Abstract
Thermogenic skunk cabbage (Symplocarpus renifolius) can produce massive heat during the female stage, but not during the subsequent male stage. Our recent studies indicated that a large number of mitochondria were observed in female-stage flowers while vacuoles were significantly developed and less mitochondria were observed in male-stage flowers (J Exp Bot, 60, p3909-22, Planta, 121, p121-30). However, molecular mechanisms underlying floral thermogenesis are largely unknown. To uncover the molecular mechanism by which regulate floral thermogenesis, we investigated the gene expression profile during floral thermogenesis using SuperSAGE. The obtained tag sequences were annotated using our cDNA dataset of skunk cabbage. During thermogenic female-stage, transcripts related to cellular respiration and mitochondrial function were abundant. In contrast, the gene encoding cysteine protease localized in vacuole was the most abundant transcript during non-thermogenic male stage. These results are consistent with our previous observation using microscopy, and we will discuss how these genes play roles in floral thermogenesis.
