Exploring combined effect of elevated CO2 and temperature on Fusarium wilt development of chickpea

Fusarium wilt (FW) caused by Fusarium oxysporum f. sp. ciceris (Foc) is one of the major diseases in chickpea. Under changing climatic scenario, elevated CO2 (eCO2) (550 and 700 ppm) and temperature (25°C, 30°C and 35°C) have potential impact on plant resistance mechanisms and pathogen virulence. Hence, the present study was aim to assess the impact of eCO2 and temperature on FW incidence and disease progression in two chickpea cultivars, JG 62 (susceptible) and WR 315 (resistant). Irrespective of temperature, the incubation period was delayed in eCO2 when compared to ambient. In case of combined effect, the maximum disease incidence was found in 30°C combined with 700 ppm as well as ambient CO2 conditions. To quantify the pathogen load and expression of several defence responsive genes in chickpea and virulence-related genes in Foc, qPCR study was employed. As compared to the eCO2, the expression of defence and virulence response genes in chickpea inoculated seedlings was highly up-regulated in ambient CO2 conditions irrespective of temperatures. The results suggested that among different defence-related genes studied, peroxidise gene was highly expressed in WR 315 cultivar, there by restricting the Foc colonization, by providing an evidence of efficient defense mechanism in the resistant cultivar. Moreover, in JG 62 the pathogenicity-causing secreted in xylem (SIX 14) gene was highly expressed as it mainly helps in colonization of Foc by defeating its defense in susceptible cultivar, which helps in providing more insights in understanding the compatible and incompatible interactions between chickpea and Fo

Exploring combined stress incited disease dynamics of chickpea x dry root rot interation

Dry root rot (DRR) of chickpea caused by Rhizoctonia bataticola (Rb) has become an emerging threat to chickpea production. Under field conditions, the disease becomes highly aggressive, coincides with higher temperatures and decrease in soil moisture content (SMC). Thus establishing a sound relation between various climatic factors and DRR is necessary to design a rational strategy for combating this disease. Hence, the present study aims to quantify the roles of temperature, soil moisture and Rb as combined stress for causing infection and subsequent disease progression in chickpea. The results proved that a significant relationship exists between the biotic and abiotic elements in predisposing chickpea to DRR. Out of two temperatures (25°C and 35°C) and two soil moisture content (60% and 80% SMC) tested, the combination of high temperature (35°C) and low SMC (60%) was successful in inciting early disease symptoms in the chickpea cultivars tested. The disease severity based on percent susceptibility index (derived from modified 0-9 rating scale) and percent loss in root biomass also provided similar insights, where plants grown under the above combination displayed higher degree of root rot than the combination of low temperature (25°C) and high SMC (80%). A high positive correlation was observed between disease severity, temperature at 35°C and SMC at 60%, whereas, a negative correlation was realized for temperature at 25°C and SMC at80%. Results of the real-time qPCR based absolute quantification for fungal propagules present in the root tissues sampled at different time points also corroborated with the above finding

Synthesis of isopongaflavone

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Evaluation of bupirimate against rose powdery mildew

Bupirimate 25% Emulsifiable concentrate (EC) was evaluated for efficacy on Sphaerotheca pannosa, the causal agent of rose powdery mildew in vivo. In this experiment Bupirimate 25% EC 6 ml/L and 4 ml/L effectively reduced the powdery mildew infection over rest of the treatments and improved the flower yield. Moreover, application of Bupirimate 25% EC at the doses of 2, 4 and 6 ml/L and even at higher dose 8 ml/L did not show any phyto-toxic symptoms on rose plant. Thus, Bupirimate 25% EC may be considered as compared to other fungicides

Diagnostic Techniques of Soil Borne Plant Diseases: Recent Advances and Next Generation Evolutionary Trends

All about 80000 diseases have been recorded in plants throughout the world, of them majority are associated with soil-borne diseases. Early, speedy and reliable detection of plant pathogens is prerequisite to optimize suitable and accurate management strategy. Traditionally, the most prevalent techniques used to identify plant pathogens relied upon culture-based morphological approaches; these methods were laborious, time-consuming. Molecular detection strategies could solve these limitations with improved accuracy and reliability. The DNA and protein based pathogen detection techniques such as DNA fingerprinting, biochemical assays, isothermal amplification techniques and serology are gaining importance in rapid soil borne pathogen detection due to their high degree of specificity to distinguish closely related organisms at different taxonomic levels. Here, we review the various molecular tools used for detection of several soil borne plant pathogens and its implementation in agriculture

Catalysing the host plant resistance: An insight into phyto-hormone mediated ISR against dry root rot of chickpea

Dry root rot (DRR) of chickpea caused by Rhizoctonia bataticola has become a serious concern to chickpea production. Changing climatic elements like frequent low soil moisture stress and high temperature are among the probable factors increasing DRR incidence in chickpea. Management of the DRR is challenging, owing to its wide host range, lack of resistant sources and uneconomical chemical control measures. Therefore, an alternate resistance management approach against this disease may be achieved by exploitation of host plant resistance through phyto-hormone mediated induced systemic resistance (ISR). The present study aims to identify the role of phyto-hormones in inducing systemic resistance against chickpea DRR. Two Phytohormones Methyl Jasmonic Acid (MeJA) and Salicylic Acid (SA) were used in this study to induce systemic resistance (ISR) against DRR. Of them MeJA was proved to be a robust in playing vital role in inducing resistance against targeted pathogen. The disease severity based on per-cent disease susceptibility index (derived from modified 0-9 rating scale) showed that plants treated with MeJA 50ppm displayed lower degree of DRR severity than the other subtreatments viz., MeJA at 25ppm and 75ppm. Also, the fungal propagule concentrations present in the root tissues sampled at different time points were analogous with theabove findings. A high positive correlation was observed in the results from real-time qPCR based absolute quantification

Diffusion with rearranging traps

A model for diffusion on a cubic lattice with a random distribution of traps is developed. The traps are redistributed at certain time intervals. Such models are useful for describing systems showing dynamic disorder, such as ion-conducting polymers. In the present model the traps are infinite, unlike an earlier version with finite traps, this model has a percolation threshold. For the infinite trap version a simple analytical calculation is possible and the results agree qualitatively with simulation.Comment: Latex, five figure

Biological Control as a Tool for Eco-friendly Management of Plant Pathogens

Crop protection is pivotal to maintain abundant production of high quality. Over the past 100 years, use of chemical fertilizers and pathocides and good agronomical practices enabled growers to maintain improved crop productivity. However, extensive use of chemicals during the last few decades in controlling pests and diseases resulted in negative impacts on the environment, producing inferior quality and harming consumer health. In recent times, diverse approaches are being used to manage and/or mitigate a variety of pathogens for control of plant diseases. Biological control is the alternative approach for disease management that is eco-friendly and reduces the amount of human contact with harmful chemicals and their residues. A variety of biocontrol agents including fungi and bacteria have been identified but require effective adoption and further development of such agents. This requires a better understanding of the intricate interactions among the pathogen, plants and environment towards sustainable agriculture. Beyond the field assessment, the analysis of microbial communities with culture-independent molecular techniques including sequencing technologies and genomics information has begun a new era of plant disease management