A partir de 1728 fragmentos de hastes e folhas de soja (Glycine max (L.) Merril). provenientes de plantas do campo e de casa de vegetação, coletadas cerca de 20 e 40 dias após a germinação das sementes, 297 fungos endofíticos foram isolados. Os gêneros encontrados foram: Alternaria, Cladosporium, Curvularia, Chaetomium, Scopulariopsis, Drechslera (todos dematiáceos) além de Colletotrichum, Fusarium, Acremonium, Aspergillus, Penicillium, Paecilomyces e Mycelia sterilia. Foram detectadas diferenças qualitativas e quantitativas entre os isolados, em relação a micobiota de hospedeiros provenientes do campo e de casa de vegetação com maior frequência de fungos isolados de plantas no campo em comparação com as de casa de vegetação. Houve diminuição da frequência de fungos com a idade das plantas crescidas no campo, ocorrendo o inverso com as da casa de vegetação, mas em ambos os casos, não houve diferença no número de fungos isolados de hastes e de folhas. Houve em plantas crescidas no campo uma maior incidência nas regiões próximas ao solo o que não ocorreu nas plantas provenientes da casa de vegetação. Os resultados podem ser de utilidade do ponto de vista biotecnológico pelo uso de endófitos introduzidos deliberadamente em plantas visando o controle biológico de pestes ou promoção de crescimento vegetal.
A total of 297 endophytic fungi were isolated from 1728 leaf and stem fragments collected about twenty and forty days after germination from soybean (Glycine max (L.) Merril) plants grown in the field and a greenhouse. The fungi belonged to eight groups, six dematiaceous genera (Alternaria, Cladosporium, Chaetomium, Curvularia, Drechslera and Scopulariopsis) and the non-dematiaceous genera Acremonium, Aspergillus, Colletotrichum, Fusarium, Paecilomyces and Penicillium along with some Mycelia sterilia.. There were qualitative and quantitative differences in the type and number of isolates obtained from greenhouse and field-grown plants, with more isolates being obtained from the latter. No difference was found in the number of fungi isolated from leaves and stems irrespective of where the plants was grown. For was field-grown plants, the number of isolates decreased as the plants aged and more fungi were found in tissues near the soil, while for greenhouse-grown plants the number of isolates increased as the plants aged but in this case no more fungi were isolated from those tissues nearer the soil. These results could have biotechnological relevance for the biological control of pests or plant growth promotion.
During some phases of of their life-cycle endophytic fungi colonize plants asymptomatically being found most frequently inside the aerial part of plant tissues. After surface disinfection of apparently healthy leaves from three varieties of mandarin orange and one tangor, and after incubation on appropriate culture medium, 407 fungal isolates were obtained, giving a total infection frequency of 81%. No fungal growth was observed from disinfected seeds, indicating that fungi are probably not transmitted via seeds. Of the fungal isolates, 27% belonged to the genus Guignardia, with 12 isolates being identified as Guignardia citricarpa Kiely, which is described as a citrus pathogen. The isolates were variable in respect to the presence of sexual structures and growth rates. Most of the isolates produces mature asci, supporting the hypothesis that they are nonpathogenic endophytes, which recently were identified as G. mangiferae. High intraspecific genetic variability (an average similarity coefficient of 0.6) was detected using random amplified polymorphic DNA (RAPD) markers generated by seven different primers. The highest similarity coefficient (0.9) was between isolates P15 and M86 and the smallest (0.22) between isolates P15 and C145. These results did not allow us to establish an association between genetic similarity of the fungal isolates and the citrus varieties from which they were obtained.