INTRODUCTION: Common bean anthracnose, caused by the fungus Colletotrichum lindemuthianum is one ... more INTRODUCTION: Common bean anthracnose, caused by the fungus Colletotrichum lindemuthianum is one of the most important diseases of this crop. However, another disease that has caused damage to common bean crop is the scab that Colletotrichum truncatum has been reported as causal agent. Strains isolated from anthracnose and scab lesions have been investigated in recent years and strains of Glomerella spp. (teleomorphic form) and Colletotrichum spp. (anamorphic form) have been obtained and identified by morphological, cytological, molecular and pathogenic analyses (Barcelos et al., 2014; Mota et al., 2016). Barcelos et al. (2014) classified Glomerella sp. strains from anthracnose lesions in two distinct groups, group I and II. Group I strains did not cause symptoms in common bean and amplified for the HMGGlo primer, specific for G. cingulata (Barcelos et al., 2011) and did not amplified by the HMGCl primer, specific for C. lindemuthianum (Garcia-Serrano et al., 2008). On the other han...
Evaluations by artificial inoculation of different races of Colletotrichum lindemuthianum can be ... more Evaluations by artificial inoculation of different races of Colletotrichum lindemuthianum can be unfeasible in a breeding program aiming at obtaining cultivars with durable resistance to anthracnose in common bean, since many physiological races have already been found. An alternative would be the use of mixtures of different races. However, information is scarce about the efficiency of this method to select resistant plants and to evaluate the virulence of the pathogen. Thus, the objective of this work was to demonstrate the feasibility of using mixtures of C. lindemuthianum races in breeding programs aiming at the development of common bean cultivars with resistance to anthracnose. Two experiments were carried out, in which races 65, 73 and 81 of C. lindemuthianum were inoculated individually and in a mixture of the three races (M1), and also mixtures of first (M2 and M3) and second (M4, M5, M6 and M7) generations, for cultivars Pérola and BRSMG Majestoso. The use of mixtures of races of C. lindemuthianum was efficient in evaluating anthracnose severity and could be recommended as an alternative method to save costs and time.
Journal of agricultural and food chemistry, Jan 13, 2017
Kaurenoic acid derivatives were prepared and submitted to in vitro assays with the fungus Colleto... more Kaurenoic acid derivatives were prepared and submitted to in vitro assays with the fungus Colletotrichum lindemuthianum, which causes anthracnose disease in the common bean. The most active substances were found to be methyl and p-bromobenzylesters, 7 and 9, respectively, of the hydrogenated kaurenoic acid, which presented a minimum inhibitory concentration (MIC) of 0.097 and 0.131 mM, respectively, while the commercial fungicide methyl thiophanate (MT) presented a MIC of 0.143 mM. Substances 7 (1.401 mM) and 9 (1.886 mM) reduced the severity of anthracnose in common bean to values statistically comparable to MT (2.044 mM). According to an in silico study, both compounds 7 and 9 are inhibitors of the ketosteroid isomerase (KSI) enzyme produced by other organisms, the amino acid sequence of which could be detected in fungal genomes. These substances appeared to act against C. lindemuthianum by inhibiting its KSI. Therefore, substances 7 and 9 are promising for the development of new ...
The Colletotrichum genus presents large genetic variability, as demonstrated by the occurrence of... more The Colletotrichum genus presents large genetic variability, as demonstrated by the occurrence of several pathogenic races and phenotypic traits. The objective of this study was to characterize 22 strains of C. lindemuthianum and Colletotrichum spp recovered from anthracnose lesions and bean scab, and to verify the relationship between species of the Colletotrichum genus, which inhabit anthracnose and scab lesions. Colony morphology, conidium size, the presence of septa, germination, sporulation, and mycelium growth rates, were analyzed in addition to the presence of mating-type genes, IRAP markers, and pathogenicity. Strains of Colletotrichum spp presented wide variation for all evaluated traits, indicating the presence of different species. Pathogenicity tests verified that the severity of the disease caused by strains of Colletotrichum spp must be evaluated 17 days after inoculation. Molecular analysis showed that only the C. lindemuthianum strains were grouped by the IRAP markers. For the physiological traits, we observed that C. lindemuthianum mycelium growth is slower than that of Colletotrichum spp strains. The information generated in this study confirms variability in the evaluated species of Colletotrichum and may direct future basic and applied studies aiming to control these diseases in common bean.
INTRODUCTION: Common bean anthracnose, caused by the fungus Colletotrichum lindemuthianum is one ... more INTRODUCTION: Common bean anthracnose, caused by the fungus Colletotrichum lindemuthianum is one of the most important diseases of this crop. However, another disease that has caused damage to common bean crop is the scab that Colletotrichum truncatum has been reported as causal agent. Strains isolated from anthracnose and scab lesions have been investigated in recent years and strains of Glomerella spp. (teleomorphic form) and Colletotrichum spp. (anamorphic form) have been obtained and identified by morphological, cytological, molecular and pathogenic analyses (Barcelos et al., 2014; Mota et al., 2016). Barcelos et al. (2014) classified Glomerella sp. strains from anthracnose lesions in two distinct groups, group I and II. Group I strains did not cause symptoms in common bean and amplified for the HMGGlo primer, specific for G. cingulata (Barcelos et al., 2011) and did not amplified by the HMGCl primer, specific for C. lindemuthianum (Garcia-Serrano et al., 2008). On the other han...
Evaluations by artificial inoculation of different races of Colletotrichum lindemuthianum can be ... more Evaluations by artificial inoculation of different races of Colletotrichum lindemuthianum can be unfeasible in a breeding program aiming at obtaining cultivars with durable resistance to anthracnose in common bean, since many physiological races have already been found. An alternative would be the use of mixtures of different races. However, information is scarce about the efficiency of this method to select resistant plants and to evaluate the virulence of the pathogen. Thus, the objective of this work was to demonstrate the feasibility of using mixtures of C. lindemuthianum races in breeding programs aiming at the development of common bean cultivars with resistance to anthracnose. Two experiments were carried out, in which races 65, 73 and 81 of C. lindemuthianum were inoculated individually and in a mixture of the three races (M1), and also mixtures of first (M2 and M3) and second (M4, M5, M6 and M7) generations, for cultivars Pérola and BRSMG Majestoso. The use of mixtures of races of C. lindemuthianum was efficient in evaluating anthracnose severity and could be recommended as an alternative method to save costs and time.
Journal of agricultural and food chemistry, Jan 13, 2017
Kaurenoic acid derivatives were prepared and submitted to in vitro assays with the fungus Colleto... more Kaurenoic acid derivatives were prepared and submitted to in vitro assays with the fungus Colletotrichum lindemuthianum, which causes anthracnose disease in the common bean. The most active substances were found to be methyl and p-bromobenzylesters, 7 and 9, respectively, of the hydrogenated kaurenoic acid, which presented a minimum inhibitory concentration (MIC) of 0.097 and 0.131 mM, respectively, while the commercial fungicide methyl thiophanate (MT) presented a MIC of 0.143 mM. Substances 7 (1.401 mM) and 9 (1.886 mM) reduced the severity of anthracnose in common bean to values statistically comparable to MT (2.044 mM). According to an in silico study, both compounds 7 and 9 are inhibitors of the ketosteroid isomerase (KSI) enzyme produced by other organisms, the amino acid sequence of which could be detected in fungal genomes. These substances appeared to act against C. lindemuthianum by inhibiting its KSI. Therefore, substances 7 and 9 are promising for the development of new ...
The Colletotrichum genus presents large genetic variability, as demonstrated by the occurrence of... more The Colletotrichum genus presents large genetic variability, as demonstrated by the occurrence of several pathogenic races and phenotypic traits. The objective of this study was to characterize 22 strains of C. lindemuthianum and Colletotrichum spp recovered from anthracnose lesions and bean scab, and to verify the relationship between species of the Colletotrichum genus, which inhabit anthracnose and scab lesions. Colony morphology, conidium size, the presence of septa, germination, sporulation, and mycelium growth rates, were analyzed in addition to the presence of mating-type genes, IRAP markers, and pathogenicity. Strains of Colletotrichum spp presented wide variation for all evaluated traits, indicating the presence of different species. Pathogenicity tests verified that the severity of the disease caused by strains of Colletotrichum spp must be evaluated 17 days after inoculation. Molecular analysis showed that only the C. lindemuthianum strains were grouped by the IRAP markers. For the physiological traits, we observed that C. lindemuthianum mycelium growth is slower than that of Colletotrichum spp strains. The information generated in this study confirms variability in the evaluated species of Colletotrichum and may direct future basic and applied studies aiming to control these diseases in common bean.
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