Morphological and Molecular Identification of Fungi Associated with Sesame Diseased Plants of the Three Agroclimatic Zones of Burkina Faso

Sesame is Burkina Faso’s second essential agricultural export after cotton. It’s consequently a supply of income for producers and foreign exchange for the country. However, sesame production is characterized by low average yields of about 538 kg·ha-1 at the farmer’s field as compared to the potential yield of the improved varieties (1500 - 2000 kg·ha-1). Fungal diseases are some of the major constraints to sesame production in Burkina Faso. The present study contributes to the development of means to control pathogenic fungi of this crop, which are responsible for significant losses. The objective is to identify the fungi associated with diseased sesame plant samples. To this end, 149 samples of diseased sesame plants were collected from different production sites located in three agro-climatic zones of the country. The analysis of the samples according to the blotting paper method, based on the morphological characteristics of the fungi, allowed the identification of 18 genera with prevalence rates from 2.68% to 97.98%. The most frequently identified genera were Macrophomina (97.98%), Cercospora (86.57%), Fusarium (85.23%), Phoma (62.41%) and Colletotrichum (61.07%). The results also showed a variable distribution of fungi according to the agro-climatic zone with the predominance of Macrophomina in all three zones. Molecular identification by DNA sequencing of 120 isolates belonging to the different fungi detected allowed the identification of 25 species of which the most representative were Macrophomina phaseolina, Cercospora sesami, Corynespora cassiicola, Alternaria simsimi, Alternaria porri, Fusarium oxysporum, F. fujikuroi, F. equiseti, Colletotrichum capsici, and C. gloesporiodes. The present study showed that diseased sesame plants collected from different production sites in Burkina Faso housed several species of fungi. The fungi presence in diseased plants indicates the need to inform and raise the stakeholders’ awareness about the phytosanitary problems of sesame, but also to develop effective and appropriate control methods against these crop pathogens in Burkina Faso.

Identification of Powdery Mildew Pathogen and Ribosomal DNA-ITS Sequence Analysis on Melon

Identification of powdery mildew pathogens on melon（Cucumis melo） is important for melon breeding and diseaseresistant germplasm selection. In this study, a powdery mildew pathogen that infected melon plants in Heilongjiang Province, China, was investigated in terms of host identification, morphological characteristics and phylogenetic relationships. The morphological characteristics of the pathogen were observed at five phases in the life cycle： germinating conidia, primary germ tube, hyphae, conidiophores, and colonization. The conidia were elliptical, colorless, catenulate, and the average length was 29.07 μm and average width was 17.82 μm. One ascus and eight ascospores were produced. DNA was extracted from 0.01 g conidiophores from a strain of powdery mildew pathogen that infected melon. ITS ribosomal DNA region（524 bp） was amplified with the universal ITS1 and ITS4 primers. The nucleotide sequence showed 100% similarity with ITS sequences for three Podosphaera fusca strains obtained from the GenBank database. The identity of the pathogen was confirmed as Sphaerotheca fuliginea. International standard differential hosts were used to identify S. fuliginea strain as 2F race. These results supported the notion that Podosphaera fusca was a synonym of S. fuliginea.

The morphological identification of Protoperidinium(Peridiniales, Dinophyceae) species on the coasts of China

The classification and identification for Protoperidinium species are the most difficult work during its taxonomic study. In this research, taxonomic status of Protoperidinium was clarified by tracing its taxonomic history, 23 species belong to genus Protoperidinium on the coasts of China were preliminarily identified, and morphological description and plate patterns were given for each species. The key differences of similar species were also discussed in this study, we believe that P. oceanicum and P. murry, P. tumidum and P. fatulipes, P. globules and P.majus are separate species; P. diabolum should be treated as the valid name instead of the reported names Peridinium globosum or Peridinium longipes; the taxonomic relationship between P. punctulatum and P.subinerme requires further study.

Species diversity of thrips (Thysanoptera) in selected avocado orchards from Mexico based on morphology and molecular data

Avocado is one of the most important crops in the world, and Mexico is the largest producer of this fruit. Several insect pests affect its production, and thrips are amongst the most important. A key step in the design of control methods is accurate species identification. Despite this, formal reports on species diversity of thrips in Mexico are very scarce. Morphological identification can sometimes be time-consuming and inconclusive. Therefore, we explored the species diversity of thrips in Mexican avocado orchards （Michoacan state） based on partial sequences of the mitochondrial gene cytochrome oxidase subunit I （COl）. Forty-four specimens were analysed, which represented approximately 8% of all individuals collected from five localities distributed in three Municipalities. All specimens were analysed using the COl marker, and specimens within the genera Frankliniella were also analysed using a marker within the D2 domain of the 28S （28SD2） nuclear ribosomal DNA. Molecular identifications were confirmed using morphological taxonomy. Overall, six genera were found （Neohydatothrips, Scirtothrips, Frankliniella, Arorathrips, Caliothrips and Leptothrips）. AII genera contained only one species, except Frankliniella, for which there were six species. Data from the two molecular markers suggest the existence of cryptic species within Mexican F. occidentalis populations.

Identification of Mulberry Endophytic Fungus Macrophomina phaseolina Strain

An endophytic fungus MOD-1 was isolated from the roots of mulberry trees,and was identified as Macrophomina phaseolina by morphology and molecular biology.The 5.8 S rDNA/ITS region sequence of the strain has been registered in GeneBank with the accession number of EU250575.

First record of the little fire ant,Wasmannia auropunctata(Hymenoptera:Formicidae),in Chinese mainland

In January 2022,we received ant specimens collected from three field colonies from Shantou City,Guangdong Province,China.They were identified as the little fire ant,Wasmannia auropunctata,through morphological and molecular analyses.Wasmannia auropunctata is listed as one of the 100 most dangerous invasive species by the International Union for Conservation of Nature(IUCN)and has spread from its native range in South America to every continent except Antarctica.DNA analysis of mitochondrial cytochrome c oxidase subunit I(COI)in nine specimens of W.auropunctata found that they had a close genetic relationship with specimens from Argentina.This study represents the first formal record of the establishment of W.auropunctata outdoor in Chinese mainland.However,the invasion stage and occurrence degree of W.auropunctata in China are not clear to date.The implementation of quarantine measures,investigation of the occurrence and distribution,and development of monitoring and control strategies are needed to actively respond to the threat posed by this highly invasive ant.

A new Curvularia lunata variety discovered in Huanghuaihai Region in China

The purpose of this study was to identify the dominant pathogens of Curvularia leaf spot and their pathogenicity variation in Huanghuaihai Region of China in recent years.In 2013 and 2016–2017,the occurrences of Curvularia leaf spots on maize were investigated in fields located in Henan,Hebei,Shandong,and Anhui provinces,and 292 fungi were isolated from diseased leaves.These fungal isolates were subjected to morphological identification,and 232 isolates were found to have about 70%uncurved conidia and were identified as Curvularia lunata var.Most of the conidia of 2 representative isolates,namely,HNWB-131 and HNWB-185,were oblong with parallel septations and were distinctly different from a reference isolate CX-3.For further determination,the internal transcribed spacer(ITS),glyceraldehyde 3-phosphate dehydrogenase(GPDH),the large subunit(LSU),and translation elongation factor 1-alpha(EF1-α)sequences of HNWB-131,HNWB-185,and CX-3 were amplified and sequenced.The results of sequence analysis showed that the 4 gene sequences from the 3 isolates had a similarity of more than 99%to C.lunata.Based on the sequences of ITS and the combined data of the 4 genes,neighbor-joining trees were constructed for phylogenetic analysis.The results indicated that these 3 isolates were clustered together with C.lunata.The expression of Clg2 p and ClUrase genes in mycelia and conidia was significantly(P<0.05)higher in CX-3 than in HNWB-131 and HNWB-185.This study found that the dominant pathogen of Curvularia leaf spot was a new variety of C.lunata with morphological variations in Huanghuaihai Region from 2013 to 2017.The pathogenicity of the C.lunata var.was not significantly enhanced,and the expression of Clg2 p and ClUrase genes of C.lunata var.was decreased.

Morphological and molecular discrimination of green macroalgae Chaetomorpha aerea and C. linum

Green macroalgae Chaetomorpha aerea and C. linum are taxonomically confused. In this paper, we tried morphological and molecular analyses to separate these two species. C. aerea and C. linum can be distinguished from morphological characteritics, such as frond dimension, cells size and shape, their mean length/width ratios（LWR）, and cell walls constriction. Thalli of C. aerea attenuate basipetally, with diameter 270–500 μm at upper portion, 160–360 μm at middle portion, 100–160 μm at basal portion. For the upper part, the length of cells is less than their diameter. Cell walls usually constrict at the dissepiments, which are pellucid or colorless and give the filament beaded appearance. In contrast, thalli of C. linum often have a constant diameter of 90–300 μm within the same individual, cell walls usually do not constrict and cells are cylindrical or barrel shaped. The LWR is larger than that of C. aerea. Results show that the pairwise distance between two species is 3.6%–3.7% for 18 S r RNA gene and 53.5%–54.3% for ITS region. In phylogeny, they distribute at distant clades, which confirms a genetic divergence at molecular level. In addition, morphological data indicates that filament diameter of C. linum samples is highly variable, ranging from 90 μm to 300 μm. Then these two species can be considered as separate species.

Isolation and species diversity of arbuscular mycorrhizal fungi in the rhizosphere of Puccinellia tenuiflora of Songnen saline-alkaline grassland,China

Salinization has led to the deterioration of the ecological environment,affected the growth of plants,and hindered the development of agriculture and forestry.Arbuscular mycorrhizal(AM)fungi,as important soil microorganisms,play significant physiological and ecological roles in promoting plant nutrient absorption and improving soil structure.Puccinellia tenuiflora(Turcz.)Scribn.et Merr.in Songnen saline-alkaline grassland was selected as the research object to observe AM fungal colonization of the roots and explore the species and diversity of AM fungi in symbiotic association with P.tenuiflora.This study showed that AM fungi colonized in P.tenuiflora roots and formed a typical Arum-type mycorrhizal structure.A significant correlation was observed between vesicular abundance and the colonization intensity of mycorrhiza.Isolation and identification revealed 40 species of AM fungi in the rhizosphere of P.tenuiflora,belonging to 14 genera,of which two species could not be identified.The richness of the genus Glomus was the highest,accounting for 30%of the total species.Funneliformis mosseae and Rhizophagus intraradices were isolated from all the samples and were the species with the widest distribution in the rhizosphere of P.tenuiflora.Correlation analysis showed that pH only had a significant impact on the distribution of a few species,such as Glomus pustulatum,Diversispora spurca,Glomus aggregatum,Rhizophagus clarum,and Acaulospora foveata.The present study provides a theoretical basis for further exploring the resources of AM fungi in saline-alkaline soil.

Morphological and microscopic identification studies of Cordyceps and its counterfeits

Macroscopic and microscopic studies were applied to distinguish Cordyceps sinensis(Berk.)Sacc.and its 5 common counterfeits.Transverse sections of stroma and larvae and surface sections of stroma of C.sinensis,Cordyceps gunnii,Cordyceps barnesii,Cordyceps gracilis,Cordyceps liangshanensis and Cordyceps militaris were examined and their morphological and microscopic features photographed.The main morphological and microscopic features of the 6 species of Cordyceps were basically similar except for certain diagnostic differences.These included macroscopic differences from C.sinensis as follows:the stroma of C.gunnii is stout and rough with sterile bulgy or branched apex;the larvae of C.barnesii has a pair of teeth on the head;the stroma of C.liangshanensi is thread-like;C.gracilis is without stroma;and C.militaris is without larvae.There were also microscopic differences:from C.sinensis as follows:the stroma of C.barnesii is without perithecia;C.gunnii,C.liangshanensis and C.gracilis are without bristles on the larva body.These differences allow C.sinensis and its counterfeits to be easily distinguished.

Pharmacognostical study of Cynanchum stauntonii and Cynanchum glaucescens,botanical sources of TCM Baiqian

Objective： Cynanchum stauntonii and Cynanchum glaucescens are botanical species of Baiqian（Cynanchi Stauntonii Rhizoma et Radix） in Chinese Pharmacopoeia, in which, however, there are no microscopic identification. Therefore, we provided the morphological and microscopic identification of the crude drug for updating Chinese Pharmacopoeia.Methods： Twelve batches of C. stauntonii and three batches of C. glaucescens and their crude drugs were taxonomically, morphologically, and microscopically examined.Results： Taxonomically, C. stauntonii had narrowly lanceolate leaves with acuminate apex and 5 mm long petiole; Whereas C. glaucescens was oblong-lanceolate or oblong with rounded or acute apex in leaves,and had very short or no petiole. Morphologically, rhizomes of C. stauntonii and C. glaucescens both had hollow pith, but the hollow pith occupied about a half of the rhizome＇s diameter in C. stauntonii, whereas only a very small proportion of the overall diameter in C. glaucescens. Moreover, microscopic observation showed the difference in the proportion of xylem and in rhizome transverse-sections of the two species along with the difference in the size of the pith. Finally, laticifers and rhizome epidermal secretory cells were present in the powders of C. stauntonii, but absent from C. glaucescens.Conclusion： Based on observation of morphological and microscopic characteristics, the two species can be distinguished by the size of the pith, proportion of xylem of rhizomes, and crude drug powder characters such as laticifers and secretory cells.