Inside out: microbiota dynamics during host-plant adaptation of whiteflies - Supplementay Material

While most insect herbivores are selective feeders, a small
proportion of them feed on a wide range of plants. This polyphagous
habit requires overcoming a remarkable array of defenses, which often
necessitates an adaptation period. Efforts for understanding the
mechanisms involved mostly focus on the insect’s phenotypic
plasticity. Here, we hypothesized that the adaptation process might
partially rely on transient associations with bacteria. To
test this, we followed in a field-like experiment, the
adaptation process of Bemisia tabaci, a generalist sap-feeder,
to pepper (a less-suitable host), after switching from watermelon (a
suitable host). Amplicon sequencing of 16S rRNA transcripts from
hundreds of dissected guts revealed the presence of active “core”
and “transient” bacterial communities, dominated by the phyla
Proteobacteria, Actinobacteria, and Firmicutes, and increasing
differences between populations grown on watermelon and pepper.
Insects grown on pepper for over two generations, presented a
significant increase in specific genera, mainly Mycobacterium,
with a predicted enrichment in degradative pathways of xenobiotics
and secondary metabolites. This result correlated with a significant
increase in the insect’s survival on pepper. Taken together, our
findings suggest that gut-associated bacteria can provide an
additional flexible metabolic “tool-box” to generalist
sap-feeders for facilitating a quick host switching process.