Transgenic rice plants that overexpress transcription factors RF2a and RF2b are tolerant to rice tungro virus replication and disease

• Published in: Proceedings of the National Academy of Sciences - PNAS 2008-12, Vol.105 (52), p.21012-21016
• Main Authors: Dai, Shunhong, Wei, Xiaoping, Alfonso, Antonio A, Pei, Liping, Duque, Ulysses G, Zhang, Zhihong, Babb, Gina M, Beachy, Roger N
• Format: Article
• Language: English
• Subjects: Agrobacterium; Basic-Leucine Zipper Transcription Factors - biosynthesis; Basic-Leucine Zipper Transcription Factors - genetics; Biological Sciences; Disease resistance; Epidemiology; Freshwater; Gene expression; Gene Expression Regulation, Viral - genetics; gene overexpression; genes; Infections; Inoculation; Oryza - genetics; Oryza - metabolism; Oryza - virology; Oryza sativa; Plant diseases; Plant Diseases - genetics; Plant Diseases - virology; plant diseases and disorders; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plant resistance; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - virology; promoter regions; Promoter Regions, Genetic - genetics; Proteins; Rice; Rice tungro bacilliform virus; RNA; transcription factor RF2a; transcription factor RF2b; transcription factors; Transgenic animals; Transgenic plants; Tungrovirus - genetics; Tungrovirus - metabolism; virus replication; Virus Replication - genetics; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0810303105

Rice tungro disease (RTD) is a significant yield constraint in rice-growing areas of South and Southeast Asia. Disease symptoms are caused largely by infection by the rice tungro bacilliform virus (RTBV). Two host transcription factors, RF2a and RF2b, regulate expression of the RTBV promoter and are important for plant development. Expression of a dominant negative mutant of these factors in transgenic rice resulted in phenotypes that mimic the symptoms of RTD, whereas overexpression of RF2a and RF2b had essentially no impact on plant development. Conversely, lines with elevated expression of RF2a or RF2b showed weak or no symptoms of infection after Agrobacterium inoculation of RTBV, whereas control plants showed severe stunting and leaf discoloration. Furthermore, transgenic plants exhibited reduced accumulation of RTBV RNA and viral DNA compared with nontransgenic plants. Similar results were obtained in studies after virus inoculation by green leafhoppers. Gaining disease resistance by elevating the expression of host regulators provides another strategy against RTD and may have implications for other pararetrovirus infections.