[P4] Crop Genetics and Physiology

[P4-05] Regulation of the Expression of OsRBCS3, a Rubisco Small Subunit Gene, by Histone Deacetylase HDA713 under Nitrogen Deficiency in Rice

*Nominated for Presentation Awards

^○Fumiya Miyamoto¹, Shicheng Feng², Sakae Agarie³, Kazuyuki Saitou⁴ (1.Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Japan, 2.Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Japan, 3.Faculty of Agriculture(Graduate School), Kyushu University, Japan, 4.Faculty of Agriculture(Graduate school), Kyushu University, Japan)

Histone modifications represent key epigenetic mechanisms that regulate gene expression. The expression of Rubisco genes is enhanced in response to nitrogen supply. However, histone modification events regulating the expression of Rubisco genes are not well understood. In the study, we investigated the relationship between the expression of HDA713, a RPD3/HAD1-type histone deacetylase gene, and the expression of OsRBCS3, a Rubisco small subunit gene, in rice. The mRNA level of HDA713 was decreased and that of OsRBCS3 was increased by nitrogen supply. To examine whether HDA713 regulates the expression of OsRBCS3, we produced overexpression transformants of HDA713 under the control of the maize ubiquitin promoter and CaMV 35S promoter, and knockdown transformants of HDA713 by RNAi. There was no correlation between the expression of HDA713 and OsRBCS3 under nitrogen sufficiency. Surprisingly, a significant positive correlation was found between the expression of GCN5, a GNAT-type histone acetyltransferase gene, and OsRBCS3. Under nitrogen deficiency, there was a significant positive correlation between the expression of HDA713 and OsRBCS3, whereas there was no correlation between the expression of GCN5 and OsRBCS3. These results indicate that the expression of OsRBCS3 is regulated by GCN5 under nitrogen sufficiency and by HDA713 under nitrogen deficiency.