Fall armyworm is recognized as one of most highly destructive global agricultural pests. In January 2020, it had first invaded Australia, posing a significant risk to its biosecurity, food security, and agricultural productivity. In this study, the migration paths and wind systems for the case of fall armyworm invading Australia were analyzed using a three-dimensional trajectory simulation approach, combined with its flight behavior and NCEP meteorological reanalysis data. The analysis showed that fall armyworm in Torres Strait most likely came from surrounding islands of central Indonesia on two occasions via wind migration. Specifically, fall armyworm moths detected on Saibai and Erub Islands might have arrived from southern Sulawesi Island, Indonesia, between January 15 and 16. The fall armyworm in Bamaga most likely arrived from the islands around Arafura Sea and Sulawesi Island of Indonesia, between January 26 and 27. The high risk period for the invasion of fall armyworm is only likely to have occurred in January–February due to monsoon winds, which were conducive to flight across the Timor Sea towards Australia. This case study is the first to confirm the immigration paths and timing of fall armyworm from Indonesia to Australia via its surrounding islands.

The brown planthopper (BPH), Nilaparvata lugens, is an important pest that affects rice (Oryza sativa) production in Asia. The flavone tricin (5,7,4′-trihydroxy-3′,5′-dimethoxy flavone) is a valuable secondary metabolite commonly found in rice plants that can defend rice plants against infestation by BPH. BPH damage can reduce the metabolic level of tricin in rice. Our preliminary transcriptome research results showed that BPH salivary protein 7 (NlSP7), is highly responsive to tricin stimuli. However, the function of NlSP7 in mediating the interaction between the rice plant and the BPH is unknown. In this study, we cloned the NlSP7 gene in N. lugens and found that its mRNA level was greater in the presence of high tricin content than low tricin content, regardless of whether the BPHs were fed a rice plant diet or an artificial diet containing 100 mg/L tricin. Knocking down NlSP7 resulted in BPH individuals spending more time in the non-penetration and pathway phase, and less time feeding on the phloem of rice plants. These changes decreased BPH food intake, feeding behavior, and fitness, as well as the tricin content of the rice plants. These findings demonstrate that the salivary protein 7 of BPH functions as an effector for tricin metabolism in rice.

Immune response in plants is tightly regulated by the coordination of the cell surface and intracellular receptors. In animals, the membrane attack complex/perforin-like (MACPF) protein superfamily creates oligomeric pore structures on the cell surface during pathogen infection. However, the function and molecular mechanism of MACPF proteins in plant pathogen responses remain largely unclear. In this study, we identified an Arabidopsis MACP2 and investigated the responsiveness of this protein during both bacterial and fungal pathogens. We suggest that MACP2 induces programmed cell death, bacterial pathogen resistance, and necrotrophic fungal pathogen sensitivity by activating the biosynthesis of tryptophan-derived indole glucosinolates and the salicylic acid signaling pathway dependent on the activity of enhanced disease susceptibility 1 (EDS1). Moreover, the response of MACP2 mRNA isoforms upon pathogen attack is differentially regulated by a posttranscriptional mechanism: alternative splicing. In comparison to previously reported MACPFs in Arabidopsis, MACP2 shares a redundant but nonoverlapping role in plant immunity. Thus, our findings provide novel insights and genetic tools for the MACPF family in maintaining SA accumulation in response to pathogens in Arabidopsis.

Meprin and TRAF homology (MATH)-domain-containing proteins are pivotal in modulating plant development and environmental stress responses. To date, members of the MATH gene family have been identified only in a few plant species, including Arabidopsis thaliana, Brassica rapa, maize, and rice, and the functions of this gene family in other economically important crops, especially the Solanaceae family, remain unclear. The present study identified and analyzed 58 MATH genes from three Solanaceae species, including tomato (Solanum lycopersicum), potato (Solanum tuberosum), and pepper (Capsicum annuum). Phylogenetic analysis and domain organization classified these MATH genes into four groups, consistent with those based on motif organization and gene structure. Synteny analysis found that segmental and tandem duplication might have contributed to MATH gene expansion in the tomato and the potato, respectively. Collinearity analysis revealed high conservation among Solanaceae MATH genes. Further cis-regulatory element prediction and gene expression analysis showed that Solanaceae MATH genes play essential roles during development and stress response. These findings provide a theoretical basis for other functional studies on Solanaceae MATH genes.

Resistant crop varieties can usually decrease the population density of insect pests; however, they can also easily cause the occurrence of highly virulent pest populations when repeatedly grown. Whether herbivorous insects feeding intermittently on a susceptible variety affects their subsequent virulence has rarely been investigated. In this paper, we examined the variations in the virulence of the brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), by alternately rearing three resistant rice varieties, Mudgo, ASD7, and Rathu Heenati, with a susceptible rice variety (TN1) in indoor experiments. The results showed that, while the susceptible rice variety was used in alternate rearing for several generations, the BPHs exhibited a higher intrinsic rate of increase (r_m) and were identified as less virulent to all three resistant varieties. Such virulence reduction by experience with a susceptible variety could delay the progression of resistance-breaking toward resistant varieties. The results suggested that careful alternation with susceptible varieties in fields is a potential method for pest variety-resistance management.

Spodoptera frugiperda is a highly destructive migratory pest of global concern that infests a wide range of crops, particularly maize, as well as rice and sugarcane, causing substantial economic losses in China. Since its invasion of China, S. frugiperda has experienced prolonged insecticide selection pressure, resulting in the accelerated evolution and increasing prevalence of resistance to specific insecticides. This study aimed to elucidate the role of cytochrome P450 monooxygenase (CYP) gene families in mediating resistance to chlorantraniliprole and to evaluate the efficacy of nanoparticle-mediated delivery systems combined with P450-specific synergists for controlling S. frugiperda. Toxicity bioassays conducted on field populations demonstrated that chlorantraniliprole still retained considerable insecticidal activity. Analyses of three detoxification enzyme activities revealed a significant elevation in cytochrome P450 activity, and expression profiling of candidate CYP genes was performed using quantitative real-time PCR (qPCR). Exposure to chlorantraniliprole resulted in a 2.53-fold upregulation of CYP4G75 expression. Furthermore, nano-agrochemical formulation assays showed that the combined application of LDHs-dsCYP4G75 and chlorantraniliprole exerted a significant synergistic effect, increasing mortality by 21.99% compared with either treatment applied alone. Overall, this study provides mechanistic insights into P450-mediated resistance and offers a promising strategy to reduce reliance on chemical insecticides, thereby contributing to the development of sustainable integrated pest management (IPM) programs.