TESIS NOEMI HERRERO.pdf - Consejo Superior de Investigaciones ...

Capítulo IV
The results obtained do not demonstrate the systemic movement of the fungus in
bean or tomato plants. A small number of infected fragments from newly formed leaves
were observed, and these could be the result of local infection instead of systemic
colonization. Further studies could be made in order to test if using other inoculation
methods, the systemic colonization of plants by T. cylindrosporum can occur. Other
inoculation procedures, most of them applied to B. bassiana, have been described in the
literature. These methods involved dressing seeds with conidia, dipping roots or rhizomes
in conidial suspensions, injecting conidia in rhizomes or stems, or even applying conidia to
plant substrates (Akello et al., 2007; Gómez-Vidal et al., 2006; Posada and Vega, 2006;
Quesada-Moraga et al., 2006a).
The two T. cylindrosporum strains used in this work were isogenic, but they
differed in the presence of a mycovirus, TcV1. A significant tendency was observed, the
TcV1 infected fungal strain appeared to better penetrate bean plants. In contrast, the virusfree
strain seemed to be more successful entering in tomato plants. This suggests that the
presence of the virus could be favourable for the fungus in one host species, and
unfavourable in another host species. If we would have done this study only with one host,
for example with bean plants, we would have concluded that TcV1 produces a positive
effect in the endophytic capability of T. cylindrosporum, and we would have arrived to the
opposite conclusion using tomato as the unique host.
In conclusion, this study demonstrates that T. cylindrosporum strains originally
isolated as endophytes from the grass Festuca rubra were able to establish an endophytic
relationship with other plant species than its original host. Therefore, T. cylindrosporum
could be used for the biological control of invertebrate herbivores or even for the control of
plant pathogens, as have been proposed for other entomopathogenic fungi (Ownley et al.,
2010). T. cylindrosporum has several characteristics that make it suitable for this purpose,
like having wide host range, being pathogenic to several insect taxa, and to other
arthropods, and its cultures sporulate abundantly, being its spores persistent in storage
(Herrero et al., 2011).
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