Soil Pathogens Detection And Soil Fungi Distribution In Soil

Soliborn plant pathogens can significatntly reduce yield and quality in crops, which causes great economic loses every year. The traditional methods for detect and identificate of the pathogen is by cultural based isolation, microscopic observation and morphological identification. These methods are difficult and time consuming, typically taking three weeks or longer to accomplish.Watermelon is an important horticulture and garden crop around the world, Fusarium wilt of watermelon is cuased by Fusarium oxysporum, is a destructive disease in watermelon cultivation. While one of the most important root diseases of cool-season turf grasses Poa and Fescuta, is summer patch, which is caused by the root-infecting fungus Magnaporthe poae, The disease was once considered a component of Fusarium blight until1984. Compared to the traditional isolation, culture, plate screening and counting method for identification and detection of pathogens, the two above-described methods are accurate, instant and time saving.Until now, there are several ways to control the pathogen grows, such as fungicides application, screen resistant genotype plant, bio-control and so on. Fungicide application is one of the most popular method for prevent disease development. The stability of soil microbial communities and resilience of physical and chemical disturbances are important indicators for soil ecosystems health and balance. However, soil fungal communities and their dynamics changes were investigated in relation to physical and chemical manners.SYBR Green I real-time PCR and Macroarray methods were used to perform quick check and quick quantification of Fusarium oxysporum in soils infected with watermelon wilt disease, and their usage was optimized and studied in lab. Results show that in rhizospheric soils, treatments N-+P-severely infected with the disease, the Macroarray System detected strong positive signals, indicating that Fusarium oxysporum f.sp.niveum existed in these soils in large quantity. In the rhizosphere soil; the real-time PCR method showed that the number of Fusarium oxysporum f.sp. niveum in the treatment N-+P-was8.89×105dRng-1soil, while in the treament N++P+was decreased to3.28X103dRng"1soil. In the bulk soil; the real-time PCR method result indicated that the number of Fusarium oxysporum f.sp.niveum in the treatment N-+P-was1.50×103dRng-1soil, in the treatment N+ +P+decreased to0.45×103dRng"-soil, and the Macroarray System didn’t detect any strong positive signals. PCR-DGGE and cloning methods were used to investigate the fungi diversity of bio-organic fertilizer added Fusarium wilt rhizosphere and bulk soil, the results showed that the fungi diverisity of four treatment is N-+P-<N-+P+<N++P-<N++P+, it’s mean that the fungi diversity and richness was enhanced after bio-organic fertilizer added in both nursery and pot, the fungi is more diverse in the rhizosphere soil than bulk soil.A culture-independent TaqMan real-time PCR assay was developed for the detection of M. poae from the roots of fungicide treated and non-treated Kentucky bluegrass(Poa pratensis). The assay was validated with the target pathogen, closely related fungal species, and a number of other microorganisms that inhabit the same host and soil environment. This TaqMan real-time PCR assay was more sensitive, rapid, and accurate. Cultural dependent and independent techniques (molecular cloning, DGGE, Illumina Genome sequencing approach) were used to investigate the rhizosphere and bulk soil fungal communities of Azoxtrobin and Fenarimol treated Magnaporthe poae infected Poa pratensis L.(Kentucky bluegrass) rhizosphere and bulk soil. The data showed that two fungicides had impact on soil fungi communities and fenarimol had more impact on rhizosphere soil fungal communities. Illumina metagenomic sequencing provided more reads and more fungal diversity than culture or molecular cloning methods21vs1040genera in turfgrass rhizosphere soil. Many of the fungi which isolated by cultural dependent or molecular cloning library methods can be found in our assembled Illumina metagenomic sequencing data. Illumina Genome Analyser (GA) technology is more informative, accretive and reads of which can captures more species when compared to other three methods. After Fenarimol treated, there were7Family,152Genus,200Species disappeared in the rhizosphere soil.