The regulation of phosphate starvation responses by strigolactones in Solanum lycopersicum

Phosphate fertilisation of crops is essential for optimal growth and yield, and has become a central issue in sustainable agriculture, as phosphate is a non-renewable resource. The phytohormones strigolactones have been receiving attention lately, for their role in responses to abiotic stresses such as phosphate starvation. Arabidopsis and rice plants defective in strigolactone perception or synthesis are impaired in some root morphological responses to phosphate deprivation, and accumulate fewer anthocyanin and transcripts of phosphate-responsive genes under phosphate starvation, compared to wild-type plants. However, very little is known about horticultural crops with primary market value, such as tomato (Solanum lycopersicum L.). This study aims to evaluate the effect of strigolactones on Phosphate Use Efficiency (PUE) and the phosphate starvation response, by contrasting wild-type tomato plants with two lines deficient either in strigolactone biosynthesis (CCD7-silenced) or perception (d14), under normal and phosphate starvation conditions. Results will be presented on biomass, PUE and key molecular markers (miR399, PHO2, PHR1), suggesting to what extent strigolactone mutants of tomato are defective in the phosphate starvation response with respect to the wild-type, and for what specific features. Most notably, plants defective in strigolactones will not stop growing during phosphate starvation.