Could biological invasion by Cryptostegia madagascariensis alter the composition of the arbuscular mycorrhizal fungal community in semi-arid Brazil?

Biological invasions pose a serious threat to native semi-arid areas of Brazil, especially in areas of the state of Ceara that are typically invaded by Cryptostegia madagascariensis, an exotic plant species from Madagascar. However, how this biological invasion influences the composition of the arbuscular mycorrhizal fungal (AMF) community and how this affects further invasion by C. madagascariensis is not well known. Here we tested how inoculation with species of AMF affects the development of this invasive plant. We analyzed and compared the AMF community composition of four different stages of biological invasion by C. madagascariensis, and examined the effects of inoculation with these four AMF communities, plus a dominant AMF species (Rhizoglomus intraradices) on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas of plants of C. madagascariensis. We found that all studied treatments (except the inoculum from the native plant root zone) promoted the growth of C. madagascariensis and lead to a higher P concentration. Our results demonstrate that the invader might be altering the composition of the AMF community in field conditions, because inoculation with this community enhanced invader growth, root colonization, and P uptake.