AM fungi and pathogen dissimilarity predicting plant-microbial
interactions strength in graminoids and forbs
Abstract
Plant-microbial interactions (PMI) play a crucial role in plant growth,
fitness and productivity, primarily through the mutualism and antagonism
interactions between plants and soil microorganisms. The colonization of
arbuscular mycorrhizal (AM) fungi and pathogen are often used to
speculate on the effects of microorganisms on plant growth, i.e.
plant-microbial interactions (PMI). However, empirical studies
demonstrate the relationship between AM fungi or pathogen and PMI
effects remains limited, especially under different biotic and abiotic
conditions. Here, we evaluated the colonization rates of AM fungi and
pathogen across 13 grassland species under individual or communal
conditions, in both overgrazed and restored soil. Furthermore, we
investigated the relationship between AM fungi or pathogen and PMI. Our
results showed that forbs exhibited significantly higher rates of AM
fungal colonization compared to graminoids in community condition and
overgrazed soil while graminoid roots showed higher pathogen infestation
compared to forbs in individual condition and overgrazed soil.
Generally, there was a positive correlation between PMI and AM fungal
colonization but a negative correlation between PMI and pathogen
disease. The PMI of graminoids exhibited a negative correlation with
pathogen disease in individual condition and overgrazed soil, but showed
no correlation with AM fungal colonization. On the other hand, the PMI
of forbs showed a positive correlation with AM colonization in both
restored and overgrazed soil, as well as in both individual and
community experiments. However, there was no correlation between PMI of
forbs and pathogen disease. The PMI of graminoids and forbs in grassland
ecosystems can be driven by distinct soil microorganisms. These insights
enable us to better understand how soil mutualists and pathogen mediate
PMI effects on plant growth, with implications for grassland management
and restoration.