Molecular aspects of 2OG-Fe (II) - dioxygenases and response to abiotic stress in rice

In specific mammalian cells, the Ten-Eleven Translocation (TET) enzymes which are family members of 2-oxoglutarate (2-OG)-and Fe (II)-dependent dioxygenase (2ODD) are responsible for the modification of 5-mC to generate oxidised products such as 5-hmC, 5-caC and 5-fC, which are involved in oxidative demethylation. In rice, some reports have also revealed that 5-hmC was also present but the enzyme(s) responsible for oxidising 5-mC has not been identified. Here, possible Tet gene homologues in rice were identified by using various databases. There are 18 genes having a 2ODD domain most similar to TETs. Moreover, additional significant information such as the relatedness of protein sequence, protein interaction, nuclear localisation prediction, mutant analysis as well as gene annotation was obtained. Next, the spatial and temporal expression patterns of these genes were analysed within seedling root, mature leaf, young leaf and young panicle by analysing data from both microarray and qPCR. It was found that Os01g0546900 had highest expression in young leaf and six genes showed highest expression in mature leaf, whereas the remaining genes showed low expression in various organs. Finally, selected contrasting cultivars of rice were used to examine the expression of three genes of 2ODD and SLENDER RICE 1 (SLR1) under flooding and drought in order to evaluate the molecular aspects of Submergence 1A (Sub1A) regulation. The results showed that the Sub1A gene of tolerant rice was highly expressed under submergence but was not expressed under drought. Os03g0803500, Os07g0194500 and Os09g0489200, and SLR1 did not show any significant difference in expression in submerged and dehydrated plants of both IR64 and IR64.S1, nor in Japonica varieties which were used as susceptible check. To conclude, this finding indicates that Os03g0803500, Os07g0194500, Os09g0489200 and SLR1 may not have a correlation with Sub1A under flooding and drought stress