Explore the vast range of titles available.

The majority of vascular plants are mycorrhizal: 72% are arbuscular mycorrhizal (AM), 2.0% are ectomycorrhizal (EcM), 1.5% are ericoid mycorrhizal and 10% are orchid mycorrhizal. Just 8% are completely nonmycorrhizal (NM), whereas 7% have inconsistent NM–AM associations. Most NM and NM–AM plants are nutritional specialists (e.g. carnivores and parasites) or habitat specialists (e.g. hydrophytes and epiphytes). Mycorrhizal associations are consistent in most families, but there are exceptions with complex roots (e.g. both EcM and AM). We recognize three waves of mycorrhizal evolution, starting with AM in early land plants, continuing in the Cretaceous with multiple new NM or EcM linages, ericoid and orchid mycorrhizas. The third wave, which is recent and ongoing, has resulted in root complexity linked to rapid plant diversification in biodiversity hotspots.

The meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Aphrophoridae), is the main vector in Europe of the recently detected plant pathogen bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae). While the ecology of continental populations is well documented, nothing is known about the insular populations of P. spumarius, such as in Corsica, where the bacterium was detected in 2015. Hence, in an epidemiological context, the ecology of P. spumarius has been studied in a maquis landscape in the Ajaccio region between 2017 and 2019. Adults and nymphs were almost exclusively collected on Cistus monspeliensis L. (Cistaceae). However, very few specimens were collected in summer, suggesting a movement of the adults to sheltered habitats. Unfortunately, despite several trapping methods used, the location of adult summer habitat remains unknown for the studied population. It might be tempting to destroy the central plant host of P. spumarius populations. However, as spittlebug nymphs are highly polyphagous on low-growing plant species and as the females can lay eggs in any dead plant tissues, such practice could have limited the impact. Instead, the strong relationship between P. spumarius and C. monspeliensis could be used to monitor spittlebug populations, to limit/concentrate the means of insect control, or in an agronomic context to lure insects away from crops. Maintaining natural arboreal vegetation around agronomic systems could help decrease insect abundance – and potentially, pathogen load – on cultivated species. Such hypotheses need to be further studied by landscape experiments.

We argue that the genetic diversity of a dominant plant is important to the associated dependent community because dependent species such as herbivores are restricted to a subset of genotypes in the host-plant population. For plants that function as habitat, we predicted that greater genetic diversity in the plant population would be associated with greater diversity in the dependent arthropod community. Using naturally hybridizing cottonwoods (Populus spp.) in western North America as a model system, we tested the general hypothesis that arthropod alpha (within cross-type richness) and beta (among cross-type composition) diversities are correlated with cottonwood cross types from local to regional scales. In common garden experiments and field surveys, leaf-modifying arthropod richness was significantly greater on either the F1(1.54 times) or backcross (1.46 times) hybrid cross types than on the pure broadleaf cross type (P. deltoides Marshall or P. fremontii Watson). Composition was significantly different among three cross types of cottonwoods at all scales. Within a river system, cottonwood hybrid zones had 1.49 times greater richness than the broadleaf zone, and community composition was significantly different between each parental zone and the hybrid zone, demonstrating a hierarchical concentration of diversity. Overall, the habitats with the highest cottonwood cross-type diversity also had the highest arthropod diversity. These data show that the genetics of habitat is an important conservation concept and should be a component of conservation theory.

This study investigates the host diversity and characteristics of the rare parasitic plant Silverberry-like taxillus (Taxillus yadoriki). Seogwipo, Jeju Island, where T. yadoriki grows naturally, was examined to clarify the diversity of host species, their location, and the part of the tree where T. yadoriki is attached. A total of 687 host trees were found. Taxillus yadoriki was intensively distributed in the lowlands below 200 m a.s.l. The host trees belonged to 40 species, four varieties, three cultivars, and two hybrids from 32 genera and 21 families, of which 23 taxa were identified as host plants for the first time in this study. Incredibly, this plant was found to be able to parasitize a variety of plants from 12 orders. Taxillus yadoriki was found to be parasitic in three orders of Gymnosperms, Ginkgoales, Cupressales, and Pinales, as well as nine orders of Angiosperms, including Magnoliales, Rosales, and Ericales. Rosaceae was the most diverse at 18.0%, and most species were broad-leaved and arboreal. Among them, Cryptomeria japonica and Litsea japonica had the highest frequency of parasitization and T. yadoriki was mainly attached to the upper part of the main tree and the main branch; as a result, T. yadoriki was distributed and showed specificity in the position of disturbance on the host. T. yadoriki’s specific distribution model was built as a Maxent program. The area under the curve of the receiver operation characteristic was 0.948 ± 0.026 (mean ± standard deviation), and the performance of the constructed model was excellent. Of the total eight environmental factors, density of artistic forest and meant temperature of coldest quarter accounted for 75.3% of the total importance, which was the main distribution determinant of species. In the average distribution probability map of T. yadoriki, the critical probability for determining distribution was calculated to be 0.2898 ± 0.1018. Accordingly, the distribution of species is predicted to expand from Jeju Island to the entire southern and southeastern coasts.

Endophytes can generate a cornucopia of marvelous bioactive secondary metabolites useful for mankind but their biodiversity and associations with host plants are still elusive. In this study, we explored the culturable endophytic microorganisms associated with 14 medicinal plants that are of high socio-economic value and/or reportedly endemic to northern Vietnam. Specifically, we isolated the endophytic microorganisms by applying surface sterilization methods and identified them based on morphological and rDNA sequence analyses. Agglomerative Hierarchical Clustering (AHC) and Principal Component Analysis (PCA) were used to analyze the correlations between the taxonomic affiliations of the culturable endophytes and the characteristics of their hosts. Most of the culturable endophytes obtained were bacteria (80), and few of those were actinomycetes (15) and fungi (8). Many of them are reported to be endophytes of medicinal plants for the first time. A number of plants (5) are also reported for the first time to contain microbial endophytes, while some plants with powerful pharmaceutical potential harbor unique endophytes. Furthermore, our results reveal a strikingly close relation between the compositions of bacterial and fungal isolates from plants having anti-bacterial activity and those from plants having anti-inflammatory activity, or between the compositions of the microbial endophytic isolates from plants having anti-cancer activity and those from plants having antioxidant activity. Altogether, the results provide new findings which can be inspiring for further in-depth studies to explore and exploit the relationships between medicinal plants and their associated endophytes in northern Vietnam and world-wide.

Fungal plant pathogens are common in natural communities where they affect plant physiology, plant survival, and biomass production. Conversely, pathogen transmission and infection may be regulated by plant community characteristics such as plant species diversity and functional composition that favor pathogen diversity through increases in host diversity while simultaneously reducing pathogen infection via increased variability in host density and spatial heterogeneity. Therefore, a comprehensive understanding of multi‐host–multi‐pathogen interactions is of high significance in the context of biodiversity–ecosystem functioning. We investigated the relationship between plant diversity and aboveground obligate parasitic fungal pathogen (“pathogens” hereafter) diversity and infection in grasslands of a long‐term, large‐scale, biodiversity experiment with varying plant species (1–60 species) and plant functional group diversity (1–4 groups). To estimate pathogen infection of the plant communities, we visually assessed pathogen‐group presence (i.e., rusts, powdery mildews, downy mildews, smuts, and leaf‐spot diseases) and overall infection levels (combining incidence and severity of each pathogen group) in 82 experimental plots on all aboveground organs of all plant species per plot during four surveys in 2006. Pathogen diversity, assessed as the cumulative number of pathogen groups on all plant species per plot, increased log‐linearly with plant species diversity. However, pathogen incidence and severity, and hence overall infection, decreased with increasing plant species diversity. In addition, co‐infection of plant individuals by two or more pathogen groups was less likely with increasing plant community diversity. We conclude that plant community diversity promotes pathogen‐community diversity while at the same time reducing pathogen infection levels of plant individuals.

Ecosystem productivity commonly increases asymptotically with plant species diversity, and determining the mechanisms responsible for this well-known pattern is essential to predict potential changes in ecosystem productivity with ongoing species loss. Previous studies attributed the asymptotic diversity-–productivity pattern to plant competition and differential resource use (e.g., niche complementarity). Using an analytical model and a series of experiments, we demonstrate theoretically and empirically that host-specific soil microbes can be major determinants of the diversity-–productivity relationship in grasslands. In the presence of soil microbes, plant disease decreased with increasing diversity, and productivity increased nearly 500%%, primarily because of the strong effect of density-dependent disease on productivity at low diversity. Correspondingly, disease was higher in plants grown in conspecific-trained soils than heterospecific-trained soils (demonstrating host-specificity), and productivity increased and host-specific disease decreased with increasing community diversity, suggesting that disease was the primary cause of reduced productivity in species-poor treatments. In sterilized, microbe-free soils, the increase in productivity with increasing plant species number was markedly lower than the increase measured in the presence of soil microbes, suggesting that niche complementarity was a weaker determinant of the diversity-–productivity relationship. Our results demonstrate that soil microbes play an integral role as determinants of the diversity-–productivity relationship.

Soil plant-pathogenic (PF) and mycorrhizal fungi (MF) are both important in maintaining plant diversity, for example via host-specialized effects. However, empirical knowledge on the degree of host specificity and possible factors affecting the fungal assemblages is lacking. We identified PF and MF in fine roots of 519 individuals across 45 subtropical tree species in southern China in order to quantify the importance of host phylogeny (including via its effects on functional traits), habitat and space in determining fungal communities. We also compared host specificity in PF and MF at different host-phylogenetic scales. In both PF and MF, host phylogeny independently accounted for > 19% of the variation in fungal richness and composition, whereas environmental and spatial factors each explained no more than 4% of the variation. Over 77% of the variation explained by phylogeny was attributable to covariation in plant functional traits. Host specificity was phylogenetically scale-dependent, being stronger in PF than in MF at low host-phylogenetic scales (e.g. within genus) but similar at larger scales. Our study suggests that host-phylogenetic effects dominate the assembly of both PF and MF communities, resulting from phylogenetically clustered plant traits. The scale-dependent host specificity implies that PF were specialized at lower-level and MF at higher-level host taxa.

Terrestrial biodiversity is dominated by plants and the herbivores that consume them, and they are one of the major conduits of energy flow up to higher trophic levels. Here, we address the processes that have generated the spectacular diversity of flowering plants (>300,000 species) and insect herbivores (likely >1 million species). Long-standing macroevolutionary hypotheses have postulated that reciprocal evolution of adaptations and subsequent bursts of speciation have given rise to much of this biodiversity. We critically evaluate various predictions based on this coevolutionary theory. Phylogenetic reconstruction of ancestral states has revealed evidence for escalation in the potency or variety of plant lineages' chemical defenses; however, escalation of defense has been moderated by tradeoffs and alternative strategies (e.g., tolerance or defense by biotic agents). There is still surprisingly scant evidence that novel defense traits reduce herbivory and that such evolutionary novelty spurs diversification. Consistent with the coevolutionary hypothesis, there is some evidence that diversification of herbivores has lagged behind, but has nevertheless been temporally correlated with that of their host-plant clades, indicating colonization and radiation of insects on diversifying plants. However, there is still limited support for the role of host-plant shifts in insect diversification. Finally, a frontier area of research, and a general conclusion of our review, is that community ecology and the long-term evolutionary history of plant and insect diversification are inexorably intertwined.

A comprehensive appraisal of the mycorrhizal literature provides data for 336 plant families representing 99% of flowering plants, with regard to mycorrhizas and other nutritional adaptations. In total, arbuscular (AM), orchid, ectomycorrhizas (EM) and ericoid mycorrhizas and nonmycorrhizal (NM) roots occur in 74%, 9%, 2%, 1% and 6% of Angiosperm species respectively. Many families of NM plants have alternative nutritional strategies such as parasitism, carnivory, or cluster roots. The remaining angiosperms (8%) belong to families reported to have both AM and NM species. These are designated as NM-AM families here and tend to occur in habitats considered non-conducive to mycorrhizal fungi, such as epiphytic, aquatic, extremely cold, dry, disturbed, or saline habitats. Estimated numbers of species in each category of mycorrhizas is presented with lists of NM and EM families. Evolutionary trends are also summarised by providing data on all clades and orders of flowering and non-flowering vascular plants on a global scale. A case study of Western Australian plants revealed that plants with specialised nutritional modes such as carnivory, cluster roots, or EM were much more diverse in this ancient landscape with infertile soils than elsewhere. Detailed information on the mycorrhizal diversity of plants presented here is linked to a website (mycorrhizas.info) to allow data to remain current. Over a century of research effort has resulted in data on mycorrhizal associations of >10,000 plant species that are of great value, but also somewhat of a liability due to conflicting information about some families and genera. It is likely that these conflicts result in part from misdiagnosis of mycorrhizal associations resulting from a lack of standardisation in criteria used to define them. Families that contain both NM and AM species provide a second major source of inconsistency, but even when these are excluded there is a ~10% apparent error rate in published lists of mycorrhizal plants. Arbuscules are linked to AM misdiagnosis since they are used less often than vesicles to recognise AM associations in roots and apparently occur sporadically in NM plants. Key issues with the diagnosis of mycorrhizal plants are discussed using the Cyperaceae as a case study. Detailed protocols designed to consistently distinguish AM from endophytic Glomeromycotan Fungus Colonisation (GFC) are provided. This review aims to stimulate debate and provide advice to researchers delving into root biology.