Abstract
Plants host diverse assemblages of fungi on their foliar tissues, both
in internal compartments and on exterior surfaces. When plant
distributions shift, they can move with their fungal associates (i.e.
co-introduction) or acquire new associates present in the novel
environment (host-jumping). The fungal communities that plants acquire
influence a plant’s ability to establish and spread in this new
environment. Here, we aimed to assess whether invasive Cenchrus
ciliaris hosts similar groups of fungi in its native and introduced
ranges and to evaluate community overlap of fungi associated with foliar
tissue of C. ciliaris and native and non-native plants within the
introduced range. In the introduced range, C. ciliaris associated
with a majority of novel OTUs, although 3.2% of OTUs were common to
both ranges. Of these shared OTU, 77.6% were found on co-occurring
natives and non-natives in the introduced range, whereas 22.4% were
completely unique to C. ciliaris indicating a possible
co-introduction. Fungal communities within the introduced range contain
a higher proportion of generalist symbionts and an increase in
heterogeneity of foliar communities than in its native range. Within the
introduced range, host phylogenetic distance explained more variation in
foliar communities than native status. Our findings provide evidence
that non-natives acquire fungi opportunistically from their environment,
although host and environmental filtering is present suggesting that
successful invasive plants may be able to limit the effect of poor
symbionts and select for better ones. Future experimental work will be
needed to confirm the occurrence of host selection and identify its
mechanisms.