Mediators of plant heat stress response
Plants respond to heat stress by producing heat shock proteins that protect against damage by reactive oxygen species (ROS). cAPXs are responsible for cleaning up ROS in response to heat shock, but their activity is not well understood. The EU-funded CAPX IN HS SIGNALING (Role of cytosolic ascorbate-peroxidases (cAPXs) in heat stress (HS) perception and in systemic HS-signaling) project aimed to better understand the behaviour of three different cAPX enzymes, called APX1, APX2 and APX6. They achieved this by studying genetically engineered Arabidopsis thaliana plants. Team members established their research methods by creating mutant plants that lacked one, two or all three of these cAPXs. This allowed them to understand the role of each by looking at the 'symptoms' of the plants lacking the enzymes. CAPX IN HS SIGNALING showed that APX2 is important in seed production during periods of heat stress, and was linked to heat tolerance in pollen. APX6, on the other hand, protects seeds and young plants from water and heat stress during the vulnerable germination period. Researchers also found that APX6 was crucial in reducing ROS levels in stressed plants. Lastly, they showed that APX6 interacts with plant hormones, possibly via a transcription factor called ABI4. This work will help plant researchers identify mechanisms in seeds, plants and pollen that allow them to acclimate to harsh conditions. Ultimately, this could contribute to heat stress-resistant crops.
Keywords
Plant, heat stress, cytosolic ascorbate peroxidases, reactive oxygen species, Arabidopsis thaliana
