Tubercle disease of sugar beet roots (Beta vulgaris) found in Poland is neither caused by Xanthomonas beticola nor by tumorigenic Agrobacterium/Rhizobium

Symptoms of tubercle disease known also as Xanthomonas gall were noticed in Poland in 2014–2017. Roots with disease symptoms showed the reduction of sucrose content compared to the healthy ones. In the literature, there are two gall diseases described: tubercle disease (also known as Xanthomonas gall) and crown gall, which is caused by Rhizobium radiobacter (syn. Agrobacterium tumefaciens). None of the bacterial strains isolated from the malformed tissues were identified as the bacterial pathogen responsible for causing Xanthomonas gall or crown gall. The result was confirmed by searching for the presence of T-DNA, which was not found. Our conclusion is that the tubercle disease observed in…