Tong Zhang

N⁶-methyladenosine (m⁶A) is a vital epitranscriptomic modification that regulates plant development and stress responses. In rice (Oryza sativa L.), the identity of the catalytic subunit (MTA) of the core m⁶A writer complex has remained controversial because of inconsistent annotations based primarily on sequence homology. Here, phylogenetic analysis identified LOC_Os02g45110 as the putative catalytic subunit OsMTA, whereas LOC_Os01g16180 and LOC_Os03g05420 were classified as the structural subunits OsMTB1 and OsMTB2, respectively. All three proteins showed nuclear enrichment. Yeast two-hybrid, luciferase complementation imaging, and bimolecular fluorescence complementation assays demonstrated that OsMTA interacts independently with OsMTB1 and OsMTB2. Moreover, transient co-expression of OsMTA with either OsMTB1 or OsMTB2 increased global m⁶A levels in a heterologous system. No homozygous plants carrying frameshift mutations in OsMTA were obtained, suggesting that complete loss of OsMTA function is lethal. Knockdown of OsMTA or CRISPR/Cas9-mediated knockout of OsMTB1 and OsMTB2 significantly delayed heading date and reduced 1000-grain weight. Conversely, overexpressing OsMTA accelerated heading, whereas overexpressing OsMTB1 or OsMTB2 generally accelerated heading but significantly reduced 1000-grain weight. Together, these findings define the core composition of the rice m⁶A writer complex and reveal its effects on heading date and grain weight.

Rice is a vital global staple crop, yet its productivity is significantly constrained by various diseases caused by pathogenic microorganisms. Developing efficient and environmentally friendly alternatives to complement or replace chemical pesticides is therefore crucial for sustainable rice production. Mesoporous silica nanoparticles have emerged as promising candidates for plant protection, owing to their unique physicochemical properties and high biocompatibility. However, the efficacy and underlying mechanisms of different mesoporous silica nanoparticles morphologies against major rice diseases remain to be fully elucidated. In this study, we synthesized two types of mesoporous silica nanoparticles with distinct morphologies–spherical (MSN) and virus-like spiky (VMSN) within a plant-absorbable size range. We systematically evaluated their protective effects against southern rice black-streaked dwarf virus (SRBSDV). The results demonstrated that both types of nanoparticles could induce viral resistance, while spherical MSN exhibited superior efficacy in pathogen suppression. Mechanistic investigations revealed that MSN and VMSN differentially up-regulated the expression of the transcription factor OsERF3, which in turn activated its downstream target gene OsRBOHE, leading to a defense-related reactive oxygen species (ROS) burst. Further genetic evidence confirmed that OsRBOHE acts as a positive regulator of rice resistance to SRBSDV. Additionally, both nanomaterials displayed favorable leaf wettability. They were efficiently absorbed and systemically translocated within rice plants, and showed no adverse effects on seed germination, seedling growth, or key agronomic traits at maturity. In conclusion, this study elucidates the molecular mechanism whereby spherical MSN functions as a potent immune primer by preferentially activating the OsERF3-OsRBOHE-ROS signaling axis. Combined with their excellent foliar delivery properties and biosafety, these findings provide a solid theoretical and practical foundation for developing sustainable, nanosilica-based crop protection strategies.

BACKGROUND: Insect‐borne viruses represent a major threat to global agriculture and public health. Rice ragged stunt virus (RRSV), a destructive pathogen transmitted by brown planthopper ( Nilaparvata lugens Stå ), lacks comprehensive understanding of the molecular mechanisms underlying its replication and transmission. RESULTS: This study reveals that the RRSV P6 protein serves as a key regulator of vector‐borne transmission by sequentially interacting with RTE1‐HOMOLOG 2 (OsRTH2) and ETHYLENE‐INSENSITIVE3‐LIKE 2 (OsEIL2) in the host ethylene signaling pathway. This biphasic strategy manipulates brown planthopper (BPH) behavior, initially promoting viral replication and subsequently facilitating epidemic spread. Furthermore, the ethylene precursor 1‐aminocyclopropane‐1‐carboxylic acid (ACC) significantly impairs BPH fitness, reducing survival and fecundity. CONCLUSIONS: Our study elucidates how a plant virus manipulates the host ethylene signaling pathway to promote its own replication and transmission. Moreover, we identify the ethylene biosynthesis precursor ACC as a potential, environmentally friendly control agent against brown planthoppers. © 2026 Society of Chemical Industry.

The white-backed planthopper ( Sogatella furcifera ) serves as the vector for the southern rice black-streaked dwarf virus (SRBSDV), with varying transmission efficiencies across populations. This research identifies Wolbachia , a common insect symbiont, as a key facilitator in breaching the salivary gland barrier for SRBSDV, revealing a mechanism by which the virus exploits an insect symbiont for transmission. Through field and laboratory investigations, it was observed that high-transmission (HT) planthopper populations contained high levels of Wolbachia , while low-transmission (LT) populations had minimal titers. Experiments involving thoracic injections confirmed Wolbachia ’s specific role in infiltrating salivary glands, as SRBSDV was unable to colonize glands in Wolbachia -depleted insects despite being present systemically. Ultrastructural analysis showed Wolbachia enveloping SRBSDV particles within gland cells, further supported by molecular assays indicating a direct interaction between Wolbachia surface protein (WSP) and viral P8 capsid protein. Disruption of this interaction using anti-WSP antibodies reduced salivary gland viral load and transmission rates, underscoring its functional importance. These results contrast with Wolbachia ’s antiviral effects in mosquitoes, highlighting a context-dependent “hitchhiking” strategy for viral dissemination. The WSP–P8 interaction presents a specific target for inhibiting SRBSDV transmission without resorting to pesticides, proposing a symbiont-informed approach as a sustainable strategy against rice viral diseases.

N6-methyladenosine (m ⁶ A), as the most abundant internal RNA modification, plays crucial, dynamic roles in in plant biology. By regulating gene expression at the post-transcriptional level, m ⁶ A modification has a broad impact on plant growth and development, and environmental stress responses including pathogen defense response. Here, we report that turnip mosaic virus (TuMV, Potyvirus rapae ) actively reprograms the global host m ⁶ A landscapes to promote infection in Arabidopsis thaliana and Nicotiana benthamiana . We show that TuMV infection induces extensive genome-wide m ⁶ A hypomethylation, suppressing more than 60% of conserved m ⁶ A modified RNAs. This is accompanied by compromised abundance and translational efficiency of defense-associated transcripts that are normally promoted by m ⁶ A modification. We further present evidence that the SUMOylated form of the TuMV RNA-dependent RNA polymerase NIb physically disrupts the m ⁶ A writer complex by displacing its core component MTB (methyltransferase B) and sequestering another key subunit MTA (mRNA adenosine methylase) in cytoplasmic viral replication factories, thereby suppressing m ⁶ A deposition. Expression of SUMOylated NIb alone is sufficient to manipulate global m ⁶ A modification and transcriptome reprogramming in the absence of viral infection. These findings reveal that viral RNA polymerase deploys a SUMO-mediated ‘writer hijacking’ strategy to remodel the host epigenetic transcriptome, thereby constructing an intracellular niche favorable for viral survival and replication.

RNA viruses often remodel host intracellular membranes to establish specialized replication compartments through viral protein–induced phase separation. However, the mechanisms underlying membrane remodeling and the characteristics that render these sites conducive to replication remain poorly understood, particularly in plant negative-strand RNA viruses. Here, we demonstrate that the phosphoprotein (P) of rice stripe mosaic virus (RSMV) forms biomolecular condensates via liquid-liquid phase separation (LLPS) to recruit essential components for viral replication factories (VFs). We identify a direct interaction between RSMV P and adenosine diphosphate (ADP) ribosylation factor 1 (OsARF1C), a crucial regulator of the coatomer protein I (COP I) vesicle transport pathway that is vital for viral replication. This interaction indirectly recruits OsARF1C’s partner, phosphatidylinositol 4-kinase beta (OsPI4KB), which drives localized phosphatidylinositol-4 phosphate (PI4P) synthesis. Concurrently, the P protein modulates its aggregates and LLPS droplets through PI4P, thereby expanding the replication site and enhancing viral replication.

Liquid-liquid phase separation (LLPS) forms membraneless condensates crucial for plant stress responses. However, how plant viruses utilize LLPS to escape host immunity remains largely unexplored. Here, we show that P6 protein encoded by southern rice black-streaked dwarf virus (SRBSDV) undergoes LLPS. P6 interacts with OsTSN1 to form the P6-OsTSN1-containing droplets co-localized with stress granules (SGs). Within these droplets, P6 enhances OsTSN1 nuclease activity via promoting its multimerization to degrade transcripts with G-A-rich motifs of two transcription factors (TFs), OsNAC15 and OsLHY. These two TFs regulate the transcription of OsJAZ6, OsJAZ12, and OsATG8C, key components of jasmonic acid (JA)- and autophagy-associated defense pathways. Furthermore, the degradation of OsNAC15 and OsLHY transcripts in P6-OsTSN1-containing droplets weakens JA- and autophagy-mediated defenses in rice, facilitating SRBSDV infection. Additionally, similar to SRBSDV P6, intrinsically disordered region (IDR)-containing RNA silencing suppressors encoded by rice black-streaked dwarf virus and rice stripe virus, also interact with OsTSN1, promoting the degradation of OsNAC15 and OsLHY transcripts to enhance viral infection. Our findings indicate that OsTSN1 acts as a central positive regulator of virus infection in rice, convergently co-opted by viruses. These insights help us to better understand the roles of LLPS and OsTSN1 in virus infection in rice.

The analysis of nonlinearity in spatial and spatial‐temporal data continues to be a challenging topic. This article introduces a two‐step estimation procedure for modeling nonstationary spatial processes that comprise a smooth bivariate trend function and a spatial autoregressive and moving average (SRAMA) error term. To remove the bivariate trend from the observed process, we apply the cutting‐edge bivariate penalized spline method. The modified maximum likelihood estimator based on the residuals, as suggested by Yao and Brockwell (2006), is shown to be consistent and oracle efficient, achieving the same efficiency asymptotically as if the true trend function were known and removed to obtain the SARMA errors. Furthermore, we establish the consistency of Bayesian information criteria for model selection concerning the residual sequence. The finite sample performance of the proposed approach is evaluated with simulations and real data.

Viral proteins can aggregate into granules within host cells, known as viral factories, or viroplasms, which play a pivotal role in facilitating viral replication and shielding the viral genome from cellular defense mechanisms. Rice stripe mosaic virus (RSMV), a plant cytorhabdovirus, is notorious for causing significant damage to rice production. Despite its impact, the mechanisms underlying the replication and assembly of RSMV remain largely unexplored. In this investigation, we established a minireplicon (MR) system of RSMV in Nicotiana benthamiana plants to assess the influence of RSMV phosphoprotein (P) on viral replication. Our findings indicate that RSMV P forms viral factory-like granules and is an important component of viral factories. Further investigation showed that the formation of P granules is indispensable for MR replication. Through deletion analysis, we identified the IDR2 region of P as crucial for granule formation and MR replication. These findings underscore the necessity of P protein granule formation in viral replication.