Genetic variability of Paecilomyces variotii isolates causal agent of Die-back disease using rDNA-ITS and RFLP markers

Paecilomyces variotii is one of the most important causal agents of dieback disease in pistachio (Pistacia vera) gardens. The disease affects different parts of the tree, such as branch and trunk. Assessment of genetic structure in different populations of this species will lead to more useful management of pistachio dieback disease. In this study, genetic variation within samples of P. variotii isolates from different geo-climatic origins of Kerman province was studied using ITS- RFLP analysis. Universal primer pairs AB28 and TW81 were used for ITS region amplification. Thirteen restriction enzymes were subjected to digest PCR products. Seven out of the 13 restriction enzyme including: EcoR І, Hpyf 3І, Apa І, Hinf І, Mbo І, Msp І, Rsa І showed restriction pattern. Jaccard's similarity coefficient used to determine of genetics similarity and cluster analysis dendrog was designed by using UPGMA algorithm method. Data analysis showed a high similarity at the level of 70% between isolates and all isolates were divided into 9 distinct groups. Analysis of molecular variance (AMOVA) showed a variation of 85% and 15% among of within isolates, respectively. Based on these results we can conclude that ITS-RFLP is useful for wider genetic diversity assessment and epidemiological studies of distantly related isolates. The future studies could be performed to develop new molecular markers to detect this fungus in field.