Research Article, Vegetos Vol: 30 Issue: 4

Post-Harvest Mycoflora of Root Vegetables from Ad Darb Markets, Jizan, Saudi Arabia

Syeda Fatima Manzelat*

Department of Botany, College of Science and Arts, Ad Darb, Jizan University, Jizan, Saudi Arabia

*Corresponding Author : Syeda Fatima Manzelat
Department of Botany, College of Science and Arts, Ad Darb, Jizan University, Jizan, Saudi Arabia
Tel: 00966-553708986
E-mail: [email protected]

Received: September 07, 2017 Accepted: October 11, 2017 Published: October 13, 2017

Citation: Manzelat SF (2017) Post-Harvest Mycoflora of Root Vegetables from Ad Darb Markets, Jizan, Saudi Arabia. Vegetos 30:4. doi: 10.5958/2229-4473.2017.00198.7

Abstract

This is the first study of post-harvest mycoflora of root vegetables from Ad Darb region of Jizan province. A total number of ten samples of root vegetables from the local markets of the place with post harvest spoilage fungi were collected and studied. The mycoflora was cultured on Potato Dextrose Agar plates. A qualitative and quantitative assessment of mycoflora was carried out by the fungal cultures on petri plates in triplicate and the slides were identified by microscopic and macroscopic characteristics. A total of 46 fungal isolates represented by 9 fungal genera were isolated from the samples belonging to the three classes of fungi i.e. Zygomycetes, Ascomycetes and Basidiomycetes. The post-harvest mycoflora was represented by Rhizopus, Aspergillus, Alternaria, Fusarium, Chaetomium, Penicillium, Geotrichum, Ulocladium and Ustilago. The most predominant genera were Fusarium with nine isolates followed by Alternaria with eight isolates. The information on the diverse groups of post harvest mycoflora can help in effective management and minimization of post-harvest economic losses and the risk of a number of human, plant and animal diseases.

Keywords: Root Vegetables; Mycoflora; Ad Darb; Jizan; Saudi Arabia

Introduction

Some products are packed in modified atmospheres to provide extension of shelf life both in relation to the potential acceptable quality and safety of the product but still due to the hot desert climate in the area even though the underground vegetables are stored for sale in air conditioned counters but still the post harvest losses encountered are heavy. During growth, harvest, transportation and further processing and handling the produce is, however, contaminated with pathogens from human or animal sources. The freshness of stored root vegetables is lost within 2-3 days and the vegetables start post harvest rotting and decaying due to pathogens. The fungal growth is apparently visible on these products by a variety of colours on their surface which later on gets either mummified in dry conditions or forms a soft wet mass under moist conditions. The fungal damage is due to their putrefying and fermentative activity which breaks down the proteins and carbohydrates into acids, gas and mycotoxins. The mycotoxins from these decaying underground vegetables not only led to economic losses but also are responsible for many human and animal diseases. They are not only responsible for allergies, botulism, lung and skin infections but also life threatening diseases like cancer etc.

The present study is the first report of post-harvest mycoflora from Ad Darb market. Hence there is an urgent need to study the post harvest mycoflora of the place. The present study lists a number of fungal pathogenic floras occurring on ten varieties of edible root tubers and bulbs. There has been no detailed work done on the post harvest mycoflora in this part of the Kingdom of Saudi Arabia, this work being the first and most comprehensive study on the subject.

The conditions in Saudi Arabia are unfavorable for the cultivation of most fruits and vegetables, with only 1.67% of arable land in the total land available. Saudi Arabia has the highest production of fruits and vegetables among all the GCC country.

Analysis of consumption and production trends of Fruits and Vegetables [1].

Root vegetables like radish, carrot, turnip and table beets which are cool season crops could be successfully grown under Jizan conditions if they are planted during the proper time of planting [2].

Some potatoes are sold fresh from the harvest, although most of the potatoes (and onions) are stored in our highly sophisticated cold stores. Over 75% of the total potato production in the Kingdom comes from small farmers grouped in different regions, and who supply local wholesale markets [3].

For the onions, the climate in Tabuk is very suitable for growing high quality and quantity. Our yellow, white or red onion are known to be the best produced in the Kingdom. Onions are sold in the markets and also exported to several countries, [3].

Potatoes have become an important food crop in Saudi Arabia in recent years. More than 15 varieties are grown in both autumn and spring seasons. Production has increased from 6700 tonnes in 1980 to about 47 000 tonnes in 1989 [4].

The Saudi Ministry of Agriculture and Water negotiated an agreement with the Netherlands to establish the Saudi Potato Development Programme (SPDP) [5].

There is large cultivated area for production of major crops like onion and potato which are grown in Saudi Arabia: [6].

R. stolonifer has been found in pea and bean seeds in Saudi Arabia (1). However, both fungi more commonly exist in the asexual state (sporangia and vegetables: asparagus, onions, beans, peas, carrots, celery, and related vegetables. [8].

Alternaria radicina (black rot of carrots) is found on carrots in Saudi Arabia, [9]. The most frequent fungal contaminants of spices are species from the genera Aspergillus and Penicillium.

The most heavily contaminated spice samples examined were observed in ginger in order of magnitude of 5325–6800 cfu/g. The most predominant fungal genera encountered were Aspergillus, Penicillium, and Rhizopus [10].

Alternaria japonica is the causal organism for pod spot of radish. Carrots, turnip, beet and radish are grown in Jizan. [11].

These finding suggest that different variety of mycoflora occur as surface inhabitants of the root vegetables under study which if consumed can lead to severe food poisoning. The post-harvest mycoflora was represented by Rhizopus, Aspergillus, Alternaria, Fusarium, Chaetomium, Penicillium, Geotrichum, Ulocladium and Ustilago. The most predominant genera were Fusarium with nine isolates. The information on the diverse groups of post-harvest mycoflora can help in effective management and minimization of post-harvest economic losses and also the risk of health to plants, animals and humans.

Sample Collection and Processing: A total of ten samples of infected post harvest underground vegetables were collected from markets of Ad Darb for a period of one year. Each of the samples were collected in sterile polythene packs and carried to the laboratory. The surface of the underground vegetables were sterilized with 6% sodium hypochlorite and then washed thoroughly with distilled water 3 times before inoculation. Sterilized samples were inoculated in the inoculation chamber using pre sterilized forceps on the petri plates. Potato dextrose agar media was used for the study.

Isolation and Identification

The fungal cultures in triplicate on the petri plates with Potato Dextrose Agar media were incubated at room temperature for five days. Lactophenol and cotton blue in lactophenol were used as mounting and staining media for preparing semi permanent slides which were sealed with DPX mountant. The fungal isolates were counted and identified by macroscopic and microscopic characters using standard procedures. Research microscope with adequate high power has been used. Identification was carried out by using standard manuals and keys to identification. Colony characters on the media, morphological characters like nature of mycelium, its colour, sexual and asexual structures and their characters, conidiophore and spore nature were used to categorise the different fungal genera. Photographs were taken of all the infected post harvest underground vegetable samples and the fungal cultures on the petriplate. Photomicrographs of the slides were also taken under the microscope with a camera. All the fungal slides are deposited at the Dept of Botany, College of Science and Arts at Ad Darb, Jizan University, Jizan under the accession FUJU.

Results and Discussion

This is the first study of post harvest mycoflora of underground vegetables from Ad Darb region of Jizan province. A qualitative and quantitative assessment of post harvest spoilage fungi was carried out by the fungal cultures on the petri plates. A total of 46 fungal colonies were isolated represented by 9 fungal genera belonging to the three classes of fungi i.e. Zygomycetes, Ascomycetes and Basidiomycetes (Table 1). The post-harvest mycoflora was represented by Rhizopus, Aspergillus, Alternaria, Fusarium, Chaetomium, Penicillium, Geotrichum, Ulocladium and Ustilago. The most predominant genera was Fusarium with nine isolates (Figures 1,2,3,6,8) followed by Alternaria with eight isolates. Rhizopus (Figures 3, 7 and 8) was represented by six isolates, Chaetomium had four isolates (Figure 5), Penicillium with five isolates (Figure 3) and four isolates of Geotrichum (Figure 7) were obtained. Ulocladium (Figure 5) and Ustilago (Figure 4) with two isolates each.

The percentage disease incidence ranged from 20-30%. Percentage of disease incidence on each sample is calculated as per the following formula:

Figure 1: Beet Root with Fusarium.

Figure 2: Colocasia with Fusarium.

Figure 3: Elephant’s Ear Yam with Alternaria.

Figure 4: Onion , Culture and Ustilago spores.

Figure 5: Garlic with Penicillium,Ulocladium and Rhizopus.

Figure 6: Carrot and its culture with Fusarium and Alternaria.

Figure 7: Potato and its culture with Chaetomium and Fusarium.

Figure 8: Radish with Alternaria and Fusarium.

Sl. No. Name of the food sample Zygomycetes   Ascomycetes Basidiomycetes % Disease Incidence
Rhizopus Alternaria Aspergillus Fusarium Chaetomium Penicillium Geotrichum Ulocladium Ustilago
1 Beet root - + - + - - - - - 20
2 Carrot - + + + + + + + - 25
3 Colocasia + + - + - - + + - 24
4 Elephant’s Ear Yam + + - + + - - - - 24
5 Garlic + + + - - + - - + 22
6 Ginger +- - +- + - + - + - 20
7 Potato - - - + + - + - - 23
8 Onion + + + + - + - - + 26
9 Radish - + - + - + - - - 23
10 Cassava + + - + + - + + - 30
46  isolates from 9 Fungal Genera 6 8 4 9 4 5 4 4 2  

Table 1: Different fungal genera on post-harvest root vegetables.

Symptoms of Different Fungal Genera of Root Vegetables

Rhizopus

The root vegetables are infected with black and brown irregular lesions show irregular brown spots which turn black. The vegetables rot and emit mouldy smell.

Alternaria

The surface infection of the vegetables crack and the tissue turns spongy, brown and leathery.

Aspergillus

It causes brown, black and powdery rots of infected vegetable. The vegetable decays and is discolored which later turns brown or black.

Fusarium

The surface of the fruits shows mats of white mycelial tissue and shows rotting on the surface.

Penicillium

The infected fruits show lesions with green or sometimes bluish growth of the fungus. The fruit tissue rots is discoloured and emits smell.

Chaetomium

The surface of the infected vegetables become hard, dry and show dark mycelial growth.

Geotrichum

It causes rotting and the tissue becomes watery and decays .The surface shows white mycelial growth of the fungus.

Ulocladium

It is a surface pathogen which causes black lesions and emits mouldy odor.

Ustilago

The surface of the infected underground bulbs shows powdery, black and sooty mass of spores.

Conclusion

The post-harvest mycoflora was represented by Rhizopus, Aspergillus, Alternaria, Fusarium, Chaetomium, Penicillium, Geotrichum, Ulocladium and Ustilago. The most predominant genera were Fusarium with nine isolates. The information on the diverse groups of post harvest mycoflora can help in effective management and minimization of post-harvest economic losses as well as risk of a number of human, plant and animal diseases.

Acknowledgement

The author thanks the Dean Dr. Ayesha Khasim Ali Al Shamakhi and the Vice Dean Dr. Wafa’a Asiri, College of Science and Arts, Ad Darb and authorities of Jizan University, Saudi Arabia for providing the facilities. The author also thanks Isra Syed Siraj, Student, College of Medicine, Al Faisal University, Riyadh for her constant help during the project.

Conflict of interest

The author declare(s) that there is no conflict of interest regarding the publication of this paper.

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