[Polymorphism of KPI-A genes from plants of the subgenus Potatoe (sect. Petota, Estolonifera and Lycopersicum) and subgenus Solanum].

Kunitz-type proteinase inhibitor proteins of group A (KPI-A) are involved in the protection of potato plants from pathogens and pests. Although sequences of large number of the KPI-A genes from different species of cultivated potato (Solanum tuberosum subsp. tuberosum) and a few genes from tomato (Solanum lycopersicum) are known to date, information about the allelic diversity of these genes in other species of the genus Solanum is lacking. In our work, the consensus sequences of the KPI-A genes were established in two species of subgenus Potatoe sect. Petota (Solanum tuberosum subsp. andigenum--5 genes and Solanum stoloniferum--2 genes) and in the subgenus Solanum (Solanum nigrum--5 genes) by amplification, cloning, sequencing and subsequent analysis. The determined sequences of KPI-A genes were 97-100% identical to known sequences of the cultivated potato of sect. Petota (cultivated potato Solanum tuberosum subsp. tuberosum) and sect. Etuberosum (S. palustre). The interspecific variability of these genes did not exceed the intraspecific variability for all studied species except Solanum lycopersicum. The distribution of highly variable and conserved sequences in the mature protein-encoding regions was uniform for all investigated KPI-A genes. However, our attempts to amplify the homologous genes using the same primers and the genomes of Solanum dulcamarum, Solanum lycopersicum and Mandragora officinarum resulted in no product formation. Phylogenetic analysis of KPI-A diversity showed that the sequences of the S. lycopersicum form independent cluster, whereas KPI-A of S. nigrum and species of sect. Etuberosum and sect. Petota are closely related and do not form species-specific subclasters. Although Solanum nigrum is resistant to all known races of economically one of the most important diseases of solanaceous plants oomycete Phytophthora infestans aminoacid sequences encoding by KPI-A genes from its genome have nearly or absolutely no differences to the same from genomes of cultivated potatoes involved by P. infestans.