Studying heat stress in plants Researchers have shown, for the first time, the effects of heat stress on plant flowering and seed formation at the molecular level. Climate Change and Environment © Thinkstock Potential heat stress is a deciding factor in the location of crops as it as has a major effect on crop productivity. However, very little has been done to better understand the epigenetic (non-genetic hereditary effects) and biochemical changes that occur in flowering plants due to heat stress. The EU-funded 'Transgenerational epigenetic regulation of heat stress response' (TRANS-EPIGEN) project aimed to investigate the epigenetic mechanisms of heat stress in Arabidopsis thaliana, a model plant species. Researchers began by comparing the different stages of flower and seed development in healthy plants against that of heat-affected plants. They showed that heat stress impacted every stage of development, and that anther wall formation and meiosis (cell division for sexual reproduction) were particularly sensitive. TRANS-EPIGEN also found that heat stress could induce the formation of multiple megaspore mother cell-like cells, which are usually seen in asexually reproducing plants called apomicts. Molecular experiments showed that this pathway is under epigenetic control. Finally, starch accumulation was studied because it has a major impact on seed formation. Physiological and molecular experiments revealed that the relationship between starch accumulation and flower development was more complex than previously thought. The TRANS-EPIGEN study has contributed to our understanding of the epigenetic and molecular effects of heat stress in A. thaliana plants. The findings will inform research into improved heat resistance in crop plants. Keywords Epigenetics, heat stress, flowering, seed formation, starch accumulation, crop productivity, heat resistance
