Constitutive overexpression of maize NPR1 (ZmNPR1), a salicylic acid receptor, in rice for enhanced pathogen resistance

• Main Author: Noni Rahmadhini
• Other Authors: Maurice S. B. Ku
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/34243516317422639122

碩士 === 國立嘉義大學 === 生物農業科技學系研究所 === 102 === Enhancing rice plant resistance to pathogen attack is one of the major priorities to increase rice productivity. Due to its long lasting and broad spectrum of effective resistance against pathogens, exploitation of systemic acquired resistance (SAR) pathway for genetic engineering of crops for enhanced disease resistance is of particular interest. In this study, we explored a SAR-related gene in an attempt to enhance rice resistance to multiple pathogenic diseases. The regulatory protein, NPR1 (nonexpressor of pathogenesis-related genes), is a central positive regulator of SAR. During SAR establishment the plant hormone salicylic acid (SA) accumulates upon pathogen infection and induces the monomeric active form of NPR1 in the nucleus to trigger the expression of defense genes, such as PR (pathogenesis-related). Production of higher PR proteins in the uninfected cells leads the SAR response to protect the affected plants from further infection. In this study, maize NPR1 (ZmNPR1) cDNA was cloned and constructed into a plasmid under the control of a constitutive ubiquitin promoter for driving its expression in rice, while bar gene in a separate plasmid was used in co-transformation as a selection marker. Co-transformation of both genes allows the generation of transgenic rice with enhanced pathogen resistance without containing the selection marker in the progenies. Several T0 transgenic rice lines expressing ZmNPR1 were obtained by Agrobacterium-mediated transformation and confirmed by genomic PCR. Real-time PCR analysis showed that transgenic rice plants express elevated levels of ZmNPR1 in the leaves, stems and florets, with a concomitant expression of PR3 that encodes chitinase. SA treatment greatly enhanced the expression of both ZmNPR1 and OsPR3. Test on the resistance of NPR1 transgenic rice plants to major rice pathogens is underway.