کنترل بیولوژیکی Penicillium chrysogenum توسط Aureobasidium pullulans و Rhodotorula graminis در سیب‌زمینی مهار زیستی Penicillium chrysogenum عامل بیمارگر سیب‌زمینی توسط Aureobasidium pullulans و Rhodotorula graminis

نوع مقاله : مقاله پژوهشی

نویسندگان

• نوشین شفیعی ¹
• کیوان بهشتی مآل ¹
• حمیدرضا عکافی ²
• هاشم نیری ³

¹ گروه میکروبیولوژی، دانشکده علوم زیستی، واحد فلاورجان، دانشگاه آزاد اسلامی، اصفهان، ایران

² گروه زیست شناسی، دانشکده علوم زیستی، واحد فلاورجان، دانشگاه آزاد اسلامی، اصفهان، ایران

³ گروه بیوشیمی، دانشکده علوم زیستی، واحد فلاورجان، دانشگاه آزاد اسلامی، اصفهان، ایران

چکیده

کلیدواژه‌ها

• فعالیت کشندگی
• ترکیبات فرار
• Penicillium chrysogenum
• Aureobasidium pullulans
• Rhodotorula graminis

موضوعات

• کنترل بیولوژیک بیمایهای گیاهی

Extended Abstract

Introduction

Potato is considered an important food all over the world. Fungi are one of the most important pathogens in potatoes and cause a lot of damage in the production of this product. The use of fungicides causes damage to humans and the environment. In general, biocontrol microorganisms isolated from the surface of fruits are more compatible with the environment. Among the microorganisms, yeasts have more advantages than other microorganisms. One of the advantages of yeasts is their ability to increase on the surface of the fruit for a long time, which causes food competition between the yeast and the pathogen. The use of biocontrol yeasts against phytopathogenic molds was proposed for the first time in 1991, and since then, more research has been done in this field. The main aim of this research was to isolate and identify potato mold pathogens and eliminate them from native yeasts in the Isfahan region.

Materials and Methods

In this research, isolation, macroscopic and microscopic examinations of potato fungal pathogens, pathogenicity test of these molds in potatoes, and their molecular identification were done. Also, new isolates of native yeasts were isolated from different regions in Isfahan province. Killing activity was measured by putting yeast isolates in the form of spots on the YEPD-MB medium, which was previously spread with the mold suspension. Measuring the in vitro antagonistic activity of yeasts against mold was done by simultaneously cultivating yeast and mold in a Petri dish. Measuring the in vivo antagonistic activity of yeasts against mold was done by classifying potatoes into positive control, treated with yeast, and negative control groups. The production of volatile compounds of yeast against mold was investigated by placing 2 plates containing yeast and mold face to face after 2 weeks Finally, the best biocontrol isolates were identified molecularly.

Results  

In this research, Penicillium chrysogenum SBAN-IAUF-11 was isolated as a pathogenic mold from the rotten parts of the potato. In the pathogenicity assay, this mold caused disease in healthy potatoes. In the killing activity assay, A13 and A14 were selected as killer yeasts. Also, the amount of in vitro antagonistic activity A13 and A14 against pathogenic mold was 54.08 and 50.57 percent, respectively. On the other hand, the inhibition rate of pathogenic mold by volatile compounds produced from A13 and A14 was 44 and 76 percent, respectively. Finally, the determination of in vivo antagonistic activity showed that the inhibition rate of pathogenic mold by A13 and A14 was 80/08 and 82/97 percent, respectively. Molecular studies showed that A13 and A14 were related to Aureobasidium pollulans SBAN-IAUF-11 and Rhodotorula graminis SBAN-IAUF-4, respectively. Finally, Aureobasidium pollulans SBAN-IAUF-11 and Rhodotorula graminis SBAN-IAUF-4 were registered in NCBI with accession numbers PP741871 and PP741860, respectively.      

Discussion

In this study, for the first time, P. chrysogenum was isolated and identified as a potato pathogen from rotten potatoes. Also, in South Korea for the first time P. sclerotigenum and P. polonicum; and in Pakistan P. solitum, P. polonicum, and P. citrinum were isolated and identified from rotten potato tubers. Therefore, different species of Penicillium can be considered a great threat to potatoes in the storage stage. In this study, the suspension of the mold was used to measure the killing activity of yeasts against pathogenic mold, but in previous studies, Saccharomyces cerevisiae NCYC 1006 was used as a sensitive strain. Using mold cells instead of sensitive yeast strain was a more accurate choice to detect killer yeasts against the same mold. The results of measuring the killing, in vitro-in vivo antagonistic activity, and the volatile compounds production of yeasts showed that A. pollulans SBAN-IAUF-11 and R. graminis SBAN-IAUF-4 can significantly inhibit pathogenic mold compared to previous studies. This is the first time that R. graminis, as a biocontrol yeast, is proposed against Penicillium sp. Also, in this study, for the first time, the biocontrol activity of                A. pollulans against P. chrysogenum in the potato tubers is reported.

Conclusion

   The results of the in-killing and antagonistic activity showed that A. pollulans SBAN-IAUF-11 and R. graminis SBAN-IAUF-4 were capable of inhibiting more than 50 percent of P. chrysogenum SBAN-IAUF-11. These strains can be used as a safe and suitable alternative to chemical fungicides in controlling green and blue mold in potatoes and other agricultural products.