Botanical Studies最新文献

Background: Xylaria collections from termite nests with dichotomously branched stromata have been identified as X. furcata. However, Léveillé's original material is no longer available, and the modern interpretation of X. furcata is based on a 1908 collection made by von Höhnel from termite nests at Buitenzorg Botanical Garden in Java. A packet of this von Höhnel material at FH was designated as the neotype by Rogers et al. in 2005.

Results: We reexamined the neotype from FH and its duplicates from various herbaria and found that three different species were mixed in these specimens. Despite that all of them have dichotomously branched stromata and tiny ascospores, only one fits the 2005 neotypification of X. furcata, where exposed perithecial mounds on the stromatal surface were unambiguously indicated. This portion of material is redesignated as the neotype, while the other two species with immersed perithecia are described as new: X. hoehnelii and X. robustifurcata. The ITS sequence obtained from the neotype helped us designate a specimen with cultures obtained from it as the epitype. From specimens identifiable as X. furcata, we describe four new species: X. brevifurcata, X. furcatula, X. insignifurcata, and X. tenellifurcata. Additionally, we recognize X. furcata var. hirsuta at the species level as X. hirsuta and consider X. scoparia a distinct species rather than a synonym of X. furcata. Molecular phylogenetic analyses based on three protein-coding loci showed that X. furcata and resembling species were grouped into two clusters: the X. furcata cluster with half-exposed to fully exposed perithecial mounds and the X. hoehnelii cluster with largely immersed perithecial mounds.

Conclusion: Ten species are recognized for X. furcata and resembling species, all of which could have been identified as X. furcata in the past. Its diversity has been overlooked primarily due to the small and similar stromata. Several additional species have been confirmed to be related to X. furcata by DNA sequences but are yet to be described due to the lack of mature stromata. While the species diversity of macrotermitine termites is equally high in Africa as in Asia, all of the species are primarily found in Asia, with X. hirsuta as the only exception. This suggests that there may be many more undiscovered species for this fungal group.

Background: Potatoes are a crucial vegetable crop in Egypt in terms of production and consumption. However, the potato industry suffers significant annual losses due to brown rot disease. This study aimed to suppress Ralstonia solanacearum (R. solanacearum), the causative agent of brown rot disease in potatoes, using efficient and economical medications such as CuO and MgO metal oxide nanoparticles, both in vitro and in vivo, to reduce the risk of pesticide residues.

Results: CuO and MgO metal oxide nanoparticles were synthesized via a simple chemical process. The average particle size, morphology, and structure of the nanoparticles were characterized using UV-visible spectroscopy, transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The growth of R. solanacearum was strongly inhibited by CuO and MgO NPs at a concentration of 3 mg/mL, resulting in zones of inhibition (ZOI) of 19.3 mm and 17 mm, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CuO-NPs and MgO-NPs were 0.5, 0.6, and 0.6, 0.75 mg/mL, respectively. When applied in vivo through seed dressing and tuber soaking at their respective MIC concentrations, CuO-NPs and MgO-NPs significantly reduced the incidence of brown rot disease to 71.2% and 69.4%, respectively, compared to 43.0% and 39.5% in bulk CuSO₄ and bulk MgSO₄ treatments, respectively. Furthermore, CuO-NPs and MgO-NPs significantly increased the yield, total chlorophyll content, and enzyme efficiency of potato plants compared with the infected control plants. TEM revealed that the bacterial cytomembrane was severely damaged by nanomechanical forces after interaction with CuO-NPs and MgO-NPs, as evidenced by lipid peroxidation and ultrastructural investigations.

Conclusion: The results of this study suggest that CuO-NPs and MgO-NPs can be used as intelligent agents to manage plant pathogens in agriculture. The use of metal oxide nanoparticles could provide a risk-free alternative for treating plant diseases, which are currently one of the biggest challenges faced by the potato industry in Egypt. The significant increase in yield, photosynthetic pigments, enzymatic activity, and total phenol-promoted resistance to R. solanacearum in potato plants treated with CuO-NPs and MgO-NPs compared to infected control plants highlights the potential benefits for the potato industry in Egypt. Further investigations are needed to explore using metal oxide nanoparticles for treating other plant diseases.

Background: Xylaria species growing on fallen leaves and petioles have not been treated systematically. One source of confusion in this group of Xylaria species has stemmed from X. filiformis, which is an ancient name published in 1805 as Sphaeria filiformis and has commonly labeled on specimen packets that contain leaf- and petiole-inhabiting Xylaria species. Here we clarified the identity of X. filiformis and distinguish it from the species that are easily confused with it, notably X. simplicissima, to which most specimens labeled as X. filiformis are referred. Our research also led us to encounter many other leaf- and petiole-inhabiting Xylaria species, prompting a comprehensive study of this group of fungi.

Results: Forty-five foliicolous and caulicolous species of Xylaria were studied, including nine newly described species-X. allima, X. appendiculatoides, X. hispidipes, X. minuscula, X. neblinensis, X. spiculaticlavata, X. vermiformis, X. vittatipiliformis, and X. vittiformis; three unnamed species-X. sp. AR1741, X. sp. GS7461A, and X. sp. GS7461B; X. simplicissima, a name newly combined with Xylaria from Rhizomorpha simplicissima; and X. noduliformis and X. imminuta, which are two new replacement names, respectively, for X. maitlandii var. nuda and X. hypsipoda var. microspora. The 45 taxa can be classified into three groups by stromatal shape and conspicuousness of perithecial mounds on the stromatal surface: (i) the X. filiformis group contains 10 species, (ii) the X. phyllocharis group contains 19 species, and (iii) the X. heloidea group contains 16 species. One of the newly described or unnamed species belongs to the X. filiformis group-X. vermiformis; nine of them belong to the X. phyllocharis group-X. allima, X. appendiculatoides, Xylaria minuscula, X. neblinensis, X. sp. AR1741, X. sp. GS7461B, X. spiculaticlavata, X. vittatipiliformis, and X. vittiformis; and three of them belong to the X. heloidea group-X. hispidipes, X. imminuta, and X. sp. GS7461A.

Conclusion: The 45 species of Xylaria associated with fallen leaves and petioles can be identified by using the dichotomous identification key that we provided herein. It is important to note that most of the studied species are represented by only one or several specimens and many have not been recollected and cultured.

Valine-glutamine genes (VQ) acted as transcription regulators and played the important roles in plant growth and development, and stress tolerance through interacting with transcription factors and other co-regulators. In this study, sixty-one VQ genes containing the FxxxVQxxTG motif were identified and updated in the Nicotiana tobacum genome. Phylogenetic analysis indicated that NtVQ genes were divided into seven groups and genes of each group had highly conserved exon-intron structure. Expression patterns analysis firstly showed that NtVQ genes expressed individually in different tobacco tissues including mixed-trichome (mT), glandular-trichome (gT), and nonglandular-trichome (nT), and the expression levels were also distinguishing in response to methyl jasmonate (MeJA), salicylic acid (SA), gibberellic acid (GA), ethylene (ETH), high salinity and PEG stresses. Besides, only NtVQ17 of its gene family was verified to have acquired autoactivating activity. This work will not only lead a foundation on revealing the functions of NtVQ genes in tobacco trichomes but also provided references to VQ genes related stress tolerance research in more crops.

Background: Globally, many undescribed fungal taxa reside in the hyperdiverse, yet undersampled, tropics. These species are under increasing threat from habitat destruction by expanding extractive industry, in addition to global climate change and other threats. Reserva Los Cedros is a primary cloud forest reserve of ~ 5256 ha, and is among the last unlogged watersheds on the western slope of the Ecuadorian Andes. No major fungal survey has been done there, presenting an opportunity to document fungi in primary forest in an underrepresented habitat and location. Above-ground surveys from 2008 to 2019 resulted in 1760 vouchered collections, cataloged and deposited at QCNE in Ecuador, mostly Agaricales sensu lato and Xylariales. We document diversity using a combination of ITS barcode sequencing and digital photography, and share the information via public repositories (GenBank & iNaturalist).

Results: Preliminary identifications indicate the presence of at least 727 unique fungal species within the Reserve, representing 4 phyla, 17 classes, 40 orders, 101 families, and 229 genera. Two taxa at Los Cedros have recently been recommended to the IUCN Fungal Red List Initiative (Thamnomyces chocöensis Læssøe and "Lactocollybia" aurantiaca Singer), and we add occurrence data for two others already under consideration (Hygrocybe aphylla Læssøe & Boertm. and Lamelloporus americanus Ryvarden).

Conclusions: Plants and animals are known to exhibit exceptionally high diversity and endemism in the Chocó bioregion, as the fungi do as well. Our collections contribute to understanding this important driver of biodiversity in the Neotropics, as well as illustrating the importance and utility of such data to conservation efforts.

Resumen: Antecedentes: A nivel mundial muchos taxones fúngicos no descritos residen en los trópicos hiper diversos aunque continúan submuestreados. Estas especies están cada vez más amenazadas por la destrucción del hábitat debido a la expansión de la industria extractivista además del cambio climático global y otras amenazas. Los Cedros es una reserva de bosque nublado primario de ~ 5256 ha y se encuentra entre las últimas cuencas hidrográficas no explotadas en la vertiente occidental de los Andes ecuatorianos. Nunca antes se ha realizado un estudio de diversidad micológica en el sitio, lo que significa una oportunidad para documentar hongos en el bosque primario, en hábitat y ubicación subrepresentatadas. El presente estudio recopila información entre el 2008 y 2019 muestreando material sobre todos los sustratos, reportando 1760 colecciones catalogadas y depositadas en el Fungario del QCNE de Ecuador, en su mayoría Agaricales sensu lato y Xylariales; además se documenta la diversidad mediante secuenciación de códigos de barras ITS y fotografía digital, la información está disponible en repositorios públicos digitales (GenBank e iNaturalist).