Tilletia fungi on wheat: biological and ecological features, distribution and harmfulness

Smut fungi of the genus Tilletia are widespread and harmful pathogens of wheat all over the world. In the last decade, due to the expansion of organic farming zones, there has been an increase in their importance, which determines the need for increased attention to this problem. A review of the literature data on fungi of the genus Tilletia (T. caries, T. laevis, T. controversa), pathogens of common and dwarf bunt of wheat is presented. The biological and ecological features of pathogens, morphology of spores, symptoms of diseases and historical aspects of their study in Russia and abroad are analyzed. Phytopathological and molecular diagnostic methods for the causative agents of smut diseases of the genus Tilletia are discussed. The limitations of phytopathological diagnostics related to the morphological similarity of teliospores of the causative agents of hard and dwarf smut are shown. A critical analysis of the development of molecular approaches to identification has been carried out, from biochemical methods and analysis of conserved genetic loci (ITS, IGS, etc.) to methods of random genomic profiling (RAPD, ISSR, etc.), MALDI–TOF mass spectrometry, isoteric amplification (LAMP), and next-generation sequencing). Special attention is paid to the problem of insufficient specificity and reproducibility of many molecular methods, including SCAR markers. The analysis of the literature data is supplemented by original experiments of the germination of T. caries and T. controversa spores and the use of a SCAR marker to identify the pathogen of dwarf wheat smut.