ABSTRACT. The present work aimed characterize isolates of C. lindemuthianum race 65 from different regions in Brazil by ITS sequencing. A total of 17 isolates of race 65, collected in the states of Mato Grosso, Minas Gerais, Paraná, Santa Catarina and São Paulo, were studied. Analysis of the sequences of isolates 8, 9, 12, 14 and 15 revealed the presence of two single nucleotide polymorphisms (SNPs) in the ITS1 region at the same positions. These isolates, when analyzed together with the sequence of isolate 17, revealed a SNP in the ITS2 region. The highest genetic dissimilarity, observed between isolates 11 and 3 and between isolates 11 and 10, was 0.772. In turn, isolates 7 and 2 were the most similar, with a value of 0.002 for genetic distance. The phylogenetic tree obtained based on the sequences of the ITS1 and ITS2 regions revealed the formation of two groups, one with a subgroup. The results reveal high molecular variability among isolates of race 65 of C. lindemuthianum.Keywords: anthracnose, genetic variability, pathogens, dissimilarity.Caracterização da raça 65 de Colletotrichum lindemuthianum utilizando sequenciamento das regiões ITS RESUMO. O presente trabalho teve como objetivo caracterizar isolados de C. lindemuthianum da raça 65 provenientes de diversas regiões do Brasil, por meio de sequenciamento de regiões ITS. Um total de 17 isolados da raça 65, coletados nos estados do Mato Grosso, Minas Gerais, Paraná, Santa Catarina e São Paulo, foram estudados. As análises das sequências dos isolados 8, 9, 12, 14 e 15 revelaram a presença de dois SNPs na região ITS1 nas mesmas posições. Estes mesmos isolados quando analisados juntamente com a sequência do isolado 17 apresentaram um SNP na região ITS2. A maior dissimilaridade genética foi de 0,772 observada entre os isolados 11 e 3 e entre os isolados 11 e 10. Por sua vez, os isolados 7 e 2 foram os mais similares, com valor de distância genética de 0,002. A árvore filogenética obtida com base nas sequências das regiões ITS1 e ITS2 revelou a formação de dois grupos, sendo um com a divisão de um subgrupo. Estes resultados revelam uma elevada variabilidade molecular entre isolados da raça 65 de C. lindemuthianum.

Colletotrichum lindemuthianum is the causal agent of anthracnose in common bean. Favorable conditions for this disease might result in up to 100% yield losses. One of the main challenges for common bean producers and breeders still remains the management disease, since this pathogen exhibits a wide genetic variability probably due to its recombination sexual reproduction. The 5·8S gene and the flanking internal transcribed spacer regions (ITS1 and ITS2) of 40 different isolates of C. lindemuthianum collected in Brazil were amplified by PCR, and sequenced in order to determine genetic variability. The results revealed that 46.88% of SNPs were detected in the ITS1 region, while 53.12% of them were located in the ITS2 region. The genetic distance ranged from 0.000 to 0.169 between races. The greatest distance was observed between the races 10 and 73 with a value of 0.169, indicating a wide genetic variability between them. The phylogenetic tree was composed of three groups. Group I had five subgroups. Similar results were also observed through population structure analysis, which revealed the presence of three clusters. These results suggest that sequence analysis of ITS rDNA regions of C. lindemuthianum may be a valuable tool to identify this pathogen through design of specific primers.

Anthracnose, which is caused by the fungus Colletotrichum lindemuthianum, is one of the most widespread and important diseases of the common bean (Phaseolus vulgaris L.) in the world. The objective of the present study was to characterize the genetic resistance of the Beija Flor cultivar by inheritance and to conduct allelism tests. The inheritance test was conducted in the F2 population derived from the Beija Flor (resistant) x TU (susceptible) cross inoculated with race 2047 of C. lindemuthianum. Furthermore, allelism tests exhibited a fitted segregation ratio of 15R:1S, thereby indicating the independence of the Beija Flor gene from the following previously characterized genes: Co-1, Co-2, Co-4, Co-42, Co-6, Co-12, Co-14, Co-15, and Co-Pe. Based on the aforementioned results, we are proposing the symbol Co-Bf to designate the new anthracnose resistance gene in the Brazilian Andean common bean cultivar Beija Flor. This cultivar is an important source of resistance to C. lindemuthianum that should provide a valuable contribution to the common bean breeding program for anthracnose resistance.

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