The invader Carpobrotus edulis promotes a specific rhizosphere microbiome across globally distributed coastal ecosystems

Abstract

The importance of plant-microbe interactions to the success of invasive plants has rarely been studied at a global scale. Carpobrotus edulis (L.) N. E. Br is an aggressive invader in many areas around the world, forming dense mats in coastal environments. In an approach at a large geographical scale, over a wide latitudinal and climatic range, we tested the ability of C. edulis to alter the local bacterial and fungal community structure and microbial activity in eight invaded coastal locations. The factors invasiveness and geographical location had a significant effect on the soil microbiota, the microbial community composition and structure from the rhizosphere of native and C. edulis plants being distinct in every location. The effect of the invader on all the chemical, physico-chemical, and microbiological properties studied depended on the invaded location. The soil bacterial and fungal community composition and structure were related to the soil available nutrients and mean annual rainfall, and those of the soil bacterial community were also linked to the soil respiration and latitude. Overall, our results reveal that the ability of the invader C. edulis to alter soil microbial community structure harboring a specific microbiome was widespread across a large invaded range - leading to concurring changes in the rhizosphere microbial functioning, such as nutrient cycling.