Foram caracterizados 41 isolados de Acidovorax avenae subsp. citrulli com base em aspectos fisiológicos e bioquímicos. Todos os isolados induziram sintomas típicos da mancha-aquosa em plântulas, plantas e frutos de meloeiro (Cucumis melo) e melancieira (Citrullus lanatus). Pelo teste de agrupamento de Scott-Knott (P = 0,05) os isolados foram separados quanto ao índice de doença em 5 e 7 grupos, respectivamente para plântulas de meloeiro e melancieira, e em 2 grupos para plantas das duas hospedeiras. Em frutos, os isolados foram separados em 3 e 10 grupos para a variável diâmetro da lesão externa e 2 e 9 grupos para profundidade da lesão, respectivamente para melão e melancia. Todos os isolados induziram reação de hipersensibilidade em fumo (Nicotiana tabacum); utilizaram os compostos asparagina, L-leucina e DL-ácido lático; produziram enzimas lipolíticas e o fitohormônio ácido indol acético; foram sensíveis a oxicloreto de cobre (120 µg mL-1), óxido cuproso (120 µg mL-1), hidróxido de cobre (138,2 µg mL-1), sulfato de estreptomicina (25 µg mL-1) e Agrimaicin 500 (428 µg mL-1); e resistentes a kasugamicina (87 µg mL-1), agrimicina (200 µg mL-1), eritromicina (15 µg), gentamicina (10 µg), amoxicilina (10 µg), neomicina (30 µg), estreptomicina (10 µg), norfloxacina (10 µg) e rifampicina (5 µg). Nenhum isolado apresentou atividade pectinolítica, amilolítica, celulolítica e proteolítica ou produção do polissacarídeo levana e da toxina siringomicina. Foi constatada variabilidade entre os 41 isolados de A. avenae subsp. citrulli quanto à sensibilidade à tetraciclina (30 µg), sendo 41,5% resistentes, 46,3% moderadamente sensíveis e 12,2% altamente sensíveis.
©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 18 (4): gmr18357 A.V. Tiago et al. 2 (SSRY47), with a mean of 0.680. The expected and observed heterozygosity showed an average of between 0.717 and 0.688, for SSRY126 and SSRY47, respectively. The heterozygosity values observed were higher than those expected in five of the six populations, generating negative values of the fixation index (-0.070). Among the six populations, Alta Floresta and Cuiabá had the highest percentage of polymorphic loci (100%). The groupings obtained by UPGMA, Structure and PCoA among the six populations were concordant in allocating the individuals into two genetic groups. We found considerable genetic diversity among the samples, evidenced by the high values in the diversity indices. These high values are possibly related to the management of the fields and the exchange of propagative material among the farmers. Therefore, it is proposed that both populations be conserved since they have potential that could be used for genetic improvement of this essential crop.
ABSTRACT. Hymenaea courbaril L. is a tropical tree species with economic and medicinal potential largely used in programs for the recovery of degraded areas. The use of molecular markers in genetic studies can 2 V.D. Rocha et al. Genetics and Molecular Research 16 (3): gmr16039706 help in the definition of forest restoration strategies. This study was conducted to analyze the genetic diversity among H. courbaril ('jatobá') genotypes naturally occurring in the north of Mato Grosso State, Brazil, using ISSR markers, aiming to contribute to the development of seed collection and seedling production strategies. Twenty-four H. courbaril individuals were sampled by collecting leaves for DNA extraction by the CTAB method. The individuals were genotyped using 14 ISSR primers, resulting in the amplification of 87 bands in total, 65 of which were polymorphic. The ISSR markers presented average polymorphism information content of 0.44. Dissimilarity values based on the Jaccard coefficient ranged from 0.12 to 0.52. The most divergent individuals were 3 and 22, whereas 14 and 19 were the most genetically similar. The UPGMA and Tocher clustering methods indicated the formation of four distinct groups, revealing genetic variability among the 24 H. courbaril genotypes. Therefore, all the evaluated genotypes can be used for seed collection and seedling production, but the most divergent individuals should be prioritized.
Cassava (Manihot esculenta) is a traditional crop in tropical and subtropical regions that is used for human consumption and in animal feed. This studied cassava landraces cultivated in northern Mato Grosso State, Brazil, to detect the variability in family farms, aiming at the preservation and use potential of these genetic resources. A total of 120 M. esculenta individuals were evaluated at the rate of 40 per location (population), where each landrace was represented by 10 plants. The 14 microsatellite markers examined showed genetic diversity. The average polymorphic information content (PIC) was 0.621 and the average number of alleles per locus was seven. Genetic diversity parameters indicated that H o was higher than H e for the three populations, showing negative fixation indices and a lack of inbreeding. AMOVA revealed greater molecular variation within the populations (92%). Bayesian analysis and the ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 18 (3): gmr18315 E.C.M. Pedri et al. 2UPGMA clustering method resulted in two main groups formed with the individuals distributed randomly; i.e., regardless of collection site (location). The gene flow found in this study is a consequence of the introduction and exchange of genetic material (landraces) performed by the farmers, who act on their farms as maintainers of local diversity. Manihot esculenta cultivation in northern Mato Grosso State ensure the on-farm conservation of genetic variability of the species and constitutes a source of genetic resources such as genes of resistance and adaptation, which can be exploited and utilized in breeding programs.
were collected during the harvest season from December 2017 to January 2018. Twenty fruits of each genotype were selected; that were visually appealing, whole and without deformation, totaling 400 samples. We measured the length, width, thickness, weight, and volume of the fruits, the length, width, thickness and weight of the seed and the thickness and weight of the pulp. The data were obtained with a digital caliper and the degrees brix measured with a refractometer. Multivariate analyses were made with UPGMA hierarchical methods and Tocher optimization, using the standardized average Euclidean distance as a measure of dissimilarity, and principal components analysis (PCA). Four distinct groups were formed based on the data. The first three principal components explained 87.51% of the total variation. The brix measurement was the trait with the greatest contribution to the differentiation of the genotypes.
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