Construction of watermelon mosaic virus-Beijing isolate infectious clone and study of the dynamic localization and accumulation of virus-encoded proteins.

Potyvirus is the largest genus of plant RNA viruses, and the members in the genus are known to cause significant damage to a wide variety of crops. In this study, we performed small RNA (sRNA) deep sequencing for identification of potential virus (es) in collected cucumber leaves with mosaic symptoms from fields in Beijing. Through this high-throughput sequencing and subsequent PCR amplification, we obtained a complete viral genome sequence of 10,044 bp, which showed the highest similarity to the watermelon mosaic virus (WMV) isolate FBR04-37 and exhibited the typical characteristics of potyviruses in its genome organization.

Viral RNA polymerase as a SUMOylation decoy inhibits RNA quality control to promote potyvirus infection.

Potyvirids are the largest group of plant RNA viruses. Pelota, a core component of RNA quality controls (RQC), promotes the degradation of potyvirids' genomic RNA by recognizing a specific GA motif. Here we demonstrate that the viral RNA-dependent RNA polymerase, NIb, acts as a SUMOylation decoy to effectively reduce Pelota SUMOylation by competing with SCE1 to inhibit Pelota-mediated RQC.

RNA modifications in plant biotic interactions.

The chemical modifications of DNA and proteins are powerful mechanisms for regulating molecular and biological functions, influencing a wide array of signaling pathways in eukaryotes. Recent advancements in epitranscriptomics have shown that RNA modifications play crucial roles in diverse biological processes. Since their discovery in the 1970s, scientists have sought to decipher, identify, and elucidate the functions of these modifications across biological systems.

A Negative Feedback Loop Compromises NMD-Mediated Virus Restriction by the Autophagy Pathway in Plants.

Nonsense-mediated decay (NMD) and autophagy play pivotal roles in restricting virus infection in plants. However, the interconnection between these two pathways in viral infections has not been explored. Here, it is shown that overexpression of NbSMG7 and NbUPF3 attenuates cucumber green mottle mosaic virus (CGMMV) infection by recognizing the viral internal termination codon and vice versa.

Plant-virus arms race beyond RNA interference.

Plants use RNA interference for basal antiviral immunity, but emerging evidence suggests that additional RNA-targeting defense mechanisms also defend against invading viruses. Recent advancements in the understanding of RNA decay, RNA quality control, and N6-methyladenosine (mA) RNA modifications have unveiled new insights into the molecular arms race between plants and viruses.

mA modification of plant virus enables host recognition by NMD factors in plants.

N-methyladenosine (mA) is the most abundant eukaryotic mRNA modification and is involved in various biological processes. Increasing evidence has implicated that mA modification is an important anti-viral defense mechanism in mammals and plants, but it is largely unknown how mA regulates viral infection in plants. Here we report the dynamic changes and functional anatomy of mA in Nicotiana benthamiana and Solanum lycopersicum during Pepino mosaic virus (PepMV) infection.

Pepino mosaic virus antagonizes plant mA modification by promoting the autophagic degradation of the mA writer HAKAI.

Unlabelled: Autophagy plays an active anti-viral role in plants. Increasing evidence suggests that viruses can inhibit or manipulate autophagy, thereby winning the arms race between plants and viruses. Here, we demonstrate that overexpression of an mA writer from , SlHAKAI, could negatively regulate pepino mosaic virus (PepMV) infection, inhibit viral RNA and protein accumulations by affecting viral mA levels in tomato plants and vice versa.

Geminiviral C2 proteins inhibit active autophagy to facilitate virus infection by impairing the interaction of ATG7 and ATG8.

Autophagy is a conserved intracellular degradation process that plays an active role in plant response to virus infections. Here we report that geminiviruses counteract activated autophagy-mediated antiviral defense in plant cells through the C2 proteins they encode. We found that, in Nicotiana benthamiana plants, tomato leaf curl Yunnan virus (TLCYnV) infection upregulated the transcription levels of autophagy-related genes (ATGs).

SUMOylation-modified Pelota-Hbs1 RNA surveillance complex restricts the infection of potyvirids in plants.

RNA quality control nonsense-mediated decay is involved in viral restriction in both plants and animals. However, it is not known whether two other RNA quality control pathways, nonstop decay and no-go decay, are capable of restricting viruses in plants. Here, we show that the evolutionarily conserved Pelota-Hbs1 complex negatively regulates infection of plant viruses in the family Potyviridae (termed potyvirids), the largest group of plant RNA viruses that accounts for more than half of the viral crop damage worldwide.

Antiviral RNAi drives host adaptation to viral infection.

Despite extensive understanding of antiviral RNAi in plants, whether and how natural variation in components of RNAi contributes to antiviral immunity remains obscure. Liu et al. recently identified novel positive and negative antiviral RNAi regulators, supporting RNAi's principal role in the dynamic virus-host coevolution in natural ecosystems.

GmTDN1 improves wheat yields by inducing dual tolerance to both drought and low-N stress.

Genetically enhancing drought tolerance and nutrient use efficacy enables sustainable and stable wheat production in drought-prone areas exposed to water shortages and low soil fertility, due to global warming and declining natural resources. In this study, wheat plants, exhibiting improved drought tolerance and N-use efficacy, were developed by introducing GmTDN1, a gene encoding a DREB-like transcription factor, into two modern winter wheat varieties, cv Shi4185 and Jimai22. Overexpressing GmTDN1 in wheat resulted in significantly improved drought and low-N tolerance under drought and N-deficient conditions in the greenhouse.

Nuclear Exportin 1 (XPO1) Binds to the Nuclear Localization/Export Signal of the Turnip Mosaic Virus NIb to Promote Viral Infection.

The nuclear localization signal (NLS) and nuclear export signal (NES) are key signatures of proteins for controlling nuclear import and export. The NIb protein of turnip mosaic virus (TuMV) is an RNA-dependent RNA polymerase (RdRP) that is absolutely required for viral genome replication. Previous studies have shown that NIb is a nucleocytoplasmic shuttling protein and contains four putative NES and four putative NLS motifs.

Nuclear exportin 1 facilitates turnip mosaic virus infection by exporting the sumoylated viral replicase and by repressing plant immunity.

Exportin 1/XPO1 is an important nuclear export receptor that binds directly to cargo proteins and translocates the cargo proteins to the cytoplasm. To understand XPO1 protein functions during potyvirus infections, we investigated the nuclear export of the NIb protein encoding the RNA-dependent RNA polymerase (RdRp) of turnip mosaic virus (TuMV). Previously, we found that NIb is transported to the nucleus after translation and sumoylated by the sumoylation (small ubiquitin-like modifier) pathway to support viral infection.

Confers Drought Stress Tolerance in Transgenic Rice by Regulating Lignin Biosynthesis and ABA Signaling Pathway.

Foxtail millet () originated in China and is generally cultivated in arid and barren soil. Through long-term harsh environmental selection, foxtail millet has acquired significant drought resistance. However, the molecular mechanism of foxtail millet drought resistance is still unknown.

SiMYB3 in Foxtail Millet () Confers Tolerance to Low-Nitrogen Stress by Regulating Root Growth in Transgenic Plants.

Foxtail millet (), which originated in China, has a strong tolerance to low nutrition stresses. However, the mechanism of foxtail millet tolerance to low-nitrogen stress is still unknown. In this study, the transcriptome of foxtail millet under low-nitrogen stress was systematically analyzed.