ECTOPIC EXPRESSION OF A GENE ENCODING RRM2 INCREASES GRAIN MASS IN TRANSGENIC RICE
Abstract
In this study the first manifestation of ectopic expression of a cDNA encoding the second RNA-recognition motif (RRM2) is shown to play an essential role in determining grain mass in the transgenic rice lines. The RRM2 gene activity resulted in grain size larger than the control; and grain weight reached to as much as 71% greater than that that of the control seeds. The study revealed that the mode of action of the RRM2 gene in affecting both of somatic and reproductive tissues, including maternal organ, embryo and endosperm. The RNA gel-blotting analyses showed that RRM2 gene has a high expression in all transgenic lines; proving that size enlargement of transgenic seeds is mainly related to the cell volume increase, which is perfectly associated with the expression of RRM2 transgene. Additionally, RRM2 has the function to regulate some homeotic MADS-box genes without any modulation of fertility. The discovery in this study suggest that ectopic-expression of RRM2 can be as potential tool for searching and isolating the regulated downstream factors that control cell volume and seed size, which will be a useful strategy for identifying new genes for the analysis of yield component of rice and other plant species as well.References
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