افزایش اُلیگاندرین در Pythium oligandrum با به‌کارگیری سامانه‌ی CRISPR/Cas9

Pythium oligandrum is a cosmopolitan oomycete that is of universally great importance due to its antagonistic role. It seems that the antagonistic nature of P. oligandrum could be because of the existence of a protein called oligandrin. In this study, the whole genome sequencing of different P. oligandrum strains were conducted to ensure the conserved nature of this region. Oligandrin role was confirmed by knocking it out using CRISPR/Cas9 system and after knocking in a strong promoter (i.e., Ham34) at the upstream of oligandrin coding gene, its expression, and the aftereffect of these changes on the antagonistic activity of this fungus-like microorganism were examined. Morphological features, antagonistic ability, and oligandrin gene expression were studied. Morphological studies of the transformants revealed that knocking out the oligandrin gene results in the production of aborted oospores, more sporangia compared to the wild-type, decreased antagonistic ability in cross-culturing with plant pathogenic oomycetes, and finally the overall reduction in the tested plant (Nicotiana benthamiana) potential against oomycete pathogen, Phytophthora capsici. In contrast, enhancing oligandrin gene expression resulted in the production of the mutants with larger oospores and fewer sporangia compared to the wild-type strain, increased antagonistic ability in cross-culturing with plant pathogenic oomycetes and lastly, enhancement of the tested plant resistance against the aforementioned pathogen. Hence, it can be concluded that oligandrin protein would probably have a significant role in sexual and asexual structures’ formation in P. oligandrum, and therefore, by producing the sexual structures which are the major elements in biofungicide formulations against plant pathogens, has the role in antagonistic nature of this oomycete microorganism.