Biology subjects

Calevo, J.

Publications and source records attributed to Calevo, J..

3 recordsLinked to original sources

bioRxiv2025

Breaking boundaries: fungi in the ''rhizoctonia'' species complex exhibit systemic colonization in three terrestrial orchid species

O_LIMost green orchids associate with orchid mycorrhizal (OrM) fungi belonging to the rhizoctonia complex, a polyphyletic group of Tulasnellaceae, Ceratobasidiaceae and Serendipitaceae (Agaricomycotina), which are generally assumed to live as saprotrophs in soil. However, OrM rhizoctonias were rarely detected by metabarcoding in soil around orchid roots, and we have tested the hypothesis that these fungi may use adult orchid plants as a niche by colonizing not only their roots, but also other organs. C_LIO_LIThe occurrence of OrM rhizoctonias inside roots, stems and leaves of three terrestrial orchid species (Spiranthes spiralis, Serapias vomeracea and Neottia ovata) was therefore investigated by metabarcoding. To test the possibility of a vertical transmission of OrM fungi, reproductive structures (capsules, as well as seeds in S. spiralis) were also analyzed in a subset of plants. C_LIO_LIIn all orchid species, a broad majority of OrM fungi found in roots was also detected in either stems or leaves of the same plant. OrM fungi were also detected in capsules/seeds. C_LIO_LISystemic colonization of orchid tissues by OrM symbionts is a novel finding that raises important questions on the plant-fungus relationship in the aerial organs and opens intriguing perspectives on the potential modes of fungal transmission to the orchid progeny. C_LI

ecology↗

bioRxiv2024

Orchid mycorrhizal communities associated with Orchis italica are shaped by ecological factors and geographical gradients

AimThe influence of mutualists on plant distributions is only beginning to be understood. Orchids depend on orchid mycorrhizal (OrM) fungi to germinate, yet the distribution of OrM and how they vary according to both abiotic and biotic factors is unclear. We investigated the abundance and diversity of OrM communities associated with the Mediterranean orchid Orchis italica and quantified how they vary according to both geographical and ecological factors. LocationMediterranean Basin. TaxonOrchis italica Poir. (Orchidaceae) MethodsWe used metabarcoding of the ITS2 region to identify OrM fungi associated with adult individuals in 23 populations of O. italica across latitudinal and longitudinal gradients in the Mediterranean region. We used both multivariate analyses and Joint Species Distribution Models (JSDMs) based on geographical, climate, and soil variables to test how both common OrM fungi and their communities vary according to geographical and ecological factors. ResultsEighty OrM OTUs were found associating with O. italica. However, five Tulasnellaceae OTUs and one Ceratobasidiaceae OTU were found in every population. Abundance of these taxa, as measured by number of reads, increased from west to east and decreased from south to north, indicating OrM abundance may be determined by geographical gradients. OrM community composition varied according to precipitation, annual mean temperature, and soil phosphorous content. JSDMs revealed there were both positive and negative co-occurrences among these ubiquitous OrM. Main ConclusionsDespite associating with many OrM across its range, only six OrM were widespread, indicating that O. italica may be an apparent generalist in its association with OrM. Abundance of these OrM is determined by geographical gradients and ecological factors. This highlights the importance of quantifying the distribution of belowground mutualists in understanding the limits to plant distributions.

ecology↗

bioRxiv2023

Drivers of species knowledge across the Tree of Life

Knowledge of biodiversity is unevenly distributed across the Tree of Life. In the long run, such disparity in awareness unbalances our understanding of life on Earth, influencing policy decisions and the allocation of research and conservation funding. We investigated how humans accumulate knowledge of biodiversity by searching for consistent relationships between scientific (number of publications) and societal (number of views in Wikipedia) interest, and species-level morphological, ecological and socio-cultural factors. Across a random selection of 3,019 species spanning 29 Phyla/Divisions, we show that socio-cultural factors are the most important correlates of scientific and societal interest in biodiversity, including the fact that a species is useful or harmful to humans, has a common name and is listed in the IUCN Red List. Furthermore, large-bodied, broadly distributed and taxonomically unique species receive more scientific and societal attention, whereas colorfulness and phylogenetic proximity to humans correlates exclusively with societal attention. These results highlight a favoritism towards limited branches of the Tree of Life, and that scientific and societal priorities in biodiversity research broadly align. This suggests that we may be missing out on key species in our research and conservation agenda simply because they are not on our cultural radar.

ecology↗