Na(+) but not Cl(-) or osmotic stress is involved in NaCl-induced expression of Glutathione reductase in roots of rice seedlings.
Glutathione reductase (GR, EC 1,6.4.2) is an important reactive oxygen species-scavenging enzyme. The present study examined the relative importance of Na(+), Cl(-), and the osmotic component in NaCl-induced expression of Oryza sativa glutathione reductase (OsGR) genes in rice roots. Semi-quantitative RT-PCR was used to quantify the mRNA levels for one cytosolic (OsGR2) and two chloroplastic (OsGR1 and OsGR3) isoforms of GR identified in the rice genome. The expression of OsGR2 and OsGR3 but not OsGR1 was increased in rice roots treated with NaCl. Treatment with 150 mM NaCl and 150 mM NaNO(3) affected OsGR2 and OsGR3 induction similarly, which suggests that Na(+) but not Cl(-) is required for the NaCl-induced expression of OsGR2 and OsGR3. We also show that Na(+) but not Cl(-) is required for NaCl-enhanced GR activity and hydrogen peroxide (H(2)O(2)) production in rice roots. In addition to its component of ion toxicity, salt concentration in soil results in an osmotic effect. Here, we show that OsGR2 and OsGR3 expression, GR activity, and H(2)O(2) content were not affected at a concentration of mannitol iso-osmotic with 150 mM NaCl. NaCl-induced OsGR2 and OsGR3 in rice roots could be associated with Na(+) but not an osmotic component.
Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan, Republic of China.
Chwan-Yang
CY
Hong
Yun-Yang
YY
Chao
Min-Yu
MY
Yang
Shih-Chueh
SC
Cho
Ching
C
Huei Kao
D002713:Chlorine / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D018745:Genome, Plant; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D012275:Oryza / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009997:Osmotic Pressure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects*
D010940:Plant Proteins; D012333:RNA, Messenger; D012965:Sodium Chloride; D002713:Chlorine; D012964:Sodium; D006861:Hydrogen Peroxide; D005980:Glutathione Reductase