A research team from Qatar University (QU) that has developed an eco-friendly solution for food security, maintains that it can prevent fungal pests in post-harvest crops in Qatar and beyond.
Prof Mohammed Abu-Dieyeh, professor of Biological Sciences and Dr Iman Saleh, lecturer of Biological Sciences Department of Biological and Environmental Sciences, College of Arts and Sciences, QU, have proposed that a water-soluble leaf ethanolic of Prosopis juliflora tree can be used as a preventive coating instead of chemical pesticides and fungicides for post-harvest fruits.
The researchers in the latest edition of the QU research magazine point out that Prosopis juliflora is a short tree, native to Mexico, South America, and the Caribbean and found in Qatar as it was introduced in the 1950s as a soil stabiliser and for greening purposes.
The researchers claim that the leaves of this plant can be used to prepare an extract that can serve as a bio-controller or natural anti-spoiling agent. According to them, this research can provide a solution to the worldwide agricultural problem and solve a major food security problem. Agricultural industry is a growing sector in Qatar but many challenges hinder the cultivation of local fresh produce, including high summer temperatures and water scarcity.
They note that post-harvest diseases impact both locally produced fruits and vegetables, as well as imported ones, especially during storage. These diseases are primarily caused by fungal and bacterial pathogens and the proposed extract can solve this issue.
According to Prof Abu-Dieyeh, the ethanolic extract from Prosopis juliflora leaves is prepared by incubating leaf powder in 70% ethanol at 45˚C with shaking at 50 cycles per minute for 48 hours. The supernatant contains all active phytochemicals, which are collected as a powdery or gummy material after the solvent has evaporated. The ethanolic crude extract is typically re-suspended in sterile distilled water to create stock solutions. Only the water-soluble portion is usually sterilised for use in further investigations.
In vitro analysis of the extract showed solid results on the efficacy of it against a wide range of pathogenic microorganisms. The results were supported by fruit bioassay results during which the extract was explored as an alternative biological controller. Artificially inoculated tomato and mango samples were completely protected from the disease caused by fungi that were inhibited by the extract in the laboratory tests.
Spraying cucumber samples with 8mg/ml of the extract extended cucumber shelf-life at 22°C by 77% and maintained samples’ acceptable quality for three weeks of storage at 8°C.
Penicillium italicum, one of the main citrus fruits spoiling agents, was 100% cured in lemons and prevented in oranges when fruits are treated with this extract. Penicillium digitatum infection was also controlled by the extract. The extract also showed success as a coating material to maintain lemons and oranges storage parameters at 4°C.
The effectiveness the extract against post-harvest phytopathogens opens doors for the application of this natural product as a replacement for chemical pesticides and to manage the invasive plant via utilisation. The researchers have already applied for the patent and suggest that the extract is ready to be taken to the next stage as an antifungal agricultural solution in the current development status for large-scale in-field trials. It can also be used as an antifungal storage coating material for large-scale storage preservation trials.