Ethylene induces soil microbes to delay fruit ripening

The consumer demand for fresh fruits and vegetables increases every year, and farmers need a low cost novel method to reduce post-harvest loss and preserve the quality of fresh fruits and vegetables. This study identifies a method to induce soil bacteria to biosynthesize a nitrile compound that potentially enters the plants tissue and negatively affects climacteric ripening and delays the ripening process at 20-30˚C. This study used soil rich with soil microbes, to delay the ripening of climacteric fruit. The soil was treated with nitrogen, a heavy metal, and ethylene gas.

Ethylene induced the soil to delay the ripening of organic bananas and peaches. A prototype transportation container maintained fruit fresh for up to 72 h at 20-30˚C. The fruit retained color, firmness, texture, no bruising and minimal spotting. The soil also prevented fungal infection in all samples. GC-MS analysis suggests ethylene induced the soil microbes to release an acetonitrile compound into the gaseous environment. The nitrile is released in low concentrations, but mature plants (fruits) contain very low levels of indole-3-acetonitrile (IAN) or indole-3-acetic acid (IAA).

The nitrile may obstruct or modify the mature plants (fruit) late stages development process, thus delay the climacteric ripening process and retarding the physiological and phenotypic effects of fruit ripening. We believe this study may have strong applications for post-harvest biotechnology.