Expansin gene expression and anoxic coleoptile elongation in rice cultivars.

Coleoptiles of rice seeds that germinate under anoxia usually elongate to a length far exceeding the elongation that takes place under aerobic conditions. It has been suggested that expansins play a role in this process, but studies examining correlations between transcript levels of expansin genes and anoxic growth of rice coleoptiles are limited. In this study, we used real-time quantitative PCR (qPCR) analysis to develop a picture of expansin gene expression (seven alpha- and eight beta-expansins) (EXPA and EXPB) in two rice cultivars showing long (cv. Arborio Precoce) or short (cv. Lamone) coleoptiles when germinated under anoxia. Our qPCR analysis suggested up-regulation occurred for several expansin genes in anoxic coleoptiles in both rice cultivars. However, we found no correlation between transcript levels and the ability to elongate the coleoptile under anoxia.