Search Results (147)

Insects and their bacterial endosymbionts form intricate ecological relationships, yet their role in host–pathogen interactions are not fully elucidated. The small brown planthopper (Laodelphax striatellus), a polyphagous pest of cereal crops, acts as a key vector for rice stripe virus (RSV), a significant threat to rice production. This study aimed to compare the endosymbiont community structures of nonviruliferous and RSV-viruliferous L. striatellus populations using 16S rRNA gene sequencing with high-throughput sequencing technology. Wolbachia was highly dominant in both groups; however, the prevalence of other endosymbionts, specifically Rickettsia and Burkholderia, differed markedly depending on RSV infection. Comprehensive microbial diversity and composition analyses revealed distinct community structures between nonviruliferous and RSV-viruliferous populations, highlighting potential interactions and implications for vector competence and virus transmission dynamics. These findings contribute to understanding virus-insect-endosymbiont dynamics and could inform strategies to mitigate viral spread by targeting symbiotic bacteria. Full article

Investigations of endogenous plant circular RNAs (circRNAs) in several plant species have revealed changes in their circular RNA profiles in response to biotic and abiotic stresses. Recently, circRNAs have emerged as critical regulators of gene expression. The destructive impacts on agriculture due to plant viral infections necessitate better discernment of the involvement of plant circRNAs during viral infection. However, few such studies have been conducted hitherto. Sobemoviruses cause great economic impacts on important crops such as rice, turnip, alfalfa, and wheat. Our current study investigates the dynamics of plant circRNA profiles in the host Arabidopsis thaliana (A. thaliana) during infections with the sobemoviruses Turnip rosette virus (TRoV) and Rice yellow mottle virus (RYMV), as well as the small circular satellite RNA of the Lucerne transient streak virus (scLTSV), focusing on circRNA dysregulation in the host plants and its potential implications in triggering plant cellular defense responses. Towards this, two rounds of deep sequencing were conducted on the RNA samples obtained from infected and uninfected plants followed by the analysis of circular RNA profiles using RNA-seq and extensive bioinformatic analyses. We identified 760 circRNAs, predominantly encoded in exonic regions and enriched in the chloroplast chromosome, suggesting them as key sites for circRNA generation during viral stress. Gene ontology (GO) analysis indicated that these circRNAs are mostly associated with plant development and protein binding, potentially influencing the expression of their host genes. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed photosynthesis as the most affected pathway. Interestingly, the non-coding exogenous scLTSV specifically induced several circRNAs, some of which contain open reading frames (ORFs) capable of encoding proteins. Our biochemical assays demonstrated that transgenic expression of scLTSV in A. thaliana enhanced resistance to TRoV, suggesting a novel strategy for improving plant viral resistance. Our results highlight the complexity of circRNA dynamics in plant–virus interactions and offer novel insights into potential circRNA-based strategies for enhancing plant disease resistance by modulating the differential expression of circRNAs. Full article

The virus-induced gene silencing (VIGS) technique can effectively inhibit systemic viral infection by down-regulating plant endogenous gene expression, and it has become an important tool to study plant gene function. However, few studies have reported that wheat dwarf virus (WDV), which enables high-throughput gene silencing, could be used in a rice VIGS system. In this study, a VIGS vector system was constructed based on WDV, and successfully silenced the Phytoene desaturase gene and the rice blast resistance gene Pi21 in rice. Pi21-silenced plants showed significantly increased resistance to rice blast, significantly reduced lesion area, and did not show high disease symptoms (grade 8–9). In addition, the WDV vector has the advantages of rapid infection, high proliferation, and an unconformity genome, and has little influence on rice growth and development. This study validates the effectiveness of the WDV-VIGS system in rice gene function studies and provides a new gene silencing tool for blast resistance breeding. Full article

Climate change is projected to increase global temperatures and alter rainfall patterns. In Peru, these changes could adversely affect the central basin of the Huallaga River by increasing pest and disease incidence, evapotranspiration, and water consumption. This basin is one of the country’s main rice-producing regions, where the crop is traditionally cultivated using inefficient practices, such as continuous flood irrigation. This study evaluated the effects of different irrigation management strategies on the growth and yield of rice (Oryza sativa var. INIA 516 LM1-La Unión 23), the water footprint as an indicator of water use efficiency, and the incidence of pests and diseases associated with irrigation regimes. Three irrigation treatments were implemented: Traditional flooding T1 (maintenance of a 0.15 m water layer with replenishment every 4 days), Optimized flooding T2 (replenishment every 7 days), and Intermittent rainfed irrigation T3 (replenishment every 14 days). Although no significant differences were observed in biometric parameters, yield, or pest and disease incidence, a trend of decreasing yield with longer irrigation intervals was noted: traditional flooding (7.91 t∙ha⁻¹) > reduced flooding (7.82 t∙ha⁻¹) > intermittent rainfed (7.14 t∙ha⁻¹). The incidence of white leaf virus and Burkholderia glumae was highest in the intermittent rainfed treatment, followed by optimized flooding, with the lowest incidence in traditional flooding. Yield reduction and the use of rainwater to cover water requirements resulted in a lower total water footprint for traditional flooding (834.0 m³∙t⁻¹), followed by optimized flooding (843.6 m³∙t⁻¹) and intermittent rainfed (923.9 m³∙t⁻¹). This reflects an improvement in rainwater use efficiency. The findings suggest intermittent rainfed irrigation enhances water use efficiency without significantly compromising rice yield or increasing disease incidence in rice var. INIA 516 LM1-La Unión 23 in the central basin of the Huallaga River. Full article

China, the largest global producer of sweet potatoes, faces significant threats from viral diseases, particularly in Fujian Province, where sweet potatoes are the second most important food crop after rice. This study identified 11 viruses, including sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV), infecting sweet potatoes in Fujian. Sequence comparisons revealed diverse strains from various sources. Virus prevalence varied across regions, with Quanzhou, Fuzhou, and Putian severely affected, detecting 10, 9, and 7 viruses, respectively, compared to only 3 in Sanming and Longyan. In particular, sweet potato virus disease (SPVD) caused the most severe damage during the seeding stages, resulting in dwarfing and leaf deformation, while the damage was lighter during the growth period, manifesting as the yellowing and brittleness of the leaves, ultimately reducing the yield. Compound infestations predominated, with between 0 and 6 viruses infecting different sweet potato varieties. Single-virus infections were observed for sweet potato virus 2 (SPV2), sweet potato symptomless virus 1 (SPSMV-1), and sweet potato pakakuy virus (SPPV), while others, particularly SPCSV, were frequently co-infected with SPFMV, leading to SPVD development. Further analysis showed that the RNase3 expression of SPCSV was correlated with the SPVD severity in sweet potato. These findings provide insights into the epidemiology of sweet potato viruses and serve as a reference for developing targeted disease management strategies. Full article

Chitin deacetylase modifies chitin and has critical functions in the growth and development of insects; however, whether it has other roles is unclear. Laodelphax striatellus not only directly feeds on the phloem sap of rice but also transmits RSV, leading to significant losses in rice production. In this study, four CDA genes were identified based on SBPH genomic data and were classified into groups I and III based on a phylogenetic analysis. The expression of LsCDA1 and LsCDA2 in RSV-infected SBPH was increased by 282% and 159%, respectively, relative to the non-infected SBPH control. Additionally, RSV enhanced the expression of LsCDA1 (increased by 194%) in the ovaries. Yeast two-hybrid and glutathione-S-transferase pull-down assays demonstrated the interaction between LsCDA1 and RSV proteins NP and NS2. Furthermore, the knockdown of LsCDA1 expression decreased viral loads in RSV-infected SBPH and its ovaries by 66% and 72% relative to the dsGFP control. Silencing LsCDA1 significantly decreased VgR expression in SBPH and its ovaries and reduced fecundity. These results indicate that LsCDA1 positively regulates RSV accumulation in the ovaries and SBPH reproduction by modulating VgR expression, which offers a novel strategy for controlling both RSV and SBPH by targeting LsCDA1. Full article

Rice is a vital staple crop for global food security, yet a worldwide comprehensive assessment of pests and diseases remains lacking. This study aims to (1) identify globally reported pests and diseases, (2) analyze their distribution patterns, and (3) assess their impact on rice productivity. A literature-based assessment with an initial pool of 15,969 articles from three online databases (PubMed, WOS, and CAB Abstract) resulted in 871 articles for analysis. The findings highlight a regional focus on Africa and Asia, where rice is predominantly produced. Pest occurrence varies across continents, with Diopsis, Maliarpha, and Chilo being prevalent in Africa, while Nilaparvata, Scirpophaga, Sogatella, and Chilo dominate in Asia. Key pathogens differ across regions, with Pyricularia, Xanthomonas, and Sobemovirus in Africa, while Fusarium and Bipolaris are common in Asia. Major yield losses are attributed to Pyricularia (Blast disease), Bipolaris (Brown Spot), Fusarium (Bakanae), and Sobemovirus (Rice Yellow Mottle Virus). The lack of data from major rice producers like Myanmar highlights reporting gaps, urging future research. This study enhances the global understanding of rice pest and disease distribution and their impacts on productivity. It could also support early warning systems and assess the effectiveness of control methods in the context of climate change. Full article

The DIR gene family, which encodes Dirigent proteins, plays a crucial role in plant development and stress responses. However, the functions and mechanisms of this family in maize remained underexplored. This study identified ZmDIR11, a member of the maize Dirigent protein family, and explored its role in drought tolerance. ZmDIR11 shared conserved regions with homologous proteins in wheat, rice, and Arabidopsis. RT-qPCR analysis revealed that ZmDIR11 expression is upregulated in leaves under drought and PEG stress, while subcellular localization confirmed its presence in the endoplasmic reticulum. Virus-induced gene silencing (VIGS) and EMS mutagenesis demonstrated that ZmDIR11 silencing or mutation significantly reduces drought tolerance in maize seedlings, indicating its positive regulatory role. Silencing or mutation of ZmDIR11 led to decreased growth parameters (plant height, root length, fresh weight, dry weight, and chlorophyll content) under drought stress, alongside a reduced antioxidant capacity, as evidenced by increased levels of MDA and ROS and decreased activities of SOD, CAT, and POD. Furthermore, ZmDIR11 mutation impaired the synthesis of ABA and zeatin, downregulating key genes in the ABA (ZmABA1, ZmNCED3, ZmSnRK2.6) and zeatin (ZmIPT4, ZmCKO5, ZmCKO4b) pathways. Drought-responsive genes (ZmRD20, ZmRD22, ZmDREB2A) and lignan biosynthesis genes (Zm4CL, ZmC3H, ZmCAD1) are also downregulated in ZmDIR11 mutants. In conclusion, ZmDIR11 enhances drought tolerance in maize by regulating antioxidant capacity, ABA and zeatin synthesis, and lignan metabolism. This study provides new insights into the role of DIR genes in drought tolerance and offers a potential genetic resource for breeding drought-resistant maize varieties. Full article

CRISPR/Cas9-mediated homology-directed repair (HDR) is a powerful tool for precise genome editing in plants, but its efficiency remains low, particularly for targeted amino acid substitutions or gene knock-ins. Successful HDR requires the simultaneous presence of Cas9, guide RNA, and a repair template (RT) in the same cell nucleus. Among these, the timely availability of the RT at the double-strand break (DSB) site is a critical bottleneck. To address this, we developed a sequential transformation strategy incorporating a deconstructed wheat dwarf virus (dWDV)-based autonomously replicating delivery system, effectively simplifying the process into a two-component system. Using this approach, we successfully achieved the targeted editing of the OsEPSPS gene in rice with a 10 percent HDR efficiency, generating three lines (TIPS1, TIPS2, and TIPS3) with amino acid substitutions (T172I and P177S) in the native EPSPS protein. The modifications were confirmed through Sanger sequencing and restriction digestion assays, and the edited lines showed no yield penalties compared to wild-type plants. This study demonstrates the utility of viral replicons in delivering gene-editing tools for precise genome modification, offering a promising approach for efficient HDR in crop improvement programs. Full article

Calcium-dependent protein kinases (CPKs) are plant proteins that directly bind calcium ions before phosphorylating substrates involved in biotic and abiotic stress responses, as well as development. Arabidopsis thaliana CPK3 (AtCPK3) is involved with plant signaling pathways such as stomatal movement regulation, salt stress response, apoptosis, seed germination and pathogen defense. In this study, AtCPK3 and its orthologues in relatively distant plant species such as rice (Oryza sativa, monocot) and kiwifruit (Actinidia chinensis, asterid eudicot) were analyzed in response to drought, bacteria, fungi, and virus infections. Two orthologues were studied in O. sativa, namely OsCPK1 and OsCPK15, while one orthologue—AcCPK16—was identified in A. chinensis. Reverse-transcriptase quantitative PCR (RT-qPCR) analysis revealed that OsCPK1 and AcCPK16 exhibit similar responses to stressors to AtCPK3. OsCPK15 responded differently, particularly in bacterial and fungal infections. An increase in expression was consistently observed among AtCPK3 and its orthologues in response to virus infection. Overexpression mutants in both Arabidopsis and kiwifruit showed slight tolerance to drought, while knockout mutants were slightly more susceptible or had little difference with wild-type plants. Overexpression mutants in Arabidopsis showed slight tolerance to virus infection. These findings highlight the importance of AtCPK3 and its orthologues in drought and pathogen responses and suggest such function must be conserved in its orthologues in a wide range of plants. Full article

Tomato yellow leaf curl virus (TYLCV) poses a significant threat to tomato production, leading to severe yield losses. The current control strategies primarily rely on the use of pesticides, which are often nonselective and costly. Therefore, there is an urgent need to identify more environmentally friendly alternatives. Dufulin, a novel compound that has been effective in controlling viral diseases in tobacco and rice, has not yet been tested against TYLCV. This study assessed the efficacy of dufulin in controlling TYLCV over a three-year span from 2021 to 2023 through field trials, by monitoring disease symptoms and viral titers. Additionally, this study assessed the expression levels of genes associated with systemic acquired resistance (SAR), specifically proteinase inhibitor II (PI II) and non-expressor of pathogenesis-related genes 1 (NPR1), using real-time qRT-PCR. The chlorophyll and nitrogen content in the leaves were also measured. Plants treated with dufulin showed reduced symptomatology and lower viral titers compared to the controls. Analysis of gene expression revealed that NPR1 was upregulated in the dufulin-treated plants, whereas PI II expression was consistently downregulated in the TYLCV-infected plants. Interestingly, PI II expression increased in the healthy plants following a seven-day post-treatment with dufulin. Moreover, the treated plants exhibited a higher chlorophyll content than the controls, though no significant differences in the nitrogen levels were observed between the dufulin-treated and water-treated plants. Overall, the application of dufulin significantly bolstered the plant’s defense response, effectively reducing TYLCV symptoms and enhancing resistance. Full article

One of the main obstacles in rice cultivation is tungro disease, caused by Rice Tungro Spherical Virus (RTSV) and Rice Tungro Bacilliform Virus (RTBV), which are transmitted by green leafhopper vectors (Nephotettix virescens). This disease can be controlled by using pesticides and refugia plants. Excessive use of pesticides can have negative impacts and high costs, so it is necessary to control the use of pesticides. In this study, a mathematical model of the spread of tungro virus disease in rice plants was developed by considering the characteristics of the virus, the presence of green leafhoppers and natural enemies, refugia planting, and pesticide use. From this model, dynamic and sensitivity analyses were carried out, and the optimal control theory was searched using the Pontryagin minimum principle. The analysis results showed three equilibriums: two non-endemic equilibriums (when plant and vector populations exist and when plant, vector, and natural enemy populations exist) and one endemic equilibrium. The non-endemic equilibrium will be asymptotically stable locally if $R_0<1$. At the same time, the parameters that greatly influence the spread of this disease are parameters $\mu , {\mu }_2$, and $\varphi$ for local sensitivity analysis and $\alpha , a, \beta , b, \varphi ,$ and ${\mu }_2$ for global sensitivity analysis. The results of the numerical simulation show that control using combined control is more effective in reducing the intensity of the spread of tungro disease in rice plants than control in the form of planting refugia plants as a source of food for natural enemies. The use of pesticides is sufficient for only four days, so the costs incurred are quite effective in controlling the spread of this disease. Full article

Unlike other ubiquitin-like family members, UBL5 is structurally and functionally atypical, and a novel role in various biological processes and diseases has been discovered. UBL5 can stabilize the structure of the spliceosome, can promote post-transcriptional processing, and has been implicated in both DNA damage repair and protein unfolding reactions, as well as cellular mechanisms that are frequently exploited by viruses for their own proliferation during viral infections. In addition, UBL5 can inhibit viral infection by binding to the non-structural protein 3 of rice stripe virus and mediating its degradation. Therefore, UBL5 is an important link between viral infections and immunity, and its study will be beneficial for the prevention and treatment of viral infections in the future. However, a review of the current findings on the role of UBL5 in viral infection has not been undertaken. Therefore, in this review, we summarize the recent progress in understanding the functions of UBL5 and discuss its putative role in viral infections. Full article

This review provides a comprehensive overview of the current understanding of rice resistance to the brown planthopper (BPH), a major pest that poses significant threats to rice production through direct feeding damage and by transmitting viruses such as Rice grassy stunt virus (RGSV) and Rice ragged stunt virus (RRSV). We highlight the emergence of various BPH biotypes that have overcome specific resistance genes in rice. Advances in genetic mapping and cloning have identified 17 BPH resistance genes, classified into typical R genes encoding nucleotide-binding leucine-rich repeat (NLR) proteins and atypical R genes such as lectin receptor kinases and proteins affecting cell wall composition. The molecular mechanisms of these genes involve the activation of plant defense pathways mediated by phytohormones like jasmonic acid (JA), salicylic acid (SA), and ethylene, as well as the production of defensive metabolites. We also examine the complex interactions between BPH salivary proteins and rice defense responses, noting how salivary effectors can both suppress and trigger plant immunity. The development and improvement of BPH-resistant rice varieties through conventional breeding and molecular marker-assisted selection are discussed, including strategies like gene pyramiding to enhance resistance durability. Finally, we outline the challenges and future directions in breeding for durable BPH resistance, emphasizing the need for continued research on resistance mechanisms and the development of rice varieties with broad-spectrum and long-lasting resistance. Full article

Rice is a crucial staple food for over half the global population, and viral infections pose significant threats to rice yields. This study focuses on the Rice Stripe Virus (RSV), which is known to drastically reduce rice productivity. We employed RNA-seq and ribosome profiling to analyze the transcriptional and translational responses of RSV-infected rice seedlings. Our results reveal that translational reprogramming is a critical aspect of the plant’s defense mechanism, operating independently of transcriptional changes. Notably, less than half of the differentially expressed genes showed concordance between transcription and translation. Furthermore, RSV infection led to significant alterations in translational efficiency for numerous genes, suggesting that the virus selectively manipulates translation to enhance its pathogenicity. Our findings underscore the necessity of examining both transcriptional and translational landscapes to fully understand plant responses to viral infections. Full article