Spodoptera frugiperda is one of the most harmful pests that attack maize and other major food crops and causes huge economic loss every year in China and other countries and regions. Beauveria bassiana, a kind of entomological fungus that is highly pathogenic to pests, is harmless to the environment and human beings. However, at present, S. frugiperda has gradually developed resistance to many pesticides and microbial insecticides. In this study, transcriptome sequencing was conducted to analyze the differences in gene expression between B. bassiana-infected and -uninfected S. frugiperda. More than 160 Gb of clean data were obtained as 150-bp paired-end reads using the Illumina HiSeq™ 4000 platform, and 2,767 and 2,892 DEGs were identified in LH36vsCK36 and LH144vsCK144, respectively. In order to explore the roles of JAK/STAT, Toll, and Imd signaling pathways in antifungal immune response in S. frugiperda against B. bassiana infection, the expression patterns of those signaling pathway-related genes in B. bassiana-infected S. frugiperda were analyzed by quantitative real-time PCR. In addition, antifungal activity experiments revealed that the suppression of JAK/STAT, Toll, and Imd signaling pathways by inhibitors could inhibit the antifungal activity to a large extent and lead to increased sensitivity of S. frugiperda to B. bassiana infection, indicating that JAK/STAT, Toll, and Imd signaling pathways and their associated genes might be involved in the synthesis and secretion of antifungal substances. This study implied that JAK/STAT, Toll, and Imd signaling pathways played crucial roles in the antifungal immune response of the S. frugiperda larvae, in which the related genes of these signaling pathways could play special regulatory roles in signal transduction. This study would improve our understanding of the molecular mechanisms underlying innate immunity and provide the basis for a wide spectrum of strategies against antifungal resistance of S. frugiperda.

The small brown planthopper (SBPH), Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae), is an increasing threat to Gramineae crops, posing significant risks to both the environment and food safety. β-asarone, as a promising green alternative to chemical insecticides, possesses wide application prospects in the crop protection field. To enhance the insecticidal activity of β-asarone, a series of derivatives were prepared through an active substructure splicing strategy, and their insecticidal activities against SBPH were evaluated. Among the 7 commercial compounds with chemical structures similar to β-asarone and 12 structural derivatives of β-asarone, compound 10, which incorporates the 2-chloropyridine functional group from flupyrimin, exhibited the most potent insecticidal activity against SBPH, with an 8.31-fold increase in insecticidal activity compared to β-asarone. Furthermore, transcriptome analysis showed that among the selected genes that may play important roles in insecticidal activity, an ABC transporter gene, MDR49, was most significantly down-regulated. MDR49 was highly expressed in the 4th-instar nymphs, with the highest expression level in the fat body, midgut, and abdomen. RNA interference (RNAi) against MDR49 significantly reduced susceptibility to compound 10 in SBPH, which revealed that MDR49 may be the candidate insecticidal target of compound 10. Additionally, the insecticidal spectrum revealed that compound 10 showed excellent efficacy against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae). This study indicates that compound 10 could be further developed as a novel eco-friendly pesticide.

Domain of unknown function (DUF) proteins play important roles in plant responses to biotic and abiotic stresses. DUF4228 proteins, as members of the DUF superfamily, are widely present in plants and exert significant functions under various stress conditions. Sugarcane is an important economic and energy crop in China. However, the role of DUF4228 family members in sugarcane has not been reported. In this study, 126 ScDUF4228 genes were identified for the first time in the genome of the modern cultivar XTT22 and systematically named based on their chromosomal locations (ScDUF4228-1 to ScDUF4228-126). These genes are located on 7 chromosomes of the XTT22 genome, exhibiting an overall uneven distribution. Phylogenetic analysis revealed that the 126 ScDUF4228 proteins can be divided into 9 groups (I–IX). Gene structure analysis indicated that most ScDUF4228 family members lack introns or contain only 1–2 introns, and all members possess a complete DUF4228 domain. Ka/Ks analysis demonstrated that the family as a whole has undergone purifying selection (Ka/Ks < 1), indicating high functional conservation during evolution. Cross-species collinearity analysis showed significant species-specific expansion of the DUF4228 gene family in the Poaceae (particularly in sugarcane and its close relatives), a phenomenon not prominently observed in dicotyledons. Analysis of tissue expression patterns, developmental stages, and diurnal rhythms revealed that the spatiotemporal expression profiles of the 126 ScDUF4228 family members vary, suggesting they may function individually or synergistically during different developmental periods in sugarcane. Yeast medium assay depicted that three members of the ScDUF4228 (ScDUF4228-7, ScDUF4228-18, ScDUF4228-23) family had significant resistance potential under drought stresses. Furthermore, transcriptome analysis after drought treatment showed that ScDUF4228-23 exhibited the most significant upregulation, suggesting it may be a key gene in sugarcane’s response to drought. These results suggest that the DUF4228 gene family has undergone dramatic expansion in sugarcane and may play a crucial regulatory role in drought stress responses. This study provides the necessary molecular foundation for further exploring the functions of ScDUF4228 family members.

Chewing cane is primarily consumed as fresh fruit and contains a variety of essential amino acids and iron. The identification and evaluation of chewing cane germplasm resources are prerequisites for the rational utilization of these resources, and phenotypic traits provide a direct and convenient means to determine breeding objectives. To facilitate the utilization and development of chewing cane germplasm, thirty-six phenotypic traits in 70 chewing cane germplasm resources were analyzed. The results revealed rich genetic diversity among the chewing cane resources. Seven phenotypic traits exhibited relatively high diversity and considerable potential for genetic improvement. The three groups exhibited relatively small genetic distances and relatively high genetic similarity coefficients, among which the Local varieties (Lv) group displayed the highest genetic diversity indices and retained more private alleles. Based on genetic similarity, the resources were classified into 3 groups, 5 subgroups, and 5 subclasses through cluster analysis, with more than half (54%) of the chewing cane materials forming a separate cluster. A total of 26 private alleles associated with 13 different phenotypic traits in chewing cane were identified across the three groups. The results of genetic diversity analysis based on phenotypic data provide important references for the utilization of chewing cane germplasm resources, selection of parents, and variety breeding.

Spodoptera frugiperda damages crops around the world and has developed resistance to many pesticides. Beauveria bassiana, a fungus that is harmless to humans and the environment, is widely used in pest control. In our study, differentially expressed genes between S. frugiperda larvae, both exposed and unexposed, to B. bassiana were analyzed by transcriptome sequencing. More than 160 Gb of clean data were obtained, and 2767 and 2892 DEGs were identified in LH36vsCK36 and LH144vsCK144, respectively. To explore the roles of glycometabolism and antioxidation-related enzyme genes in S. frugiperda against B. bassiana infection, the expression patterns of those genes when under attack from B. bassiana were analyzed by quantitative real-time PCR. The results of enzyme activity experiments revealed that S. frugiperda larvae exposed to B. bassiana could upregulate these genes to produce more enzymes related to the maintainance of normal glucose metabolism, as well as regulate the expression of detoxification and antioxidant factors to enhance the larvae's detoxification and antioxidant capacity. The result implied that glycometabolism and antioxidation-related enzymes and genes played critical roles in the antifungal immune process of S. frugiperda larvae. This study enhances our understanding of the molecular mechanisms related to regulation of metabolism and provides a basis for exploring new methods to combat antifungal resistance in S. frugiperda.