Publications by authors named "Hui-Shan Guo"

Nitric oxide (NO) is a crucial signaling molecule that regulates a wide range of metabolic pathways in different strata of organisms. In plants, nitrate reductase (NR) is a key enzyme for NO biosynthesis. There are two NR-encoding genes in Arabidopsis genome, NIA1 and NIA2, which are precisely regulated and expressed in a tissue-specific manner.

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RNA silencing (or RNA interference, RNAi) is a conserved mechanism for regulating gene expression in eukaryotes, which plays vital roles in plant development and response to biotic and abiotic stresses. The discovery of trans-kingdom RNAi and interspecies RNAi provides a theoretical basis for exploiting RNAi-based crop protection strategies. Here, we summarize the canonical RNAi mechanisms in plants and review representative studies associated with plant-pathogen interactions.

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Unlabelled: Small RNA (sRNA)-mediated RNA silencing (also known as RNA interference, or RNAi) is a conserved mechanism in eukaryotes that includes RNA degradation, DNA methylation, heterochromatin formation and protein translation repression. In plants, sRNAs can move either cell-to-cell or systemically, thereby acting as mobile silencing signals to trigger noncell autonomous silencing. However, whether and what proteins are also involved in noncell autonomous silencing have not been elucidated.

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Accurate determination of protein localization, levels, or protein-protein interactions is pivotal for the study of their function, and in situ protein labeling via homologous recombination has emerged as a critical tool in many organisms. While this approach has been refined in various model fungi, the study of protein function in most plant pathogens has predominantly relied on ex situ or overexpression manipulations. To dissect the molecular mechanisms of development and infection for , a formidable plant pathogen responsible for vascular wilt diseases, we have established a robust, homologous recombination-based in situ protein labeling strategy in this organism.

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Small RNA (sRNA)-mediated trans-kingdom RNA interference (RNAi) between host and pathogen has been demonstrated and utilized. However, interspecies RNAi in rhizospheric microorganisms remains elusive. In this study, we developed a microbe-induced gene silencing (MIGS) technology by using a rhizospheric beneficial fungus, Trichoderma harzianum, to exploit an RNAi engineering microbe and two soil-borne pathogenic fungi, Verticillium dahliae and Fusarium oxysporum, as RNAi recipients.

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The soil-borne fungus Verticillium dahliae, the most notorious plant pathogen of the Verticillium genus, causes vascular wilts in a wide variety of economically important crops. The molecular mechanism of V. dahliae pathogenesis remains largely elusive.

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Bidirectional trans-kingdom RNA silencing [or RNA interference (RNAi)] plays a key role in plant-pathogen interactions. It has been shown that plant hosts export specific endogenous miRNAs into pathogens to inhibit their virulence, whereas pathogens deliver small RNAs (sRNAs) into plant cells to disturb host immunity. Here, we report a trans-kingdom fungal sRNA retarding host plant floral transition by targeting a miRNA precursor.

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Trans-kingdom RNA interference (RNAi) has been reported in several plant-fungal pathosystems. Our recent works have demonstrated natural RNAi transmission from cotton plants into Verticillium dahliae, a soil-borne phytopathogenic fungus that infects host roots and proliferates in vascular tissues, and successful application of trans-kingdom RNAi in cotton plants to confer Verticillium wilt disease resistance. Here, we provide a detailed protocol of cotton infection with V.

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Communication between interacting organisms via bioactive molecules is widespread in nature and plays key roles in diverse biological processes. Small RNAs (sRNAs) can travel between host plants and filamentous pathogens to trigger transkingdom RNA interference (RNAi) in recipient cells and modulate plant defense and pathogen virulence. However, how fungal pathogens counteract transkingdom antifungal RNAi has rarely been reported.

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Host-induced gene silencing (HIGS) based on trans-kingdom RNA interference (RNAi) has been successfully exploited to engineer host resistance to pests and pathogens, including fungi and oomycetes. However, revealing the mechanisms underlying trans-kingdom RNAi between hosts and pathogens lags behind applications. The effectiveness and durability of trans-kingdom silencing of pathogenic genes are uncharacterized.

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RNA silencing (or RNA interference, RNAi) is a conserved mechanism for regulating gene expression in eukaryotes. The discovery of natural trans-kingdom RNAi indicated that small RNAs act as signaling molecules and enable communication between organisms in different kingdoms. The phenomenon and potential mechanisms of trans-kingdom RNAi are among the most exciting research topics.

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The genetic improvement of nitrogen use efficiency (NUE) of crops is vital for grain productivity and sustainable agriculture. However, the regulatory mechanism of NUE remains largely elusive. Here, we report that the rice Grain number, plant height, and heading date7 (Ghd7) gene genetically acts upstream of ABC1 REPRESSOR1 (ARE1), a negative regulator of NUE, to positively regulate nitrogen utilization.

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The phenomenon and potential mechanisms of trans-kingdom RNA silencing (or RNA interference, RNAi) are among the most exciting topics in science today. Based on trans-kingdom RNAi, host-induced gene silencing (HIGS) has been widely applied to create crops with resistance to various pests and pathogens, overcoming the limitations of resistant cultivars. However, a lack of transformation technology in many crops limits the application of HIGS.

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Molecular plant-virus interactions provide an excellent model to understanding host antiviral immunity and viral counter-defense mechanisms. The primary antiviral defense is triggered inside the infected plant cell by virus-derived small-interfering RNAs, which guide homology-dependent RNA interference (RNAi) and/or RNA-directed DNA methylation (RdDM) to target RNA and DNA viruses. In counter-defense, plant viruses have independently evolved viral suppressors of RNAi (VSRs) to specifically antagonize antiviral RNAi.

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Flowering plants and mammals contain imprinted genes that are primarily expressed in the endosperm and placenta in a parent-of-origin manner. In this study, we show that early activation of the geminivirus genes and in Arabidopsis () plants, encoding a viral suppressor of RNA interference and a replication enhancer protein, respectively, is correlated with the transient vegetative expression of (), an endosperm imprinted gene that is conserved in diverse plant species. VIM5 is a ubiquitin E3 ligase that directly targets the DNA methyltransferases MET1 and CMT3 for degradation by the ubiquitin-26S proteasome proteolytic pathway.

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Reactive oxygen species (ROS) production is one of the earliest responses when plants percept pathogens and acts as antimicrobials to block pathogen entry. However, whether and how pathogens tolerate ROS stress remains elusive. Here, we report the chromatin remodeling in Verticillium dahliae, a soil-borne pathogenic fungus that causes vascular wilts of a wide range of plants, facilitates the DNA damage repair in response to plant ROS stress.

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In plants, high disease resistance often results in a reduction of yield. Therefore, breeding crops with balanced yield and disease resistance has become a major challenge. Recently, microRNA (miRNA)-mediated R gene turnover has been shown to be a protective mechanism used by plants to prevent autoimmunity in the absence of pathogens.

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Plant plasmodesmata (PDs) are specialized channels that enable communication between neighboring cells. The intercellular permeability of PDs, which affects plant development, defense, and responses to stimuli, must be tightly regulated. However, the lipid compositions of PD membrane and their impact on PD permeability remain elusive.

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Soil-borne fungal pathogens that cause crop disease are major threats to agriculture worldwide. Here, we identified a secretory polysaccharide deacetylase (PDA1) from the soil-borne fungus Verticillium dahliae, the most notorious plant pathogen of the Verticillium genus, that facilitates virulence through direct deacetylation of chitin oligomers whose N-acetyl group contributes to host lysine motif (LysM)-containing receptor perception for ligand-triggered immunity. Polysaccharide deacetylases are widely present in fungi, bacteria, insects and marine invertebrates and have been reported to possess diverse functions in developmental processes rather than virulence.

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Trans-kingdom RNA plays a key role in host-parasite interactions. Hosts export specific endogenous microRNAs (miRNAs) into pathogens to target pathogen virulence genes and inhibit their invasion. In addition, trans-kingdom sRNAs produced by parasites may function as RNA effectors to suppress host immunity.

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MiRNAs in animals and plants play crucial roles in diverse developmental processes under both normal and stress conditions. miRNA-like small RNAs (milRNAs) identified in some fungi remain functionally uncharacterized. Here, we identified a number of milRNAs in Verticillium dahliae, a soil-borne fungal pathogen responsible for devastating wilt diseases in many crops.

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RNA silencing (or RNA interference, RNAi) plays direct roles in plant host defenses against viruses. Viruses encode suppressors of RNAi (VSRs) to counteract host antiviral defenses. The generation of transgenic plants expressing VSRs facilitates the understanding of the mechanisms of VSR-mediated interference with the endogenous silencing pathway.

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