Dataset Information

Virus-induced gene silencing (VIGS) in Cannabis sativa L.

ABSTRACT: Background:The raised demand of cannabis as a medicinal plant in recent years led to an increased interest in understanding the biosynthetic routes of cannabis metabolites. Since there is no established protocol to generate stable gene knockouts in cannabis, the use of a virus-induced gene silencing (VIGS) method, resulting in a gene knockdown, to study gene functions is desirable. Results:For this, a computational approach was employed to analyze the Cannabis sativa L. transcriptomic and genomic resources. Reporter genes expected to give rise to easily scorable phenotypes upon silencing, i.e. the phytoene desaturase (PDS) and magnesium chelatase subunit I (ChlI), were identified in C. sativa. Subsequently, the targets of specific small interfering RNAs (siRNAs) and silencing fragments were predicted and tested in a post-transcriptional gene silencing (PTGS) approach. Here we show for the first time a gene knockdown in C. sativa using the Cotton leaf crumple virus (CLCrV) in a silencing vector system. Plants transiently transformed with the Agrobacterium tumefaciens strain AGL1, carrying the VIGS-vectors, showed the desired phenotypes, spotted bleaching of the leaves. The successful knockdown of the genes was additionally validated by quantitative PCR resulting in reduced expression of transcripts from 70 to 73% for ChlI and PDS, respectively. This is accompanied with the reduction of the chlorophyll a and carotenoid content, respectively. In summary, the data clearly demonstrate the potential for functional gene studies in cannabis using the CLCrV-based vector system. Conclusions:The applied VIGS-method can be used for reverse genetic studies in C. sativa to identify unknown gene functions. This will gain deeper inside into unknown biosynthetic routes and will help to close the gap between available genomic data and biochemical information of this important medicinal plant.

SUBMITTER: Schachtsiek J

PROVIDER: S-EPMC6931244 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Virus-induced gene silencing (VIGS) in <i>Cannabis sativa</i> L.

Schachtsiek Julia J Hussain Tajammul T Azzouhri Khadija K Kayser Oliver O Stehle Felix F

Plant methods 20191226

<h4>Background</h4>The raised demand of cannabis as a medicinal plant in recent years led to an increased interest in understanding the biosynthetic routes of cannabis metabolites. Since there is no established protocol to generate stable gene knockouts in cannabis, the use of a virus-induced gene silencing (VIGS) method, resulting in a gene knockdown, to study gene functions is desirable.<h4>Results</h4>For this, a computational approach was employed to analyze the <i>Cannabis sativa</i> L. tra ...[more]

PMID: 31889981

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Project description:BackgroundVirus-induced gene silencing (VIGS) has emerged as a method for performing rapid loss-of-function experiments in plants. Despite its expanding use, the effect of host gene insert length and other properties on silencing efficiency have not been systematically tested. In this study, we probed the optimal properties of cDNA fragments of the phytoene desaturase (PDS) gene for efficient VIGS in Nicotiana benthamiana using tobacco rattle virus (TRV).ResultsNbPDS inserts of between 192 bp and 1304 bp led to efficient silencing as determined by analysis of leaf chlorophyll a levels. The region of the NbPDS cDNA used for silencing had a small effect on silencing efficiency with 5' and 3' located inserts performing more poorly than those from the middle. Silencing efficiency was reduced by the inclusion of a 24 bp poly(A) or poly(G) homopolymeric region. We developed a method for constructing cDNA libraries for use as a source of VIGS-ready constructs. Library construction involved the synthesis of cDNA on a solid phase support, digestion with RsaI to yield short cDNA fragments lacking poly(A) tails and suppression subtractive hybridization to enrich for differentially expressed transcripts. We constructed two cDNA libraries from methyl-jasmonate treated N. benthamiana roots and obtained 2948 ESTs. Thirty percent of the cDNA inserts were 401-500 bp in length and 99.5% lacked poly(A) tails. To test the efficiency of constructs derived from the VIGS-cDNA libraries, we silenced the nicotine biosynthetic enzyme, putrescine N-methyltransferase (PMT), with ten different VIGS-NbPMT constructs ranging from 122 bp to 517 bp. Leaf nicotine levels were reduced by more than 90% in all plants infected with the NbPMT constructs.ConclusionBased on the silencing of NbPDS and NbPMT, we suggest the following design guidelines for constructs in TRV vectors: (1) Insert lengths should be in the range of ~200 bp to ~1300 bp, (2) they should be positioned in the middle of the cDNA and (3) homopolymeric regions (i.e. poly(A/T) tails) should not be included. Our VIGS-cDNA library method, which incorporates these guidelines to produce sequenced, VIGS-ready cDNAs, will be useful for both fast-forward and reverse genetics experiments in TRV vectors.

Project description:BackgroundCassava mosaic disease (CMD) is a major constraint to cassava production in sub-Saharan Africa. Under field conditions, evaluation for resistance to CMD takes 12-18 months, often conducted across multiple years and locations under pressure from whitefly-mediated transmission. Under greenhouse or laboratory settings, evaluation for resistance or susceptibility to CMD involves transmission of the causal viruses from an infected source to healthy plants through grafting, or by using Agrobacterium-mediated or biolistic delivery of infectious clones. Following inoculation, visual assessment for CMD symptom development and recovery requires 12-22 weeks. Here we report a rapid screening system for determining resistance and susceptibility to CMD based on virus-induced gene silencing (VIGS) of an endogenous cassava gene.ResultsA VIGS vector was developed based on an infectious clone of the virulent strain of East African cassava mosaic virus (EACMV-K201). A sequence from the cassava (Manihot esculenta) ortholog of Arabidopsis SPINDLY (SPY) was cloned into the CP position of the DNA-A genomic component and used to inoculate cassava plants by Helios® Gene Gun microparticle bombardment. Silencing of Manihot esculenta SPY (MeSPY) using MeSPY1-VIGS resulted in shoot-tip necrosis followed by death of the whole plant in CMD susceptible cassava plants within 2-4 weeks. CMD resistant cultivars were not affected and remained healthy after challenge with MeSPY1-VIGS. Significantly higher virus titers were detected in CMD-susceptible cassava lines compared to resistant controls and were correlated with a concomitant reduction in MeSPY expression in susceptible plants.ConclusionsA rapid VIGS-based screening system was developed for assessing resistance and susceptibility to CMD. The method is space and resource efficient, reducing the time required to perform CMD screening to as little as 2-4 weeks. It can be employed as a high throughput rapid screening system to assess new cassava cultivars and for screening transgenic, gene edited and breeding lines under controlled growth conditions.

Project description:Proteomic approaches were applied to identify protein spots involved in cold responses in wheat. By comparing the differentially accumulated proteins from two cultivars (UC1110 and PI 610750) and their derivatives, as well as the F10 recombinant inbred line population differing in cold-tolerance, a total of 20 common protein spots representing 16 unique proteins were successfully identified using 2-DE method. Of these, 14 spots had significantly enhanced abundance in the cold-sensitive parental cultivar UC1110 and its 20 descendant lines when compared with the cold-tolerant parental cultivar PI 610750 and its 20 descendant lines. Six protein spots with reduced abundance were also detected. The identified protein spots are involved in stress/defense, carbohydrate metabolism, protein metabolism, nitrogen metabolism, energy metabolism, and photosynthesis. The 20 differentially expressed protein spots were chosen for quantitative real-time polymerase chain reaction (qRT-PCR) to investigate expression changes at the RNA level. The results indicated that the transcriptional expression patterns of 11 genes were consistent with their protein expression models. Among the three unknown proteins, Spot 20 (PAP6-like) showed high sequence similarities with PAP6. qRT-PCR results implied that cold and salt stresses increased the expression of PAP6-like in wheat leaves. Furthermore, VIGS (virus-induced gene silencing)-treated plants generated for PAP6-like were subjected to freezing stress, these plants had more serious droop and wilt, an increased rate of relative electrolyte leakage, reduced relative water content (RWC) and decreased tocopherol levels when compared with viral control plants. However, the plants that were silenced for the other two unknown proteins had no significant differences in comparison to the BSMV0-inoculated plants under freezing conditions. These results indicate that PAP6-like possibly plays an important role in conferring cold tolerance in wheat.

Project description:Background and aimsEschscholzia californica (California poppy) is an emerging model plant for 'evo-devo' studies from the basal eudicot clade of Papaveraceae. California poppy has a relatively small genome, a short life cycle and, most importantly, it is amenable for transformation. However, since this transformation protocol is time consuming, virus-induced gene silencing (VIGS) was evaluated as a fast method to obtain functional data for California poppy genes.MethodsCommercially available California poppy plants were infiltrated with Agrobacterium tumefaciens carrying the tobacco rattle virus plasmids pTRV1 and pTRV2. pTRV2 contained part of the eschscholzia Phytoene Desaturase (EcPDS) gene whose loss of function results in photobleaching of the green parts of the plant and in a lack of floral coloration. The degree and duration of these symptoms was evaluated for vegetative rosettes and plants in flower.Key resultsIt is shown that VIGS is able to effectively down-regulate the EcPDS gene in eschscholzia. Various degrees of silencing were observed starting <2 weeks after infiltration with Agrobacterium tumefaciens in 92 % of the plants. Tissue with silencing symptoms also showed complete or strong reduction of EcPDS transcripts. Strong silencing resulted in almost completely white petals, fruits, shoots and leaves. Plants with a strong degree of silencing will eventually die off; however, others are able to produce EcPDS gene product even after a strong initial silencing and will recover. Silencing was found to be not always systemic, but was often restricted to certain organs or parts of organs.ConclusionsVIGS is an effective, fast and transient method to down-regulate gene expression in eschscholzia. It serves well to detect prominent phenotypes which may become obvious even if some target gene transcript remains in the plant tissue. However, subtle phenotypes will be more difficult to detect, as extremely strong silencing effects occur in <10 % of all flowers from infected plants.

Dataset Information

Virus-induced gene silencing (VIGS) in Cannabis sativa L.

Publications

Virus-induced gene silencing (VIGS) in <i>Cannabis sativa</i> L.

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