Transgenic poplar expressing <i>Arabidopsis NDPK2</i> enhances growth as well as oxidative stress tolerance

다국어 초록 (Multilingual Abstract)

<P><B>Summary</B></P><P>Nucleoside diphosphate kinase 2 (NDPK2) is known to regulate the expression of antioxidant genes in plants. Previously, we reported that overexpression of <I>Arabidopsis NDPK2</I> (<I>AtNDPK2</I>) under the control of an oxidative stress‐inducible <I>SWPA2</I> promoter in transgenic potato and sweetpotato plants enhanced tolerance to various abiotic stresses. In this study, transgenic poplar (<I>Populus alba </I>× <I>Poplus glandulosa</I>) expressing the <I>AtNDPK2</I> gene under the control of a <I>SWPA2</I> promoter (referred to as SN) was generated to develop plants with enhanced tolerance to oxidative stress. The level of <I>AtNDPK2</I> expression and NDPK activity in SN plants following methyl viologen (MV) treatment was positively correlated with the plant’s tolerance to MV‐mediated oxidative stress. We also observed that antioxidant enzyme activities such as ascorbate peroxidase, catalase and peroxidase were increased in MV‐treated leaf discs of SN plants. The growth of SN plants was substantially increased under field conditions including increased branch number and stem diameter. SN plants exhibited higher transcript levels of the auxin‐response genes <I>IAA2</I> and <I>IAA5</I>. These results suggest that enhanced <I>AtNDPK2</I> expression affects oxidative stress tolerance leading to improved plant growth in transgenic poplar.</P>