THE STATE OF MOLECULAR GENETIC RESEARCH IN THE FIELD OF ORNAMENTAL WOODY SPECIES’ RESISTANCE TO POWDERY MILDEW

The review identifies the dominant deciduous species in the ornamental landscapes of the Imereti lowland (Krasnodar Territory, FT Sirius), analyzes their infestation by powdery fungi and the state of molecular genetic studies of their resistance to powdery mildew. The analysis of the genetic mechanisms of perennial woody plants’ resistance to obligate phytopathogens of fungal nature was carried out. Among deciduous foliaceous trees in the Imereti lowland, largely affected by powdery mildew Quercus hartwissiana Steven, Lagerstroemia indica L., Catalpa bignonioides Walter, Platanus acerifolia (Aiton) Willd., Morus alba L. and Fraxinus excelsior L. are widely used in landscaping of the resort area. No genetic studies have been conducted for Q. hartwissiana, but reference genomes have been obtained and studies have been performed to mapping the QTL and GWAS genes of resistance to powdery mildew for closely related species (Q. robur L. and Q. petraea (Matt.) Liebl.) Transcriptomic analysis identified more than 400 genes potentially responsible for resistance to powdery mildew (Erysiphe australiana (McAlpine) U. Braun & S. Takam.) in L. indica of susceptible (‘Carolina Beauty’) and moderately resistant (‘Natchez’) cultivars. The resistance of 24 C. bignonioides taxa to powdery mildew in closed and open ground conditions was studied, and different resistance degrees to powdery mildew were revealed. Genetics of the relationship of P. acerifolia with Erysiphe platani (Howe) U. Braun & S. Takam was underexplored, but the presence of cultivars with polar resistance is a good material for carrying out these studies. No direct studies were conducted to identify the MLO genes that determine M. alba resistance to powdery mildew, but in the East Asian species M. notabilis C.K. Schneider. 16 genes were identified as potentially responsible for resistance to the disease. The study of F. excelsior resistance genes to powdery mildew has not been conducted before. Further development of studies on deciduous trees resistance to powdery mildew should be based on the integration of the latest biotechnological and breeding approaches.