Biology subjects

Buyck, B.

Publications and source records attributed to Buyck, B..

4 recordsLinked to original sources

bioRxiv2024

A revision of the African Russula radicans and allies in subgen. Heterophyllidiae provides an example of a clade that exhibits recent diversification and extensive phenotypic plasticity.

Russula subsection Radicantinae is described for R. radicans and allies, while subsection Aureotactinae is again restricted to R. aureotacta, the subsectional type species that has never been recollected since its original description. Russula radicans, originally described from Madagascar, as well as the Central African R. brunneoannulata, are epitypified. Russula xylophila is the first confirmed annulate species belonging to Sect. Ingratae and a close relative to R. oleifera. An ITS sequence has been obtained from the R. xylophila holotype collection made in 1928, but it is slightly different from those obtained from all new collections. For this reason and some minor morphological differences, we refrained from epitypification. Russula acriannulata, another species attributed to Aureotactinae in the past, is now also excluded from the subsection, but needs more sequencing to solve its systematic placement. The Malagasy Russula cibaensis and R. tapiae, as well as the Central African R. cameroonensis and R. afrovinacea are new species in Radicantinae.At least three more undescribed species are revealed by environmental sequences. The West African R. sankarae is reduced to a form of R. radicans. The latter species exhibits an impressive phenotypic plasticity in response to differences in habitat or host associations. It has a very wide distribution covering littoral rain forest in eastern Madagascar (forma radicans), Zambezian woodlands in Central and Eastern Africa (forma miomboensis fo. nov.) and gallery forests in West Africa (forma sankarae).

molecular biology↗

bioRxiv2024

Revisiting sour rot of grapevine through disease-associated microbiomes: a tripartite co-infection?

Sour rot in grapevines is thought to result from berry infection by yeasts, acetic acid bacteria and vinegar flies. To better characterize the role of each of the actors involved in sour rot expression, we conducted experiments involving the isolation of 1593 fungi and bacteria to understand the composition and dynamics of the microbiomes associated with healthy berries, diseased berries and insect vectors. As some grape clusters became symptomatic for sour rot in the absence of acetic acid bacteria, the latter might not necessarily be needed for disease expression. Similar to other yeast genera, the yeast genus Geotrichum is here also reported for the first time to be able to initiate sour rot in grapes, however, this finding has to be confirmed by further studies. By allowing or denying the access of insect vectors to intact or artificially wounded grapes we could emphasize that they accelerate the expression of the disease when berries are injured. Moreover, the microbial communities identified on native vinegar flies (Drosophila spp.) and the introduced Drosophila suzukii were similar and yeast dominated. This highlights the key role of these insect vectors in the transmission of microorganisms inflicting sour rot to wounded berries. Finally, our data also suggest that sour rot and grey mould can coexist in a vineyard at an advanced stage of grape decomposition, which runs counter to recent studies that emphasize the supremacy of sour rot over grey mould. IMPORTANCEThis study sheds new light on the complex interactions between microbiomes, insect vectors and physical factors favoring the development of sour rot. While previous studies suggested that acetic acid bacteria were mandatory for sour rot expression our results suggest that grape sour rot could also result solely from yeast infection. Moreover, native vinegar flies and the introduced D. suzukii host and vectorize a similar microbial community to injured berries in vineyards and their presence accelerates the infection process and consequently the expression of sour rot.

pathology↗

bioRxiv2023

Russula (Basidiomycota, Russulales, Russulaceae) subsect. Roseinae down under.

The present contribution presents species of Russula subsect. Roseinae Sarnari from the southern hemisphere. Russula incrustata Buyck, sp. nov. and R. koniamboensis Buyck, sp. nov. are described from New Caledonia, R. purpureotincta R. F. R. McNabb from New Zealand is redescribed in detail and two secotioid species, R. albobrunnea T. Lebel from Australia and R. kermesina (R. F. R. McNabb) T. Lebel from New Zealand are shown to be the first known secotioid taxa in Roseinae. The systematic placement and importance of these southern taxa is discussed.

molecular biology↗

bioRxiv2023

Russula subgen. Cremeoochraceae subgen. nov.: a very small and ancient lineage sharing with Multifurca (Russulaceae) an identical, largely circum-Pacific distribution pattern

The application of DNA data on a worldwide sampling has revolutionized the infrageneric classification of the highly diverse ectomycorrhizal genus Russula. Based on collections made in New Zealand, East Asia and North America, this study describes the new subgenus Cremeoochraceae, the ninth subgenus in Russula. Even though BLASTn of the ITS sequences suggested affinities with species of subgenera Russula and Heterophyllidiae, the phylogenetic analysis based on a five-locus DNA dataset placed the target samples in an independent major clade that is systematically equivalent to subgenus. The new subgenus shares with subgen. Brevipedum subsect. Pallidosporinae the general field habit, the unequal lamellae and the relatively small spores with inamyloid suprahilar spot and similar spore ornamentation. It differs from the latter subsection principally in the poor contents of all types of cystidioid cells and the often areolate-scurfy pileus surface composed of slender, undulating hyphal terminations with frequent subcapitate apices. Biogeographically, subgen. Cremeoochraceae shares with Multifurca, the sister genus of Lactarius, a circum-Pacific distribution pattern with the exception of South America. Both lineages lack representatives in Europe and Africa. The hypothesis proposing an African origin for the genus is considered unlikely.

molecular biology↗