Identification Key for <i>Aspergillus</i> Species Isolated from Maize and Soil of Nandi County, Kenya

Abstract

The aim of this study was to identify Aspergillus species isolated from maize kernels and soils of maize fields of Nandi County using macro and micro morphological characteristics. A cross sectional research design was used in the study and purposive sampling was employed to determine districts of Nandi County and sub locations where sampling was done. This study was part of a larger project whose aim was to survey aflatoxin exposure in the maize value chain. Aspergillus species were isolated from maize and soil samples using quarter strength potato dextrose agar and modified Rose Bengal agar respectively. Pure cultures of the isolates were sub cultured and transferred onto differential media; malt extract agar, czapek yeast extract agar and czapek dox agar for species identification using macro morphological characteristics. Fungal slides were prepared from pure cultures on potato dextrose agar media after three days to identify micro morphological characteristics. Based on morphological characteristics, seven sections of Aspergillus namely: Flavi, Fumigati, Nigri, Circumdati, Clavati, Nidulantes and Candidi were identified. Aspergillus section Flavi was the most predominant with 57% followed by section Nigri with 27% from maize and 58% of section Flavi followed by 26% of section Nigri from the soil across the three locations. Aspergillus sections Nidulantes and Candidi were rare and only recovered from the soil samples of Kaptumo location. All the Aspergillius flavus that formed sclerotia both from the soils or maize kernels were of the L strains. In conclusion Aspergillus section Flavi was most frequent during the isolation process and dominated with Aspergillus flavus from both the maize and soil. Morphological characteristics remain the primary tool for detection and identification of Aspergillus species. The significance for high incidence of Aspergillus section Flavi is in regard to their aflatoxin production profiles that poses a health threat to the community and it is of public health concern. Morphological characteristics as a primary tool for Aspergillus identification should be embraced and more personnel with the knowledge are required since modern and faster techniques are scarce and expensive.

Identification of Toxigenic Aspergillus Species from Rice of Khuzestan and Mycotoxins in Imported Cereals

“…Gao et al (2007) showed that Aspergillus flavus was the main pollutant in oilseeds (pistachio, almond, hazelnut), corn, wheat, cereals, and beans, respectively. The results of the studies of Makun et al (2007), Amadi et al (2009) were also consistent with this study (13,14,15,16,17). Because of the saprophyte and widespread toxinogenic fungi such as Aspergillus, rice and cereal products have some relative contamination from the beginning.…”

Isolation and identification of fungi responsible for leaf spots disease of mango (<i>Mangifera indica linneaus</i>) in Sokoto state, Nigeria

“…Aspergillus niger was confirmed by various studies such as Nyongesa et al (2015), Awa et al (2012), Diedhiou et al (2007), Khaskheli et al (2008) among others implicated these fungi species to be the fungi responsible for postharvest diseases of mango associated with fruit rotting during ripening. Mango leaves could also be affected as the dusty charcoal spores of the black mold which could easily be dispersed by air from infected fruits.…”

“…and were identified as such. A total of eleven pathogens (Alternaria longipes, Aspergillus fumigatus, Aspergillus niger, Colletotrichum gloesporioides, Fusarium oxysporum, Fusarium mangifera Pestalotiopsis mangiferae, Phoma mangiferae, Phomopsis mangiferae, Pseudofusicoccum spp., and Rhizopus oryzae) were identified and were then described and classified based on conidia and colony morphology as described by Barnett and Hunter (1998), Ellis and Hermanis (2003), Palvic et al (2008), Guo-yin et al (2013), Nyongesa et al (2015), and Gagkaeva (2008). Stock cultures of all the isolates were maintained on PDA slopes in McCartney bottles at 4°C in the dark.…”

Biological Control of &lt;i&gt;Pyricularia oryzae&lt;/i&gt; Using Antifungal Compounds Produced by &lt;i&gt;Aspergillus niger&lt;/i&gt;

“…These two isolates were revealed typical characteristics of blast pathogen. Besides, pure isolates of A. niger colony aged 7 days was observed as grayish black to black colony with white mycelia at the edge of the fungus colony [17].…”