4 research outputs found
Linkage and mapping of quantitative trait loci associated with angular leaf spot and powdery mildew resistance in common beans
Angular leaf spot (ALS) and powdery mildew (PWM) are two important fungi diseases causing significant yield losses in common beans. In this study, a new genetic linkage map was constructed using single sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), in a segregating population derived from the AND 277 x SEA 5 cross, with 105 recombinant inbred lines. Phenotypic evaluations were performed in the greenhouse to identify quantitative trait loci (QTLs) associated with resistance by means of the composite interval mapping analysis. Four QTLs were identified for ALS resistance. The QTL ALS11AS, linked on the SNP BAR 5054, mapped on chromosome Pv11, showed the greatest effect (R2 = 26.5%) on ALS phenotypic variance. For PWM resistance, two QTLs were detected, PWM2AS and PWM11AS, on Pv2 and Pv11, explaining 7% and 66% of the phenotypic variation, respectively. Both QTLs on Pv11 were mapped on the same genomic region, suggesting that it is a pleiotropic region. The present study resulted in the identification of new markers closely linked to ALS and PWM QTLs, which can be used for marker-assisted selection, fine mapping and positional cloning
Bioprospection of yeast and bacteria isolates from oral secretion of field-collected diatraea saccharalis (fabricius, 1794) (Lepidoptera: Crambidae) Antagonic to Fusarium verticillioides (Nirenberg, 1976) AND Colletotrichum falcatum (Went, 1893)
Insect symbionts may have unknown functions in the interaction between insect-plant
and insect with microorganisms that co-inhabit the same space. The objective of this
study was to investigate the antagonism potential of symbiont microbiota from oral
secretion D. saccharalis collected in the field, against Fusarium verticillioides and
Colletotrichum falcatum pathogens commonly found inside the cane. For this, 4° and
5° instar caterpillars were collected inside sugarcane varieties RB-835 054 and SP-
813 250, and brought to the lab inside the cane stalks. The microbiota of oral
secretion was transferred to two selective media, NA (nutrient agar) for bacteria and
DRBC (dicloran Rose Bengal Chloramphenicol) for yeast. Based on morphology and
coloration of the colonies twenty colonies of bacteria and yeast were selected. Four
culture media were tested in co-cultivation of F. verticillioides and C. falcatum versus
bacteria or yeast isolates: PDA (potato, dextrose, agar), YEPD (yeast extract,
peptone, dextrose), CCS (supplemented cane broth) and NA (Nutrient Agar). The
most suitable culture medium for growth of most microorganisms was BDA.
Antagonism potential of 82 bacterial isolates and 87 yeast isolates to C. falcatum and
F. verticillioides was assessed using a visual scale of categories 1 to 4, with 4 being
the maximum degree of antagonism. Isolates that allocated category greater than or
equal to 2 were evaluated in co-culture with C. falcatum and F. verticillioides as the
percentage of growth inhibition. It was possible to identify four isolates of bacteria
which have the potential to inhibit growth of pathogens and 9 isolates with the same
potential but with much lower percentages. These results demonstrate that some
isolates of bacteria and yeast may influence the relationship between the bit-rot
complex and sugarcane plant, may in future be used as a biological control of these
pathogens or have some molecules of biotechnological interest extracted and
purified.Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Simbiontes de insetos podem ter funções desconhecidas na interação entre insetoplanta
e do inseto com microrganismos que co-habitam o mesmo espaço. O objetivo
desse estudo foi investigar o potencial de antagonismo da microbiota simbionte,
presentes na secreção oral de Diatraea saccharalis, com os fitopatógenos Fusarium
verticillioides e Colletotrichum falcatum que habitam o colmo de cana-de-açúcar.
Para isso, foram coletadas, nas variedades de cana RB-835054 e SP-813250,
lagartas de 4° e 5° instar e trazidas para o laboratório junto aos toletes de cana. A
microbiota da secreção oral foi transferida para dois meios de cultura seletivos, NA
(nutrient agar) para bactérias e DRBC (Dicloran Rosa-de-Bengala Cloranfenicol)
para leveduras. Baseado na morfologia e coloração das colônias, foram
selecionadas, vinte colônias de bactéria e também de levedura de 5 lagartas. Foram
testados quatro meios de cultura: BDA (batata, dextrose, agar), YEPD (yeast extract,
peptone, dextrose), CCS (caldo-de-cana suplementado) e NA para os testes de
cultivo pareado. O meio de cultura mais adequado para o crescimento da maioria
dos microrganismos foi o BDA. O potencial de antagonismo de 82 isolados de
bactéria e 87 isolados de levedura a C. falcatum e F. verticillioides foi avaliado
através de uma escala visual de categorias de 1 a 4, sendo 4 o grau máximo de
antagonismo. Os isolados a que foi atribuÃda categoria maior ou igual a dois foram
avaliados em co-cultivo com C. falcatum e F. verticillioides quanto à porcentagem de
inibição do crescimento. Foi possÃvel identificar 4 isolados de bactéria que tem o
potencial de inibir o crescimento dos fitopatógenos e 9 isolados com o mesmo
potencial, porém com porcentagens menores. Esses resultados demonstram que
alguns isolados de bactérias e leveduras podem influenciar na relação existente
entre o complexo broca-podridão e a planta de cana-de-açúcar, podendo,
futuramente, serem utilizados como controle biológico desses fitopatógenos ou
terem algumas moléculas de interesse biotecnológico extraÃda e purificada
Linkage and mapping of quantitative trait loci associated with angular leaf spot and powdery mildew resistance in common beans
Abstract Angular leaf spot (ALS) and powdery mildew (PWM) are two important fungi diseases causing significant yield losses in common beans. In this study, a new genetic linkage map was constructed using single sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), in a segregating population derived from the AND 277 x SEA 5 cross, with 105 recombinant inbred lines. Phenotypic evaluations were performed in the greenhouse to identify quantitative trait loci (QTLs) associated with resistance by means of the composite interval mapping analysis. Four QTLs were identified for ALS resistance. The QTL ALS11AS, linked on the SNP BAR 5054, mapped on chromosome Pv11, showed the greatest effect (R2 = 26.5%) on ALS phenotypic variance. For PWM resistance, two QTLs were detected, PWM2AS and PWM11AS, on Pv2 and Pv11, explaining 7% and 66% of the phenotypic variation, respectively. Both QTLs on Pv11 were mapped on the same genomic region, suggesting that it is a pleiotropic region. The present study resulted in the identification of new markers closely linked to ALS and PWM QTLs, which can be used for marker-assisted selection, fine mapping and positional cloning