Phosphorus fertilization and intercropping interactively affect tomato and potato onion growth and rhizosphere arbuscular mycorrhizal fungal community

Abstract

ABSTRACT Arbuscular mycorrhizal fungi (AMF) play key roles in nutrient cycling and supporting agricultural productivity. Although both phosphorus (P) fertilization and plant–plant interactions can induce changes in the AMF community, if and how their interaction effects can affect the AMF community remain unknown. A greenhouse experiment was conducted to investigate plant growth, P concentration and content and AMF root colonization in intercropped potato onion and tomato system under five P levels. Quantitative PCR and Illumina MiSeq sequencing were applied to evaluate AMF community abundance and composition. Enhanced growth and P concentration of intercropped tomato were most pronounced without P fertilization compared with monocropping system, while interspecific interactions negatively affected potato onion growth. Intercropping increased AMF abundance in tomato but decreased that in potato onion, although higher P fertilization depressed AMF abundance, diversity and root colonization. AMF community compositions of the two plants were primarily affected by P fertilization, and the AMF composition of potato onion was also separated by cropping system. Overall, interspecific interactions between tomato and potato onion were asymmetric with a negative effect on potato onion growth. P fertilization had a stronger influence than intercropping on rhizosphere AMF community, and interspecific interactions on the AMF community were not symmetric.