Agrobacterium-Mediated Gene Transient Overexpression and Tobacco Rattle Virus (TRV)-Based Gene Silencing in Cassava

Agrobacterium-mediated transient expression and virus-induced gene silencing (VIGS) are very useful in functional genomics in plants. However, whether these methods are effective in cassava (Manihot esculenta), one of the most important tropical crops, remains elusive. In this study, we used green fluorescent protein (GFP) and β-glucuronidase (GUS) as reporter genes in a transient expression assay. GFP or GUS could be detected in the infiltrated leaves at 2 days postinfiltration (dpi) and were evidenced by visual GFP and GUS assays, reverse-transcription PCR, and Western blot. In addition, phytoene desaturase (PDS) was used to show the silencing effect in a VIGS system. Both Agrobacterium GV3101 and AGL-1 with tobacco rattle virus (TRV)-MePDS-infiltrated distal leaves showed an albino phenotype at 20 dpi; in particular, the AGL-1-infiltrated plants showed an obvious albino area in the most distal leaves. Moreover, the silencing effect was validated by molecular identification. Notably, compared with the obvious cassava mosaic disease symptom infiltrated by African-cassava-mosaic-virus-based VIGS systems in previous studies, TRV-based VIGS-system-infiltrated cassava plants did not show obvious virus-induced disease symptoms, suggesting a significant advantage. Taken together, these methods could promote functional genomics in cassava.

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Virus-induced gene silencing in the perennial woody Paeonia ostii

PeerJ ◽

10.7717/peerj.7001 ◽

2019 ◽

Vol 7 ◽

pp. e7001

Author(s):

Lihang Xie ◽

Qingyu Zhang ◽

Daoyang Sun ◽

Weizong Yang ◽

Jiayuan Hu ◽

...

Keyword(s):

Gene Silencing ◽

Fluorescent Protein ◽

Molecular Genetic ◽

Functional Characterization ◽

Tobacco Rattle Virus ◽

Vacuum Infiltration ◽

Genomic Research ◽

Virus Induced Gene Silencing ◽

Tree Peony ◽

Medicinal Value

Tree peony is a perennial deciduous shrub with great ornamental and medicinal value. A limitation of its current functional genomic research is the lack of effective molecular genetic tools. Here, the first application of a Tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) in the tree peony species Paeonia ostii is presented. Two different approaches, leaf syringe-infiltration and seedling vacuum-infiltration, were utilized for Agrobacterium-mediated inoculation. The vacuum-infiltration was shown to result in a more complete Agrobacterium penetration than syringe-infiltration, and thereby determined as an appropriate inoculation method. The silencing of reporter gene PoPDS encoding phytoene desaturase was achieved in TRV-PoPDS-infected triennial tree peony plantlets, with a typical photobleaching phenotype shown in uppermost newly-sprouted leaves. The endogenous PoPDS transcripts were remarkably down-regulated in VIGS photobleached leaves. Moreover, the green fluorescent protein (GFP) fluorescence was detected in leaves and roots of plants inoculated with TRV-GFP, suggesting the capability of TRV to silence genes in various tissues. Taken together, the data demonstrated that the TRV-based VIGS technique could be adapted for high-throughput functional characterization of genes in tree peony.

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A rapid virus-induced gene silencing (VIGS) method for assessing resistance and susceptibility to cassava mosaic disease

Virology Journal ◽

10.1186/s12985-017-0716-6 ◽

2017 ◽

Vol 14 (1) ◽

Cited By ~ 11

Author(s):

Getu Beyene ◽

Raj Deepika Chauhan ◽

Nigel J. Taylor

Keyword(s):

Gene Silencing ◽

Mosaic Disease ◽

Cassava Mosaic Disease ◽

Virus Induced Gene Silencing

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Tobacco mosaic virus 126-kDa Protein Increases the Susceptibility of Nicotiana tabacum to Other Viruses and Its Dosage Affects Virus-Induced Gene Silencing

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-21-12-1539 ◽

2008 ◽

Vol 21 (12) ◽

pp. 1539-1548 ◽

Cited By ~ 23

Author(s):

Phillip A. Harries ◽

Karuppaiah Palanichelvam ◽

Sumana Bhat ◽

Richard S. Nelson

Keyword(s):

Nicotiana Tabacum ◽

Gene Silencing ◽

Tobacco Mosaic Virus ◽

Mosaic Virus ◽

Fluorescent Protein ◽

Tobacco Rattle Virus ◽

Potato Virus X ◽

Brome Mosaic Virus ◽

Virus Induced Gene Silencing ◽

Suppressor Activity

The Tobacco mosaic virus (TMV) 126-kDa protein is a suppressor of RNA silencing previously shown to delay the silencing of transgenes in Nicotiana tabacum and N. benthamiana. Here, we demonstrate that expression of a 126-kDa protein–green fluorescent protein (GFP) fusion (126-GFP) in N. tabacum increases susceptibility to a broad assortment of viruses, including Alfalfa mosaic virus, Brome mosaic virus, Tobacco rattle virus (TRV), and Potato virus X. Given its ability to enhance TRV infection in tobacco, we tested the effect of 126-GFP expression on TRV-mediated virus-induced gene silencing (VIGS) and demonstrate that this protein can enhance silencing phenotypes. To explain these results, we examined the poorly understood effect of suppressor dosage on the VIGS response and demonstrated that enhanced VIGS corresponds to the presence of low levels of suppressor protein. A mutant version of the 126-kDa protein, inhibited in its ability to suppress silencing, had a minimal effect on VIGS, suggesting that the suppressor activity of the 126-kDa protein is indeed responsible for the observed dosage effects. These findings illustrate the sensitivity of host plants to relatively small changes in suppressor dosage and have implications for those interested in enhancing silencing phenotypes in tobacco and other species through VIGS.

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Virus-Mediated Transient Expression Techniques Enable Functional Genomics Studies and Modulations of Betalain Biosynthesis and Plant Height in Quinoa

Frontiers in Plant Science ◽

10.3389/fpls.2021.643499 ◽

2021 ◽

Vol 12 ◽

Author(s):

Takuya Ogata ◽

Masami Toyoshima ◽

Chihiro Yamamizo-Oda ◽

Yasufumi Kobayashi ◽

Kenichiro Fujii ◽

...

Keyword(s):

Gene Silencing ◽

Functional Genomics ◽

Transient Expression ◽

Inbred Lines ◽

Limiting Factor ◽

Cytochrome P450 Enzyme ◽

Virus Induced Gene Silencing ◽

In Planta ◽

Apple Latent Spherical Virus ◽

Reduced Height

Quinoa (Chenopodium quinoa), native to the Andean region of South America, has been recognized as a potentially important crop in terms of global food and nutrition security since it can thrive in harsh environments and has an excellent nutritional profile. Even though challenges of analyzing the complex and heterogeneous allotetraploid genome of quinoa have recently been overcome, with the whole genome-sequencing of quinoa and the creation of genotyped inbred lines, the lack of technology to analyze gene function in planta is a major limiting factor in quinoa research. Here, we demonstrate that two virus-mediated transient expression techniques, virus-induced gene silencing (VIGS) and virus-mediated overexpression (VOX), can be used in quinoa. We show that apple latent spherical virus (ALSV) can induce gene silencing of quinoa phytoene desaturase (CqPDS1) in a broad range of quinoa inbred lines derived from the northern and southern highland and lowland sub-populations. In addition, we show that ALSV can be used as a VOX vector in roots. Our data also indicate that silencing a quinoa 3,4-dihydroxyphenylalanine 4,5-dioxygenase gene (CqDODA1) or a cytochrome P450 enzyme gene (CqCYP76AD1) inhibits betalain production and that knockdown of a reduced-height gene homolog (CqRHT1) causes an overgrowth phenotype in quinoa. Moreover, we show that ALSV can be transmitted to the progeny of quinoa plants. Thus, our findings enable functional genomics in quinoa, ushering in a new era of quinoa research.

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Optimisation of tobacco rattle virus-induced gene silencing in Arabidopsis

Functional Plant Biology ◽

10.1071/fp05096 ◽

2006 ◽

Vol 33 (4) ◽

pp. 347 ◽

Cited By ~ 46

Author(s):

Changchun Wang ◽

Xinzhong Cai ◽

Xuemin Wang ◽

Zhong Zheng

Keyword(s):

Gene Silencing ◽

High Throughput ◽

Function Analysis ◽

Tobacco Rattle Virus ◽

Phytoene Desaturase ◽

Growth Stages ◽

Virus Induced Gene Silencing ◽

Gene Functions ◽

Genes Encoding ◽

Gene Function Analysis

Arabidopsis thaliana (L.) Heynh. is a model plant species in which to study plant gene functions. Recently developed virus-induced gene silencing (VIGS) offers a rapid and high-throughput technique platform for gene function analysis. In this paper we report optimisation of tobacco rattle virus (TRV)-induced gene silencing in Arabidopsis. The parameters potentially affecting the efficiency of VIGS in Arabidopsis were investigated. These included the concentration and pre-incubation of Agrobacterium inocula (agro-inocula), the concentration of acetosyringone included in agro-inocula, the Agrobacterium inoculation (agro-inoculation) method, the ecotypes and the growth stages of Arabidopsis plants for agro-inoculation, and the growth temperature of agro-inoculated plants. The optimised VIGS procedure involves preparing the agro-inocula with OD600 of 2.0, pre-incubating for 2 h in infiltration buffer containing 200 μm acetosyringone, agro-inoculating by vacuum infiltration, and growth of agro-inoculated plants at 22 −24°C. Following this procedure consistent and highly efficient VIGS was achieved for the genes encoding phytoene desaturase (PDS) and actin in Arabidopsis. The silencing phenotype lasts for at least 6 weeks, and is applicable in at least seven ecotypes, including Col-0, Cvi-0, Sd, Nd-1, Ws-0, Bay-0 and Ler. TRV-induced VIGS was expressed not only in leaves, but also in stems, inflorescences and siliques. However, VIGS was not transmissible through seed to the subsequent generation. The optimised procedure of the TRV-induced gene silencing should facilitate high-throughput functional analysis of genes in Arabidopsis.

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WRKY Transcription Factors in Cassava Contribute to Regulation of Tolerance and Susceptibility to Cassava Mosaic Disease through Stress Responses

Viruses ◽

10.3390/v13091820 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1820

Author(s):

Warren Freeborough ◽

Nikki Gentle ◽

Marie E. C. Rey

Keyword(s):

Transcription Factors ◽

Stress Responses ◽

Regulatory Networks ◽

Large Scale ◽

Mosaic Disease ◽

African Cassava Mosaic Virus ◽

Cassava Mosaic Disease ◽

Manihot Esculenta Crantz ◽

Transcriptional Reprogramming ◽

Negative Role

Among the numerous biological constraints that hinder cassava (Manihot esculenta Crantz) production, foremost is cassava mosaic disease (CMD) caused by virus members of the family Geminiviridae, genus Begomovirus. The mechanisms of CMD tolerance and susceptibility are not fully understood; however, CMD susceptible T200 and tolerant TME3 cassava landraces have been shown to exhibit different large-scale transcriptional reprogramming in response to South African cassava mosaic virus (SACMV). Recent identification of 85 MeWRKY transcription factors in cassava demonstrated high orthology with those in Arabidopsis, however, little is known about their roles in virus responses in this non-model crop. Significant differences in MeWRKY expression and regulatory networks between the T200 and TME3 landraces were demonstrated. Overall, WRKY expression and associated hormone and enriched biological processes in both landraces reflect oxidative and other biotic stress responses to SACMV. Notably, MeWRKY11 and MeWRKY81 were uniquely up and downregulated at 12 and 67 days post infection (dpi) respectively in TME3, implicating a role in tolerance and symptom recovery. AtWRKY28 and AtWRKY40 homologs of MeWRKY81 and MeWRKY11, respectively, have been shown to be involved in regulation of jasmonic and salicylic acid signaling in Arabidopsis. AtWRKY28 is an interactor in the RPW8-NBS resistance (R) protein network and downregulation of its homolog MeWRKY81 at 67 dpi in TME3 suggests a negative role for this WRKY in SACMV tolerance. In contrast, in T200, nine MeWRKYs were differentially expressed from early (12 dpi), middle (32 dpi) to late (67 dpi) infection. MeWRKY27 (homolog AtWRKY33) and MeWRKY55 (homolog AtWRKY53) were uniquely up-regulated at 12, 32 and 67 dpi in T200. AtWRKY33 and AtWRKY53 are positive regulators of leaf senescence and oxidative stress in Arabidopsis, suggesting MeWRKY55 and 27 contribute to susceptibility in T200.

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