Plant-Fungi Interactions: Where It Goes?

Fungi live different lifestyles-including pathogenic and symbiotic-by interacting with living plants. Recently, there has been a substantial increase in the study of phytopathogenic fungi and their interactions with plants. Symbiotic relationships with plants appear to be lagging behind, although progressive. Phytopathogenic fungi cause diseases in plants and put pressure on survival. Plants fight back against such pathogens through complicated self-defense mechanisms. However, phytopathogenic fungi develop virulent responses to overcome plant defense reactions, thus continuing their deteriorative impacts. Symbiotic relationships positively influence both plants and fungi. More interestingly, they also help plants protect themselves from pathogens. In light of the nonstop discovery of novel fungi and their strains, it is imperative to pay more attention to plant-fungi interactions. Both plants and fungi are responsive to environmental changes, therefore construction of their interaction effects has emerged as a new field of study. In this review, we first attempt to highlight the evolutionary aspect of plant-fungi interactions, then the mechanism of plants to avoid the negative impact of pathogenic fungi, and fungal strategies to overcome the plant defensive responses once they have been invaded, and finally the changes of such interactions under the different environmental conditions.

Integrative Taxonomy of Novel Diaporthe Species Associated with Medicinal Plants in Thailand.

During our investigations of the microfungi on medicinal plants in Thailand, five isolates of Diaporthe were obtained. These isolates were identified and described using a multiproxy approach, viz. morphology, cultural characteristics, host association, the multiloci phylogeny of ITS, tef1-α, tub2, cal, and his3, and DNA comparisons. Five new species, Diaporthe afzeliae, D. bombacis, D. careyae, D. globoostiolata, and D. samaneae, are introduced as saprobes from the plant hosts, viz. Afzelia xylocarpa, Bombax ceiba, Careya sphaerica, a member of Fagaceae, and Samanea saman. Interestingly, this is the first report of Diaporthe species on these plants, except on the Fagaceae member. The morphological comparison, updated molecular phylogeny, and pairwise homoplasy index (PHI) analysis strongly support the establishment of novel species. Our phylogeny also revealed the close relationship between D. zhaoqingensis and D. chiangmaiensis; however, the evidence from the PHI test and DNA comparison indicated that they are distinct species. These findings improve the existing knowledge of taxonomy and host diversity of Diaporthe species as well as highlight the untapped potential of these medicinal plants for searching for new fungi.

Lignicolous freshwater fungi in Yunnan Province, China: an overview.

Yunnan Province is one of the rich biodiversity hotspots with abundant resources of lignicolous freshwater fungi. A total of 281 species of lignicolous freshwater fungi from 1986 to the present in Yunnan Province. They are mostly distributed in the classes Dothideomycetes and Sordariomycetes, a few species in the Eurotiomycetes and Leotiomycetes, and rarely reported in Orbiliomycetes and Pezizomycetes. Lignicolous freshwater fungi can decompose lignocellulose substrates and release energy and nutrients, and thus playing an important role in freshwater environment. This study briefly reviewed the biodiversity and taxonomic status of lignicolous freshwater fungi in Yunnan, the ecological functions of lignicolous freshwater fungi, factors affecting community distribution, application status, and research difficulties.

Taxonomic Reappraisal of Periconiaceae with the Description of Three New Periconia Species from China.

As a result of an ongoing research survey of microfungi in Yunnan, China, several saprobic ascomycetes were collected from various host substrates. Preliminary morphological analyses identified a few of these taxa as Periconia species. We obtained DNA sequence data of the Periconia species from pure cultures and investigated their phylogenetic affinities. Phylogenetic analyses of a combined LSU, ITS, SSU and tef1-α sequence dataset demonstrated that five isolates of Periconia formed well-resolved subclades within Periconiaceae. Accordingly, three new Periconia species are introduced viz. P. artemisiae, P. chimonanthi and P. thysanolaenae, and new host and geographical records of P. byssoides and P. pseudobyssoides, are also reported from dead branches of Prunus armeniaca and Scrophularia ningpoensis. Periconia celtidis formed a monophyletic clade with P. byssoides in the present phylogenetic analyses. Results of the pairwise homoplasy index (PHI) test indicated significant recombination between P. byssoides and P. celtidis. Therefore, P. celtidis has been synonymized under P. byssoides. In addition, we re-illustrated and studied the type specimen of the sexual genus Bambusistroma. As a type species of Bambusistroma, B. didymosporum features similar morphology to the sexual morph of Periconia homothallica and P. pseudodigitata. We therefore synonymize Bambusistroma under Periconia based on morphological and phylogenetic evidence. Furthermore, our new isolates produced brown conidia of asexual morph in agar media typical of the genus Noosia. Based on morphological comparison with Periconia in vitro and phylogenetic status of Noosia, we also treat Noosia as a synonym of Periconia. Detailed descriptions and illustrations of three novel taxa and two new records of Periconia byssoides and P. pseudobyssoides as well as the illustration of P. didymosporum comb. nov. are provided. An updated phylogenetic tree of Periconiaceae using maximum likelihood and Bayesian inference analyses is constructed. Generic circumscription of Periconia is amended.

Lignicolous freshwater ascomycetes from Thailand: Introducing Dematipyriformamuriformis sp. nov., one new combination and two new records in Pleurotheciaceae.

During the study of lignicolous freshwater fungi from Thailand, three pleurotheciaceous species were collected from freshwater habitats in Thailand. Two were identified as Pleurotheciumaquaticum and Rhexoacrodictysfimicola, and the third is a new species Dematipyriformamuriformis sp. nov.. Rhexoacrodictys is accepted in Pleurotheciaceae based on phylogenetic analysis. Rhexoacrodictysnigrospora is transferred to Dematipyriforma based on phylogenetic analysis and morphological characters. Pleurotheciumaquaticum and Rhexoacrodictysfimicola are reported from Thailand for the first time.

Two novel species and two new records of Distoseptispora from freshwater habitats in China and Thailand.

During investigations into freshwater fungi from the Great Mekong Subregion, four Distoseptispora taxa were collected from China and Thailand. Based on morphological characteristics, and phylogenetic analyses of combined LSU, ITS, SSU, TEF1-α, and RPB2 sequence data, two new species Distoseptisporabangkokensis and D.lancangjiangensis are introduced, and two known species D.clematidis and D.thysanolaenae were first reported in freshwater habitat. Illustrations and descriptions of these taxa are provided, along with comparisons with extant taxa in the genus.

Yuxiensis granularis gen. et sp. nov., a Novel Quellkörper-Bearing Fungal Taxon Added to Scortechiniaceae and Inclusion of Parasympodiellaceae in Coronophorales Based on Phylogenetic Evidence.

An undetermined saprobic fungal taxon from Yunnan (China) is revealed as a new genus in Scortechiniaceae (Coronophorales). The novel taxon, Yuxiensis, is characterized by immersed to erumpent, semi-globose ascomata, which are not surrounded by any tomentum or conspicuous subiculum, a subcylindrical quellkörper in the centrum, clavate asci with long pedicels and allantoid hyaline ascospores with granular contents. Maximum likelihood and Bayesian posterior probability analyses based on LSU, ITS, tef1 and rpb2 sequence data depict a close phylogenetic relationship of the new genus to Pseudocatenomycopsis, hence, confirming its placement in Scortechiniaceae. Parasympodiellaceae, thus far belonging to Parasympodiellales, is transferred to Coronophorales based on multi-gene phylogenetic evidence. Additionally, the incertae sedis monotypic genus Arthrocristula is treated as a synonym of Parasympodiella, with Arthrocristula hyphenata recombined as Parasympodiella hyphenata comb. nov., as the type strain of Arthrocristula hyphenata clusters inside the Parasympodiellaceae clade along with other Parasympodiella taxa.

Two novel species of Neoaquastroma (Parabambusicolaceae, Pleosporales) with their phoma-like asexual morphs.

The monotypic genus Neoaquastroma (Parabambusicolaceae, Pleosporales) was introduced for a microfungus isolated from a collection of dried stems of a dicotyledonous plant in Thailand. In this paper, we introduce two novel species, N. bauhiniae and N. krabiense, in this genus. Their asexual morphs comprise conidiomata with aseptate and hyaline conidia. Neoaquastroma bauhiniae has ascomata, asci and ascospores that are smaller than those of N. krabiense. Descriptions and illustrations of N. bauhiniae and N. krabiense are provided and the two species compared with the type species of the genus, N. guttulatum. Evidence for the introduction of the new taxa is also provided from phylogenetic analysis of a combined dataset of partial LSU, SSU, ITS and tef1 sequence data. The phylogenetic analysis revealed a distinct lineage for N. bauhiniae and N. krabiense within the family Parabambusicolaceae.