Dissecting the roles of phytochrome signaling in the reproductive development of tomato under high temperature

• Grant number: 25/01145-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: June 01, 2025
• End date: September 30, 2027
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Luciano Freschi
• Grantee: José Laurindo dos Santos Júnior
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 23/03330-3 - Light and stress signal transduction pathways: how to optimize multiple responses for improving crop yield and quality, AP.TEM

Abstract

The higher incidence of extreme climate events, such as heatwaves, challenges fruit production in various crops, including tomato (Solanum lycopersicum), particularly during the reproductive phase, when pollen development is vulnerable and affects productivity. A key factor in temperature perception in plants is the phytochrome B (PHYBs), which, in addition to functioning as a photoreceptor, also acts as a thermosensor. The role of PHYBs in thermoperception is linked to the acceleration of the conversion from their active form (Pfr) to the inactive form (Pf) in response to increasing temperature. However, their function as thermosensors during the reproductive stage under high temperatures remains virtually unexplored. Even less is known about the role of PHYBs and PHYB-associated signaling proteins (HY5 and PIFs) in thermoperception in cultivated species, such as tomato. Therefore, this project aims to investigate the role of phytochromes PHYBs (SlPHYB1/B2) and the proteins SlHY5 and SlPIFs during signaling events in tomato under high-temperature conditions, with a focus on reproductive development and fruit metabolism. For this, the reproductive development of mutant and transgenic plants with modifications in the SlPHYB1/B2-SlPIFs-SlHY5 signaling module will be compared under two conditions: control (25°C day/18°C night) and high temperature (32°C day/25°C night). Through a multidisciplinary approach combining genetics, physiology, and biochemistry, we will investigate genomic, transcriptomic, metabolic, physiological, and biochemical changes induced by high temperature. The expected results will provide new insights into the regulatory processes connecting the PHYB-HY5-PIF module to thermotolerance, contributing to the development of tomato varieties, and potentially other agricultural species, more resilient to high temperatures, with the potential to enhance fruit productivity and quality under adverse climatic conditions.