- Rice stripe virus (RSV) is a significant insect-borne plant virus transmitted by the small brown planthopper (Laodelphax striatellus) in a persistent and propagative manner, posing a serious threat to rice production in Asian countries. Within its insect vector, RSV must overcome multiple tissue barriers, e.g., midgut, salivary glands and ovaries, and meanwhile must evade insect immune defense and regulate tissue microenvironments to achieve both horizontal and vertical transmission, reflecting a complex co-evolutionary relationship between virus and vector. In recent years, the rapid development of molecular biology technologies such as genomic sequencing and small RNA sequencing of L. striatellus, along with molecular interaction studies, has led to significant progress in China in understanding RSV receptor recognition, immune evasion, cross-kingdom regulation and manipulation of vector insect behavior. In this article, we reviewed the key findings in the insect transmission mechanism field of RSV from the past decade, covering: the molecular mechanisms underlying RSV’s horizontal and vertical transmission, dynamic interactions between RSV and the vector insect immune system, viral manipulation of vector behavior and metabolism, differential adaptation mechanisms of RSV in insect vector and host plant, and miRNA-mediated cross-kingdom transmission mechanism of virus. Collectively, these studies provide deep insights into the molecular interaction network among RSV, L. striatellus and rice, revealing an asymmetric manipulation-adaptation symbiotic relationship that favors viral transmission. We further proposed that future research should focus on the cellular and molecular mechanisms underlying viral dissemination across insect tissues, the role of symbiotic microbes in modulating transmission efficiency, and the strategies by which RSV manipulates L. striatellus physiology and behavior. Integrating these insights with eco-friendly control approaches such as RNA interference holds promise for developing precise and sustainable strategies to block RSV transmission, and offers new directions for environmentally sound management of arboviral diseases.

 Rice black-streaked dwarf virus disease (RBSDVD), caused by rice black-streaked dwarf virus (RBSDV), is a devastating viral disease that poses a significant threat to rice production in China and East Asia, historically causing severe yield losses. RBSDV belongs to the genus Fijivirus in the family Spinareoviridae and is primarily transmitted in nature by the small brown planthopper (Laodelphax striatellus) in a persistent and propagative manner. In recent years, significant progress has been made in understanding the mechanisms of virus-vector-host rice interactions and in rice breeding for disease resistance. Regarding virus-vector interactions, the RBSDV outer capsid protein P10 induces autophagy by promoting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) phosphorylation in vector and subsequently hijacks phosphatidylinositol 3, 5-bisphosphate ［PI(3, 5)P2］ to escape autophagic degradation. The viral matrix protein P9-1 facilitates viral accumulation by competitively binding to the 26S proteasome subunit RPN8 of vector, thereby inhibiting the ubiquitin-proteasome pathway. Additionally, the virus exploits the L. striatellus sugar transporter LsST6 to cross the midgut barrier, and modulates vector miRNAs and lncRNAs to facilitate infection. In terms of virus-host rice interactions, the virus-encoded protein P6 functions as an RNA silencing suppressor, impairing host antiviral defenses by mediating the degradation of the rice SUMO-conjugating enzyme OsSCE1b. Furthermore, RBSDV fine-tunes plant hormone signaling networks via proteins such as P5-1, P7-2 and P8. These mechanisms include suppressing jasmonic acid biosynthesis, blocking gibberellin signal transduction by binding to GID2 and interfering with the auxin pathway, collectively promoting viral infection and causing plant dwarfing. Meanwhile, rice endogenous pathways involving nitric oxide, lncRNAs and epigenetic modifications have also been reported to participate in the regulation of RBSDV infections. In this article, in the field of resistance breeding, we summarized the progress in discovering resistant germplasms, such as W44 and Tetep, and highlighted the cloning and functional characterization of key resistance genes like OsAP47 and OsGLK1. We also discussed the application outcomes of modern biotechnologies, including marker-assisted selection (MAS), gene editing and RNA interference (RNAi) in breeding for resistance. Future research should systematically elucidate the tripartite virus-vector-plant interactions and co-evolutionary mechanisms, accelerate the mining and utilization of resistance genes, address the impact of climate change and rhizosphere microecology on disease epidemics, and establish a long-term dynamic monitoring and early warning system for diseases. This review aims to provide theoretical references and technical support for the integrated management of RBSDVD and the breeding of resistant rice varieties.

The leafhopper, as one of the agricultural pests, not only causes direct feeding damage, but also further harms rice by transmitting viral diseases. To date, seven rice viruses transmitted by leafhoppers have been identified. Among them, the rice reoviruses such as rice dwarf virus (RDV) and rice gall dwarf virus (RGDV) of Phytoreovirus have persistently occurred since their initial discovery in China, causing severe damage to rice production. After over half a century of continuous research by scientists worldwide, great progress has been made in understanding the mechanisms of leafhopper-mediated transmission of plant reoviruses. In this article, the transmission characteristics of rice reoviruses by leafhoppers, the mechanisms of rice reoviral propagation within leafhoppers and the horizontal and vertical transmission of rice reoviruses by their vector leafhoppers, the strategies by which reoviruses overcome insect immune barriers, and the interaction mechanisms among rice reoviruses, leafhopper vectors and host rice, were reviewed. The characteristics of rice reoviruses transmitted by leafhoppers in a persistent-propagative manner were summarized. It was clarified that rice reoviruses use the viroplasm as the replication site and the virion-containing tubular structure to spread in leafhoppers. Meanwhile, salivary proteins act as effector proteins to promote viral horizontal transmission from the salivary gland to the phloem of plants. The unique mechanism that rice reoviruses are carried by leafhopper symbiotic bacteria and sperm to break through the vertical transmission barrier has been revealed. However, the mechanisms of the intermittent, explosive and migratory nature of viral diseases remain unclear, and there is still a lack of effective prevention and control strategies for viral diseases. Future research needs to further reveal the interaction mechanism between rice reoviruses and vectors, discover new antiviral genes and germplasm resources, and develop efficient virus prevention and control strategies, with the aim to provide references for the research and prevention and control of rice reoviruses and other insect-borne plant viruses.

 Begomoviruses are a group of major pathogens that extract a heavy toll on the production of many crops such as tomato and tobacco in China. Begomoviruses are exclusively transmitted by the insect vector Bemisia tabaci under natural conditions, and the transmission process mediated by B. tabaci thus becomes one of the major factors driving the widespread of begomoviruses in the field. Here we reviewed the progresses made by Chinese scientists since 2000 in dissecting the factors impacting the transmission of begomoviruses by B. tabaci, begomovirus transport within B. tabaci, the induction and suppression on the immunity responses of B. tabaci by begomoviruses, and B. tabaci-begomovirus-plant tripartite interactions. Many factors including the cryptic species, gender and symbionts of B. tabaci may significantly impact the transmission efficiency of begomoviruses, and the transport of begomoviruses in B. tabaci relies on the factors of B. tabaci such as clathrin. Upon infection, begomoviruses induce or suppress the antiviral immunity responses of B. tabaci. Further, begomoviruses may affect the fitness and behavior of B. tabaci directly or in a plant-mediated manner, begomovirus infection may affect the modulation of plant physiology and biochemistry by B. tabaci, and B. tabaci infestation may modulate virus infection in host plants. Finally, we identified the key areas for future research to further dissect the molecular mechanisms underlying the differential virus transmission efficiency among cryptic species, the identification of viral receptors in B. tabaci, and the viral factors and mechanisms inducing antiviral defenses in B. tabaci, the processes and molecular mechanisms underlying B. tabaci-virus-plant tripartite interactions.

Plant viruses pose a severe threat to agricultural production and quality safety, and their epidemics and outbreaks depend heavily on transmission by insect vectors. Aphids are one of the most important insect vectors of plant viruses in nature, which can efficiently transmit hundreds of plant viruses in a non-persistent manner. Since the viral transmission processes are extremely rapid from seconds to minutes in aphids, it is difficult to precisely control the spread of aphid-borne viruses using conventional strategies. The transmission efficiency of non-persistent viruses is closely associated with the piercing-sucking activities and highly specialized structure of stylet of aphids. In recent years, significant progresses have been made in the mechanisms governing virions to recognize and attach with specific sites of aphid stylet, the regulatory roles of aphid salivary effectors in viral acquisition and transmission, and the molecular functions of virus-encoded proteins in regulating viral accquisition and transmission. In this review, we systematically summarized the transmission strategies of non-persistent viruses and the molecular basis for efficient aphid-mediated virus transmission. The specialized stylets of aphids are the key sites for virus attachment, with identified cuticular proteins proven to function as viral binding sites. The feeding and salivary secretion behaviors of aphids are closely linked to the virus transmission process. Key salivary components achieve efficient viral transmission by suppressing plant immune defenses and modulating the microenvironment of plant tissues.  Finally, we proposed that the identification of the virus receptors of aphid stylet, analysis of binding and dissociation mechanisms, and exploration of the new functions of salivary sheath proteins are future research hotspots and cutting-edge directions in this field. The outcomes lay a theoretical foundation for a deeper understanding that aphids are the major insect vectors for the transmission of non-persistent plant viruses, and provide practical targets for the development of precise control technology based on viral binding sites of aphid stylet.

Citrus huanglongbing, caused by the phloem-limited Candidatus Liberibacter asiaticus (CLas), is a major quarantine disease of citrus. In nature, the pathogen is mainly transmitted by the Asian citrus psyllid (Diaphorina citri) in a persistent propagative manner. In this review, we systematically summarized the research progress on the interactions among CLas, the host citrus and the insect vector D. citri. In 2009, the complete genome of CLas was obtained from a single citrus psyllid, and 86 Sec-dependent secreted proteins were identified. D. citri nymphs exhibit higher CLas acquisition and transmission efficiency than adults, with 25 ℃ being the optimal temperature for CLas acquisition by the vector. The CLas infection cycle within D. citri lasts 15-20 d. CLas enters D. citri cells via clathrin-mediated endocytosis, forms Liberibacter-containing vacuoles (LCVs), and utilizes its outer membrane proteins (OMPs) to reshape gut actin protein and overcome midgut barriers. Furthermore, CLas enhances the fecundity of D. citri to promote transmission by regulating the juvenile hormone (JH), adipokinetic hormone (AKH) and vitellogenin receptor (VgR) pathways, and related microRNAs. To counteract D. citri innate immunity, CLas achieves immune evasion by inducing mild autophagy through interaction with the autophagy-related proteins ATG8/ATG14 of D. citri and inhibiting the melanization-related PGRP-CLIP1-CLIP4-PPO-PO signaling cascade via its effector protein SDE3230. In the CLas-citrus-D. citri tripartite interaction, CLas infection manipulates the synthesis of citrus volatile compounds to attract D. citri for feeding. In response, D. citri secretes salivary effectors to suppress citrus immune pathways, thereby facilitating pathogen spread. Current research has not yet clarified the key scientific issues such as CLas proliferation, host-pathogen immune game, and LCV formation in D. citri. Future research should focus on three key areas, including the molecular mechanisms underlying CLas-D. citri immune homeostasis, CLas proliferation strategies within D. citri, and the signaling networks of the tripartite interactions among CLas, citrus and D. citri. Concurrently, an integrated approach involving gene editing-based germplasm improvement, AI-driven high-throughput screening of antimicrobial peptides, synthetic biology techniques and nano delivery system is proposed to develop effective prevention, control and management strategies for CLas.

 Arthropod-transmitted plant pathogens are major contributors to global crop yield losses, however, our understanding of the insect-specific viruses (ISVs) harbored by these vectors remains relatively limited. In recent years, the application of high-throughput sequencing technologies has been more and more widely used in novel virus identification and revealed remarkable diversity of ISVs within important plant pathogen vectors, including aphids, planthoppers and thrips. In this review, we systematically summarized the recent advances in the study of ISV diversity in these insect vectors. Current data reveal over 300 ISVs across 44 vector species of dozens of virus families. Dominated by RNA viruses, this diverse group encompasses a broad range of genome types, including positive-sense single-stranded RNA (+ssRNA) virus, negative-sense single-stranded RNA (-ssRNA) virus, double-stranded RNA virus (dsRNA virus) and single-stranded DNA (ssDNA) virus. These findings have significantly expanded the known RNA virosphere and filled critical gaps in current viral phylogenetic trees. Furthermore, accumulating evidence shows that several plant viruses share close evolutionary relationships with ISVs, supporting the hypothesis that plant viruses may have originated from arthropod viruses through cross-species transmission events. Beyond their taxonomic diversity, recent studies suggest that ISVs perform multiple biological functions in their hosts, such as inducing pathogenicity to hosts, modulating host physiology and biochemistry, and influencing the hosts’ capacity to acquire and transmit plant pathogens. Collectively, this review focused on the diversity of ISVs in plant pathogen vectors, highlighted their significance in viral evolution, and emphasized their potential as a valuable resource pool for developing environmentally sustainable pest and disease control strategies.