Biology subjects

Holzhausen, A.

Publications and source records attributed to Holzhausen, A..

3 recordsLinked to original sources

bioRxiv2024

Chara canescens part I: Oospore differentiation of parthenogenic and dioecious strains and salt-dependent oospore sizes

Chara canescens Loisel. is one of two European species of the section Desvauxia R.D. Wood of the genus Chara L. Whereas most populations of C. canescens reproduce parthenogenetically, a few sites with sexual reproducing populations are known. Studies of European C. canescens oospore morphology led to open questions about the taxonomic status. Here we investigated nearly 1000 oospores from 16 European populations originated from plant release, sediments, germination experiments and herbaria and two Asian populations resulting in a regional determination key for studied populations as well as important database implications regarding origin, oospore plant position and equipment used. The impact of salinisation on oospore morphology were tested by artificial salt levels. The longest but smallest oospores were formed at 3 PSU, whereas the widest at 0.1 PSU and the shortest at 5 PSU. Basal width and shape, on the other hand, seem to be only affected by higher salt contents. This study contributes the lacking oospore-information for both reproduction modes of European of C. canescens - populations.

plant biology↗

bioRxiv2023

Insight into the central and nodal cells transcriptome of the streptophyte green alga Chara braunii S276

Chara braunii is an emerging model system for streptophyte terrestrialization and early land plant evolution. In this study, tissue containing nodal cells was prepared under the stereomicroscope and an RNA-seq dataset generated and compared to transcriptome data from whole plantlets. In both samples, transcript coverage was high for genes encoding ribosomal proteins and a homolog of the putative PAX3- and PAX7-binding protein 1. Gene ontology-based functional assignments revealed for the nodal cell sample main upregulated molecular functions related to protein binding, nucleic acid binding and DNA binding. Looking at specific genes, several signalling-related genes and genes encoding sugar-metabolizing enzymes were found to be expressed at a higher level in the nodal cell sample, while photosynthesis-and chloroplast-related genes were expressed at a comparatively lower level. We detected the transcription of 21 different genes encoding DUF4360-containing cysteine-rich proteins. The data contribute to the growing understanding of charophyte developmental genetics by providing a first insight into the transcriptome composition of Chara central and nodal cells.

plant biology↗

bioRxiv2022

Plastid DNA sequences and oospore characters of some European species of Tolypella section Tolypella (Obtusifolia, Characeae) indicate a new cryptic Tolypella species from the Mediterranean island Sardinia

In Europe, the genus Tolypella (Characeae) comprises four to eight Tolypella species in sections Rothia and Tolypella that have been distinguished by vegetative morphology and gametangial characters such as antheridial size and oospore cell wall ornamentation. However, morphological species differentiation is difficult in some cases due to overlapping and variable vegetative features, which in many cases are difficult to observe clearly. To clarify the taxonomic status of the five European species of Tolypella in section Tolypella, sequence data of the plastid genes atpB, rbcL and psbC for Tolypella glomerata (Desv.) Leonh., Tolypella hispanica Allen, Tolypella nidifica (O.F. Mull.) A. Braun, Tolypella normaniana (Nordst.) Nordst. and Tolypella salina Cor. were combined with data on oospore morphology, including oospore wall ornamentation. Gene sequence data identified five distinct clusters, but they differed from the morphologically identified five species. T. glomerata consisted of some of the samples morphologically identified as T. glomerata and seven samples of T. normaniana, while the remaining T. glomerata samples clustered with specimens of unclear affiliation ("Tolypella. sp."). T. hispanica I consisted of samples from various locations, whereas "T. hispanica II" consisted of samples of T. hispanica from the Mediterranean island, Sardinia. The remaining cluster consisted of all the specimens that had been determined as T. salina or T. nidifica in addition to two specimens of T. normaniana. Oospore morphology was most clearly distinguishable for T. glomerata. Oospore characteristics for all other taxa were not as informative but showed some geographical and/or environmentally influenced differences, especially for T. nidifica and T. salina. Our results suggest a significantly different taxonomy of Tolypella sect. Tolypella in which specimens normally identified as T. glomerata might be two different species, T. glomerata and an unidentified species; T. nidifica and T. salina are not separate species; T. normaniana is a diminutive variant of T. nidifica or T. salina; and T. hispanica comprises two different species, one from the Mediterranean island Sardnia.

plant biology↗