Bacterial wilt limits tomato production and resistant rootstocks could be important for the integrated management of the disease. Since there is an interaction between local bacterial strains and tomato genotype, this study aimed to evaluate 14 tomato rootstocks to bacterial wilt in the Mata mesoregion of Pernambuco state, Brazil. The rootstocks reaction to two sequevars of Ralstonia solanacearum and two of R. pseudosolanacearum was evaluated in four experiments carried out in the greenhouse using the completely randomized experimental design, with four replications composed of four plants each. Seven genotypes were selected to evaluate the reaction to bacterial wilt as rootstocks grafting in tomato plants ‘Tomini F1’ in a production area with disease history in the Chã Grande municipality, using randomized block design with four plants per treatment in each block. In the field experiment, disease symptoms were not observed in the grafted plants in ‘Guardião’, ‘Woodstock’, and ‘Yoshimatsu’. Regarding all experiments, ‘Guardião’ and ‘Muralha’ showed the best resistance levels and could be used in the integrated management of bacterial wilt and studied in plant breeding programs.

Cashew (Anacardium occidentale L.) angular leaf spot is caused by pigmented and non-pigmented strains of Xanthomonas citri pv. anacardii, which have been isolated from infected plants in Brazil. The disease symptoms may be observed in leaves, stems, and fruits. Given that infection in young fruits results in fruits unsuitable for commercialization, angular leaf spot represents a serious threat to the cashew crop in Brazil. Here, we report the genomic sequencing of seven pigmented strains of X. citri pv. anacardii, obtained from the leaves of cashew trees from São Paulo state, Brazil, in 2009. The construction of the libraries was carried out according to the manufacturer, and whole-genome sequencing was performed using the Illumina HiSeq 2500 platform. Genomes size, number of coding sequences, largest contig length, and N50 ranged from 4,996,984 to 5,003,485 bp, 4,621 to 4,643, 212,513 to 362,232, and 113,582 to 141,003. GC content and RNA numbers were 64.68% and 54 for all strains. ANIm and dDDH analyses showed values above 99.5% and 92.1% among these strains and the non-pigmented pathotype strain of X. citri pv. anacardii (IBSBF2579PT). Maximum likelihood tree built with 2,708 core genes grouped all X. citri pv. anacardii strains in the same clade, with a 100% bootstrap. These resources will contribute in a relevant way to help understand the ecological, taxonomic, evolutionary, pathogenicity, and virulence aspects of X. citri pv. anacardii, which will be useful for the study and development of techniques for managing cashew angular leaf spot.

Angular leaf spot of cashew tree in Brazil has been attributed to pigmented and nonpigmented strains of Xanthomonas citri pv. anacardii. Due to the possibility of dissemination of the disease by propagating material, it is necessary to understand the survival mechanisms of the causal agent. Thus, the present study aimed to characterize the behavior of viable but non-cultivable cells (VBNC) in two pigmented strains (CCRMTAQ13 and CCRMTAQ18) and one nonpigmented strain (IBSBF2579) of X. citri pv. anacardii, integrating in silico, in vitro, and in vivo studies. Thirteen genes associated with the VBNC phase were identified in the genomes of these strains. The log phase was observed at 24, 48, and 120 h for CCRMTAQ13, CCRMTAQ18, and IBSBF2579 strains, respectively. The death phase was observed at 96 h for both pigmented strains and 168 h for the nonpigmented strain. Using qPCR analyses, it was possible to characterize the occurrence of VBNC for the three strains. When inoculated, the strains showed 100% incidence during the VBNC phase, with the IBSBF2579 strain having the longest incubation period (IP). The strains did not differ concerning final severity (FS) in the VBNC phase. To our knowledge, this is the first report of the occurrence of the VBNC mechanism in X. citri pv. anacardii strains. Furthermore, it has been demonstrated that X. citri pv. anacardii in the VBNC state is potentially infective when they meet their host’s apoplast, which points to the need to use integrated practices to detect this bacterium in cashew seedlings.