Assessment of resistance to rice tungro disease in popular rice varieties in India by introgression of a transgene against Rice tungro bacilliform virus
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Rice crops in South and Southeast Asian countries suffer critical yield losses due to rice tungro disease caused by joint infection with rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). Previously, for generating RNA interference-based transgenic resistance against tungro viruses, RTBV ORF IV was used as a transgene to develop RTBV resistance in a popular high-yielding scented rice variety. The transgene from this line was then introgressed into five popular high-yielding but tungro-susceptible rice varieties by marker-assisted backcross breeding with a view to combine the resistant trait with the agronomic traits. The present work includes a resistance assay of the BC3F5 lines of these varieties under glasshouse conditions. Out of a total of 28 lines tested, each consisting of 12 individual plants, eight lines showed significant amelioration in height reduction and 100- to 1000-fold reduction in RTBV titers. The RNAi-mediated resistance was clearly manifested by the presence of virus-derived small RNA (vsRNA) specific for RTBV ORF IV in the transgenic backcrossed lines.
This work was funded by Department of Biotechnology, Government of India (Grant No. BT/PR-15033/AGR/02/773/2011). GK is indebted to University Grants Commission, New Delhi, for research fellowships during this work. Funds received from R&D Grant of University of Delhi, DST-PURSE Grant, and the departmental infrastructure grant from DST-FIST are also gratefully acknowledged.
Compliance with ethical standards
This work was performed keeping in mind all applicable ethical standards.
Conflict of interest
There exists no conflict of interest among the authors pertaining to this work.
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