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.

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 Leafhopper Viral Pathogens: Ultrastructure of salivary gland infection of Taastrup-like virus inPsammotettix alienusDahlbom; and a novel Rhabdovirus inHomalodisca vitripennis(Germar) Hemiptera: Cicadellidae

2018 ◽  
Author(s):  
Thorben Lundsgaard ◽  
Wayne B. Hunter ◽  
Scott Adkins
Keyword(s):  
Next Generation Sequencing ◽  
Plant Pathogens ◽  
Insect Pests ◽  
Economic Losses ◽  
Type I ◽  
Next Generation ◽  
Viral Pathogen ◽  
Thin Sections ◽  
Wide Range ◽  
Generation Sequencing

AbstractViruses that are pathogenic to insect pests can be exploited as biological control agents. Viruses that are pathogenic to beneficial insects and other arthropods, as in honey bees, silk worms, and shrimp, cause millions of dollars of losses to those industries. Current advances in next generation sequencing technologies along with molecular and cellular biology have produced a wealth of information about insect viruses and their potential applications. Leafhoppers cause economic losses as vectors of plant pathogens which significantly reduce the worlds’ food crops. Each year more viruses are discovered primarily through the use of next generation sequencing of the leafhopper hosts. The diversity of viruses from leafhoppers demonstrates a wide range of taxonomic members that includes genomes of DNA or RNA from families like: Reoviridae, Iridoviridae, Dicistroviridae, Iflaviridae, and others yet to be classified. Discussed is a recent viral pathogen isolated from the leafhopperPsammotettix alienus, name Taastrup Virus. Taastrup virus (TV) is a novel virus with a RNA genome, a Filovirus-like morphology, being tentatively placed within theMononegavirales. AdultPsammotettix alienusinfected with TV, showed the highest concentration of virions in salivary glands, consisting of a principal gland (type I-VI-cells) and an accessory gland. Examination of thin sections revealed enveloped particles, about 1300 nm long and 62 nm in diameter, located singly or in paracrystalline arrays in canaliculi of type III- and IV-cells. In gland cells with TV particles in canaliculi, granular masses up to 15 μm in diameter were present in the cytoplasm. These masses are believed to be viroplasms, the sites for viral replication. TV particles were observed at the connection between a canaliculus and the salivary duct system. A TV-like virus with strongly similar morphology was discovered in the ornamental plant,Liriope, near Fort Pierce, Florida, USA. When the virus was inoculated to a leafhopper cell culture, HvWH, made from the glassy-winged sharpshooter,Homalodisca vitripennis(Germar), the cells rapidly degraded with 100% mortality in 48 hours. These two instances are the only reported cases of this newly discovered viral pathogen of leafhoppers.

scholarly journals Aptitude of endophytic microbes for production of novel biocontrol agents and industrial enzymes towards agro-industrial sustainability

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ayodeji O. Falade ◽  
Kayode E. Adewole ◽  
Temitope C. Ekundayo
Keyword(s):  
Plant Pathogens ◽  
Insect Pests ◽  
Biocontrol Agents ◽  
Main Body ◽  
Industrial Sectors ◽  
Industrial Sustainability ◽  
Significant Damage ◽  
Wide Range ◽  
Potential Applications ◽  
To Receive

Abstract Background Endophytes have continued to receive increased attention worldwide, probably, due to the enormous biotechnological potentials spanning through various industrial sectors. This paper outlines the biotechnological potentials of endophytes in biocontrol and industrial enzyme production, and the possible contribution towards achieving agro-industrial sustainability using published articles on endophytes in both Web of Science and Scopus (1990–2020). Main body of the abstract This review discusses the potential of endophytes to produce novel secondary metabolites with effective biocontrol activity against insect pests and plant pathogens. More so, the aptitude of endophytes for production of a wide range of enzymes with potential applications in agriculture, energy and health is discussed in this review. Furthermore, this review highlights the emerging potentials of endophytes in the production of exopolysaccharide and fatty acids. This paper also advocates the need for bioprospecting endophytes for novel biocontrol agents against termites, which are known for causing significant damage to forest and stored products. Short conclusion Exploration of endophytes for biocontrol and production of biomolecules of industrial significance could contribute significantly towards agricultural and industrial sustainability.

Endocarp Structural Components of Insect Resistance in Almond

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 526d-526
Author(s):  
M. Freeman ◽  
C. Walters ◽  
M.A. Thorpe ◽  
T. Gradziel
Keyword(s):  
Insect Resistance ◽  
Insect Pests ◽  
Stone Fruit ◽  
Structural Components ◽  
Insect Infestation ◽  
Insect Feeding ◽  
Kernel Development ◽  
X Ray ◽  
Seal Integrity ◽  
Structural Barrier

Almond, as with other stone fruit, possesses a highly lignified endocarp or shell. The dominant hard-shelled trait (D-) is positively associated with greater resistant to insect infestation than nuts expressing the paper-shelled (dd) trait. Hard-shelled genotypes have undesirable effects, including a lower kernel meat-to-nut crack-out ratio, greater kernel damage during mechanical shelling, and a reduction in plant energy available to kernel development. Histogenic analysis shows that the almond endocarp, unlike peach, has a tri-partite structure. Insect feeding studies have subsequently demonstrated that the inner endocarp layer, which is similar in both hard and paper-shelled types, is the most important structural barrier to insect infestation. Shell-seal integrity and X-ray studies have confirmed that discontinuities at the inner endocarp suture seal are the primary, though not the sole site of entry for insect pests. Paper-shelled almond selections with highly lignified and well-sealed inner endocarps show resistance levels comparable to hard shelled types but with crack-out ratios 30% to 40% higher. Pseudo-paper-shelled types have also been selected, in which a highly lignified outer endocarp is formed, but is retained by the fruit hull at dehiscence. An understanding of endocarp morphology and development is thus important in breeding for insect resistance as well as the commercial utilization of both kernel and hull.

scholarly journals Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 645 ◽  
Author(s):  
Hamed K. Abbas ◽  
Nacer Bellaloui ◽  
Cesare Accinelli ◽  
James R. Smith ◽  
W. Thomas Shier
Keyword(s):  
Culture Media ◽  
Leaf Disc ◽  
Toxin Production ◽  
Macrophomina Phaseolina ◽  
Economic Losses ◽  
Limit Of Quantification ◽  
Charcoal Rot ◽  
Wide Range ◽  
Soybean Plants ◽  
Rot Disease

Charcoal rot disease, caused by the fungus Macrophomina phaseolina, results in major economic losses in soybean production in southern USA. M. phaseolina has been proposed to use the toxin (-)-botryodiplodin in its root infection mechanism to create a necrotic zone in root tissue through which fungal hyphae can readily enter the plant. The majority (51.4%) of M. phaseolina isolates from plants with charcoal rot disease produced a wide range of (-)-botryodiplodin concentrations in a culture medium (0.14–6.11 µg/mL), 37.8% produced traces below the limit of quantification (0.01 µg/mL), and 10.8% produced no detectable (-)-botryodiplodin. Some culture media with traces or no (-)-botryodiplodin were nevertheless strongly phytotoxic in soybean leaf disc cultures, consistent with the production of another unidentified toxin(s). Widely ranging (-)-botryodiplodin levels (traces to 3.14 µg/g) were also observed in the roots, but not in the aerial parts, of soybean plants naturally infected with charcoal rot disease. This is the first report of (-)-botryodiplodin in plant tissues naturally infected with charcoal rot disease. No phaseolinone was detected in M. phaseolina culture media or naturally infected soybean tissues. These results are consistent with (-)-botryodiplodin playing a role in the pathology of some, but not all, M. phaseolina isolates from soybeans with charcoal rot disease in southern USA.

scholarly journals Low Light/Darkness as Stressors of Multifactor-Induced Senescence in Rice Plants

2021 ◽  
Vol 22 (8) ◽  
pp. 3936
Author(s):  
Ahmed G. Gad ◽  
Habiba ◽  
Xiangzi Zheng ◽  
Ying Miao
Keyword(s):  
Leaf Senescence ◽  
Crop Yields ◽  
Crop Improvement ◽  
Light Response ◽  
Development Stage ◽  
Regulatory Mechanisms ◽  
Economic Losses ◽  
Low Light ◽  
Chlorophyll Breakdown ◽  
Premature Leaf Senescence

Leaf senescence, as an integral part of the final development stage for plants, primarily remobilizes nutrients from the sources to the sinks in response to different stressors. The premature senescence of leaves is a critical challenge that causes significant economic losses in terms of crop yields. Although low light causes losses of up to 50% and affects rice yield and quality, its regulatory mechanisms remain poorly elucidated. Darkness-mediated premature leaf senescence is a well-studied stressor. It initiates the expression of senescence-associated genes (SAGs), which have been implicated in chlorophyll breakdown and degradation. The molecular and biochemical regulatory mechanisms of premature leaf senescence show significant levels of redundant biomass in complex pathways. Thus, clarifying the regulatory mechanisms of low-light/dark-induced senescence may be conducive to developing strategies for rice crop improvement. This review describes the recent molecular regulatory mechanisms associated with low-light response and dark-induced senescence (DIS), and their effects on plastid signaling and photosynthesis-mediated processes, chloroplast and protein degradation, as well as hormonal and transcriptional regulation in rice.

The Effects of Technology Supports on Community Grocery Shopping Skills for Students With Intellectual and Developmental Disabilities: A Meta-Analysis

2021 ◽  
pp. 016264342198997
Author(s):  
Sojung Jung ◽  
Ciara Ousley ◽  
David McNaughton ◽  
Pamela Wolfe
Keyword(s):  
Developmental Disabilities ◽  
Positive Impact ◽  
Single Case ◽  
Effect Sizes ◽  
Future Research ◽  
Intellectual And Developmental Disabilities ◽  
Positive Effects ◽  
Analytic Review ◽  
Wide Range ◽  
The Impact

In this meta-analytic review, we investigated the effects of technology supports on the acquisition of shopping skills for students with intellectual and developmental disabilities (IDD) between the ages of 5 and 24. Nineteen single-case experimental research studies, presented in 15 research articles, met the current study’s inclusion criteria and the What Works Clearinghouse (WWC) standards. An analysis of potential moderators was conducted, and we calculated effect sizes using Tau-U to examine the impact of age, diagnosis, and type of technology on the reported outcomes for the 56 participants. The results from the included studies provide evidence that a wide range of technology interventions had a positive impact on shopping performance. These positive effects were seen for individuals across a wide range of ages and disability types, and for a wide variety of shopping skills. The strongest effect sizes were observed for technologies that provided visual supports rather than just auditory support. We provide an interpretation of the findings, implications of the results, and recommended areas for future research.

scholarly journals Enhanced Bilosomal Properties Resulted in Optimum Pharmacological Effects by Increased Acidification Pathways

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1184
Author(s):  
Armin Mooranian ◽  
Thomas Foster ◽  
Corina M Ionescu ◽  
Daniel Walker ◽  
Melissa Jones ◽  
...  
Keyword(s):  
Bile Acids ◽  
Biological Effects ◽  
Cellular Respiration ◽  
Full Potential ◽  
Protective Effects ◽  
Pharmacological Effects ◽  
Β Cells ◽  
Positive Effects ◽  
Wide Range ◽  
Anti Inflammatory

Introduction: Recent studies in our laboratory have shown that some bile acids, such as chenodeoxycholic acid (CDCA), can exert cellular protective effects when encapsulated with viable β-cells via anti-inflammatory and anti-oxidative stress mechanisms. However, to explore their full potential, formulating such bile acids (that are intrinsically lipophilic) can be challenging, particularly if larger doses are required for optimal pharmacological effects. One promising approach is the development of nano gels. Accordingly, this study aimed to examine biological effects of various concentrations of CDCA using various solubilising nano gel systems on encapsulated β-cells. Methods: Using our established cellular encapsulation system, the Ionic Gelation Vibrational Jet Flow technology, a wide range of CDCA β-cell capsules were produced and examined for morphological, biological, and inflammatory profiles. Results and Conclusion: Capsules’ morphology and topographic characteristics remained similar, regardless of CDCA or nano gel concentrations. The best pharmacological, anti-inflammatory, and cellular respiration, metabolism, and energy production effects were observed at high CDCA and nano gel concentrations, suggesting dose-dependent cellular protective and positive effects of CDCA when incorporated with high loading nano gel.

scholarly journals Characterization of symbiotic and associated bacteria from entomopathogenic nematode Heterorhabditis sp. (nematode: Heterorhabditidae) isolated from India

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Rashid Pervez ◽  
Showkat Ahmad Lone ◽  
Sasmita Pattnaik
Keyword(s):  
Insect Pests ◽  
Entomopathogenic Nematode ◽  
Alcaligenes Faecalis ◽  
Symbiotic Bacteria ◽  
Rrna Gene ◽  
Main Body ◽  
Associated Bacteria ◽  
Molecular Approaches

Abstract Background Entomopathogenic nematodes (EPNs) harboring symbiotic bacteria are one of the safest alternatives to the chemical insecticides for the control of various insect pests. Infective juveniles of EPNs locate a target insect, enter through the openings, and reach the hemocoel, where they release the symbiotic bacteria and the target gets killed by the virulence factors of the bacteria. Photorhabdus with Heterorhabditis spp. are well documented; little is known about the associated bacteria. Main body In this study, we explored the presence of symbiotic and associated bacteria from Heterorhabditis sp. (IISR-EPN 09) and characterized by phenotypic, biochemical, and molecular approaches. Six bacterial isolates, belonging to four different genera, were recovered and identified as follows: Photorhabdus luminescens, one each strain of Providencia vermicola, Pseudomonas entomophila, Alcaligenes aquatilis, and two strains of Alcaligenes faecalis based on the phenotypic, biochemical criteria and the sequencing of 16S rRNA gene. Conclusion P. luminescens is symbiotically associated with Heterorhabditis sp. (IISR-EPN 09), whereas P. vermicola, P. entomophila, A. aquatilis, and A. faecalis are the associated bacteria. Further studies are needed to determine the exact role of the bacterial associates with the Heterorhabditis sp.

scholarly journals Integration of early disease-resistance phenotyping, histological characterization, and transcriptome sequencing reveals insights into downy mildew resistance in impatiens

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ze Peng ◽  
Yanhong He ◽  
Saroj Parajuli ◽  
Qian You ◽  
Weining Wang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Downy Mildew ◽  
Transcriptome Sequencing ◽  
Early Stage ◽  
Economic Losses ◽  
Potential Candidate ◽  
Early Disease ◽  
True Leaf ◽  
Cotyledon Stage ◽  
Wide Range

AbstractDowny mildew (DM), caused by obligate parasitic oomycetes, is a destructive disease for a wide range of crops worldwide. Recent outbreaks of impatiens downy mildew (IDM) in many countries have caused huge economic losses. A system to reveal plant–pathogen interactions in the early stage of infection and quickly assess resistance/susceptibility of plants to DM is desired. In this study, we established an early and rapid system to achieve these goals using impatiens as a model. Thirty-two cultivars of Impatiens walleriana and I. hawkeri were evaluated for their responses to IDM at cotyledon, first/second pair of true leaf, and mature plant stages. All I. walleriana cultivars were highly susceptible to IDM. While all I. hawkeri cultivars were resistant to IDM starting at the first true leaf stage, many (14/16) were susceptible to IDM at the cotyledon stage. Two cultivars showed resistance even at the cotyledon stage. Histological characterization showed that the resistance mechanism of the I. hawkeri cultivars resembles that in grapevine and type II resistance in sunflower. By integrating full-length transcriptome sequencing (Iso-Seq) and RNA-Seq, we constructed the first reference transcriptome for Impatiens comprised of 48,758 sequences with an N50 length of 2060 bp. Comparative transcriptome and qRT-PCR analyses revealed strong candidate genes for IDM resistance, including three resistance genes orthologous to the sunflower gene RGC203, a potential candidate associated with DM resistance. Our approach of integrating early disease-resistance phenotyping, histological characterization, and transcriptome analysis lay a solid foundation to improve DM resistance in impatiens and may provide a model for other crops.

Sign in / Sign up

Export Citation Format

Share Document