Characterizing the Soil Microbiome of Invasive Halophytes in Disturbed and Non-Disturbed Sites

Tamarix sp. of the Tamaricaceae are an invasive tree common in riparian areas across the South West United States which can outcompete native Salicaceae trees. Tamarix sp. are drought-adapted halophytes with the capacity to concentrate salt in their foliar tissue. At the end of a growing season, the senesced leaves contribute to increased salinity in the topsoil giving this organism an advantage over native plants. In order to examine the effect of Tamarix sp. on the soil microbiota we collected soil along a gradient of distance from Tamarix sp. trunks in areas with different disturbance history and shade aspects. Soil samples were tested for macronutrient content and salinity. Serial dilutions of the soil were used to observe culturable microbes. We found differences in salinity, nitrate content, and bacterial and fungal community compositions based on proximity to Tamarix sp. and disturbance status. The undisturbed plots had the highest alpha diversity of bacteria within the canopy and lowest outside the canopy, while the disturbed plots had intermediate values. Additionally, we have employed ITS/16S metabarcoding to characterize the full microbial communities associated with each site, finding that the most abundant species of fungi across samples are plant pathogens, with the exception of Pseudogymnoascus destructans, the cause of White Nose Syndrome in bats.