Ascomycetes from freshwater habitats: Ascolacicola aquatica gen. et sp. nov., and a new species of Ascotaiwania from wood submerged in a reservoir in Hong Kong

Ascolacicola aquatica gen. et sp. nov., and Ascotaiwania mitriformis sp. nov., from decaying submerged wood collected in the Plover Cove Reservoir in Hong Kong are described and illustrated. Ascolacicola aquatica has characteristics that are common to both Ascotaiwania and Savoryella, but the anamorph is Trichocladium uniseptatum. A new genus is therefore introduced to accommodate this fungus. Ascotaiwania mitriformis sp. nov. is typical of the genus and differs from other species in having large brown fusiform ascospores with mitriform end cells. Its anamorph is an undescribed species of Monotosporella and both states of the fungus are described and illustrated.published_or_final_versio

Molecular characterisation of Mycovellosiella koepki, the causal agent of yellow spot disease of sugarcane

Yellow spot of sugarcane is a fungal disease caused by Mycovellosiella koepki. Yellow spot symptoms are variable and differ in several sugarcane varieties and the existence of more than one strain of thefungus has been evoked. 29 isolates of the fungus were characterised morphologically and no significant differences were observed on the type, colour and size of the spores. Following restriction digestion of the ITS region, no significant differences were observed among isolates of the fungus and DNA sequencing of this region of the ribosomal DNA confirmed the absence of polymorphisms among the fungal strains

Ascal ultrastructural study in Annulatascus hongkongensis sp. nov., a freshwater ascomycete

A new species of Annulatascus, A. hongkongenszs, is described from freshwater habitats. This species differs from other Annulatascus species as ascospores are ellipsoidal, 3-septate, verruculose and are surrounded by a thick mucilaginous sheath. Annulatascus hongkongenszs is described and illustrated with light and transmission electron micrographs, and compared with other Annulatascus species.published_or_final_versio

Molecular and Antibacterial Profile of Edible Oyster Mushrooms Pleurotus sajor-caju

Pleurotus varieties cultivated in Mauritius include 3 strains: Pleurotus sajor-caju strain CC114, Pleurotus sajor-caju strain CC200 and Pleurotus sajor-caju strain CC201. In this study the chemical composition, antimicrobial properties and genetic variation of the three Pleurotus strains were explored. Chemical screening of crude extracts of the Pleurotus strains revealed the presence of terpenes, phenols, alkaloids, saponins and hydrolysable tannins. Flavonols were however identified only in Pleurotus strain CC200 extracts and leucoanthocyanins were detected only in the extracts of Pleurotus CC114 strain. Antimicrobial activity was tested against Bacillus subtilis, Escherichia coli and Staphylococcus aureus. Pleurotus sajor-caju strain CC200 had more significant antimicrobial effect than Pleurotus sajor-caju strain CC114 and Pleurotus sajorcaju strain CC201 which both demonstrated nearly similar antimicrobial activity. Genomic DNA extraction was successfully carried out using the Phenol/Chloroform DNA extraction protocol and the DNA was purified using an RNAse treatment. Genetic relatedness among the three strains of Pleurotus sajorcaju was assessed using the RAPD technique. Out of the 50 primers used, maximum polymorphism was observed using 8 Operon primers. Out of the 73 amplification products obtained with all three Pleurotus species, there was 28.8 % polymorphism which was observed. Maximum polymorphism was obtained following amplification using OPL 05. The fact that Pleurotus sajor-caju strain CC200 was least related to Pleurotus sajor-caju strain CC114 and Pleurotus sajor-caju strain CC201 could possibly explain the differences in the bioactivity of these mushrooms.Keywords: Antimicrobial activity, Flavonoids, Pleurotus, Genetic diversit

Vertexicola caudatus gen. et sp. nov., and a new species of Rivulicola from submerged wood in freshwater habitats

Vertexicola caudatus gen. et sp. nov., is described and illustrated from sibmerged wood collected from a creek in the Philippines and a river in Hong Kong. Vertexicola differs from other genera in the Annulatascaceae (Sordariales) in having thickwalled distoseptate ascospores and asci with a tail-like structure. The placement of Vertexicolawithin the Annulatascaceae is discussed and it is compared with other genera in this family. Rivulicola aquatica sp. nov. is also described and illustrated.published_or_final_versio

Detection of somaclonal variation in micropropagated Hibiscus sabdariffa L. using RAPD markers

The main objective of micropropagation is to produce clones i.e. plants which arephenotypically and genetically identical to the mother plants. The culture of organized meristems usually guarantees the production of true-to-type plants but variations in the progenies have been widely reported. Hibiscus sabdariffa L. plants were regenerated on MS (Murashige and Skoog) medium containing BAP (Benzyl amino purine) and IBA (Indole 3 butyric acid) and were propagated in vitro on hormone-free MS medium. The aim of this study was to detect variation in micropropagated plantlets of Hibiscus sabdariffa using RAPD amplification. DNA extraction from Hibiscus sabdariffa L. plants was optimized using CTAB buffer supplemented with 5M NaCl to eliminate polysaccharides and the isolated DNA proved amenable to PCR amplification. RAPD analysis was carried out on DNA samples to compare the mother plant with 10 randomly selected regenerated plants. Out of 30 primers screened, primers OPB-01, OPX-06 and DK-02 produced polymorphic bands. These results show that RAPD is a suitable technique which can be used to detect genetic change caused by somaclonal variation and could be promising for the selection of desirable traits or transformation systems.Keywords: Hibiscus sabdariffa L. In vitro culture. RAPD, SomaclonalVariatio

Greenhouse-grown tomatoes : microbial diseases and their control methods : a review

The cultivation of tomatoes in greenhouse structures is becoming increasingly common as a crop production system. However, the environmental conditions inside a greenhouse favour the development of microbial diseases. These diseases have an adverse effect on the tomato yield and can lead to serious economic losses. This review will give an insight into the major diseases affecting greenhouse-grown tomatoes, the respective causal agents and recommended control strategies. Some of the major diseases are of a bacterial, fungal, viral or nematode origin and include bacterial spot and speck, bacterial canker, early blight, gray mold, leaf mold, powdery mildew, tomato mosaic virus, tomato big bug and root knot. For each disease, the symptoms and risk factors responsible for disease development are described. In addition, the different structural designs and set-ups of tomato greenhouses are covered along with their advantages and limitations, especially any adverse effects on yield and susceptibility to disease. Although conventional control measures are discussed, greater emphasis is laid on the use of alternative biocontrol measures that include Effective Microorganisms, natural antimicrobials and nanobiopesticides. Moreover, information gathered in this review is based on a combination of available literature and expert guidance. This compilation is hoped to be instructive for tomato growers opting for greenhouse farming and assist them in the application of timely and more effective control measures.https://esciencepress.net/journals/phytopathhj2024Forestry and Agricultural Biotechnology Institute (FABI)SDG-02:Zero Hunge

Biochemical and phylogenetic analysis of Eugenia and Syzygium species from Mauritius

The Myrtaceae represents a plant family with several species having important medicinal virtues. In view of these properties four Syzygium species namely S. latifolium, S. commersonii, S. coriaceum, S. petrinense and two Eugenia species namely E. pollicina and E. pyxidata were studied. Phytochemical analysis showed that the methanol extracts had higher content of total phenolics and total flavonoids than the hexane extracts. The in vitro antioxidant activity evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant potential (FRAP) assays was significant. The antibacterial activity of the extracts against Staphylococcus epidermidis, Staphylococcus aureus, Propionibacterium acnes and Escherichia coli was also promising. Species studied displayed significant tyrosinase inhibitory activity with S. petrinense having the highest activity. Interestingly, when the expression analysis of the tyrosinase cDNA in mouse melanocyte cells was studied it was observed that the methanolic Syzygium extracts inhibited melanogenesis by upregulating or downregulating the tyrosinase gene. Phylogenetic analysis of the ribosomal DNA sequences showed the genetic uniqueness of each plant species reflecting in their unique biological activity. Bioprospecting of endemic Mauritian Eugenia and Syzygium could be envisaged against acne vulgaris, skin hyperpigmentation and possible exploitation as phytotherapeutics.The University of Mauritiushttp://www.elsevier.com/locate/jarmap2020-03-03hj2020Plant Production and Soil Scienc

Discovery of the teleomorph of the hyphomycete, Sterigmatobotrys macrocarpa, and epitypification of the genus to holomorphic status

Sterigmatobotrys macrocarpa is a conspicuous, lignicolous, dematiaceous hyphomycete with macronematous, penicillate conidiophores with branches or metulae arising from the apex of the stipe, terminating with cylindrical, elongated conidiogenous cells producing conidia in a holoblastic manner. The discovery of its teleomorph is documented here based on perithecial ascomata associated with fertile conidiophores of S. macrocarpa on a specimen collected in the Czech Republic; an identical anamorph developed from ascospores isolated in axenic culture. The teleomorph is morphologically similar to species of the genera Carpoligna and Chaetosphaeria, especially in its nonstromatic perithecia, hyaline, cylindrical to fusiform ascospores, unitunicate asci with a distinct apical annulus, and tapering paraphyses. Identical perithecia were later observed on a herbarium specimen of S. macrocarpa originating in New Zealand. Sterigmatobotrys includes two species, S. macrocarpa, a taxonomic synonym of the type species, S. elata, and S. uniseptata. Because no teleomorph was described in the protologue of Sterigmatobotrys, we apply Article 59.7 of the International Code of Botanical Nomenclature. We epitypify (teleotypify) both Sterigmatobotrys elata and S. macrocarpa to give the genus holomorphic status, and the name S. macrocarpa is adopted for the holomorph. To evaluate the ordinal and familial affinities of Sterigmatobotrys and its relationships with the morphologically similar genera Carpoligna and Chaetosphaeria, phylogenetic relationships were inferred based on aligned sequences of the large subunit nuclear ribosomal DNA (ncLSU rDNA)