Brazilian pepper tree

Emerging insights on the role of microbiomes in the sustainability of ecosystems and plant cover are transforming knowledge-driven agro-environmental management practices. For more than a century, the Brazilian pepper tree -BP (Schinus terebinthifolius), a category 1 invasive plant in Florida has defied numerous conventional control measures directed at its well-known ecology. This dissertation is one of the pioneer studies designed to determine whether microorganisms play a role in the aggressive invasion of BP in Florida and examine potential mechanisms with the goal of creating supplemental restoration tools. To test the hypothesis that enhanced mutualism of Brazilian pepper tree with microbes, compounded by relatively low biotic resistance of Florida soils is a critical driver of its invasion, plant biomass indices, metagenomics analysis of microbial community shifts, electron microscopy of endomycorrhizal infection and qPCR of key rhizobacterial taxa were measured. A multifactorial grow-room experiment was conducted simulating invasion with BP and two Florida natives (Pinus elliottii and Bidens alba) in a sterile, bioinoculant supplemented, and non-sterile control soils with various plant combinations.

The Brazilian pepper tree (BP, Schinus terebinthifolius), introduced to the United States
in the 1800s, has since become a category one invasive plant in Florida, aggressively
spreading to 3000 km2 of prime habitat. There is a serious dearth of knowledge on
whether the rhizobiome plays any roles in the displacement of native flora and the range
expansion of BP. This thesis discusses the well-established plant invasion mechanisms of
the BP and highlights key emerging mechanisms and gaps in (a) the current
understanding of the molecular, below-ground processes of BP invasion and (b) studies
on the potential role of microbial interactions in the success of BP invasion already
established for other select invasive species, and the intervention of soil metagenomic
studies to elucidate plant invasive mechanisms. These poorly studied mechanisms could further explain the aggressive spread and resilience of BP and contribute significantly to
the development of effective and sustainable control measures, enabling appropriate
strategies for restoring native plants.