Detection of Fungal Pathogens in the Environment

Abstract

The presence of fungal pathogens in the environment has to be detected and also quantified rapidly and precisely, because the inoculum for infection of crop plants comes from the pathogen propagules present in the soil, water, air and alternative host plant species. Soilborne pathogens may have different degrees of saprophytic ability, utilizing the organic matter present in the soil for their survival in the absence of crop plants. They produce different structures such as chlamydospores and sexual spores that are long-lived and are capable of surviving in the soil for several years. Fungal structures may be carried by irrigation water or rain water from one part of the field to other parts or to different fields. It has been possible to detect and identify the fungal pathogens in the irrigation water, recycled water used for growing hydroponic plants and also in wash water in the storage facilities for fruits and vegetables. The pathogens infecting aerial plant parts/organs are generally disseminated by wind to different locations. Traditionally spore traps have been used for assessing the spore load of air. Various biological, immunological and nucleic acid-based techniques have been employed for the detection, identification and quantification of pathogen propagules in the environment. Significant improvements have been made in the sensitivity and specificity of detection of fungal pathogens by applying immunoassys and nucleic acid-based methods that are capable of providing reproducible results rapidly and reliably. The relative usefulness and limitations of the detection techniques applied for the detection of fungal pathogens in the environment are discussed.Studies on the ecology of plant hosts provide information on the influence of environment on the growth and development of plants. Likewise, the influence of the environment on the microbial plant pathogens is studied to understand the extent of population build up resulting in the incidence of diseases in different agroecological conditions. Crop husbandry techniques aim to increase the crop yield to the maximum levels. But some of these techniques like monoculture and excessive application of nutrients may provide favorable conditions for pathogen development. Epidemiology deals with effects of biotic and abiotic environments on disease development in plant populations. Microbial pathogens multiply at different rates in a given set of environmental conditions and exhibit wide variations in their pathogenic potential (aggressiveness). The crop plants also have varying growth

Global Ramifications of Dust and Sandstorm Microbiota

“…Long distance dissemination of airborne Puccinia spores by winds, for example, were responsible for the crop stem rust in the North American continent ( Eversmeyer and Kramer 2000 ), the wheat leaf rust in the Indian subcontinent ( Nagarajan and Singh 1990 ), the sugarcane rust, stem rust, and stripe rust across different continents ( Watson and De Sousa 1983 ; Purdy et al. 1985 ; Wellings and McIntosh 1990 ), and the loss of the cereal crops worldwide ( Narayanasamy 2011 ). Other important fungal crop pathogens such as Hemileia vastatrix causing the coffee leaf rust ( Bowden et al.…”

Specific and Sensitive Detection of Phytophthora nicotianae by Nested PCR and Loop‐mediated Isothermal Amplification Assays

“…Phytophthora nicotianae is a common and destructive pathogen of numerous agronomic and horticultural crops, such as tobacco, tomato and citrus. It can cause fruit and foliar blights, as well as root, stem and crown rot in many plants (Erwin and Ribeiro ; Narayanasamy ). Symptoms of the diseases develop rapidly in many hosts during periods of high soil moisture associated with prolonged rainy weather or frequent irrigation.…”