Plant viruses cause many diseases that lead to significant economic losses. However, most of the approaches to control plant viruses, including transgenic processes or drugs are plant-species-limited ...or virus-species-limited, and not very effective. We introduce an application of jasmonic acid (JA) and salicylic acid (SA), a broad-spectrum, efficient and nontransgenic method, to improve plant resistance to RNA viruses. Applying 0.06 mM JA and then 0.1 mM SA 24 h later, enhanced resistance to Cucumber mosaic virus (CMV), Tobacco mosaic virus (TMV) and Turnip crinkle virus (TCV) in Arabidopsis, tobacco, tomato and hot pepper. The inhibition efficiency to virus replication usually achieved up to 80-90%. The putative molecular mechanism was investigated. Some possible factors affecting the synergism of JA and SA have been defined, including WRKY53, WRKY70, PDF1.2, MPK4, MPK2, MPK3, MPK5, MPK12, MPK14, MKK1, MKK2, and MKK6. All genes involving in the synergism of JA and SA were investigated. This approach is safe to human beings and environmentally friendly and shows potential as a strong tool for crop protection against plant viruses.
Arabidopsis thaliana homeodomain-leucine zipper protein 1 (HAT1) belongs to the homeodomain-leucine zipper (HD-Zip) family class II that plays important roles in plant growth and development as a ...transcription factor. To elucidate further the role of HD-Zip II transcription factors in plant defense, the A. thaliana hat1, hat1hat3 and hat1hat2hat3 mutants and HAT1 overexpression plants (HAT1OX) were challenged with Cucumber mosaic virus (CMV). HAT1OX displayed more susceptibility, while loss-of-function mutants of HAT1 exhibited less susceptibility to CMV infection. HAT1 and its close homologs HAT2 and HAT3 function redundantly, as the triple mutant hat1hat2hat3 displayed increased virus resistance compared with the hat1 and hat1hat3 mutants. Furthermore, the induction of the antioxidant system (the activities and expression of enzymatic antioxidants) and the expression of defense-associated genes were down-regulated in HAT1OX but up-regulated in hat1hat2hat3 when compared with Col-0 after CMV infection. Further evidence showed that the involvement of HAT1 in the anti-CMV defense response might be dependent on salicylic acid (SA) but not jasmonic acid (JA). The SA level or expression of SA synthesis-related genes was decreased in HAT1OX but increased in hat1hat2hat3 compared with Col-0 after CMV infection, but there were little difference in JA level or JA synthesis-related gene expression among HAT1OX or defective plants. In addition, HAT1 expression is dependent on SA accumulation. Taken together, our study indicated that HAT1 negatively regulates plant defense responses to CMV.
(A) The coarse-grained granite that contains partly epidotized plagioclase crystals. (B) The albitized fine-grained porphyry that was crosscut by numerous melanocratic veinlets. (C) An example of the ...fine-grained porphyry that was subjected to intense hematitization and was crosscut by the REE-bearing melanocratic veinlets. Yellow circles delineate the occurrence of snowball quartz crystals. (D) Diorite dikes that postdated and crosscut the fine-grained porphyry. Abbreviations: Kfs = K-feldspar, Plg = plagioclase, Qz = Quartz, Ep = epidote.
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•We report SHRIMP U-Pb ages of a Nb-REE-Zr-mineralized fine-grained porphyry (453.8 ± 3.1 Ma) and of a coarse-grained granite (487.0 ± 4.0 Ma), into which the fine-grained porphyry intruded.•The coarse-grained granite contains magmatic zircon only, whereas magmatic and metasomatic zircon is both present in the fine-grained porphyry. The subtle time difference between magmatic and deuteric zircon cannot be shown by SHRIMP U-Pb ages of zircon.•SHRIMP U-Pb-O isotopes of zircon suggest that the fine-grained porphyry and the coarse-grained granite derived from different magma chambers and were genetically not related.•Nb-REE mineralization in the fine-grained porphyry postdated zircon, and occurred either as a replacement after the deuteric zircon or in late chlorite-/quartz-dominant veinlets. The Nb-REE minerals precipitated from an aqueous fluid that was constrained to the fine-grained porphyry.
Niobium, rare earth elements (REE = lanthanides + Y), and zirconium, are widely used in high-tech applications. The Nb-REE-Zr mineralization in the No. 782 deposit of NE China developed in a fine-grained porphyry (porphyry) that occurs as a ring-shaped stock. The ore-forming porphyry is hosted in a coarse-grained granite (granite) that dominates the study area. Zircon is the only Zr-bearing mineral in both the porphyry and the granite. In contrast to the granite that hosts only magmatic zircon, both magmatic (type I) and metasomatic (type II) zircon crystals or aggregates are present in the porphyry. Most type I zircon occurs as individual crystals and are hosted mainly in interstitial quartz, with evident oscillatory zoning. Most type II zircon occurs as aggregates rather than individual crystals and exhibits vague zoning. Distribution of the type II zircon in the porphyry is heterogeneous, with great abundance in places where there are substantial albitization and snowball quartz crystals. Textural and chemical features of the type II zircon and of the associated albite and snowball quartz crystals suggest that all these minerals are metasomatic. Nb is hosted mainly by fergusonite-(Y) and, REE by fergusonite-(Y) and to a lesser extent, by bastnäsite-(Ce) and parisite-(Ce), where parisite-(Ce) occurs as a replacement of bastnäsite-(Ce). The Nb-REE mineralization occurs either as a replacement of the type II zircon or in chlorite-/quartz-dominant veinlets that postdated both the type I and the type II zircon. Most type I zircon crystals in the porphyry were intact from the replacement or alteration by the postdated Nb-REE minerals, possibly because the type I crystals were encased earlier by other magmatic minerals. The chronological and oxygen isotopic data of zircon suggest that the porphyry (453.8 ± 3.1 Ma) is younger than the granite (487.0 ± 4.0 Ma), and that the two granitic phases derived from different magma chambers. The subtle age difference between magmatic type I and metasomatic type II zircon cannot be shown by SHRIMP U-Pb data of zircon. The mineral assemblages associated with type II zircon and the chronological data suggest that the medium from which type II zircon precipitated is likely an internally-derived hydrosilicate liquid (HSL) that lies compositionally in between a silicate melt and a hydrothermal fluid during the magmatic-hydrothermal transition. Textural features of the Nb-REE minerals, combined with the fact that Nb-REE mineralization developed only inside the porphyry, but not in surrounding country rocks (i.e. the granite) suggest that the Nb-REE mineralization originated from an aqueous fluid that was constrained to the porphyry.
•We studied the mechanisms of AOX in the systemic antiviral defense response.•We used VIGS to investigate the role of AOX in N-mediated resistance to TMV.•NbAOX plays an important role in the ...systemic resistance to virus infection.•NbAOX is required for N-mediated resistance to TMV.
The alternative oxidase (AOX) functions in the resistance to biotic stress. However, the mechanisms of AOX in the systemic antiviral defense response and N (a typical resistance gene)-mediated resistance to Tobacco mosaic virus (TMV) are elusive. A chemical approach was undertaken to investigate the role of NbAOX in the systemic resistance to RNA viruses. Furthermore, we used a virus-induced gene-silencing (VIGS)-based genetics approach to investigate the function of AOX in the N-mediated resistance to TMV. The inoculation of virus significantly increased the NbAOX transcript and protein levels and the cyanide-resistant respiration in the upper un-inoculated leaves. Pretreatment with potassium cyanide greatly increased the plant's systemic resistance, whereas the application of salicylhydroxamic acid significantly compromised the plant's systemic resistance. Additionally, in NbAOX1a-silenced N-transgenic Nicotiana benthamiana plants, the inoculated leaf collapsed and the movement of TMV into the systemic tissue eventually led to the spreading of HR-PCD and the death of the whole plant. The hypersensitive response marker gene HIN1 was significantly increased in the NbAOX1a-silenced plants. Significant amounts of TMV-CP mRNA and protein were detected in the NbAOX1a-silenced plants but not in the control plants. Overall, evidence is provided that AOX plays important roles in both compatible and incompatible plant-virus combinations.
Members of the plant mitochondrial energy-dissipation pathway (MEDP) coordinate cellular energy metabolism, redox homeostasis and the balance of ROS production. However, the roles of MEDP members, ...particularly uncoupling protein (UCP), in resistance to turnip crinkle virus infection (TCV) are poorly understood. Here, we showed that disrupting some MEDP genes compromises plant resistance to TCV viral infection and this is partly associated with damaged photosynthetic characteristics, altered cellular redox and increased ROS production. Experiments using mutant plants with impaired cellular compartment redox poising further demonstrated that impaired chloroplast/mitochondria and cystosol redox increases the susceptibility of plants to viral infection. Our results illustrate a mechanism by which MEDP and cellular compartment redox act in concert to regulate plant resistance to viral infections.
•MEDP disruption compromises Arabidopsis resistance to TCV infection.•Chloroplast and mitochondrial redox homeostasis are central in plant TCV resistance.•Arabidopsis lacking MEDP show an increased ROS accumulation.•Arabidopsis lacking MEDP show altered cellular redox.•Arabidopsis lacking MEDP have damaged photosynthesis.
Polymer microspheres with uniform size, composition, and surface property have gained extensive researches in past decades. Conventional bottom-up approaches are using monomers or oligomers to build ...up desired polymer microspheres. However, directly shaping high-molecular-weight polymers into well-ordered polymer microspheres remains a great challenge. Herein, we reported a facile and efficient top-down approach to fabricate microspheres with high-molecular-weight polymer microfibers. By harnessing interfacial engineering-control during the polymer microspheres formation, uniformly sized microspheres could be produced with widely ranged diameters (from 10 µm to the capillary length of each polymer melt). The size limitation of this approach could be further extended by a controllable Plateau-Rayleigh instability phenomenon. Principally, the top-down approach allows fabrication of microspheres by various polymer melts with surface energy higher than 25 mN/m. Our work paves a way for green, cost-effective, and customizable production of a variety of functional polymer microspheres without any chemical reaction assistant.
Human bocavirus (HBoV) is a newly discovered parvovirus associated with acute respiratory tract illness (ARTI) and gastrointestinal illness. Our study is the first to analyze the characteristics of ...HBoV-positive samples from ARTI patients with a wide age distribution from Guangzhou, southern China.
Throat swabs (n=2811) were collected and analyzed from children and adults with ARTI over a 13-month period. The HBoV complete genome from a 60 year-old female patient isolate was also determined.
HBoV DNA was detected in 65/2811 (2.3%) samples, of which 61/1797 were from children (<18 years old) and 4/1014 from adults (≥18 years old). Seasonal peaks of 4.8% and 7.7% were detected in May and June, respectively. 28 of 65 (43.1%) HBoV-positive samples were co-detected with 11/16 other potential pathogens. Mycoplasma pneumoniae had the highest frequency of 16.9% (11/65). Upper and lower respiratory tract illness were common symptoms, with 19/65 (29.2%) patients diagnosed with pneumonia by chest radiography. All four adult patients had systemic influenza-like symptoms. Phylogenetic analysis of the complete genome revealed a close relationship with other HBoVs, and a more distant relationship with HBoV2 and HBoV3.
HBoV was detected from children and adults with ARTI from Guangzhou, southern China. Elderly people were also susceptive to HBoV. A single lineage of HBoV was detected among a wide age distribution of patients with ARTI.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Key message
There are significant differences between the DGIs and LGTs. Additionally, most of the characteristics indicate that the DGIs are more similar to recovered tissue and can resist viral ...attacks.
Dark green islands (DGIs) surrounded by light green tissues (LGTs) are common leaf symptoms of plants that are systemically infected by various mosaic viruses. We performed cytological, physiological and molecular biological analyses of the DGIs and LGTs in
cucumber mosaic virus
-infected
Nicotiana tabacum
leaves. Our results indicated that the DGIs contained less virus than did the LGTs. Compared to the LGTs, the DGIs contained higher levels of the metabolites involved in plant defence. The contents of reduced glutathione and ascorbic acid were increased in the DGIs to reach levels that were even higher than those of control plants. Moreover, hormone measurements and quantitative real-time PCR analysis revealed that the endogenous salicylic acid, ethylene and defence genes mediated these elevations by playing positive roles in the regulation of the DGIs responses to viral infection. The accumulation of cytokinin was also much greater in the DGIs than in the LGTs. Finally, northern blotting analysis indicated that the accumulation of viral small interfering RNAs was decreased in the DGIs compared to the LGTs. Taken together, these results suggest that DGIs might represent leaf areas that have recovered from viral infection due to locally enhanced defence responses.
Genetic, physiological, and molecular analyses have revealed that the stress-related phytohormones salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) are known to participate in defense ...responses to mitigate biotic stress in plants. Recent evidence suggests that N-gene (a typical resistance gene) transcription is upregulated by Tobacco mosaic virus (TMV) infection, which is specifically a TMV-related phenomenon. In this study, we investigated N-gene transcription in tobaccoᴺᴺ infected with Chilli veinal mottle virus (ChiVMV). Furthermore, we used a virus-induced gene-silencing-based genetics approach to investigate the function of SA, JA, and ET biosynthesis or signaling genes in systemic resistance to ChiVMV. Northern blot and qRT-PCR analysis indicate that N-gene transcription is stimulated by ChiVMV. Hormone measurements demonstrate that JA and ET increase rapidly during the early stages of ChiVMV infection, whereas SA increases slightly at later stages. JA and ET biosynthetic, signaling, and marker genes are significantly activated after ChiVMV inoculation, whereas SA biosynthetic, signaling, and marker genes are increased slightly. Silencing of JA, ET biosynthetic and signaling genes strongly increase the plants’ susceptibility to ChiVMV, whereas silencing of SA biosynthetic and signaling genes only partly compromise systemic resistance. Extensive ROS accumulate in JA, ET biosynthetic and signaling gene-silenced plants after ChiVMV infection, whereas only slight ROS produce in SA biosynthetic and signaling gene-silenced plants. Taken together, our results indicate that N-gene transcription is upregulated by ChiVMV infection, and the JA/ET pathways play an important role in plant systemic resistance against ChiVMV, whereas the SA pathway is only minorly involved.
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