BrUGE1 Transgenic Rice Showed Improved Growth Performance with Enhanced Drought Tolerance

UDP-glucose 4-epimerase (UGE) catalyzes the reversible conversion of UDP-glucose to UDP-galactose. To understand the biological function of UGE from Brassica rapa, the gene BrUGE1 was cloned and transformed into wild type ‘Gopum’ genome of Oryza sativa L. using Agrobacterium-mediated methods. Out of six transgenic plants, four lines which showed a single copy through Southern analysis were selected and developed into T₃ generation. Agronomic traits evaluation of the transgenic T₃ lines (CB01, CB03, and CB06) under optimal field condition revealed enriched biomass production particularly in panicle length, number of productive tillers, number of spikelets per panicle, and filled spikelets. These remarkable improved agronomic traits were ascribed to higher photosynthetic rate complemented with higher CO₂ assimilation. Transcripts of BrUGE1 in transgenic lines continuously accumulated at higher levels after the 20% PEG6000 treatment implying its probable role to drought stress regulation. This was paralleled by rapid accumulation of soluble sugars which act as osmoprotectants, leading to a delayed leaf rolling and drying. Our findings entail the potential of BrUGE1in improving rice growth performance under optimal and water deficit conditions.

This work was supported by grants from the Next-Generation BioGreen 21 Program (PJ01131901), Rural Development Administration, and from the iPET (PJ008529), Ministry of Agriculture, Food and Rural Affairs, Republic of Korea.                 * Corresponding author: Tel. 82-43-261-2514, E-mail: ygcho@cbnu.ac.kr