Avocado (Persea americana Mill.) is grown for its nutritious fruit. However, the quantity and quality of these fruits are threatened by some fungal organisms which can cause health complications when it is consumed by man. DNA extraction provides a unique tool for identification of organisms. This study was conducted to isolate and identify fungal species associated with avocado fruit using both morphological and molecular techniques. Fungal species were isolated from Persea americana purchased from Choba market, Port Harcourt, Rivers State, Nigeria using Potato Dextrose Agar (PDA) as a growth medium. The morphology of isolated fungi on PDA were cotton-like blackish grey spots, white villous colonies, greyish powdery spores and black spores for isolates 1 to 4 respectively. Extraction of DNA from fungal isolates was carried out using Zymo Fungal/Bacteria DNA Miniprep Kit. PCR amplification of the ITS1-2 regions of isolates was carried out using fungal universal primer pair; ITS4 and ITS5.PCR amplification of the ITS1-2 gene sequences yielded amplicons between 537-580 base pairs. PCR products were sequenced and the sequencing result after BLAST search revealed the identity of the four fungal species as follows: Lasiodiplodia theobromae, Fusarium proliferatum, Penicillium sp. and Aspergillus niger. This study will promote the knowledge of specific fungal species associated with Persea americanna and help plant pathologists to proffer preventive and control measures to enhance fruit protection and yield quality.

The decay of faecal matter from a septic system causes the arousal of fungi in the surrounding soil. These fungi can cause diseases if there is sewage spillage containing untreated or improperly treated wastewaters. Molecular techniques of identification of fungi have shown to be more dependable than traditional methods of identifying fungal species. This study was carried out to identify the fungal species associated with soil obtained from sewage-impacted soil near a septic tank using both traditional cultural techniques and molecular method. Fungi associated with the soil samples were isolated using serial dilution and Potato Dextrose Agar (PDA) method. Deoxyribonucleic Acid (DNA) was extracted from the pure cultures of fungal isolates using Quick DNA Fungal/Bacterial Miniprep kit. Polymerase Chain Reaction (PCR) amplification of internal transcribed spacer (ITS) region of the fungal isolates was carried out using universal primer pair; ITS4 and ITS5. The PCR products were sequenced and the sequences were blasted against National Centre for Biotechnology Information database. The result of the nucleotide sequence analysis revealed the identity of the isolates as Trichoderma harzanium with 580 base pairs and Aspergillus welwitschiae with 560 base pairs. Sequences of the isolates were aligned and compared with sequences on GenBank and a phylogenetic tree was constructed. The cultural method only aided in suggesting the suspected genera of the isolates while the molecular method was able to identify the isolates to the species level. This study will promote the knowledge of the fungal species associated with sewage-impacted soil and also aid researchers in proffering ways to enhance the prevention/control of diseases associated with sewage spill. Keyword: Septic tank, fungi, soil, phylogeny, sequencing

Dung is the undigested remains of food taken in by herbivores. It is a combination of faeces and urine at a ratio of 3:1. It mostly consists of cellulose, hemicelluloses and lignin. Cow dung harbours several microorganisms, including various species of fungi. The aim of this study was to isolate and characterize the fungal organisms associated with cow dung-impacted soil using both traditional cultural techniques and molecular method. DNA extraction was carried out using Zymo Quick DNA Fungal/Bacterial Mini prep kit. The Polymerase Chain Reaction (PCR) amplification of the Internal Transcribed Spacer (ITS) genes, using the universal primer pair; ITS4 and ITS5, generated amplicon sizes of 372 and 834 base pairs. The amplicons were sequenced using Sanger sequencing and the isolates were identified as Lichtheimia ramosa and Galactomyces pseudocandidus. Phylogenetic analysis showed the relationship that exists between the fungal species and other closely-related species in GenBank such as: Aspergillus amstelodami, Absidia corymbifera, Mycocladus corymbiferus and Geotrichum candidum. This study has provided information on some of the fungal organisms harboured by cowdung-impacted soil which will help predict the possibility for disease transmission to plants or humans through cow dung.

Seeds are usually infected by microorganisms and pests during storage, causing deterioration and reduction in the nutritive and market value of these seeds. In this study, the proximate composition of Vigna unguiculata seeds inoculated with different fungal organisms was determined to ascertain the level of deterioration caused by fungi on the seeds. The fungi used in the study were Botryodiplodia theobromae, Fusarium oxysporum, Rhizopus stolonifer and Aspergillus niger. There was a significant increase (p<0.05, 0.008) in the protein content of seeds inoculated with fungi. Fusarium oxysporum (29.45%) caused the highest increase in protein followed by Aspergillus niger (28.14%), Botryodiplodia theobromae (27.85%) and Rhizopus stolonifer (27.50%). The increase could be attributed to the proteineous content of the fungal mycelia. There was a significant increase (p<0.05, 0.005/0.014) in moisture and ash content of inoculated seeds respectively. Fusarium oxysporum caused the highest increase in ash (7.93) while Rhizopus stolonifer (5.4) caused the lowest increase. The increase in ash content is due to the presence of minerals like potassium and phosphorus in the mycelia of the fungi. There was a significant decrease (p<0.05, 0.019) in the carbohydrate, lipid, fibre and dry matter content of fungi-inoculated seeds when compared with the control. Fusarium oxysporum (36.6) caused the highest decrease while Rhizopus stolonifer (43.2) caused the lowest decrease in dry matter of inoculated seeds. Decrease in dry matter may be as a result of production of enzymes by these fungi.