Advancing crop disease resistance through genome editing: a promising approach for enhancing agricultural production

Modern agriculture has encountered several challenges in achieving constant yield stability especially due to disease outbreaks and lack of long-term disease-resistant crop cultivars. In the past, disease outbreaks in economically important crops had a major impact on food security and the economy. On the other hand climate-driven emergence of new pathovars or changes in their host specificity further poses a serious threat to sustainable agriculture. At present, chemical-based control strategies are frequently used to control microbial pathogens and pests, but they have detrimental impact on the environment and also resulted in the development of resistant phyto-pathogens. As a replacement, cultivating engineered disease-resistant crops can help to minimize the negative impact of regular pesticides on agriculture and the environment. Although traditional breeding and genetic engineering have been instrumental in crop disease improvement but they have certain limitations such as labour intensity, time consumption, and low efficiency. In this regard, genome editing has emerged as one of the potential tools for improving disease resistance in crops by targeting multiple traits with more accuracy and efficiency. For instance, genome editing techniques, such as CRISPR/Cas9, CRISPR/Cas13, base editing, TALENs, ZFNs, and meganucleases, have proved successful in improving disease resistance in crops through targeted mutagenesis, gene knockouts, knockdowns, modifications, and activation of target genes. CRISPR/Cas9 is unique among these techniques because of its remarkable efficacy, low risk of off-target repercussions, and ease of use. Some primary targets for developing CRISPR-mediated disease-resistant crops are host-susceptibility genes (the S gene method), resistance genes (R genes) and pathogen genetic material that prevents their development, broad-spectrum disease resistance. The use of genome editing methods has the potential to notably ameliorate crop disease resistance and transform agricultural practices in the future. This review highlights the impact of phyto-pathogens on agricultural productivity. Next, we discussed the tools for improving disease resistance while focusing on genome editing. We provided an update on the accomplishments of genome editing, and its potential to improve crop disease resistance against bacterial, fungal and viral pathogens in different crop systems. Finally, we highlighted the future challenges of genome editing in different crop systems for enhancing disease resistance

Thermoelectric Properties of Oxide Semiconductors

In this chapter, we have explored the potential of oxide semiconductors for thermoelectric power generation. Various oxides (Cu2InO4, CuAlO2, and Zn2GeO4) were grown on Si substrate by thermal evaporation method using tube furnace. After the growth, a representative sample of each oxide was cut into pieces and was annealed at various temperatures from 600 to 800°C in oxygen environment for 1 h using a programmable furnace. The structure of all annealed sample was verified by performing X-ray powder diffraction (XRD) measurements. XRD data suggested that all oxide materials show crystalline behavior at annealing temperature 800°C. XRD results further confirmed that crystal structure of investigated samples improved significantly with annealing because the intensity of oxygen-sensitive (0 0 6) plane was found to be increased with annealing temperature. To investigate the thermoelectric properties of annealed samples, Seebeck effect and Hall effect measurements were performed in the temperature range 25–100°C. It was found that the value of Seebeck coefficient and power factor increased as the annealing temperature increases. Zn2GeO4 was found to be a potential thermoelectric material because it has the highest value of Seebeck coefficient and power factor. This highest value is related to the presence of secondary phases in this oxide

Virus Disease (Indian Journal of Virology)

Not AvailableFor breeding resistant cultivars, understanding the nature and distribution of PVY strains is indispensable. In present study, during the course of survey two hundred potato samples showing symptoms of vein clearing, mosaic, stunting, mottling, curling and vein banding were collected from 4 major potato growing districts of Kashmir valley. The disease incidence ranged from 16 to 27.33% with maximum in district Srinagar (27.33%). All the samples were serologically tested for PVY infection using DAS-ELISA and 74 tested positive for PVY infection. Out of 74 positive samples forty samples were re-confirmed by RT-PCR by amplifying 900 bp using coat protein (CP) gene specific primers. The PCR-positive samples were further characterized into different strains using strain specific primers. The strains NTN, N and O were reported and among them NTN strain was found to be most prevalent throughout the valley. The phylogenetic analysis of selected isolates carried out with known PVY strains also confirmed that the isolates belong to the N, NTN and O strains of PVY. The study will help in developing point of care strain specific diagnostics and also in devising the strategy for developing PVY resistant varieties, because when we have the complete information about the virus and its strains it will help us in screening the germplasm against each strain and, therefore, eventually development of a multi-strain resistant variety

Molecular Biology Reports

Not AvailableBakanae is the emerging disease threating the rice cultivation globally. Yield reduction of 4?70% is recorded in different parts of the world. A total of 119 Fusarium isolates were collected from rice plants at different geographical locations and seeds of different rice cultivars. The isolates were evaluated for morphological, biochemical and pathogenic diversity. The amplification of TEF-1? gene was carried out for exploring the species spectrum associated with the cultivated and pre-released rice varieties. The production of gibberellin varied from 0.53 to 2.26 ?g/25 ml, while as that of Indole acetic acid varied from 0.60 to 3.15 ?g/25 ml among the Fusarium isolates. The phylogenetic analysis identified 5 different species of the genus Fusarium viz. Fusarium fujikuroi, F. proliferatum, F. equiseti, F.oxysporum and F. persicinum after nucleotide blasting in NCBI. Only two Fusarium spp. F. fujikuroi and F. proliferatum were found to be pathogenic under virulence assays of the isolates. The isolates showed a considerable variation in morphological and pathogenic characters. The isolates were divided into different groups based on morphology and pathogenicity tests. The isolates showed a considerable variation in morphology, phytohormone profile and virulence indicative of population diversity. Three species F. equiseti, F.oxysporum and F. persicinum which have not been reported as pathogens of rice in India were found to be associated with bakanae disease of rice, however their pathogenicity could not be established

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Not AvailablePreharvest fruit drop (PFD) is an important cause of fruit loss in apple industry and has been a recognized as severe problem in apple production for many years. Pre harvest fruit drop (PFD) in which fruits are shed from the tree before ripening phase prior to horticultural maturity can occur in several apple cultivars. The severity of drop is cultivar specific and cultivars have been categorized according to propensity to drop: less prone, intermediate and more prone. Studies in the early part of the 20th century were concerned with the physiology of fruit abscission as it occurred in the orchard. However, with the discovery of plant bio regulating chemicals (PBRs), the research priorities changed drastically from physiology of abscission to the efficacy of PGRs. The discovery of the abscission delaying properties of PBRs with auxin-like activity opened the new vistas for the development of chemical horticultural tools to reduce preharvest drop losses. Since the use of stop-drop materials became a common practice, research on preharvest apple fruit abscission has focused on development of better ways to use chemicals with commercial registrations. Unfortunately, chemicals used as horticultural tools have limited life spans and are primarily governed by regulatory and economic variables which are outside the control of apple growers.Not Availabl

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Not AvailableClimate change is the biggest threat to mankind, affecting agriculture due to 0.74C average global increase in temperature in the last 100 years and atmospheric CO2 concentration rise from 280 ppm in 1750 to 400 ppm in 2014-15. Such changes pose a drastic influence on the growth and cultivation of the different crops on the Earth as global food production must increase by 50% to meet the projected demand of the world’s population by 2050. Simultaneously, these changes will also affect the reproduction, spread and severity of many plant pathogens, thus posing a threat to our food security. Pest and disease management has played its role in doubling food production in the last 40 years, but pathogens still claim 10–16% of the global harvest. Integrated solutions and international co-ordination in disease management strategies should be reoriented under changing climatic conditions with amalgamation of new strategies for sustainable food production and food security.Not Availabl

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Not AvailableIrigenin belongs to family of isoflavonoids, isolated from Iris Plant of Kashmir Himalaya. A rapid and specific reverse phase high pressure chromatography (RP HPLC) method for quantitative analysis of irigenin in the different species of Iris Plant was developed. The samples were analyzed on RP-C18 e column (chromolith, 5µm, 4.6×100 mm). The HPLC system was operated at ambient temperature (±30c). The mobile phase consisted of methanol: water. The detecting wavelength at 260 nm and flow rate of 0.6 ml/min. The standard irigenin was diluted using the mobile phase at a known concentration of 1mg/ml; the sample was filtered through sample filter of 0.45 µ pore size. The filtrate was introduced on to a reverse phase analytical column. The content of irigenin in the different species of Iris Plant was determined. The HPLC showed an excellent performance in separating the irigenin in different species of Iris Plant. Furthermore, the antipathogenic activity. The test compound at each respective concentration was found to be statistically superior against scab. Furthermore, the test compound @ 5000 ppm proved significantly most effective by providing (82.49%) inhibition in the mycelia growth of apple scab. It was followed by fusarium (77.27%) at 5000 ppm. Lowest reduction in mycelia growth (65.78%) was recorded in marssonina and did not differ significantly from Alternaria (67.47%) at 5000 ppm. Furthermore, lowest inhibition of mycelia growth was recorded at 1000 ppm. Similar trend was recorded for rest of the pathogens i.e. highest reduction at 5000 ppm, lowest at 1000 ppm and at 2000, 3000 and 4000 ppm it ranges between the first two but increases with increase in concentration. From this study irigenin is potent compound which can be used for controlling the growth of respective pathogens.Not Availabl