Nanodiagonastic methods in plant pathology are used for enhancing detection and identification of different plant pathogens and toxigenic fungi. Improvement of the specificity and efficiency of the polymerase chain reaction (PCR) by using some nanoparticles is emerging as a new area of research. In the current research, silver, zinc, and gold nanoparticles were used to increase the yield of DNA for two plant pathogenic fungi including soil-borne fungus Rhizoctonia solani and toxigenic fungus Alternaria alternata. Gold nanoparticles combined with zinc and silver nanoparticles enhanced both DNA yield and PCR products compared to DNA extraction methods with ALB buffer, sodium dodecyl sulfate, ALBfree from protinase K, ZnNPs and AgNPs. Also, by using ZnNPs and AgNPs the DNA yield was enhanced and the sensitivity of random amplified polymorphic DNA (RAPD) PCR products was increased. Application of nanomaterials in the PCR reaction could increase or decrease the PCR product according to the type of applied nanometal and the type of DNA template. Additions of AuNPs to PCR mix increased both sensitivity and specificity for PCR products of the tested fungi. Thus, the use of these highly stable, commercially available and inexpensive inorganic nano reagents open new opportunities for improving the specificity and sensitivity of PCR amplicon, which is the most important standard method in molecular plant pathology and mycotoxicology.

The root-knot nematode Meloidogyne graminicola is an economically important pest in rice production. The identification of a nematode species is an important basis in nematode management to reduce yield losses by extracting nematode DNA as an early step in molecular identification. This study aimed to investigate the optimal extraction method and number of M. graminicola for nematode genomic analysis based on PCR (polymerase chain reaction) and Sanger sequencing. The DNA extraction methods used in this study were the CTAB, SDS, and commercial kit (GeneAidTM Tissue/Blood DNA Mini Kit). The results revealed that the three DNA extraction methods could be used to analyze the nematode genomics based on PCR and Sanger sequencing using one nematode, both in a second-stage juvenile and a female, equipped with the process of nematode destruction by freezing. This finding was shown by the amplification of all DNA templates with Mg-F3 and Mg-R2 primers through PCR with a size of 370 bp, while Sanger sequencing obtained 372 bp.