanding of venom–mediated host-parasitoid interactions.

Tea (Camellia sinensis (L.) O. Kuntze) is an important economic crop cultivated in China. In March 2019, leaf blight symptoms were observed on tea trees (C. sinensis cv. Fuding-dabaicha) in Enshi City (30º02'66" S, 109º01'56" W), Hubei Province (Fig. 1A). The disease occurred on the senescent flowers and mature leaves. The average disease incidence was approximately 10% of plants in the surveyed 30 ha tea garden. Initial symptoms consisted of brown lesions, which expanded and became covered with gray mold, followed by abscission. To identify the pathogen, 20 symptomatic leaves were collected and 0.5 cm² diseased leaf pieces were excised and surface sterilized by immersion in 1.5% sodium hypochlorite (NaOCl) for 2 min, and rinsed three times in sterilized distilled water. The leaf pieces were allowed to dry, placed on potato dextrose agar (PDA) plates, and incubated at 20°C under 12h fluorescent light. The fungus formed gray to grayish brown colonies (Fig. 1B) and produced conidia after 1 week. The isolate was purified by single spore isolation. The conidia were one-celled, ellipsoid or ovoid, almost colorless, with a size range of 5.3 to 10.24 × 5.2 to 8.1 μm (n = 50) (Fig. 1C). The sclerotia produced in culture were black, round or irregular in shape and 1.3 to 2.2 × 2.0 to 3.3 mm (average 1.8 × 2.3 mm) in size. Morphological characteristics of these isolates matched the description of Botrytis spp. (Hong et al. 2001). Representative isolate LCHM was selected for molecular identification based on DNA sequencing of the ITS region of rDNA and three nuclear protein-coding genes (G3PDH, HSP60 and RPB2) (Staats et al. 2005). BLAST analysis showed that isolate LCHM (GenBank Acc. Nos. MN448502, MN448500, MN433708 and MN448501 for ITS, G3PDH, HSP60 and RPB2, respectively) shared 99 to 100% identity with B. cinerea (GenBank Acc. Nos. MH316147.1, MG846500.1, MG846504.1 and MG846510.1, respectively), which suggested that isolate LCHM belongs to B. cinerea. This identification was further confirmed by phylogenetic analysis based on combined DNA sequence data of G3PDH, HSP60 and RPB2 (Fig. 2). For the pathogenicity test, needle-wounded, attached leaves on 1-year-old C. sinensis cv. Fuding-dabaicha plants were inoculated with mycelial plugs (6 mm diameter from 2-day-old PDA cultures) or a conidial suspension (20 μL, 1×10⁶ conidia/ml in half strength potato dextrose broth) of isolate LCHM on three plants per treatment (six leaves). The control treatments were also wounded, but only treated with agar plugs or half strength PDB. All inoculated plants and controls were incubated in a growth chamber (20°C, 90 ± 10% RH). Leaves inoculated with mycelial plugs, whether wounded or not, showed brown necrotic lesions around the agar plugs after 2 days (Fig. 1D, E), whereas conidial inoculations of wound sites showed necrotic lesions after 6 days (Fig. 1 F, G). Non-wounded leaves inoculated with conidia and all the control treatments remained symptomless. B. cinerea was reisolated from the inoculated leaves and isolates were morphologically similar to the original cultures. Gray mold of C. sinensis caused by B. cinerea has been recorded in Japan, Turkey, and Brazil (Hamaya 1981, Aziz and Harun 2010, Pereira and Mio, 2020). To our knowledge, this is the first report of gray mold caused by B. cinerea on C. sinensis in China. B. cinerea may cause economic losses of tea, therefore, more surveys in other tea-growing regions should be done to specifically search for this disease.