Agrobacterium tumefaciens-mediated introduction of polygalacturonase inhibiting protein 2 gene (pvpgip2) from Phaseolus vulgaris into sugar beet (Beta vulgaris L.)

Sugar beet (Beta vulgaris L.) is an important industrial crop, the yield of which is strongly affected by numerous diseases caused by fungal pathogens. To the aim of developing transgenic plants resistant to fungi, two transgenic diploid sugar beet genotypes expressing the gene encoding the polygalacturonase inhibiting protein 2 of Phaseolus vulgaris (PvPGIP2) were generated by Agrobacterium tumefaciens-mediated transformation. PGIPs are plant cell wall leucine-rich repeat (LRR) proteins that bind to and inhibit fungal polygalacturonase (PG), thus slowing down the plant cell wall degradation and limiting fungal colonization of the plant tissues. Leaf blade explants carrying the bases of regenerated shoots, a highly regenerative tissue, were used for transformation. PCR screening using specific primers showed the presence of the transgene in more than 40% of the regenerated kanamycin-resistant plants. A transformation rate of 4.4-4.2% (depending on the genotype) was achieved as revealed by agarose diffusion assay of the PvPGIP2 activity in the crude protein extracts of shoot tissues. The intact integration of the transgene cassette into the genome was confirmed by Southern blot analysis. The inhibitory activity against Fusarium phyllophilum polygalacturonase (FpPG) was found at various levels in several transgenic plants. No alterations of growth and development of the transgenic plants were observed.