Broadening the spectrum of nitric oxide action in plant photomorphogenesis and stress physiology

Abstract

Light drives photosynthesis and informs plants about their surroundings. The information provided by the light environment is perceived by multiple plant photoreceptors, including phytochromes (PHYs), which are sensitive to red and far-red light and are implicated in most plant photomorphogenesis events. Regarded as a multifunctional signaling molecule in plants, nitric oxide (NO) has been repeatedly demonstrated to interact with light signaling cascades to control plant growth, development and metabolism. However, up to now, NO signaling action in plant photomorphogenesis has been mainly investigated during early plant development, including seed germination and seedling deetiolation. Much less is known about the involvement of NO in light-regulated developmental processes that take place later in the plant life cycle, including photoperiodic flowering, shade-avoidance responses, fruit growth and ripening, and leaf senescence. In this project, we aim to significantly amplify the spectrum of plant photomorphogenic events in which the crosstalk between NO and light signaling has been investigated. Tomato (Solanum lycopersicum), which is a major crop plant and a model system for fruit physiology, was selected for this investigation to allow exploring NO-light interplay not only during vegetative growth, but also in fleshy fruit development and ripening. Moreover, since high temperatures are among the most relevant abiotic stresses limiting tomato production worldwide, we will also explore the importance of PHYs as temperature sensors and NO as a priming agent in tomato plants under warm conditions. Developmental genetics, genetic engineering, omics, and bioinformatics approaches will be employed in this project. As the different light-controlled processes investigated in this project can affect the ability of plants to acclimate, survive and reproduce in natural and agricultural ecosystems, we foresee this research as providing important molecular and physiological insights for improving productivity, nutritional quality and stress resistance in tomato and other crops through biotechnology. (AU)