Diversidade do complexo de espécies Ralstonia solanacearum no estado de Alagoas, Brasil

Abstract

The bacterial wilt caused by species of Ralstonia solanacearum complex is considered one of the most destructive diseases in world agriculture, due to its wide geographical distribution, extensive range of hosts and difficult control. The use of resistant varieties, mainly rootstocks, is considered an efficient measure to control of bacterial wilt. However, the breakdown of resistance occurs frequently due to the high genetic and phenotypic variability found within the R. solanacearum species complex. Therefore, the genetic diversity of Ralstonia solanacearum (phylotype II) (55.3%) and R. pseudosolanacearum (phylotype I) (44.7%) were analyzed in a total of 103 isolates, obtained from symptomatic plants of banana, eggplant, pepper and tomato in the Agreste and Eastern mesoregions of the state of Alagoas, Brazil. Based on genotyping using REP markers, it was possible to observe the presence of 11 clonal lines among the 103 isolates analyzed, 22 of which were selected for sequencing of the egl gene. R. solanacearum prevailed in the Agreste mesoregion, where only isolates of sequevar IIA-6/35 were detected, which did not amplify the 220bp band specific to sequevar 6 by Mmx-PCR. R. pseudosolanacearum prevailed (53.9%) in the East mesoregion, with sequevars I-17 and I-18 being characterized. It is worth noting that R. solanacearum was also significantly found (46.1%) in this mesoregion, with the sequevars IIA-36, IIA-41, IIA-53 being identified. This is the first work that reports the diversity of the R. solanacearum species complex in the state of Alagoas, Northeast region, Brazil.