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Evaluation of Plant Signaling Networks in Natural Environments

Periodic Reporting for period 2 - SIGNAT (Evaluation of Plant Signaling Networks in Natural Environments)

Reporting period: 2017-07-01 to 2019-06-30

A critical characteristic of plant development is the strong influence of environmental factors as modulators of developmental programs. Among those factors, light, temperature and nutrient availability dominate developmental decisions, and can dramatically alter plant shape, biomass production and fruit set –all of them important agronomic traits. Research during the past thirty years has defined different molecular mechanisms by which plants perceive environmental signals and transduce this information into changes in gene expression and other cellular processes, ultimately triggering the appropriate adaptive responses. However, current knowledge has at least two important weaknesses: (i) it is based on mostly on the analysis under conditions where only one environmental factor is changed, while natural environments are more complex; and (ii) most studies have been performed at the seedling stage, while the influence of the environment becomes even more relevant at later stages from an agronomical perspective.
This project addresses the evaluation plant performance under complex combinations of light, temperature and nutrient conditions, using the previous knowledge generated by the participants and other laboratories, and analyzing three key stages of a plant’s life: seedling establishment, vegetative growth (biomass production), and reproductive development (flowering and fruit set). The international consortium is formed by researchers from five countries, with strong complementary technical and scientific expertises spanning light and temperature signaling, hormone action, natural genetic variation, large-scale phenotyping of adult plants, nutrient assimilation and systems biology integration.
The Consortium has defined a set of wild-type and mutant plants affected in the transduction of environmental signals and endogenous pathways involving hormones, and has started the physiological and molecular characterization of their behaviour under complex combinations of environmental conditions (ie, mixing different light regimes with different growth temperatures and/or nutrient availability. As a result, several conclusions have been reached at the moment: (i) several light receptors also act as temperature sensors; (ii) the activity of several hormone signaling elements is dramatically affected under shaded conditions; (iii) plants reorient their growth towards light through complex interaction between hormones and light photoreceptors; (iv) nutrient availability affects flowering time through the regulation of hormone levels, overriding the control by daylength; and (v) the expression of the florigen gene quantitatively integrates daylength information.
The Consortium has also implemented a dedicated training program that includes secondments of PhD students to foreign institutions, and has organized a PhD School on Environmental Regulation of Plant Development which took place in Valencia (Spain) in May 2016, which was open for free registration by international PhD students of the participating Institutions and also worldwide. Moreover, the activities of the Consortium include dissemination actions such as the participation in national Open Doors Days, the International Fascination of Plants Day, and guided tours to our labs open to Science high-school teachers and their classes.
The scientific results produced in the framework of SIGNAT have uncovered new roles for already known light signaling elements, and have described molecular mechanisms that allow signal integration under complex environments, such as the combined action of nutrients, temperature and light. We expect these results to set a benchmark for the activity of other colleagues worldwide, and we will transfer this knowledge to the agronomically oriented industry via joint meetings with companies during the last semester of the project.
Arabidopsis plants are able to adapt to changing environments