During tomato fruit ripening a series of biochemical and metabolic changes alter fruit pigmentation, texture, flavor and aroma. However, in the late stages of ripening other changes, such as the rapid softening and increased susceptibility to microbial infection, negatively affect fruit quality and significantly determine the harvest, transport, storage and marketing of the fruit. Although the biochemical and metabolic processes related to fruit quality have been extensively studied in tomato, other less-characterized biochemical processes, like sterol metabolism, may also play important roles not only in fruit development and ripening but also in mediating stress responses.
In plants sterols are found in free and conjugated forms. Steryl glucosides (SG) and and acylsteryl glucosides (ASG) are minor components in the membranes of most plants. However, tomato tissues accumulate large amounts of SG and ASG, particularly in the fruit. Remarkable changes in the abundance and relative ratios of free sterols and their conjugated forms take place in the tomato fruit during ripening and cold acclimation. At present, very little is known about the role of sterols in plant growth, fruit development and ripening, cold injury and resistance or susceptibility to pathogen attack. Research activities of the group are mainly focused on the study of different aspects of sterol metabolism in tomato, including the role of sterols in fruit development and ripening, and their involvement in biotic and abiotic stress responses.