Weeds often grow alongside crop plants. In addition to competing with crops for nutrients, water and space, weeds host insect vectors or act as reservoirs for viral diversity. However, little is known about viruses infecting rice weeds. In this work, we used metatranscriptomic deep sequencing to identify RNA viruses from 29 weed samples representing 23 weed species. A total of 224 RNA viruses were identified: 39 newly identified viruses are sufficiently divergent to comprise new families and genera. The newly identified RNA viruses clustered within 18 viral families. Of the identified viruses, 196 are positive-sense single-stranded RNA viruses, 24 are negative-sense single-stranded RNA viruses and 4 are double-stranded RNA viruses. We found that some novel RNA viruses clustered within the families or genera of several plant virus species and have the potential to infect plants. Collectively, these results expand our understanding of viral diversity in rice weeds. Our work will contribute to developing effective strategies with which to manage the spread and epidemiology of plant viruses.
Rice false smut, caused by Ustilaginoidea virens, threatens rice production by reducing yields and contaminating grains with harmful ustiloxins. However, studies on resistance genes are scarce. In this study, the resistance level of IR28 (resistant cultivar) to U. virens was validated through artificial inoculation. Notably, a reactivation of resistance genes after transient down-regulation during the first 3 to 5 dpi was observed in IR28 compared to WX98 (susceptible cultivar). Cluster results of a principal component analysis and hierarchical cluster analysis of differentially expressed genes (DEGs) in the transcriptome exhibited longer expression patterns in the early infection phase of IR28, consistent with its sustained resistance response. Results of GO and KEGG enrichment analyses highlighted the suppression of immune pathways when the hyphae first invade stamen filaments at 5 dpi, but sustained up-regulated DEGs were linked to the ‘Plant–pathogen interaction’ (osa04626) pathway, notably disease-resistant protein RPM1 (K13457, CNLs, coil-coiled NLR). An analysis of CNLs identified 245 proteins containing Rx-CC and NB-ARC domains in the Oryza sativa Indica genome. Partial candidate CNLs were shown to exhibit up-regulation at both 1 and 5 dpi in IR28. This study provides insights into CNLs’ responses to U. virens in IR28, potentially informing resistance mechanisms and genetic breeding targets.
11 March 2025 in Microbiology Resource Announcements
The complete genome sequence of Colletotrichum jinshuiense , a goldthread anthracnose pathogen, was sequenced using PacBio Revio and MGI DNBSEQ-T7 PE150. It contains 10 chromosomes, 5 mini chromosomes, a circular mitochondrial chromosome, and 13,129 genes predicted with RNA-Seq data in a 52.13-Mb genome with an N50 of 5.05 Mb.
Metabolic resistance is commonly attributed to the overexpression of detoxification enzymes, whereas the metabolic systems that sustain detoxification remain less well resolved. Here, we integrated widely targeted metabolomics and transcriptomics to compare the clothianidin-resistant brown planthopper strain CLR with the susceptible strain CLS and validated candidate genes in an independent nitenpyram-resistant background. CLR and CLS exhibited distinct metabolomic profiles. Differential genes and metabolites converged on carbon metabolism, glycolysis/gluconeogenesis, the tricarboxylic acid cycle, glutathione metabolism, pentose and glucuronate interconversions, cytochrome P450-mediated xenobiotic metabolism, and ABC transporters. These changes were summarized into four interconnected modules involving glycolytic energy supply, protective sugar-derived metabolites, pyruvate–TCA–malate metabolism, and UGT-mediated glycosylation. Expression analysis identified a mitochondrial NADP-dependent isocitrate dehydrogenase gene and UDP-glucosyltransferase 2 (UGT2) as consistently upregulated in both resistant backgrounds. Silencing NADP reduced the LC50 of nitenpyram and clothianidin by 1.84- and approximately 1.81-fold, respectively, whereas UGT2 silencing produced corresponding reductions of 1.89- and 1.83-fold. These findings indicate that neonicotinoid resistance in Nilaparvata lugens is supported by coordinated remodelling of central metabolism and detoxification and identify two candidate metabolic nodes for further resistance management research.