Effect of fungal filtrates on germination of wheat grains and the biological control of these fungi using black pepper extract

Abstract

Wheat is one of the world's most abundant and essential food crops. It covers a significant area of the earth's surface, higher than any other plant, and tends to be among the top strategic crops. Wheat contamination with fungi leads to rapid deterioration of quantity and quality of wheat products. Many of those fungi are potential mycotoxins producers. This study aimed to isolate and identify fungi that contaminating the wheat grains from the Misurata Agricultural Research Center area and the South Region of Libya. Fungi contaminating wheat grains were isolated on Potato Dextrose Agar (PDA) and identified by culture characteristics and microscopically. Fungal filtrates of two fungal isolates, Aspergillus niger and Rhizopus sp., were tested for their effects on the germination and seedlings of wheat grains. Furthermore, the effect of acetonic extracts of Black pepper (Piper nigrum) on the growth of the isolated fungi was also investigated. Ten types of fungi belonging to four genera were isolated and identified. The germination rate of wheat grains irrigated with the filtrate of A. niger and Rhizopus sp. was 20% and 80% respectively, compared with 100% of the control grains, which were irrigated with water. The culture filtrates of both A. niger and Rhizopus sp. affect not the only percentage of grains germination but also the morphology of wheat seedlings. It adversely affected the length of the radicles and coleoptiles. The acetone extract of P. nigrum showed inhibitory effect (85.7% ± 3.7 and 44.0% ± 3.1) on the germination of A. niger and Rhizopus sp. respectively. This study concludes that fungal secretions have pathogenic effects on plant growth, which can lead to potential health risks for the human population. Biological control such as Piper nigrum extracts can be an alternative to chemical pesticides for controlling fungal pathogens and their secretions.