Determination of the pathogenic and mycoparasitic pythium species in wheat cultivation areas of eski̇şehi̇r province, their pathogenicity and enzyme activities

Wheat is one of the most important cereal species which is the main food source for about 35% of the human population. It was produced in 32% of total cultivated area and in 102 countries. Pythium species are soil-borne plant pathogens causing serious economical losses and limiting agricultural production worldwide. In this study, Pythium isolates from plant and soil samples collected in wheat fields of Eskişehir province were identified by morphological and molecular techniques and their pathogenicity and enzyme activities were investigated. A total of 219 isolates were obtained from the soil samples and classified into three morphological groups: hyphal swelling producing group, and oogonia with smooth or spiny walls producing groups. Molecular analyses confirmed the identifications of the isolates as P. heterothallicum, P. oligandrum, P. paroecandrum, P. rhizosaccharum, P. sp. hordeum, and P. ultimum var. ultimum. Among these, P. heterothallicum and P. ultimum var. ultimum reduced wheat seed germination and caused severe damping-off in the pathogenicity test. Conversely, P. oligandrum and P. paroecandrum isolates displayed low to moderate pathogenicity and exhibited mycoparasitic traits. Enzyme activity analyses revealed that P. heterothallicum had the highest cellulase, chitinase and β-1,3-glucanase activities, while P. ultimum showed high polygalacturonase activity. In dual culture and in vivo tests, mycoparasitic isolates inhibited P. ultimum growth and reduced damping-off severity when applied before the pathogens. The results support the use of biological control agents, but highlight the need for further studies to enhance their effectiveness and practical application under field conditions.