Effects of elevated temperature on the organ-specific expression of superoxide dismutase gene family in potato, Solanum tuberosum L.

Abstract

Potato, Solanum tuberosum L., is the leading vegetable crop in the world and is highly vulnerable to elevated ambient temperatures. Since high-temperature stress causes the accumulation of reactive oxygen species (ROS) in plant cells, investigations regarding major enzymatic components of the potato antioxidative system are of importance. Superoxide dismutases (SODs) are metalloenzymes that play an important role as primary ROS scavengers. Previously, we conducted a detailed in silico analysis and characterization of the potato SOD gene family. In the present study, we analyzed the expression of potato SOD-encoding genes, three StCu/ZnSODs, one StMnSOD and four StFeSODs, in different organs of potato cv. Désirée plants at optimal growth conditions (20/17 °C, 70% humidity) and during mild heat stress (30/20 °C, 70% humidity) on the 1st, 7th and 21st day of treatment. Our results revealed that cytosolic StCu/ZnSOD1, chloroplast StCu/ZnSOD2 and StFeSOD3, and mitochondrial StMnSOD were characterized by a high level of expression in potato organs, especially leaves and stolons. Conversely, chloroplast StFeSOD1 and StFeSOD4 expression levels were very low in all investigated organs. Under mild heat stress, the significant increase in the abundance of most StSODs transcripts was mainly observed in leaves and stolons after 7 days of the treatment. Interestingly, transcript levels of all eight potato StSODs were the lowest in developing tubers compared to other organs, regardless of temperature treatment. Our findings provide insight into the modulation of organ-specific expression of eight potato SODs by elevated temperature and may contribute to a better understanding of potato antioxidant response to mild heat stress.