INBA   12521
INSTITUTO DE INVESTIGACIONES EN BIOCIENCIAS AGRICOLAS Y AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Positive association between Neotyphodium endophyte and arbuscular mycorrhiza fungi: a widespread trait in native grasses.
Autor/es:
NOVAS V,; IANONE L,; VIGNALE MV,; SCERVINO JM
Reunión:
Conferencia; 7th International Symposium on Fungal Endophyte of Grasses; 2010
Resumen:
The potential impact of foliar endophytes on below-ground process, in particular on arbuscular mycorrhiza fungi (AMF), has received little attention, and the existing results are contradictory. Here we, firstly, review the research performed on the endophyte-AMF interaction in three native grasses, from different environmental regions in Argentina, at field conditions. Secondly, we report the results obtained from in vitro assays to test the effect of the endophyte on the pre-infective state of AMF. AMF roots colonization was studied in Neotyphodium-infected (E+) and uninfected (E-) plants in natural populations of Bromus setifolius and Poa bonariensis, while roots of B. auleticus were obtained from plants in an experimental field were the effect of N fertilization was also studied. In vitro assays were performed using four different strains of Neotyphodium , isolated from B. setifolius, and two species of AMF: Gigaspora margarita and G. rosea. The AMF colonization was significantly higher in plants from (E+) infected populations than in plants from (E-) non-infected populations for all three hosts. No significant differences were detected between E+ and E- plants when they coexist in the same population. FALTA ANALISIS DE VICKY. In vitro assays revealed that root exudates from E+ plants and exudates from endophytes strains significantly enhanced hyphal length and the number of hyphal branches in AMF. However, this effect varied depending on the endophyte strain and the AMF species couple. Our results suggest that the positive effect of Neotyphodium endophytes on AMF, increasing the root plant colonization, would be a widespread phenomenon in native grasses. Furthermore, regarding the in vitro assays, the higher colonization could, at least, be partially explained by the positive effect of the endophyte strains on the pre-symbiotic stages of the AM fungi.