¿La composición comunidad de AMF está determinada por el P del suelo sólo si el N no limita el crecimiento del cultivo?.

GASSET B; FERRARI M; CAVILGLISASSO P; .RUBIO G.; FAGGIOLI V

Leticia

Simposio; III international Symposium on Mycorryizal Symbiosis in South America; 2023

Agroecosystems receive elevated inputs of nutrients, but the consequences of this for soil arbuscular mycorrhizal fungi (AMF) remain unclear. In this study, we evaluated the long-term effects of N and P fertilisation on soil-borne AMF. Our hypothesis was that AMF community will be primarily governed by soil P only if N content does not limit crop growth. The field experiment was located in Pergamino, Argentina. The fertilisation treatments were: P0N0, P0N1, P1N0, P1N1. We sequenced 18S rARN subunit from soil samples at vegetative (Vs) and reproductive (Rs) stages of maize. We assessed mycorrhizal colonisation at seven times during crop season and measured N and P in plant tissues. Arbuscules ranged from 83% in P0N1 to 71% in P1N1 and 79% P0N1 to 62% in P1N1 in Vs and Rs, respectively. We did not find long-term effects of P fertilisation on AMF alfa-diversity. Contrariwise, N1 exhibited higher observed richness and Shannon index than N0, regardless of the level of P. Observed richness ranged from 66 to 68 VTX in N1, and 50 to 59 VTX in N0, and the Shannon index reached 2.7 in N1, and 2.5 in N0. We observed a lower abundance of Glomeraceae in P1 compared to P0 in Vs and Rs. However, in Rs, N fertilisation increased the abundance of Glomeraceae, Paraglomeraceae, Claroideoglomeraceae, Ambisporaceae, Geosiphonaceae, Gigasporaceae, Achaeosporaceae, Acaulosporaceae, and Pacisporaceae. In conclusion, this study demonstrates that N was the dominant nutrient in determining crucial aspects of AMF community composition under contrasting P fertilisation.