IMPROVING QUALITY AND REDUCING LOSSES IN SPECIALTY FRUIT CROPS THROUGH STORAGE TECHNOLOGIES

Cold intolerance precludes the cold preservation (by refrigeration) of harvested crops, particularly warm zone plant species, resulting in significant postharvest losses of around 40% world-wide. Control of cold stress might alleviate these problems. For example, shelf life prolongation could create marketing and thus new production opportunities for cold-intolerant crops, particularly in warm zone regions. Our background studies led to the suggestion that a fundamental effect in chilling stress is cold-induced dehydration of hydrophobic (water-insoluble) matrices in cellular biopolymers, membrane lipid for example. Consequently, hydrophobic domains in cellular biopolymers aggregate to form an abnormal structure resulting in their loss of function. It is believed that this is a fundamental cold-induce process, gives rise to the myriad of physiological and metabolic abnormalities manifested in chilling stress. Moreover, this perspective is a conceptual frame work for engineering new strategies to control cold stress and creation of chilling tolerance. The outlined hypothesis will be tested with the use of hydrophobic compounds, lipids found in biological membranes for example. We will test whether cold stress leads in test compounds to dehydration and their consequent aggregation. We will examine, furthermore, whether prevention of cold-induced macromolecular dehydration and subsequent aggregation might be engineered by introducing molecular features that increase their water affinity and whether cold-induced aggregation is prevented by metabolites acting apparently as water substituents, various sugars or amine compounds known to be associated with chilling tolerance.The overall goal of this project is to examine and, hopefully validate a fundamental process, which presumably governs the response of plants (and other organisms) to cold stress. Aside from gaining new understanding, this study might give rise to an insight that could be exploited to control cold stress, resulting in practical benefits. Examples include crop protection or cold storage of cold-intolerant warm-zone plant crop that would enable their marketing and, thereby, new production opportunities, particularly in developing countries.