Influence of Phytochromes Bs and PIFs on tomato microsporogenesis and fruit development under high ambient temperature

Abstract

Tomato (Solanum lycopersicum) is one of the most cultivated crops in the world; however, adverse abiotic conditions, especially increments in ambient temperature, are well known to cause significant loss in tomato productivity. For most commercial tomato genotypes, increments of a few degrees above the ideal growth temperature result in significant fruit yield reductions. Indeed. Fruit production is considered one of the most critical parameters for screening high temperature-tolerant tomato genotypes, and this trait is frequently correlated to differences in stress susceptibility during pollen development and germination. In addition to their well-established roles in light perception, phytochromes B (PHYBs) also act as thermoreceptors in plants. The action of PHYBs in plant thermoperception mainly relies on the influence of temperature on the conversion of Pfr form (active) to Pf form (inactive). Therefore, based on the hypothesis that the molecular mechanisms associated with PHYBs signaling must be a suitable biotechnological target for mitigation of elevated ambient temperature-related impacts on plant physiology, this project aims to investigate the possible involvement of SlPHYB1 and SlPHYB2, as well as SlPIF3 and SlPIF4, as part of the signal network linked to microsporogenesis, fruitset and fruit development on tomato under elevated ambient temperature conditions. For that, the reproductive success of mutant and transgenic plants with modifications on the SlPHYB1/B2-SlPIF3/4 signal module will be compared under two growth conditions: control temperature (25°C day/ 18°C night) or moderate-high ambient temperature (32°C day/ 25°C night). Parameters such as fruit set rate, fruit and seed development, pollen viability and germination, as well as pollen structure will be compared during the two treatments. The data obtained generated by this project may provide important information and support future biotechnological advances on temperature resilience in tomato or even others crops that also suffer productive loss under elevated ambient temperature conditions.