Spore Abundance Research Articles

Exploration and Identification of Arbuscular Mycorrhizal Fungi (FMA) in Sungkai Plants (Peronema canescens Jack) at Various Soil Depths

Sungkai (Peronema canescens Jack.) is one of the native species that can be developed in plantation forest development, where almost all soil types can be grown by sungkai because sungkai is one of the leading plant species. Therefore, it is necessary to carry out further sungkai cultivation activities to be developed and cultivated. The provision of FMA inoculation in plants to assist growth will be more optimal if using indigenous FMA spores (from the original plant stand). This research aims to explore and identify the types of Arbuscular Mycorrhizal Fungi found under Sungkai stands and analyze the effect of soil depth on the diversity and abundance of FMA spores under Sungkai stands. This research was conducted in sungkai stands with an area of 1.5 Ha by purposive sampling at a depth of 20-60 cm. Soil samples were taken from 5 points then composited and taken as much as 1 kg and inserted into an airtight plastic bag. The results of identification showed that there were 5 FMA genus in the Sungkai Planting Area, namely Glomus, Acaulospora, Entrospora, Gigaspora, and Scutellospora. The highest FMA spore density in each research location was found in the location at a depth of 20 cm with an average of 48 spores

Биологично базиран подход за борба с питийно кореново гниене по оранжерийни краставици, отглеждани в каменна вата

This study aimed to examine the effect of co-cultured consortium of four Trichoderma spp., including T. asperellum, T. koningii, T. polysporum and T. gamsii on Pythium root rot of greenhouse cucumbers grown in rockwool hydroponic culture. Experiments were carried out: (1) in experimental hydroponic system constructed with reused rockwool slabs “naturally” infested with Pythium spp. and additionally inoculated with P. aphanidermatum, P. ultimum, Pythium groups G and F; and (2) in commercial greenhouse wherein cucumber plants (c. Boncanale) were grown in reused Pythium infested rockwool system. The bioagents were co-produced on autoclaved barley grain. The abundant spore mass was suspended in ready-to-use fertigation solution, filtered twice and adjusted to 5.0-7.5 x 107 spores ml-1. 150 ml of this solution were applied to the roots of treated plants zero, once, twice or three times. Treatments were performed manually in the experimentally constructed system starting at day 7th after sowing and followed at intervals of 14 days, or through the dripping irrigation system in the commercial greenhouse where the first treatment was performed immediately after planting while next two followed at 30 days intervals. Significant reduction in disease incidence was achieved through two or three subsequent treatments: total numbers of wilted and dead plants were reduced by 50% and 73%, respectively, in the experimental system, and by 60% and 40% in the commercially conducted experiments. This study suggests innovative biocontrol approach using preparation of multicomponent bioagent spore suspension directly in the fertigation solution, and application to the plants through dripping irrigation system.

First Report of Colletotrichum gigasporum causing Anthracnose of chili pepper in South Korea.

Anthracnose, a destructive fungal disease, poses a significant threat to chili pepper (Capsicum annuum L.) production worldwide (de Silva et al. 2019). In South Korea, anthracnose outbreaks have traditionally been attributed to several Colletotrichum species such as C. gloeosporioides and C. acutatum. About 10% of the yield (chili production) is lost annually in South Korea due to chili anthracnose (Oo et al. 2020). During field surveys conducted in August 2017, symptomatic lesions resembling anthracnose were observed on chili pepper in two farmer's fields (Gochang and Cheongyang) in South Korea. Affected fruits exhibited characteristic symptoms, including circular sunken lesions with dark margins and abundant orange spore masses on the surface. About 20% of chili pepper fruit were affected in each field with an area of about 0.2 ha. Five putative Colletotrichum spp. isolates were obtained from six affected fruits (three from each field) following the procedure described by Cai et el. (2009). Three isolates (C01049, C01111, and C01115), representing each location, were selected to identify at the species level. Colonies on potato dextrose agar (incubated at 25°C in the dark for 7 days) were cottony with entire margins, white aerial mycelium and dark gray in the center. Conidia were hyaline, aseptate, cylindrical with bothnds round, and 17.8 - 30.5 × 6.0 -10.0 µm (mean 23.8 ×7.9 μm, n = 30). Appressoria were dark brown, irregular but mostly ovoid with smooth walls. These morphological features align with those of Colletotrichum spp. within the Colletotrichum gigasporum species (Liu et al. 2014). The identity of the pathogen was further confirmed through multi-locus phylogenetic analysis. The target genes including ITS, ACT, CHS-1, GAPDH, TUB2, and GS were amplified and sequenced using the primer sets ITS1/ITS4, ACT 512F/ ACT-783R, CHS-79F/ CHS-345R, GDF/GDR, T1/Bt2b, and GSF1/GSR1, respectively (Weir et al. 2012; Liu et al. 2014). The resulting sequences were deposited in GenBank (accession no: ITS: MT605261, MT605262, LC823714; ACT: MT612991, MT612992, LC823718; CHS-1: MT612993, MT612994, LC823717; GAPDH: LC811375, LC811376, LC823716; TUB2: MT612997, MT612998, LC823715; GS: LC811377, LC811378, LC823719). The constructed Bayesian and maximum likelihood tree based on combined sequences of ITS, ACT, CHS-1, GAPDH, TUB2, and GS confirmed the identification of the isolates (C01049, C01111, C01115) as C. gigasporum. Pathogenicity tests were conducted by inoculating healthy chili fruit with 70 µL of a conidial suspension (1×106 conidia /mL) of pure cultures of the isolates. The conidial suspension was applied on 10 wounded or 10 non-wounded fruit. The same number of fruit were treated with sterile distilled water as controls. Within 5 days of inoculation, symptoms consistent with anthracnose developed on the inoculated wounded fruit, whereas non-wounded and control fruit remained asymptomatic. This experiment was repeated twice. Colletotrichum gigasporum was re-isolated from diseased tissue of inoculated fruit. Colletotrichum gigasporum has been identified as the cause of anthracnose on Dalbergia odorifera, Carica papaya in China, and Brassica oleracea in India (Wan et al., 2018; Saini et al. 2022; He et al. 2023). To the best of our knowledge, this report marks the first documented instance of C. gigasporum causing anthracnose of chili pepper in South Korea. These results indicate that various species of Colletotrichum can be the fungi causing chili pepper anthracnose. The findings of this study emphasize the need for effective disease management strategies to mitigate impact of C. gigasporum on chili pepper cultivation in the region.

Catching some air: a method to spatially quantify aerial triazole resistance in Aspergillus fumigatus.

Airborne triazole-resistant spores of the human fungal pathogen Aspergillus fumigatus are a significant human health problem as the agricultural use of triazoles has been selecting for cross-resistance to life-saving clinical triazoles. However, how to quantify exposure to airborne triazole-resistant spores remains unclear. Here, we describe a method for cost-effective wide-scale outdoor air sampling to measure both spore abundance as well as antifungal resistance fractions. We show that prolonged outdoor exposure of sticky seals placed in delta traps, when combined with a two-layered cultivation approach, can regionally yield sufficient colony-forming units (CFUs) for the quantitative assessment of aerial resistance levels at a spatial scale that was up to now unfeasible. When testing our method in a European pilot sampling 12 regions, we demonstrate that there are significant regional differences in airborne CFU numbers, and the triazole-resistant fraction of airborne spores is widespread and varies between 0 and 0.1 for itraconazole (∼4 mg/L) and voriconazole (∼2 mg/L). Our efficient and accessible air sampling protocol opens up extensive options for fine-scale spatial sampling and surveillance studies of airborne A. fumigatus.IMPORTANCEAspergillus fumigatus is an opportunistic fungal pathogen that humans and other animals are primarily exposed to through inhalation. Due to the limited availability of antifungals, resistance to the first choice class of antifungals, the triazoles, in A. fumigatus can make infections by this fungus untreatable and uncurable. Here, we describe and validate a method that allows for the quantification of airborne resistance fractions and quick genotyping of A. fumigatus TR-types. Our pilot study provides proof of concept of the suitability of the method for use by citizen-scientists for large-scale spatial air sampling. Spatial air sampling can open up extensive options for surveillance, health-risk assessment, and the study of landscape-level ecology of A. fumigatus, as well as investigating the environmental drivers of triazole resistance.

Arbuscular Mycorrhizal Fungi Consortia in Six Vegetable Crops in the Tepeaca Valley, Puebla, Mexico

The objectives of this work were to search for and evaluate arbuscular mycorrhizal fungi (AMF) in six crops of agricultural importance in the horticultural region of Tepeaca valley, Puebla, Mexico, where Cambisols type soil predominates since the communities and consortia of AMF and their functionality in various crops of economic importance in Mexico are still unknown. The search for and identification of AMF spores was carried out in dif ferent vegetable crops. Five subsamples were collected from 6 dif ferent crop fields with vegetables (cilantro, cabbage, spinach, parsley, lettuce, and pumpkin); each subsample consisted of soil and roots. Roots 5 mm long were selected and stained using the Phillips-Hayman technique. Spore extractions and physicochemical determinations (soil texture, pH, relative humidity (RH), and electrical conductivity (EC)) were performed from soil. The results obtained from staining showed vesicles and spores in roots except in the pumpkin subsamples; of spore extractions from the soil of the six crops, 9 genera and 14 morphotypes of mycorrhizae were found, highlighting Funneliformis mosseae, Claroideoglomus Claroideum, and Glomus sp. as dominant species. By soil physicochemical characterizations were found: sandy texture, pH between 5.8 to 6.8; RH of 9.4 to 13%, and EC of 0.10 to 0.93 mS cm-1. In conclusion, the analyses of similarity and main components suggested that species of vegetables and soil conditions do not af fect the spore abundance, but they do af fect the richness and composition of AMF species, observing particular mycorrhizal consortia for each crop; therefore, it is suggested to evaluate their ef fectiveness in each of the crops to promote them as biofertilizer in the agricultural region of Tepeaca valley, Puebla, Mexico.

The K/Pg event at high southern latitudes: New evidence from continental deposits in the Magallanes/Austral Basin, Patagonia, South America

The Cretaceous/Paleogene boundary (K/Pg) event, associated with a meteorite impact at Chicxulub, Mexico, is globally recognized as one of the largest mass extinctions in natural history, marking the end of the Mesozoic Era. However, most of the outcrops with records and geochemical evidence of this boundary are distributed in the Northern Hemisphere and at mid-latitudes. Here, aiming to contribute to the knowledge of this event at high southern latitudes, we characterize a single iridium anomaly correlated with the K/Pg boundary, present within a carbonaceous mudstone level in a continental depositional environment in the Río de las Chinas Valley, Chilean Patagonia. High-resolution geochemical and palynofacies analyses were performed on a stratigraphic section from the top of the Dorotea Formation. Results showed that the iridium enrichment coincides with an anomaly of other platinum group elements. In addition, the palynofacies analysis showed a disturbance in the depositional environment, marked by an abrupt change from non-degraded phytoclasts (e.g., cuticles) to pseudoamorphous and degraded cuticles, and by an increase in the abundance of spores at the same level. The Río de las Chinas Valley locality provides new evidence for the comprehensive study of the end-Cretaceous event, from the poorly represented continental environments of high southern latitudes.

Climate-forced Hg-remobilization associated with fern mutagenesis in the aftermath of the end-Triassic extinction

The long-term effects of the Central Atlantic Magmatic Province, a large igneous province connected to the end-Triassic mass-extinction (201.5 Ma), remain largely elusive. Here, we document the persistence of volcanic-induced mercury (Hg) pollution and its effects on the biosphere for ~1.3 million years after the extinction event. In sediments recovered in Germany (Schandelah-1 core), we record not only high abundances of malformed fern spores at the Triassic-Jurassic boundary, but also during the lower Jurassic Hettangian, indicating repeated vegetation disturbance and stress that was eccentricity-forced. Crucially, these abundances correspond to increases in sedimentary Hg-concentrations. Hg-isotope ratios (δ202Hg, Δ199Hg) suggest a volcanic source of Hg-enrichment at the Triassic-Jurassic boundary but a terrestrial source for the early Jurassic peaks. We conclude that volcanically injected Hg across the extinction was repeatedly remobilized from coastal wetlands and hinterland areas during eccentricity-forced phases of severe hydrological upheaval and erosion, focusing Hg-pollution in the Central European Basin.

Glomeromycotina Guild Spore Abundance Correlates with Soil Organic Carbon in Homegardens and Seasonal Forests in Yucatan, Mexico

Soil organic carbon (SOC) is a key indicator of soil health. Arbuscular mycorrhizal fungi (AMF) have been shown to increase SOC and respond to SOC content, which in turn, is directly related to land use. We investigated the relationships between land use and Glomeromycotina AMF spore abundance of two AMF functional guilds, rhizophilic (having high root internal AMF hyphal length) and edaphophilic (with high external soil hyphal length) to SOC content in agroforestry systems (AS) and seasonal forest (SF) of Tzucacab, Yucatan, Mexico. Our results indicate greater SOC values in SF than AS of the same age with a trend of increasing SOC with system age. Rhizophilic spore abundance correlated with SOC content, showing dif ferences among land uses and system ages but not between seasons. No relationship was observed between edaphophilic spore abundance to SOC. Thus, we suggest that Glomeromicotyna spore abundance (measured at any time of the year) of rhizophilic fungi could be a good indicator of SOC and, a tool to monitor soil health due to land use changes.

COMPOSICIÓN DE COMUNIDADES DE HONGOS MICORRÍZICOS ARBUSCULARES EN AGROECOSISTEMAS DEL ÁREA DE PROTECCIÓN DE FLORA Y FAUNA CAÑÓN DEL USUMACINTA EN TABASCO, MÉXICO

<p><strong>Background.</strong> The mutualistic interaction with Arbuscular Mycorrhizal Fungi (AMF) is one of the main strategies used by plants to improve their absorption of nutrients and cope with adverse environmental conditions. They are ubiquitous microorganisms that help maintain soil health and crop nutrition, which is why they are considered an essential component in agroecosystems. However, its presence is affected by multiple biotic and abiotic factors such as tree cover and management intensity. <strong>Objective. </strong>Evaluate and compare the AMF communities and tree cover of the main agroecosystems present in the Usumacinta Canyon Flora and Fauna Protection Area (APFFCU) in the humid tropics of southeastern México. <strong>Methodology.</strong> The abundance of spores and the number of AMF morphospecies and the density and diversity of trees were counted in 25 plots of the agroecosystems Potrero (P), Milpa (M), Huerto Familiar (HF), Acahual (A) and Plantación Forestal (PF). An Analysis of Variance (ANOVA) was applied to the set of data obtained from each variable to detect the presence of significant differences between each of the agroecosystems evaluated. Likewise, to observe the effect between the variables, the Pearson correlation analysis was carried out. Finally, Principal Component Analysis (PCA) was carried out to visualize the grouping of the study plots. <strong>Results.</strong> The ANOVA detected significant differences when comparing the variables of interest. The highest abundance of spores was found in P and PF, while A and PF presented the highest richness of AMF morphospecies. Acaulosporaceae and Glomeraceae were the most representative families and <em>Acaulospora kentinensis</em> was the only morphospecies that was observed in all the agroecosystems evaluated. The highest values of tree density and diversity were observed in A. The lowest tree density was present in P and the lowest tree diversity in PF. The PCA allowed us to group the plots with the highest tree density, spore abundance and morphospecies richness on average. <strong>Implications.</strong> The information derived from this study highlights the importance of the presence of trees in agricultural productivity and the design of long-term sustainable agroecosystems. <strong>Conclusion.</strong> It was concluded that the AMF communities of the agroecosystems evaluated in the APFFCU vary in spore abundance and morphospecies richness, which is correlated with the characteristics of their tree cover.</p>

The forced activation of asexual conidiation in Aspergillus niger simplifies bioproduction

Aspergillus niger is an efficient cell factory for organic acids production, particularly l-malic acid, through genetic manipulation. However, the traditional method of collecting A. niger spores for inoculation is labor-intensive and resource-consuming. In our study, we used the CRISPR-Cas9 system to replace the promoter of brlA, a key gene in Aspergillus conidiation, with a xylose-inducible promoter xylP in l-malic acid-producing A. niger strain RG0095, generating strain brlAxylP. When induced with xylose in submerged liquid culture, brlAxylP exhibited significant upregulation of conidiation-related genes. This induction allowed us to easily collect an abundance of brlAxylP spores (>7.1 × 106/mL) in liquid xylose medium. Significantly, the submerged conidiation approach preserves the substantial potential of A. niger as a foundational cellular platform for the biosynthesis of organic acids, including but not limited to l-malic acid. In summary, our study offers a simplified submerged conidiation strategy to streamline the preparation stage and reduce labor and material costs for industrial organic acid production using Aspergillus species.

Fungal Spore Richness and Abundance of Allergenic Taxa: Comparing a Portable Impactor and Passive Trap Indoors and Outdoors in an Urban Setting

Fungal spores are common airborne allergens, and fungal richness has been implicated in allergic disease. Amplicon sequencing of environmental DNA from air samples is a promising method to estimate fungal spore richness with semi-quantification of hundreds of taxa and can be combined with quantitative PCR to derive abundance estimates. However, it remains unclear how the choice of air sampling method influences these estimates. This study compared active sampling with a portable impactor and passive sampling with a passive trap over different durations to estimate fungal spore richness and the abundance of allergenic taxa. Air sampling was conducted indoors and outdoors at 12 residences, including repeated measurements with a portable impactor and passive traps with 1-day and 7-day durations. ITS2 amplicon sequence data were transformed to spore equivalents estimated by quantitative PCR, repeated active samples were combined, and abundance-based rarefaction was performed to standardize sample coverage for estimation of genus-level richness and spore abundance. Rarefied fungal richness was similar between methods indoors but higher for passive traps with a 7-day duration outdoors. Rarefied abundance of allergenic genera was similar between methods but some genera had lower abundance for passive traps with a 1-day duration, which differed indoors and outdoors indicating stochasticity in the collection of spores on collocated samplers. This study found that similar estimates of fungal spore richness and abundance of allergenic taxa can be obtained using a portable impactor or a passive trap within one day and that increased passive sample duration provides limited additional information.

Soil biological quality in rhizosphere, growth, and yield of upland rice grown on acid soil after amended biochar enriched sap of Kappaphycus alvarezii

Abstract. Rakian TC, Kilowasid LMH, Afa LO, Riskyana A, Nurazizah, Wijayanti Y, Bahrun A, Subair I, Rahni NM, Alam S, Sarawa, Karimuna L. 2023. Soil biological quality in rhizosphere, growth, and yield of upland rice grown on acid soil after amended biochar enriched sap of Kappaphycus alvarezii. Biodiversitas 24: 6780-6792. Biological soil quality is essential in evaluating soil management practices using biochar enriched for upland rice growth on acid soil. Therefore, the study aimed to (i) analyze the effect of biochar-enriched sap of Kappaphycus alvarezii (K-sap) on the abundance of Arbuscular Mycorrhizae Fungi (AMF), bacteria, and protozoa in rhizosphere soil, growth, and yield of upland rice, and (ii) the relationship between the abundance of soil biota and the growth and yield components, as well as straw N, P, and K content on acid soil. Four upland rice were grown on acid soil incubated with biochar-enriched sap for two weeks in pots. Nine treatments of the biochar-enriched sap were tested, namely control, 5% biochar-0% K-sap, 5% biochar-5% K-sap, 5% biochar -10% K-sap, 5% biochar-15% K-sap, 7.5% biochar-0% K-sap, 7.5% biochar-5% K-sap, 7.5% biochar-10% K-sap, and 7.5% biochar-15% K-sap. Each treatment was three replicates in a randomized block design. The results demonstrated that the AMF spores quantity decreased while flagellates increased in the soil rhizosphere. The P and K content increased, the N:P decreased, and P:K ratio varied in the straw of the upland rice. Plant height and total spikelets increased, while root dry weight and roots to shoots ratio (R:S) decreased with biochar enriched. The abundance of AMF spores and flagellates correlated positively and negatively with R:S. Furthermore, R:S was negatively correlated with plant height and total spikelets. Plant height and total spikelets showed a positive correlation, while root dry weight and R:S was negatively correlated with K content in shoot tissue. The P and K contents with N:P ratio and N:P with P:K were negatively correlated. In conclusion, biochar-enriched K-sap effectively regulated the activity and composition of soil biota in the rhizosphere, influencing upland rice's growth, yield, and nutrient balance uptake on acid soils.

Biostratigraphy of Late Holocene bottom sediments from the Northern part of Chukchi Sea

The research goal is the investigation of environmental processes of recent sedimentation in the Arctic Ocean area. A short core (length – 37 cm) was taken from the Northern part of the Chukchi Sea. Analytical methods included macroscopic sedimentological description by smear-slides, dating by γ-measurements of 137Cs and 210Pb, diatom and palynological analyses. Sedimentation rates at the research site have been determined to be 1 mm y-1. Thus, the age of the cored sediments spans approximately 400 years, which includes the period of the Little Ice Age. Abundant cold-water diatom species and spores of terrestrial plants within the lower part of the sediment core are characteristic for cold climate conditions, which dominated the Little Ice Age. The occurrence of Jurassic, Cretaceous, and Neogene species of spores and pollen in the Holocene deposits are the evidence of coastal abrasion and the subsequent transfer of the material to the coring site by currents. Southern, subtropical, and tropical species of diatoms within the upper, more recent part of the core reveal the transfer of material by currents from the Pacific Ocean to the Arctic Ocean through the Bering Strait. The results of biostratigraphic analyses indicate environmental changes during the last 400 years, revealed in bottom sediments of the Northern part of the Chukchi Sea.

Palynology and palynofacies of the Permian Paso Aguiar and Yaguarí formations (Paraná Basin, Uruguay): Paleoclimatic, paleoenvironmental, and biostratigraphic implications

The palynological information of the Paso Aguiar Formation (Paraná Basin, Uruguay) is scarce, and the overlying Yaguarí Formation has been hitherto considered as barren. In this study, the palynology and palynofacies of 17 samples recovered from borehole DINAMIGE 943 “Estancia El Águila”, drilled in the Cerro Largo Department (northeastern Uruguay), are analyzed. Palynological assemblages are dominated by striate bisaccate pollen grains, mainly those assigned to the genera Staurosaccites and Lueckisporites, and subordinated apiculate monolete and cingulizonate-cavate spores, essentially represented by Thymospora and Lundbladispora, Gondisporites, and Spelaeotriletes, respectively. The assemblages also include non-taeniate bisaccate and plicate-colpate pollen grains, laevigate and apiculate trilete spores, and algae. Moreover, laevigate monolete spores, non-taeniate and taeniate monosaccate pollen grains, and acritarchs are present in low quantities. The diverse palynoassemblages constitute evidence of a source palaeoflora primarily composed of gymnosperms, with important contributions from glossopterids and conifers. This is complemented by sub-dominant ferns and lycophytes, implying seasonally warmer and humid climates. The palynofacies analysis suggests marine depositional environments with terrestrial inputs related to fluvio-deltaic discharges. Proximal-distal variations are inferred for the lower and middle levels of the Paso Aguiar Formation, while high-energy proximal marine settings with variable redox conditions are deduced for the upper Paso Aguiar Formation and the lower Yaguarí Formation. The abundance of spores recorded is noteworthy, particularly when considering the environmental interpretations for these units. However, the influence of differences in preservation among palynomorphs cannot be entirely ruled out. The assemblages are assigned to the Striatoabieites anaverrucosus-Staurosaccites cordubensis Zone of the Paraná Basin in Uruguay. Nevertheless, obtaining additional data from the studied geological units is crucial to enhance and fine-tune the existing palynostratigraphic framework. Considering the radiometric ages available for the Paraná Basin, along with the ages proposed for comparable biozones in the region and assemblages from correlative units in Brazil, a late Cisuralian–late Guadalupian (Kungurian to Capitanian) age is suggested for the studied section.

Palynological study of archaeometallurgical artefacts from the Late Bronze Age copper smelting sites (Georgia): First results

This article focuses on the palynological (pollen and non-pollen palynomorphs) study of material found with artefacts from Late Bronze Age archaeometallurgical sites in the Lechkhumi area of the mountainous south-west Caucasus region of ancient Colchis. The analysis of organic residues recovered from voids in slag and crucible fragments have revealed an abundance of pollen and spores of diverse plant taxa. Many non-palynological palynomorphs were also found. In total, more than 50 palynomorphs were identified. It was observed that the chemical composition of the copper smelting slag fragments has contributed to the good preservation of the pollen grains, though detailed chemical analyses and experiments are needed. The spectrum from slag includes taxa that are more poorly preserved in sediments, including soil. This preservation undoubtedly makes palynological research of slag residues promising in the future. The range of fossilized plants and spores recovered proves that during the Late Bronze Age in Lechkhumi, forests dominated by chestnut (Castanea sativa) occupied a much larger area than today. Other thermophilic trees, such as zelkva (Zelkova carpinifolia), oak (Quercus), lime (Tilia), and hornbeam (Carpinus betulus) were also present. Thermophilic ferns thrived in the undergrowth as well. In the 13th–9th centuries BC, the existence of warmer climatic conditions in Lechkhumi compared to that we have now is additionally confirmed by the presence of freshwater thermophilic algae Pseudoschizaea, Spirogyra and other Zygnemataceae found in the spectra. Spores of bracken fern (Pteridium aquilinum) and fungus Ustulina most probably reflect felling and human exploitation of the woodland in the close neighbourhood of the site. Comparison of palynological and wood charcoal analyses has demonstrated that the metallurgists of that time used the nearby woods as a source of fuel. Thanks to favourable climatic conditions, beside copper smelting some small-scale agricultural activities were performed which was visible in the composition of herbaceous plant taxa.

Seasonal Periodicity of the Airborne Spores of Fungi Causing Grapevine Trunk Diseases: An Analysis of 247 Studies Published Worldwide.

Grapevine trunk diseases (GTDs) are among the most devastating grapevine diseases globally. GTDs are caused by numerous fungi belonging to different taxa, which release spores into the vineyard and infect wood tissue, mainly through wounds caused by viticultural operations. The timing of operations to avoid infection is critical concerning the periodicity of GTD spores in vineyards, and many studies have been conducted in different grape-growing areas worldwide. However, these studies provide conflicting and fragmented information. To synthesize current knowledge, we conducted a systematic literature review, extracted quantitative data from published papers, and used these data to identify trends and knowledge gaps that need to be addressed in future studies. Our database included 26 papers covering 247 studies and 3,529 spore sampling records concerning a total of 29 fungal taxa responsible for Botryosphaeria dieback (BD), Esca complex (EC), and Eutypa dieback (ED). We found a clear seasonality in the presence and abundance of BD spores, with a peak from fall to spring, more in the northern hemisphere than in the southern hemisphere, but not for EC and ED. Spores of these fungi were present throughout the growing season in both hemispheres, possibly because of higher variability in spore types, sporulation conditions, and spore release mechanisms in EC and ED fungi than in BD. Our analysis has limitations because of knowledge gaps and data availability for some fungi (e.g., basidiomycetes, which cause EC). These limitations are discussed to facilitate further research.

Endophytic Streptomyces sp. NEAU-ZSY13 from the leaf of Perilla frutescens, as a promising broad-spectrum biocontrol agent against soil-borne diseases.

Soil-borne diseases cause significant economic losses in global agricultural production. These diseases are challenging to control due to the invasion of multiple pathogens into host plants, and traditional chemical control methods often yield unsatisfactory results. In this study, we isolated and identified an endophytic Streptomyces, designated as NEAU-ZSY13, from the leaf of Perilla frutescens. This isolate exhibited broad-spectrum antifungal activity against 17 soil-borne phytopathogenic fungi, with Bipolaris sorokiniana being the most prominent. Additionally, it displayed strong antibacterial activity against the soil-borne phytopathogenic bacterium Ralstonia solanacearum. To assess its biocontrol potential, the isolate was utilized to produce a biofertilizer through solid-state fermentation. The fermentation conditions were optimized using response surface methodology to maximize the spore production. The results revealed that more abundant spores were produced with a 1:2 ratio of vermicompost to wheat bran, 60% water content, 20% inoculation amount and 28°C. Subsequent pot experiments demonstrated that the application of the biofertilizer with a spore concentration of 108 CFU/g soil effectively suppressed the occurrence of tomato bacterial wilt caused by R. solanacearum and wheat root rot caused by B. sorokiniana, with biocontrol efficacies of 72.2 and 78.3%, respectively. Chemical analysis of NEAU-ZSY13 extracts, using nuclear magnetic resonance spectrometry and mass analysis, identified niphimycin C and niphimycin A as the primary active constituents. These compounds exhibited high activity against R. solanacearum (EC50 of 3.6 and 2.4 μg mL-1) and B. sorokiniana (EC50 of 3.9 and 3.4 μg mL-1). In conclusion, this study demonstrates the potential of Streptomyces sp. NEAU-ZSY13 as a biofertilizer for the control of soil-borne diseases.

PHOSPHORUS FRACTIONS AND ARBUSCULAR MYCORRHIZAL FUNGI AS INFLUENCED BY FOREST CONVERSION IN CENTRAL HIGHLANDS OF KENYA

<p><strong>Background:</strong> Forest conversion to other land use types lead to changes in soil physico-chemical properties and a reduction in soil fertility. Although forest conversion is extensively recognized to alter soil properties, the influence on distribution of soil phosphorus (P) fractions and abundance and diversity of soil biota is not well explored. <strong>Objective:</strong> To assess the effects of converting undisturbed natural forest to plantation forest (cypress), grazed pastures and potato fields on soil phosphorus (P) fractions and abundance and diversity of arbuscular mycorrhizal fungi (AMF) in Nyandarua County, Kenya. <strong>Methodology:</strong> Transects laid out in triplicate were established in each land use type. In potato fields and grazed pastures, transects measured 50 m with three sampling points established 15 m apart along each transect, each point measuring 1 m² divided into 25 grids with each grid being 400 cm². Transect length was increased to 150 m in forest sites due to relatively larger size of the area studied and sampling points were placed at 50 m apart, each point measuring 25 m² and divided into 1² m grids. Soil and plant samples were randomly collected from sampling points and were used to determine chemical properties, soil P fractions and AMF spore examination. Data were analyzed by analysis of variance (ANOVA). <strong>Results:</strong> Soil chemical properties were significantly (<em>p</em><0.001) higher in natural forest compared to potato fields, grazed pasture and cypress forest. On the contrary, readily labile and moderately labile P was higher in fields cultivated with potato (125.3 mg and 258.2 mg P kg<sup>-1</sup>, respectively) than in natural forest (51.1 mg and 95.3 mg P kg<sup>-1</sup>) and cypress forest (36.4 mg and 82.7 mg P kg<sup>-1</sup>, respectively). However, non-labile P was higher in natural forest (599.1 mg P kg<sup>-1</sup>) and lower in cypress forest (251.3 mg kg<sup>-1</sup>). Of the ten AMF genera identified, only <em>Glomus</em> and <em>Acaulospora</em> were significantly (<em>p</em><0.01) affected by land use change, where they were more abundant in fields cultivated with potato than the other three land use types. Land use type did not significantly influence diversity and richness in AMF. However, AMF composition varied across the land use types. <strong>Implication:</strong> Land use change may negatively affect soil chemical properties, enhance redistribution of soil P, and change AMF community composition, and this could have long-term implications on soil fertility. <strong>Conclusion:</strong> Land use change from natural ecosystems to croplands, grazed pastures and tree plantations alter soil chemical properties, AMF composition and spore abundance, and redistribute soil P fractions by increasing labile P and reducing non-labile P fractions showing that the type of land use chosen significantly influence soil physical and chemical properties and soil biodiversity.</p>

Palynological investigation of an Upper Triassic sequence in Nanjing area, eastern China, with paleoecological implications

The end-Triassic is characterized by a significant biotic crisis in both marine and terrestrial realms. However, terrestrial records in eastern Tethys are relatively limited, especially in eastern China. The Fanjiatang Formation represents the Upper Triassic sequence in southern Jiangsu and Anhui provinces of eastern China, yielding a rich plant and bivalve fossil record. The present study provides the first detailed palynological investigation for the Upper Triassic of Nanjing area, eastern China. Six of twenty processed palynological samples are productive, and more than 70 terrestrial spore and pollen fossil taxa were identified. A palynological assemblage, namely, the Concavisporites–Dictyophyllidites–Kyrtomisporis–Classopollis Assemblage was established, characterized by abundant fern spores, mainly including Concavisporites, Dictyophyllidites and Kyrtomisporis, and much less abundant gymnosperm pollen grains (important taxa include Alisporites, Chasmatosporites, and Classopollis), indicating a Late Triassic Norian–Rhaetian age. In conjunction with previously reported macro-plant data, the palynofloral analysis reveals a vegetation dominated by ferns, with diverse cycadophytes, less abundant lycophytes, bryophytes, equisetales, ginkgophytes and seed ferns, and a few conifers. Paleovegetation and semiquantitative palynological analysis permit a paleoecological interpretation, suggesting a lowland groundcover-dominated vegetation under (sub)tropical warm and humid climate in Nanjing area during this time interval. More detailed palynological and macro-plant data through the whole Upper Triassic in this region are necessary in the future to better reveal the Late Triassic paleoecological settings and variations on land prior to the end-Triassic mass extinction in eastern Tethys.

Recurring Patterns of Sea Level Changes within a Palynological-Based Sequence Stratigraphy Framework of the Middle Jurassic Organic Matter-Rich Khatatba Formation, Egypt

The Middle Jurassic was a time of marginal to shallow shelf settings dominated by organic matter-rich deposition in northern Egypt, southern Tethys. Paleoenvironmental and sequence stratigraphic reconstructions are of paramount significance for a better understanding of basin history and related reservoirs and source rock units. For this purpose, a detailed palynomorph and palynofacies analysis of the Middle Jurassic Khatatba Formation in the Dahab-Mireir Basin, north Western Desert, was conducted. A moderately to well-preserved, moderately diverse palynomorph assemblage of spores, pollen, and dinoflagellate cysts is identified. Marker dinoflagellate cysts, including Dichadogonyaulax sellwoodii, Escharisphaeridia pocokii, Gonyaulacysta adecta, Korystocysta gochtii, Pareodinia ceratophora, and Wanaea acollaris, defined a Bajocian to Callovian age. Palynofacies analysis of the Khatatba Formation revealed two assemblages, whereby PFA-1 is the most abundant in the study well and is comprised mainly of terrestrial phytoclasts deposited nearby fluvio-deltaic sources. The infrequently reported PFA-2 consists of moderate abundances of phytoclasts and AOM, deposited in an inner shelf environment. A more reliable paleoenvironmental interpretation was indicated based on three palynomorph assemblages. The spore-dominated assemblage indicated deposition in a deltaic environment, while the mixed palynomorph assemblage revealed fluvio-deltaic to marginal shallow marine conditions. The microplankton-dominated assemblage is represented by minor samples and reflects an offshore inner shelf condition. Furthermore, the Middle Jurassic relative sea level was reconstructed based on the quantitative variations in the terrestrial/marine (T:M) ratios and abundances of spores, pollen, and dinoflagellate cysts. This led to the subdivide of the Khatatba Formation into thirteen third-order transgressive-regressive sequences, which can be correlated with the global Jurassic short-term sea level changes. Active tectonics and accelerated drifting of the Eurasian Plate during the Middle Jurassic are suggested to control basin uplift/subsidence and, therefore, recurring patterns of relative sea level change.