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Results
103
Capítulo V
Incidence and patterns of dsRNA elements
Eighty five B. bassiana isolates were analyzed to study the incidence of
mycoviruses among isolates collected in different habitats (soil, phylloplane of holm oak
and associated adventitious plants, and internal tissues of grass leaves) in Spain and
Portugal (Tables 1-3). Fifty of these isolates (58.8%) harboured dsRNA elements.
Mycovirus incidence was also analyzed separately according to the habitat and
extent of the area from which the strains were isolated. Twenty nine out of fifty four
(53.7%) strains collected from soils of natural and cultivated areas throughout Spain and
Portugal harboured dsRNA elements (Figs. 1-2). The mycovirus incidence found in this
group was the lowest, while that found among B. bassiana isolates sampled in the same
geographical point from the soil, phylloplane and adventitious plants associated to a single
holm oak (Quercus ilex) was the highest, 68.8% of the sixteen analyzed strains harboured
dsRNA elements (Figs. 3-4). Two thirds (66.7%) of the fifteen endophytic isolates
obtained from grasses were infected by viruses (Fig. 5). The differences found in the
percentages of incidence in the three analyses were not large. In fact, the dsRNA
incidences among endophytic isolates and those collected in the same sampling point were
very similar.
Fig. 1. Electrophoretic banding patterns of dsRNA elements isolated from different strains of B. bassiana.
Letters on the top indicate different isolates: A=Bb 01/39; B=Bb 01/75; C=Bb 01/33; D=Bb 01/132; E=Bb
06/02; F=Bb 06/03; G=Bb 09/03; H=Bb 09/08; I=Bb 00/08; J=Bb 00/11; K=Bb 01/15; L=Bb 01/35; M=Bb
01/110; N=Bb 09/07; O=Bb 01/88; P=Bb 08/09; Q=Bb 09/09; R=Bb 01/103. Lane MW contains a size
marker and numbers on the left indicate kbp.
MW A B C D E F G H I J K L M N O P Q R
10.0
8.0
6.0
5.0
4.0
3.0
2.5
2.0
1.5
1.0
0.75