Tobacco (Nicotiana tabacum L.), which creates jobs for 33 million people and contributes two trillion dollars’ tax annually, is one of the most important economic plants globally. However, tobacco is seriously threatened by numerous diseases during production. Previously, the field survey of tobacco diseases was conducted in the Guizhou and Guangxi provinces, the two main tobacco-producing areas in China. A serious leaf spot disease, with a 22% to 35% incidence, was observed in farming plants. In order to determine the causal agents, we collected the disease samples and isolated the pathogenic fungi. The pathogen was identified as Fusariumipomoeae, based on the morphological characteristics and phylogenetic analysis. Pathogenicity tests showed that F. ipomoeae could induce tobacco leaf spot and blight. To our knowledge, this is the first report worldwide of F. ipomoeae causing leaf spots and stems on tobacco. Our study reveals the serious consequences of F. ipomoeae on tobacco filed production and provides information for future diagnosis and management of the Fusarium disease.

Spodoptera frugiperda, a worldwide pest, can feed on 353 crops species, including corn, rice, and sorghum. It is highly adaptable to various environments. Heat shock protein 90 kDa (Hsp90) plays a crucial role in the environmental adaptation of insects. To explore the role of SfHsp90 genes coding for Hsp90 proteins in the high temperature and insecticides stress resistance of Spodoptera frugiperda, we identified the complete complementary DNA sequences of two SfHsp90s. Both of them were expressed at different developmental stages and tissues in S. frugiperda. The expression levels of the SfHsp90s were significantly upregulated when exposed to durations of extreme temperature (45?C) and lethal concentrations of emamectin benzoate (LC₁₀ and LC₂₀). The viability of S. frugiperda under 45?C and emamectin benzoate stresses was examined. The mortality rate of S. frugiperda was significantly increased when subjected to 45?C and emamectin benzoate after knockdown of SfHsp90s by RNAi. These results suggest that SfHsp90s are essential for the resistance of S. frugiperda to high temperature and emamectin benzoate stresses.

Ultraviolet B (UV-B) is a significant environmental factor affecting insect development, survival, and reproduction. DNAJ proteins are molecular chaperones found ubiquitously in insects that are crucial for their adaptation to environmental stresses. This study aimed to elucidate the roles of DNAJ genes in the response of Myzus persicae to UV-B stress. Herein, we identified six DNAJ genes in the aphid M. persicae, a devastating agricultural pest. We analyzed their expression profiles at different stages of development, in different tissues and for various durations of UV-B exposure. The expression levels of MpDNAJC30, MpDNAJC11, MpDNAJC2, and MpDNAJC3 were highest in wingless adults, while MpDNAJC9 and MpDNAJC17 were highest in second- and third-instar nymphs, respectively. Six MpDNAJs had higher expression levels in the epidermis and embryos, and lower levels in the head. Additionally, the expression levels of all genes increased significantly under different durations of UV-B exposure. Knockout of the DNAJ genes using RNA interference caused a significant decline in the survival rate, weight, body length, and body width of M. persicae exposed to UV-B radiation. Our research provides valuable insights into the stress response mechanisms of M. persicae, highlighting the importance of DNAJ genes in mediating their adaptation to UV-B stress.

Spodoptera litura is a globally distributed agricultural pest across Asia and Australia (EPPO database, https://gd.eppo.int/taxon/PRODLI/distribution ), whose gut microbiota significantly influences host feeding, digestion, immunity, and development. We used whole metagenomic sequencing to analyze the diversity and functional roles of gut bacteria at different developmental stages (eggs, first to sixth instar larvae, pupae, and adults). Findings revealed that Pseudomonadota predominated at the phylum level, with notable differences across instars: Bacillota was dominant in young larvae, whereas Verrucomicrobiota was added in older larvae, eggs, pupae, and adults. At the genus level, Pseudomonas dominated, Enterococcus was prevalent in larvae, and Piscirickettsia was prevalent in eggs, pupae, and adults. Metagenomic analysis identified numerous carbohydrate-active enzymes (CAZy database) aiding in plant cell wall polysaccharide digestion. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated differential gene expression in metabolism and xenobiotic degradation across instars, with metabolic gene annotation levels declining as development progressed. Detoxification-related enzyme genes were predominantly expressed in early instar larvae and adults, uncovering microbial origins of these enzymes. IMPORTANCE: Our study provides evidence that the gut microbiota significantly modulates the physiology of Spodoptera litura , with profound effects on its dietary habits, metabolic processes, and host fitness. Using whole metagenomic sequencing, we analyzed gut bacteria across different life stages. At the phylum level, Pseudomonadota and Bacillota were dominant, while at the genus level, Pseudomonas was the most abundant taxon. Metagenomic analysis identified enzymes aiding in plant cell wall digestion. Kyoto Encyclopedia of Genes and Genomes analysis showed varying gene expression in metabolism and detoxification, with higher expression in early instar larvae and adults. This research enhances understanding of S. litura gut microbiota-host interactions and supports novel pest control strategies targeting gut microbiota.