Abstract:
AIMS: The rhizosphere microbiome substantially affects
plant health, yet comparatively little is known regarding
the foliar community dynamics. Here, we examine the
relationship between the microbiota and their response
to natural infection by pathogens.
METHODS: We established an experimental system using
a set of sorghum recombinant inbred lines (RILS).
These RILS included four models denoted as resistant,
moderately resistant, susceptible and highly susceptible.
A combination of 16S rRNA and ITS gene amplicon
approaches was used to assess bacteria and fungi, respectively, in foliar samples.
RESULTS: We show that the foliar microbiome differs substantially in asymptomatic and symptomatic RILs subsequent to natural infection by pathogens. A significant
association was found between plant health and microbial community structure. Our analyses revealed several
distinct fungal and bacterial pathogens. These pathogens
included Gibberella and Pantoea genera, which were
associated with the highly susceptible group. In addition
to these pathogens, we also found signatures for
Ascochyta, a known plant pathogenic genus. Members
of the bacterial genus Methylorubrum and the fungal
genus Hannaella, both known to exhibit plant growthpromoting (PGP) traits, were associated with the resistant
and moderately resistant groups. These data also reveal
numerous highly diverse fungal and bacterial taxa in
RILs that did not show symptoms. We also found taxonomic differences between the microbiota hosted by the
symptomatic and asymptomatic RILs.
CONCLUSIONS: Together, these data suggest that pathogen
infection may result in distinct microbiota. These results
suggest that highly diverse microbiome may promote
the plants ability to resist the effects of pathogens potentially contributing to plant health.
