Increased photosyntethic efficiency generated by fungal symbiosis in Agave victoria-reginae

A unique non-pathogenic strain of Fusarium oxysporum was isolated from field-collected plants of Agave victoria-reginae Moore. It was then re-introduced into micropropagated plants of the same species under greenhouse conditions. The fungic inoculation induced a 225% increase in the length of roots, 50% in the number of root branches and 50% in the number of stomata on the adaxial surface of leaves. Also, an increment of 167% in nocturnal acidity and a 122% in malic acid was observed and nocturnal pH was significantly more acid in the inoculated plants. Total chlorophyll and sugar content increased 14 and 172%, respectively. These results indicate a higher photosynthetic efficiency of the plants inoculated with the fungus than those plants which were not inoculated; therefore the association of this unique F. oxysporum strain with A. victoria-reginae Moore was considered as a beneficial symbiosis.