HighlightsCassava genotypes respond differently to infection by cassava mosaic geminiviruses.Cassava mosaic disease resistant loci prompt recovery from systemic infection.CMD symptoms are directly correlated with contents of viral DNA and virus specific small RNAs.CMD infected plants abundantly accumulate 21–24 nt of virus specific small RNAs.VsRNAs heterogeneously map the entire virus genome in both polarities.

No abstract

Mushrooms have been used as food for centuries all over the world because of their characteristic soft texture and mild flavor. They are documented as being good source of nutrients and bioactive compounds that are beneficial to the human body (Chang, 2011). While the exotic varieties have been extensively analyzed, local edible wild mushrooms have not and yet they are consumed by communities living near the forests. This research aimed at screening and determination of phytochemicals compounds in wild edible mushroom found in selected areas in Kenya Two commercially grown mushrooms, oyster (Pleurotus florida) and button (Agaricus bisporus), and ten edible wild mushrooms species were collected from different locations of the country. They were analyzed for total polyphenols, flavonoids and radical scavenging activity using standard methods. All the analysis was done in triplicate. Phytochemical screening showed presence of saponins, polyphenols and terpenoids. Total polyphenols values obtained ranged between 210-1614 mg Gallic Acid equivalent (GAE)/100g, dry weight basis (dwb) and flavonoids 214-1695 mg Quercetin Equivalent (QE)/100 g dwb. Total polyphenols (R 2 = 0.82, P ≤ 0.05) and flavonoids values showed a positive correlation with the radical scavenging activity.The results show that cultivated and wild edible mushrooms are rich in health-promoting phytochemical compounds.

The obstacle to optimal utilization of biogas technology is poor understanding of biogas microbiomes diversities over a wide geographical coverage. We performed random shotgun sequencing on twelve environmental samples. Randomized complete block design was utilized to assign the twelve treatments to four blocks, within eastern and central regions of Kenya. We obtained 42 million paired-end reads that were annotated against sixteen reference databases using two ENVO ontologies, prior to β-diversity studies. We identified 37 phyla, 65 classes and 132 orders. Bacteria dominated and comprised 28 phyla, 42 classes and 92 orders, conveying substrate’s versatility in the treatments. Though, Fungi and Archaea comprised 5 phyla, the Fungi were richer; suggesting the importance of hydrolysis and fermentation in biogas production. High β-diversity within the taxa was largely linked to communities’ metabolic capabilities. Clostridiales and Bacteroidales, the most prevalent guilds, metabolize organic macromolecules. The identified Cytophagales, Alteromonadales, Flavobacteriales, Fusobacteriales, Deferribacterales, Elusimicrobiales, Chlamydiales, Synergistales to mention but few, also catabolize macromolecules into smaller substrates to conserve energy. Furthermore, δ-Proteobacteria, Gloeobacteria and Clostridia affiliates syntrophically regulate PH2 and reduce metal to provide reducing equivalents. Methanomicrobiales and other Methanomicrobia species were the most prevalence Archaea, converting formate, CO2(g), acetate and methylated substrates into CH4(g). Thermococci, Thermoplasmata and Thermoprotei were among the sulfur and other metal reducing Archaea that contributed to redox balancing and other metabolism within treatments. Eukaryotes, mainly fungi were the least abundant guild, comprising largely Ascomycota and Basidiomycota species. Chytridiomycetes, Blastocladiomycetes and Mortierellomycetes were among the rare species, suggesting their metabolic and substrates limitations. Generally, we observed that environmental and treatment perturbations influenced communities’ abundance, β-diversity and reactor performance largely through stochastic effect. Understanding diversity of biogas microbiomes over wide environmental variables and its’ productivity provided insights into better management strategies that ameliorate biochemical limitations to effective biogas production.

Members of the genus Pleurotus, also commonly known as oyster mushroom, are well known for their socioeconomic and biotechnological potentials. Despite being one of the most important edible fungi, the scarce information about the genetic diversity of the species in natural populations has limited their sustainable utilization. A total of 71 isolates of Pleurotus species were collected from three natural populations: 25 isolates were obtained from Kakamega forest, 34 isolates from Arabuko Sokoke forest and 12 isolates from Mount Kenya forest. Amplified fragment length polymorphism (AFLP) was applied to thirteen isolates of locally grown Pleurotus species obtained from laboratory samples using five primer pair combinations. AFLP markers and internal transcribed spacer (ITS) sequences of the ribosomal DNA were used to estimate the genetic diversity and evaluate phylogenetic relationships, respectively, among and within populations. The five primer pair combinations generated 293 polymorphic loci across the 84 isolates. The mean genetic diversity among the populations was 0.25 with the population from Arabuko Sokoke having higher (0.27) diversity estimates compared to Mount Kenya population (0.24). Diversity between the isolates from the natural population (0.25) and commercial cultivars (0.24) did not differ significantly. However, diversity was greater within (89%; P > 0.001) populations than among populations. Homology search analysis against the GenBank database using 16 rDNA ITS sequences randomly selected from the two clades of AFLP dendrogram revealed three mushroom species: P. djamor, P. floridanus and P. sapidus; the three mushrooms form part of the diversity of Pleurotus species in Kenya. The broad diversity within the Kenyan Pleurotus species suggests the possibility of obtaining native strains suitable for commercial cultivation.

No abstract

No abstract

The common bean (Phaseolus vulgaris L.) is a significant vegetable crop, grown because it is a rich source of protein, carbohydrates, and vitamin B complex. Fusarium solani and Rhizoctonia solani are the most widely known pathogens contributing to large yield losses for this crop. The use of cultural and chemical control practices has been ineffective. Therefore, a sustainable, affordable, and effective control method is urgently required. In this study, we aimed to isolate and characterize Bacillus velezensis from Lake Bogoria as a potential biocontrol agent for Fusarium solani. Bacteria were isolated from soil and sediments using the serial dilution technique. Molecular characterization was performed using the 16S rRNA gene. A total of 13 bacteria were isolated from soil and sediments. Based on the partial sequences, BLAST analysis showed two isolates, B20 (Bacillus velezensis strain QH03-23) and B30 (Bacillus velezensis strain JS39D), belonging to Bacillus velezensis. Other isolates were identified as Bacillus tequilensis, Brevibacillus brevis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus licheniformis. The effectiveness of their antifungal properties was determined via co-culturing, and we found mycelial inhibition rates of 28.17% (for B20) and 33.33% (for B30) for the Fusarium solani isolates. The characterization of the Bacillus velezensis strain revealed that they were Gram-positive and grew well at pH 7.0 and 8.5, although growth was recorded at pH 5.0 and 10.0. In terms of temperature, the optimal temperature conditions were 30−35 °C, with an optimum salinity of 0–0.5 M NaCl. When these isolates were tested for their ability to produce secondary metabolites, they were found to produce phosphate, pectinase, chitinase, protease, indole -3- acetic acid (IAA), and hydrogen cyanide (HCD), making them potential biocontrol agents.