Mainland and island populations of Mussaenda kwangtungensis differ in their phyllosphere fungal community composition and network structure

Abstract

We compared community composition and co-occurrence patterns of phyllosphere fungi between island and mainland populations within a single plant species (Mussaenda kwangtungensis) using highthroughput sequencing technology. We then used 11 microsatellite loci for host genotyping. The island populations differed significantly from their mainland counterparts in phyllosphere fungal community structure. Topological features of co-occurrence network showed geographic patterns wherein fungal assemblages were less complex, but more modular in island regions than mainland ones. Moreover, fungal interactions and community composition were strongly influenced by the genetic differentiation of host plants. This study may advance our understanding of assembly principles and ecological interactions of phyllosphere fungal communities, as well as improve our ability to optimize fungal utilization for the benefit of people. The phyllosphere provides a unique habitat for a diverse community of microorganisms that live within or on the surface of leaves 1. Phyllosphere fungi have been considered pivotal determinants of host-plant fitness, productivity, and ecosystem functioning 2,3. For example, phyllosphere fungi may confer salt, heat or herbivory tolerance to host plants 4-6 , they may potentially be a source of plant diseases due to the pathogenic phases in their life cycles 7,8 , or they may act as initial decomposers of leaf litter and play important roles in nutrient cycling 9,10. With advances in high-throughput sequencing technologies where DNA samples can be extracted directly from leaves, phyllosphere fungal communities have been examined to determine the community composition and potential drivers of this high diversity 11. Yang et al. 12 found that leaf carbon was the main driver of changes for the foliar fungal community composition of Betula ermanii along a subalpine timberline. Zimmerman et al. 13 showed that climate factors such as temperature and rainfall strongly structured fungal communities in the leaves of Metrosideros polymorpha across a Hawaiian landscape. A different study conducted in tropical lowland rainforests focused on the factors shaping the community structure of phyllosphere fungi and found that plant traits and taxonomy were critical factors 14. Moreover, several studies have explored the relationship between the genetic identity of a conspecific host and the community composition of its phyllosphere fungi, but no consensus was established. Variation in phyllosphere fungal community composition in Fagus sylvatica and Mussaenda pubescens var. alba was mostly explained by host genotype 15,16. In contrast, plant genotype had no significant effect on the phyllosphere fungal microbiome of Picea glauca 17. Microorganisms often vary across trophic modes and functionally distinct niches, which allows them to co-exist and to form complex ecological networks comprising microbial members that interact with each other 18,19. A comprehensive exploration of co-occurrence networks is critical to understanding t...

Effects of precipitation change and nitrogen addition on the composition, diversity, and molecular ecological network of soil bacterial communities in a desert steppe

“…Finally, the "randomize the network structure and then calculate network" was run. Random networks were generated for comparison with the topology of the empirical network; each link had the same probability of being assigned to any node [ 52 ].…”

Cross‐phytogroup assessment of foliar epiphytic mycobiomes

“…In addition, fungi play a variety of roles with different functions and potential effects on the host, which can be attributed to pathotrophic (harming host cells), symbiotrophic (exchanging resources with host cells), and saprotrophic (decomposing dead host cells) lifestyles (Nguyen et al ., 2016). To date, relatively fewer studies have conducted analyses that encompass foliar epiphytic fungi hosted by multiple plant species (Balint et al ., 2013; Kembel and Mueller, 2014; Sapkota et al ., 2015; Unterseher et al ., 2018; Zheng and Gong, 2019; Qian et al ., 2020), e.g., the foliar mycobiomes of 51 tree species (Kembel and Mueller, 2014). However, the small sample sizes and small numbers of species examined in these studies generally cannot effectively represent plants or foliar fungal epiphytes, and epiphytic mycobiome patterns across multiple plant taxa remain unexplored.…”

Comparative analyses of sooty mould communities from Brazil and Central Europe

“…The colour scale illustrates the dominance (%) within the sites. The dendrogram on top illustrates the similarity of the sites; the one on the left represents the similarity in the pattern of occurrence of the individual fungal OTUs and Corlett 2019; Egidi et al 2019;Epstein et al 2019;Li et al 2019;Lynikiene et al 2020;Morales-Rodriguez et al 2019;Nerva et al 2019;Qian et al 2020;Ricks and Koide 2019;Saravesi et al 2019;Wilkinson et al 2019;Würth et al 2019;Yao et al 2019;Zhang et al 2019), others strongly recommended the use of ITS1 (Mbareche et al 2020), as it had already been implemented in many studies (Beule et al 2019;Checinska Sielaff et al 2019;Del Frari et al 2019;Schiro et al 2019). Few studies are based on both ITS regions (Janakiev et al 2019).…”

“…The use of operational taxonomic units (OTUs) versus the recent use of amplicon sequence variants (ASVs) is also inconsistent. Although there are recommendations to use only ASVs (Callahan et al 2017), resulting in a reduction in the number of dominant species (Egidi et al 2019), many of the current studies are still based on OTUs (Bao et al 2019;Beng and Corlett 2019;Beule et al 2019;Checinska Sielaff et al 2019;Epstein et al 2019;Janakiev et al 2019;Lynikiene et al 2020;Morales-Rodriguez et al 2019;Nerva et al 2019;Pan et al 2019;Qian et al 2020;Ricks and Koide 2019;Saravesi et al 2019;Wilkinson et al 2019;Würth et al 2019;Yao et al 2019;Zhang et al 2019), but others rely on ASVs (Del Frari et al 2019;Egidi et al 2019;Li et al 2019), or OTUs generated from ASVs (Ezeokoli et al 2020), and even OTUs from cultivationbased Sanger sequencing are still in use (Janowsky et al 2019). With the availability of the VSEARCH tool within the QIIME2 pipeline, allowing the easy aggregation of OTUs from ASVs, the Illumina sequencing datasets in this Fig.…”

“…Most current studies do not distinguish between epiphytic and endophytic fungal communities, as the complete microbiome is usually extracted from whole leaves (Lynikiene et al 2020;Qian et al 2020;Würth et al 2019). This is problematic in that endophytic fungi are more hostdependent than epiphytic fungi (Fonseca-García et al 2016;Lau et al 2013;Peršoh 2013).…”