AGRONOMIC CHARACTERISTICS OF TRANSGENIC RICE WITH ENHANCED PHOSPHATE UPTAKE ABILITY BY OVER- EXPRESSED TOBACCO HIGH AFFINITY PHOSPHATE TRANSPORTER

This study was conducted to examine phosphate (Pi) accumulation and performance of agronomic traits of transgenic rice overexpressing a tobacco high affinity phosphate transporter (NtPT1) gene. Transgenic plants containing one copy of NtPT1 transgene were selected and advanced to T3 generation based on the stability of inheritance and expression of the transgene. Performance of major agronomic traits was examined for the 19 selected T3 transgene-homozygous lines. In the transgenic line 1-7-8, seed phosphorous (P) content, 1,000 grains weight, number of panicles per hill, and number of grains per panicle were increased by 17%, 6%, 3%, and 10%, respectively, compared to those in the control plants. Yield per plant of the lines 1-7-6, 1-7-8, 1-9-3, and 10-2-7 was 2-6% higher than that of the control variety. In the lines with increased yield per plant, number of panicles per hill and number of grains per panicle were increased. Nitrogen content, chlorophyll content and CO2 assimilation rate increased concurrently with P content in the flag leaf of the transgenic lines. Some NtPT1 transgenic lines like 1-7-8 showed increased P accumulation with improved or acceptable performance of agronomic and quality traits. In conclusion, these results indicate that the regulation of PT activity at the transcription level can contribute to increase Pi uptake and improve the performance of agronomic traits like seed yield.