Abstract: Sixteen different localities in Southern area of Saudi Arabia were examined for their fungal mycoflora. A modified soil-dilution plate method was used for isolating the fungi. Sixty four species in twenty two genera were reported. Of these species five were Phycomycetes, ten were Ascomycetes and forty nine were Deuteromycetes. Of the reported species 55 are new records to the Flora of Saudi Arabia and one of these is a new species.
Introduction
Few investigations have been made of soil fungi in Saudi Arabia. Fathi et al. (1975) studied the activities of the soil fungi in Riyad region. Ali (1977) conducted a general survey of the fungal flora in Wadi Hanifa. Subsequently, Ali et al. (1977) recorded the seasonal fluctuations of different fungi in the rhizosphere of some plants. Abdel-Hafez (1982) in a preliminary survey of the mycoflora of desert soils in Saudi Arabia isolated thirty four different fungal genera and 80 species from different places. He also recorded more than forty tow new fungal species. Some of the important reviews dealing with fungal flora were those of Chaudhuri and Sachar (1934), Bisby et al. (1935), Taber (1951), Miller et al. (1957), Doory et al. (1959), Borut (1960), Kendrick (1962), Jensen (1963), Waheeb and Yusef (1968), Christensen (1969), Bhatt (1970), Moubasher and Moustafa (1970) and Samuels (1996). The present study was undertaken to characterize the soil mycoflora of different localities in Southern area of Saudi Arabia as being recorded for the first time.
Materials and Methods
Soil samples were collected from sixteen localities in Southern area in December and April 2000, 2001(Fig. 1), according to the method described by Johnson et al. (1960). The Southern region, laying to the east of South Hijaz, to the South of Najd to and the north of Yemen. It includes, Abha, Bisha, Gizan and Najran areas (Migahid, 1978). The surveyed localities include the coastal area of the Red sea from Al Gunfudah to Najran and from Al Baha to Khamis Mushayt. The methods applied for soil analysis were based on those referred to in Piper (1947). The dilution plate method was used, for the estimation of soil fungi, as described by Johnson et al. (1960), but with some modifications. The primary suspension was prepared from 25 g of the soil in a pint Mason jar containing 250 mL of sterile 0.15% water agar. This primary suspension was blended for 15 min. A dilution series was prepared from this primary suspension. Samples from 1:100 and 1:1000 dilutions of the primary suspension were plated out in triplicate using modified Czapek's Dox medium in which glucose (10 g L-1) replaces sucrose and supplemented with 0.5 g yeast extract, rose bengal and streptomycin. The plates were incubated at 22-23°C and examined periodically. Dilution plates were kept for at least 3 weeks before being discarded to allow slow-growing colonies to develop. The fungal colonies growing on the dilution plates were transferred to fresh Czapeck's Dox agar and pure cultures of isolated fungi were obtained by making spored- or single-hyphal tip isolations. Prepared slides of lactophenol-cotton blue were examined and identification of the isolated fungal species was done using stereoscopic binocular (40x) and compound research binocular microscopes (1000x).
| Fig. 1: | Map locating sites where the different soil samples were collected *1 = Al Gunfudah; 2 = Al Baha; 3 = AL Majardah; 4 = Annamas; 5 = Abha; 6 = Khamis Mushayt; 7 = Al Gawz; 8 = Kayad; 9 = As Saidah; 10 = Amaq; 11 = Dabsa; 12 = Al Birk; 13 = Al Tirq; 14 = Gizan; 15 = Ash Shugaig; 16 = Najran |
| Table 1: | Characteristics of soils of the different localities in Southern region of Saudi Arabia |
Results and Discussion
The results given in Table 1 show that the Southern area soils are generally poor in inorganic content. The total soluble salt content varies from a low value (0.08) to relatively high value (0.6). The pH values of the soil samples reveal no appreciable differences; all are alkaline and the pH ranges from 7.2-8.1. The soil samples are of characteristical desert type. They are light and sandy.
Records of Fungal Genera
In the isolation studies of the fungi from southern region soils a total
of 64 species in 22 genera were recovered. Most of the fungal genera isolated
belonged to the class Deuteromycetes. Four species were Phycomycetes,
ten were Ascomycetes and forty nine were Deuteromycetes. The various
fungal species are listed according to their occurrence in the following localities:
Al Gunfudah
Pleospora herbarum, Alternaria alternata, Aspergillus niger,
Cladosporium cladosporioides, Penicillium crustosum, Penicillium
chrysogenum, Penicillium decumbens, Trichoderma aureoviride,
Trichoderma harzianum, Trimmatostroma sp.
Al Baha
Alternaria alternata, Cladosporium cladosporioides, Fusarium
acuminatum, Fusarium semitectum, Penicillium chrysogenum.
AL Majardah
Rhizopus stolonifer, Pleospora infectoria, Alternaria alternata,
Alternaria sp., Cladosporium cladosporioides, Fusarium oxysporum,
Fusarium semitectum, Penicillium decumbens, Trimmatostroma
sp.
Annamas
Mucor hiemalis, Chaetomium bostrychodes, Chaetomium irregulare,
Chaetomium cf. mollicellum, Chaetomium sp. (new species), Pleospora
infectoria, Alternaria alternata, Aspergillus flavus, Aspergillus
niger, Aspergillus ustus, Cladosporium cladosporioides,
Cladosporium macrocarpum, Chaetomidium subfimeti, Coniothyrium
sp., Penicillium canescens, Penicillium chrysogenum, Penicillium
frequentans.
Abha
Chaetomium spirale, Neurospora crassa, Aspergillus ochraceus,
Aspergillus versicolor, Cladosporium cladosporioides, Penicillium
canescens, Penicillium cyclopium, Penicillium crustosum.
Khamis Mushayt
Rhizopus arrhizus, Chaetomium fusisporum, Chaetomium cf.
mollicellum, Pleospora infectoria, Aspergillus glaucus, Cladosporium
cladosporioides, Coniothyrium fuckelii, Fusarium concolor,
Gliocladium roseum, Penicillium canescens, Penicillium cyclopium,
Penicillium frequentans, Penicillium funiculosum, Penicillium
janthinellum, Phoma sp., Scolecobasidium variabile, Stachybotrys
sacchari, Ulocladium atrum.
Al Gawz
Pleospora infectoria, Aspergillus ustus, Cladosporium tenuissimum,
Penicillium canescens, Phoma exigua.
Kayad
Chaetomium jodhpurense, Aspergillus nidulans, Aspergillus
tamarii, Fusarium acuminatum.. Penicillium canescens, Penicillium
cyclopium.
As Saidah
Cladosporium cladosporioides, Fusarium concolor, Penicillium
canescens.
Amaq
Cladosporium sphaerospermum, Penicillium decumbens, Trimmatostroma
sp.
Dabsa
Aspergillus fumigatus, Aspergillus niger, Cladosporium
sphaerospermum, Penicillium chrysogenum.
Al Birk
Fusarium semitectum, Penicillium canescens, Trichoderma
viride.
Al Tirq
Rhizopus stolonifer, Fusarium equiseti, Penicillium chrysogenum.
Gizan
Myrothecium roridum, Peniciliium lilacinum, Cladosporium
aureoviride, Stachybotrys atra corda.
Ash Shugaig
Mortierella sp., Aspergillus flavipes, Cladosporium cladosporioides,
Cladosporium sphaerospermum, Penicillium canescens, Penicillium
cyclopium, Penicillium chrysogenum, Penicillium decumbens,
Penicillium frequentans, Penicillium thomii, Phoma exigua,
Trimmatostroma sp., Ulocladium atrum.
Najran
Cladosporium macrocarpum, Fusarium solani, Penicillium
cyclopium, Penicillium frequentans, Phoma sp.
All these fungal species were new records from Southern area soils except Aspergillus flavus, Aspergillus fumigatus, Aspergillus glaucus, Aspergillus niger, Fusarium equiseti, Fusarium oxysporum, Fusarium solani and Penicillium chrysogenum.
According to their occurrence in the soil samples, Penicillium and Cladosporium are of high occurrence in Southern area soils. The former was present in all the soil samples and the other was absent from four samples only.
Aspergillus and Fusarium were of moderate occurrence. Five genera were of low occurrence, namely Alternaria, Pleospora, Rhizopus, Chaetomium and Phoma. Twelve genera i.e., Trichoderma, Trimmatostroma, Chaetomidium, Coniothyrium, Mucor, Neurospora, Scolecobasidium, Stachybotrys, Ulocladium, Gliocladium, Myrothecium and Mortierella were rare.
Aspergillus and Penicillium were the fungal genera having the highest number of isolated species. Ten species from each genus were recorded. Seven species were recovered from both Fusarium and Chaetomium, four species from Cladosporium and Trichoderma, two species from Alternaria, Pleospora, Rhizopus, Stachybotrys, Coniothyrium and Phoma. Only one species was recorded from the rest of fungal genera namely, Trimmatostroma, Scolecobasidium, Chaetomidium, Mucor, Ulocladium, Gliocladium, Neurospora, Mortierella and Myrothecium. The broadest range of genera and species isolated from the different soil samples where from Annamas, Khamis Mushayt and Ash Shugaig. These results are in close agreement with those reported early in Saudi Arabia (Ali, 1977; Ali et al., 1977; Abdul-Hafez, 1982; Arif and Hashem, 1998) and elsewhere in the neighboring regions (Doory et al., 1959; Waheeb and Yusef, 1968).
Acknowledgements
The author is very grateful to all members of the Commonwealth Mycological Institute, Kew, England, for their kind help in identifying or confirming some of the identification of most of the species recorded in this investigation.