scholarly journals Amenability of Maruca vitrata (Lepidoptera: Crambidae) to gene silencing through exogenous administration and host-delivered dsRNA in pigeonpea (Cajanus cajan L.)

2021 ◽  
Author(s):  
Madhurima Chatterjee ◽  
Jyoti Yadav ◽  
Maniraj Rathinam ◽  
Kesiraju Karthik ◽  
Gopal Chowdhary ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Target Genes ◽  
Insect Pests ◽  
Crop Improvement ◽  
Maruca Vitrata ◽  
Economic Losses ◽  
In Planta ◽  
Biotic Stresses ◽  
Pod Borer ◽  
Plant Level

Abstract Insect pests are one of the major biotic stresses limiting yield in commercially important food crops. The lepidopteran polyphagous spotted pod borer, Maruca vitrata causes significant economic losses in legumes including pigeonpea. RNAi-based gene silencing has emerged as one of the potential biotechnological tools for crop improvement. We report in this paper, RNAi in M. vitrata through exogenous administration of dsRNA encoding three functionally important genes, Alpha-amylase (α-amylase), Chymotrypsin-like serine protease (CTLP) and Tropomyosin (TPM) into the larval haemolymph and their host-delivered RNAi in pigeonpea. Significant decline in the expression of selected genes supported by over-expression of DICER and generation of siRNA indicated the occurrence of RNAi in the dsRNA-injected larvae. Additionally, the onset of RNAi in the herbivore was demonstrated in pigeonpea, one of the prominent hosts, by host-delivered RNAi. Transgenics in pigeonpea (cv. Pusa992), a highly recalcitrant crop, were developed through a shoot apical meristem-targeted in planta transformation strategy and evaluated. Plant level bioassays in transgenic events characterized and selected at molecular level showed mortality of M. vitrata larvae as well as reduced feeding when compared to wild type. Furthermore, molecular evidences for down regulation of target genes in the insects that fed on transgenics authenticated RNAi. Considering the variability of gene silencing in lepidopteran pests, this study provided corroborative proof for the possibility of gene silencing in M. vitrata through both the strategies.

scholarly journals RNAi-Mediated Management of Whitefly Bemisia tabaci by Oral Delivery of Double-stranded RNAs

Proceedings ◽  
2019 ◽  
Vol 36 (1) ◽  
pp. 11
Author(s):  
Jain ◽  
Robinson ◽  
Mitter
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Bemisia Tabaci ◽  
Oral Delivery ◽  
Target Genes ◽  
Insect Pests ◽  
Control Strategies ◽  
Plant Viruses ◽  
Potential Game ◽  
Viable Approach

The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is a significant global pest of economically important vegetable, fibre, and ornamental crops. Whiteflies directly damage the plants by piercing and sucking essential nutrients, indirectly through honeydew secretion and by transmitting more than 200 plant viruses that cause millions of dollars in produce losses per year. Whitefly management is mostly reliant on the heavy use of chemical insecticides. However, this ultimately leads to increasing resistance development, detrimental effects on beneficial insects and biomagnification of ecologically harmful chemicals in the environment. Responding to consumer demands for more selective, less toxic, non-GM insect control strategies, RNA interference (RNAi) has emerged as a potential game-changing solution. The RNA interference (RNAi) is a homology-dependent mechanism of gene silencing that represents a feasible and sustainable technology for the management of insect pests. In the present study, twenty-two whitefly genes were selected based on their essential function in the insect and tested in artificial diet bioassays for mortality and gene silencing efficacy. The nine most effective dsRNA constructs showed moderate-to-high whitefly mortality as compared to negative controls six days post-feeding. qPCR analysis further demonstrated significant knockdown of target gene mRNA expression. Additionally, uptake and spread of fluorescently labelled dsRNA was evident beyond the midgut of the whitefly supporting the systemic spreading of RNAi effectors. Taken together, the oral delivery of dsRNA shows effective RNAi mediated gene silencing of target genes and offers a viable approach for the development of dsRNA biopesticides against hemipteran pest.

scholarly journals Efficacy of a cry1Ab Gene for Control of Maruca vitrata (Lepidoptera: Crambidae) in Cowpea (Fabales: Fabaceae)

2020 ◽  
Vol 113 (2) ◽  
pp. 974-979
Author(s):  
Prince C Addae ◽  
Mohammad F Ishiyaku ◽  
Jean-Batiste Tignegre ◽  
Malick N Ba ◽  
Joseph B Bationo ◽  
...  
Keyword(s):  
Insect Pests ◽  
Field Trials ◽  
Genetically Engineered ◽  
Maruca Vitrata ◽  
Sub Saharan Africa ◽  
High Dose ◽  
Cry1ab Protein ◽  
Cry1ab Gene ◽  
Pod Borer ◽  
Sub Saharan

Abstract Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20–80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists. The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.

scholarly journals RNA interference as a gene silencing tool to controlTuta absolutain tomato (Solanum lycopersicum)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2673 ◽  
Author(s):  
Roberto A. Camargo ◽  
Guilherme O. Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-AandArginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet forT. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliverin planta-transcribed dsRNA to target insect genes.Tuta absolutalarvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage byT. absolutain these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

scholarly journals Legume biology: the basis for crop improvement

2013 ◽  
Vol 40 (12) ◽  
pp. v ◽  
Author(s):  
Rajeev K. Varshney ◽  
Himabindu Kudapa
Keyword(s):  
Target Genes ◽  
Crop Improvement ◽  
Crop Productivity ◽  
Food Sources ◽  
Yield Potential ◽  
Systematic Research ◽  
Breeding Programs ◽  
Biotic Stresses ◽  
Legume Crop ◽  
Precise Understanding

Legumes represent the most valued food sources in agriculture after cereals. Despite the advances made in breeding food legumes, there is a need to develop and further improve legume productivity to meet increasing food demand worldwide. Several biotic and abiotic stresses affect legume crop productivity throughout the world. The study of legume genetics, genomics and biology are all important in order to understand the limitations of yield of legume crops and to support our legume breeding programs. With the advent of huge genomic resources and modern technologies, legume research can be directed towards precise understanding of the target genes responsible for controlling important traits for yield potential, and for resistance to abiotic and biotic stresses. Programmed and systematic research will lead to developing high yielding, stress tolerant and early maturing varieties. This issue of Functional Plant Biology is dedicated to ‘Legume Biology’ research covering part of the work presented at VI International Conference on Legume Genetics and Genomics held at Hyderabad, India, in 2012. The 13 contributions cover recent advances in legume research in the context of plant architecture and trait mapping, functional genomics, biotic stress and abiotic stress.

scholarly journals Enhancement of the use and impact of germplasm in crop improvement

2014 ◽  
Vol 12 (S1) ◽  
pp. S155-S159 ◽  
Author(s):  
H. D. Upadhyaya ◽  
S. L. Dwivedi ◽  
S. Sharma ◽  
N. Lalitha ◽  
S. Singh ◽  
...  
Keyword(s):  
Insect Pests ◽  
Raw Materials ◽  
Plant Genetic Resources ◽  
Crop Improvement ◽  
Breeding Programs ◽  
Genome Wide ◽  
Pod Borer ◽  
Genetic Stocks ◽  
Beneficial Traits ◽  
Allelic Variations

Plant genetic resources are raw materials and their use in breeding is one of the most sustainable ways to conserve biodiversity. The ICRISAT has over 120,000 accessions of its five mandate crops and six small millets. The management and utilization of such large diversity are greatest challenges to germplasm curators and crop breeders. New sources of variations have been discovered using core and minicore collections developed at the ICRISAT. About 1.4 million seed samples have been distributed; some accessions with specific attributes have been requested more frequently. The advances in genomics have led researchers to dissect population structure and diversity and mine allelic variations associated with agronomically beneficial traits. Genome-wide association mapping in sorghum has revealed significant marker–trait associations for many agronomically beneficial traits. Wild relatives harbour genes for resistance to diseases and insect pests. Resistance to pod borer in chickpea and pigeonpea and resistance to rust and late leaf spot in groundnut have been successfully introgressed into a cultivated genetic background. Synthetics in groundnut are available to broaden the cultigen's gene pool. ICRISAT has notified the release of 266 varieties/cultivars, germplasm, and elite genetic stocks with unique traits, with some having a significant impact on breeding programs. Seventy-five germplasm lines have been directly released for cultivation in 39 countries.

scholarly journals RNA interference as a gene silencing tool to control Tuta absoluta in tomato (Solanum lycopersicum)

2016 ◽  
Author(s):  
Roberto A Camargo ◽  
Guilherme O Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes [Vacuolar ATPase-A and Arginine kinase] based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ~60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

scholarly journals ​Screening of Black Gram Genotypes against Major Pod Borers

2021 ◽  
Author(s):  
Abhishek Yadav ◽  
Gaje Singh ◽  
Amit Yadav ◽  
Hem Singh ◽  
Veer Singh ◽  
...  
Keyword(s):  
Insect Pests ◽  
Storage Condition ◽  
Maruca Vitrata ◽  
Black Gram ◽  
Resistant Cultivars ◽  
Kharif Season ◽  
Pulse Crop ◽  
Unique Position ◽  
Indian Agriculture ◽  
Pod Borer

Background: Blackgram (Vigna mungo L.) is an important pulse crop occupying a unique position in Indian agriculture and it stands fourth in area and production among the pulses. The popularity of this pulse is due to its nutritional and industrial values. Blackgram crop is attacked by a number of insect pests from sowing to harvest in the field as well as in storage condition. Among these insects-pests pod borers i.e. spotted pod borer, Maruca vitrata (Geyer) and gram pod borer, Helicoverpa armigera (Hubner) are serious insect-pests of black gram causing seed and pod damage. Therefore, keeping these views in mind, the present study was conducted. Methods: Present investigations were carried out during Kharif season of 2018 and 2019 to identify the resistant cultivars that are less susceptible to spotted pod borer and gram pod borer in black gram. Result: Fifteen black gram genotypes were screened against pod borers i.e. M. vitrata and H. armigera. When the data of both years were pooled, the two genotypes viz., KU-99-05 and Azad Urd-1 were found with minimum pod infestation of 7.67 and 9.67 per cent, respectively and categorized as resistant (R) against M. vitrata. The four genotypes KU-99-05, Azad Urd-1, Shekhar-2 and PU-6 were classified as resistant (R) against H. armigera with minimum pod infestation of 5.83, 6.17, 8.50 and 9.83 per cent, respectively during both the consecutive seasons (Kharif, 2018 and 2019).

scholarly journals Recent advances in engineering crop plants for resistance to insect pests

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Shilpa Kamatham ◽  
Sandhya Munagapati ◽  
Kota Neela Manikanta ◽  
Rohith Vulchi ◽  
Kiranmai Chadipiralla ◽  
...  
Keyword(s):  
Insect Resistance ◽  
Insect Pests ◽  
Crop Improvement ◽  
Crop Plants ◽  
Economic Losses ◽  
Food Crops ◽  
Main Body ◽  
Novel Technologies ◽  
Positive Effects ◽  
Wide Range

Abstract Background While the rapidly increasing global population has led to a dramatically increased demand for the agricultural production, there have been heavy economic losses owing to various pest attacks on different food crops. The advancement of various biotechnological techniques have come as a boon in addressing the global concern and leads to the development of novel varieties that have proven to be highly economical, pesticide resistant and environmentally safe. Main body The present review was aimed to update the recent developments that have taken place in the field of crop production. Major focus was laid predominantly on such genes that have demonstrated positive effects and proved to be of commercial success at the market primarily due to the development of pest-resistant transgenic food crops with expression of Bacillus thuringiensis toxins. This technology has been effective against a wide range of pests including coleopterans, lepidopterans, hemipterans, dipterans, strongylida (nematodes) and rhabditida. In similar lines various plant derived toxic proteins were also discussed along with different genes that code for insect resistant proteins such as δ-endotoxins and secreted toxins. This article also helps in understanding the structural features of the genes that are endowed with insect resistance followed by their mechanism of action on pests. Further the role of secondary metabolites in controlling the pests was addressed. The Pros and Cons of existing tools of insect pest management were demonstrated. Conclusions Novel technologies are necessary in crop improvement to progress the pace of the breeding programs, to confer insect resistance in crop plants. Therefore, the future aim of crop biotechnology is to engineer a sustainable, multi-mechanistic resistance to insect pests considering the diversity of plant responses to insect attack.

Simultaneous silencing of two target genes using virus-induced gene silencing technology in Nicotiana benthamiana

2019 ◽  
Vol 74 (5-6) ◽  
pp. 151-159
Author(s):  
Feng Zhu ◽  
Yanping Che ◽  
Fei Xu ◽  
Yangkai Zhou ◽  
Kun Qian ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Nicotiana Benthamiana ◽  
Target Genes ◽  
Function Analysis ◽  
Tobacco Rattle Virus ◽  
Pcr Analysis ◽  
Virus Induced Gene Silencing ◽  
Biotic Stresses ◽  
Overlap Extension

Abstract Virus-induced gene silencing (VIGS) is an effective strategy for rapid gene function analysis. It is well established that the NAC transcription factor and salicylic acid (SA) signal pathway play essential roles in response to biotic stresses. However, simultaneous silencing of two target genes using VIGS in plants has been rarely reported. Therefore, in this report, we performed VIGS to silence simultaneously the SA-binding protein 2 (NbSABP2) and NbNAC1 in Nicotiana benthamiana to investigate the gene silencing efficiency of simultaneous silencing of two genes. We first cloned the full-length NbNAC1 gene, and the characterization of NbNAC1 was also analysed. Overlap extension polymerase chain reaction (PCR) analysis showed that the combination of NbSABP2 and NbNAC1 was successfully amplified. Bacteria liquid PCR confirmed that the combination of NbSABP2 and NbNAC1 was successfully inserted into the tobacco rattle virus vector. The results showed that the leaves from the NbSABP2 and NbNAC1 gene-silenced plants collapsed slightly, with browning at the base of petiole or veina. Quantitative real-time PCR results showed that the expression of NbSABP2 and NbNAC1 were significantly reduced in 12 days post silenced plants after tobacco rattle virus infiltration compared with the control plants. Overall, our results suggest that VIGS can be used to silence simultaneously two target genes.

scholarly journals Comparative Analysis Delineates the Transcriptional Resistance Mechanisms for Pod Borer Resistance in the Pigeonpea Wild Relative Cajanus scarabaeoides (L.) Thouars

2020 ◽  
Vol 22 (1) ◽  
pp. 309
Author(s):  
Isaac Njaci ◽  
Abigail Ngugi-Dawit ◽  
Richard O. Oduor ◽  
Leah Kago ◽  
Brett Williams ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Insect Pests ◽  
Crop Improvement ◽  
Crop Wild Relatives ◽  
Wild Relatives ◽  
Agricultural Pests ◽  
Wild Genotype ◽  
Pod Borer ◽  
In The Wild ◽  
Wild Pigeonpea

Insect pests pose a serious threat to global food production. Pod borer (Helicoverpa armigera (Hübner)) is one of the most destructive pests of leguminous crops. The use of host resistance has been an effective, environmentally friendly and sustainable approach for controlling several agricultural pests. The exploitation of natural variations in crop wild relatives could yield pest-resistant crop varieties. In this study, we used a high-throughput transcriptome profiling approach to investigate the defense mechanisms of susceptible cultivated and tolerant wild pigeonpea genotypes against H. armigera infestation. The wild genotype displayed elevated pest-induced gene expression, including the enhanced induction of phytohormone and calcium/calmodulin signaling, transcription factors, plant volatiles and secondary metabolite genes compared to the cultivated control. The biosynthetic and regulatory processes associated with flavonoids, terpenes and glucosinolate secondary metabolites showed higher accumulations in the wild genotype, suggesting the existence of distinct tolerance mechanisms. This study provides insights into the molecular mechanisms underlying insect resistance in the wild pigeonpea genotype. This information highlights the indispensable role of crop wild relatives as a source of crucial genetic resources that could be important in devising strategies for crop improvement with enhanced pest resistance.

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