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A survey to investigate the occurrence of cassava anthracnose disease (CAD) and distribution of Colletotrichum spp. in cassava plantations in different eco-zones of the Reconcavo Region in Bahia, Brazil, investigated during the rainy season of 2014. A total of 50 cassava fields distributed among 18 municipalities were visited and intensity of anthracnose evaluated. The highest disease incidence (DI) (83.3%) was in samples collected in São Félix, and the lowest (34.4%), in Varzedo. Municipalities that presented the highest values for DI were located within the 'Af' Köppen-Geiger eco-zone, also presenting the highest values for the estimated McKinney disease index. Based on previous studies of multilocus phylogeny, seven different species of Colletotrichum were identified (Colletotrichum fructicola, Colletotrichum tropicale, Colletotrichum gloeosporioides s.s, Colletotrichum theobromicola, Colletotrichum siamense, Colletotrichum brevisporum and Colletotrichum plurivorum) and a new approach based on ERIC-PCR was used aiming to group the 82 isolates according to these findings. The highest percentage of genetic variance (> 78%) was among isolates within fields. Based on the survey and genetic analysis, C. fructicola is probably the main causal agent of cassava anthracnose in the Recôncavo Region, since this species was present with highest incidence in all eco-zones, 47.61, 42.86 and 57.14% for Af (tropical rainforest climate), As (tropical dry savanna climate) and Aw (tropical wet savanna climate), respectively. This study is the first report of C. fructicola lineages as the most likely pathogen causing anthracnose disease of cassava in Brazil, and these findings may be used to guide the selection of resistant varieties.

Several molecular techniques have been used to differentiate species or genetic lineages of microorganisms prior to sequencing. Among them, BOX-and ERIC-PCRs may provide specific banding patterns for different species, allowing its differentiation.Therefore, the objective of this study was to evaluate these techniques as a tool for differentiation of phylogenetic lineages belonging to the Colletotrichum gloeosporioides species complex associated with cassava anthracnose disease. Sets of BOX-and ERIC-PCR primers were used to assess the differentiation of lineages belonging to the complex with 81 C. gloeosporioides sensu lato (s.l.) isolates from different cassava producing regions. Some were identified by sequencing, such as Colletotrichum fructicola, Colletotrichum tropicale, C. gloeosporioides s.s, Colletotrichum theobromicola, Colletotrichum siamense, Colletotrichum brevisporum and Colletotrichum sichuanensis.The primers were able to amplify DNA fragments from all isolates. The ERIC-PCR presented a wider range of banding patterns in comparison to BOX-PCR, providing better differentiation of the individuals, as well as a higher correlation with the phylogenetic data was obtained by ERIC-PCR and the combined data set for "BOX-/ ERIC-PCRs," inferred by Mantel test. However, the use of concatenated data (BOX-/ ERIC-PCRs) reduced the discriminatory capacity presented by ERIC-PCR alone, probably due to the lowest resolution of BOX-PCR. Therefore, ERIC-PCR technique enabled efficient differentiation of isolates belonging to the C. gloeosporioides complex and can be used to analyse multiple isolates in a collection and also being an important tool as a guide in the decision-making process prior to sequencing. Based on this methodology, it was possible to identify two new species associated with cassava anthracnose disease, C. brevisporum and C. sichuanensis, being the first report of these two species associated with cassava anthracnose disease in Brazil. K E Y W O R D SColletotrichum spp., DNA fingerprint, Rep-PCR, species complex | 219 LOPES SILVA Et AL.

The biological nitrogen fixation constitutes a strategy to accelerate soil reclamation and the symbiotic systems Rhizobium-legume is the major N2-fixing in which the enzyme carboxymethyl cellulase plays a key role. As many rhizobia species are cellulase negative, the association with cellulolytic bacteria can be a strategy for the recovery of degraded ecosystems. It has been hypothesized that the sharing of resources should mostly be prevalent among phylogenetically and metabolically different species. Accordingly, twenty-seven actinobacteria isolates from Actinobacteria phyla and twenty-six rhizobia isolates from Proteobacteria phyla were selected from the bacterial collection of the Laboratory of Environmental Microbiology of the Federal University of Ceará. The presence of cellulolytic activity was observed for the rhizobia isolates at 28 °C and for actinobacteria isolates at 28, 39, 41, 43 and 45 °C. Rhizobia isolates deficient in cellulase and actinobacteria isolates with enzymatic activity detected at higher temperature were selected and characterized. The antagonism between isolates of two groups was tested and the pairs antagonistic were eliminated. The cross-feeding test between actinobacteria and rhizobia isolates was realized in a chemically defined medium containing carboxymethyl-cellulose as the only carbon and energy source. Growth of rhizobia strains in 50% of the pairwise indicated that the cellulose hydrolyzed by actinobacteria was used as substrate for the growth of the rhizobia. The Bradyrhizobium strain R10 associated with Streptomyces strains A09 and A18 and Nocardia A11 are promissory inoculants for recovery of semi-arid regions.