Bacterial Communities in Malagasy Soils with Differing Levels of Disturbance Affecting Botanical Diversity

Abstract

Madagascar is well-known for the exceptional biodiversity of its macro-flora and fauna, but the biodiversity of Malagasy microbial communities remains relatively unexplored. Understanding patterns of bacterial diversity in soil and their correlations with above-ground botanical diversity could influence conservation planning as well as sampling strategies to maximize access to bacterially derived natural products. We present the first detailed description of Malagasy soil bacterial communities from a targeted 16S rRNA gene survey of greater than 290,000 sequences generated using 454 pyrosequencing. Two sampling plots in each of three forest conservation areas were established to represent different levels of disturbance resulting from human impact through agriculture and selective exploitation of trees, as well as from natural impacts of cyclones. In parallel, we performed an in-depth characterization of the total vascular plant morphospecies richness within each plot. The plots representing different levels of disturbance within each forest did not differ significantly in bacterial diversity or richness. Changes in bacterial community composition were largest between forests rather than between different levels of impact within a forest. The largest difference in bacterial community composition with disturbance was observed at the Vohibe forest conservation area, and this difference was correlated with changes in both vascular plant richness and soil pH. These results provide the first survey of Malagasy soil bacterial diversity and establish a baseline of botanical diversity within important conservation areas.

Microbial Response to Soil Liming of Damaged Ecosystems Revealed by Pyrosequencing and Phospholipid Fatty Acid Analyses

“…It also improves soils fertility, promotes circulation of soil materials and increases soil microbial activity [31]. The relative abundance of Buckholderia observed in the unlimed soil is consistent with the recent classification of this genus as an acid tolerant group [45]. Bradyrhizobia are often found in acid soils and they were identified in both limed and unlimed soil samples.…”

Rhizosphere Bacterial Communities Differ According to Fertilizer Regimes and Cabbage (Brassica oleracea var. capitata L.) Harvest Time, but Not Aphid Herbivory

“…Thus, compositional shifts in these communities can have significant consequences for the nutritional status and health of crops. Modern farming practices, such as fertilizer applications, can alter soil microbial communities through their impact on various edaphic factors, including soil moisture, pH ( Li et al, 2012 ; Tripathi et al, 2012 ; Blasiak et al, 2014 ), nutrient availability, organic matter content, and temperature ( Kowalchuk and Stephen, 2001 ; Bulluck et al, 2002 ; Bates et al, 2011 ; de Vries et al, 2012b ). In comparison to mineral fertilizers, organic fertilizers (e.g., animal manures and compost) have been reported to enhance the bacterial richness (number of species) and lower evenness (relative abundance of taxa) of soil communities ( Hartmann et al, 2015 ; Lupatini et al, 2017 ).…”

Phytobeneficial bacteria improve saline stress tolerance in Vicia faba and modulate microbial interaction network

“…showing that these are the most common groups in different agricultural systems or other soil types, based on pyrosequencing surveys (Haichar et al, 2008;Lauber et al, 2009;Blasiak et al, 2014;El Khalloufi et al, 2016;Yaish et al, 2016). Nevertheless, each of the dominant phyla exhibited differences in average abundance level between the two studied compartments (root tissue and RAS).…”