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

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

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

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

Phylogeny of Trochetia species based on morphological and molecular markers

Trochetia is a genus of six species out of which five are endemic to Mauritius. Its taxonomic classification has been  hanged from the Sterculiaceae family to the Malvaceae recently. Molecular and morphological  characterization was carried out for the five Trochetia species as a means to conserve endangered Trochetia  species and to understand their genetic diversity. Hibiscus genevii and Dombeya mauritiana were also included in  the study as outgroups to infer the phylogeny of Trochetia. A modified protocol was used for DNA extraction using  CTAB. Morphological characterization was based on both quantitative and qualitative traits. Random Amplified   Polymorphic DNA (RAPD) technique was used for assessing genetic diversity of Trochetia species. High levels of  polymorphism were noted among the Trochetia species using RAPD markers. Both molecular and morphological  data were cladistically analyzed using the unweighted pair group method with arithmetic average (UPGMA) based  on Jaccard’s coefficient. Cluster analysis revealed two different phylogenies of Trochetia for the two different markers used. T. triflora was found to have more similar features to D. mauritiana as compared to its congeneric  species, as evident from the dendogram based on morphological characters. Out of the twenty nine morphological  haracters used, T. triflora bears four characters similar to D. mauritiana as compared to the other Trochetia species. Moreover, both T. triflora and D. mauritiana are best adapted to similar climatic conditions and  have similar geographical distribution, suggesting that their close similarity may possibly be due to convergence.  Sterculiaceae family has been reported to be polyphyletic and hence similar characters might have been derived  from same or different ancestors for both T. triflora and D. mauritiana. However, the molecular characters  separated the genus Trochetia as a different clade from the outgroups. The use of other techniques such as DNA  sequencing may elucidate further the phylogenetic relationships of Trochetia species.Keywords: Trochetia, morphological data, molecular markers

A review of soft corals (Octocorallia: Alcyonacea) and their symbionts: Distribution of clades and functionality

Even though soft corals are an integral part of the coral reef ecosystem, very little research has focused on theirendosymbiotic association with the zooxanthellae (Symbiodiniaceae). Symbiotic algae appear in soft corals from both the tropical seas as well as temperate regions across the world. The present study provides a list of soft corals along with their associated zooxanthellae using published data. By combining all the data, 52 soft coral species belonging to 21 genera were identified and their corresponding specific Symbiodiniaceae genera were analysed. It was important to initially compare soft corals and distinguish zooxanthellae at clade level to find any host specificity. The vast majority (75 %) of soft corals predominantly hosted the genus Cladocopium (Clade C) and therefore the focus of this study was to evaluate its geographical distribution. The genus Cladocopium consists of many species which are classified as subclades in this study, exhibiting high intra-clade diversity. For 40 of the 52 soft corals reviewed, 18 % had the same clade type C1 (considered as generalists and ancestral) and 13 % contained the clades C15, C64 and C1:3a, respectively. Analysis showed that some clades (C71a, C15b and C64) were confined to specific geographical regions while clade C1 was distributed worldwide. Understanding the distribution of endosymbionts may enable predictions of which symbioses will survive and exist under future climate change scenarios

Conservation of Beclardia macrostachya

Beclardia macrostachya is a critically endangered orchid species in Mauritius. Very low level of fruit set has  been attributed to contribute to the decline in its population. Surveys carried out in the different forest regions  reveal the occurrence of this orchid at only one location, Pigeon Wood, with a present population of only 75  individuals. Biological studies at Reunion Island reveal preferential adaptation to higher altitudes, evidenced by  observed differences in fertility rates at different forest areas. Taxonomic studies using morphological characters suggest the placement of Beclardia macrostachya within a group that includes Cryptopus elatus and Aerides lawrenceae. When cultured in vitro, leaf explants developed nodular mass which failed to develop into protocorm-like bodies (PLBs). However, embryo rescue proved to be an efficient way for micropropagation of this orchid with a high regeneration capacity. Breeding programs carried out in Mauritius yielded capsules and the latter were successfully cultured to generate PLBs which would subsequently grow into plantlets

Molecular studies on the Creole cattle breed in Mauritius

ABSTRACT There are three main cattle breeds in Mauritius; the Friesian cows, the Creole cows and the Cross (Creole and Friesians) breeds. The main objective of the study was to differentiate the Creole breeds from the other two breeds thus valorizing and conserving the Creole cow which is in danger of extinction. Random Amplified Polymorphic DNA and random microsatellite analysis were the two PCR based techniques used. The populations studied consisted of 5 Friesians, 5 Creole breeds and 5 Cross breeds. The breeds were obtained from the Curepipe Livestock Research Station which is the only place where there is a record of Creole cows in Mauritius. Among the 5 Creoles breeds chosen, 2 of them could have been impure breeds due to their morphological characteristics. DNA extraction was carried out from blood taken from the cows selected, and yielded DNA of good quality and quantity. Polymorphic bands were obtained from the Random Amplified Polymorphic DNA primers and random microsatellite primers and the data obtained were used for constructing a dendogram. From the dendogram obtained, the breeds were separated and the two Creole samples, which were suspected to be impure, formed different clusters from the true Creole breeds. From the results obtained, the Creole breed was easily distinguishable from the other breeds studied using molecular techniques