Mechanism for Higher Tolerance to and Lower Accumulation of Arsenite in <i>NtCyc07</i>-Overexpressing Tobacco

• Main Authors: DongGwan Kim, Ramin Bahmani, Mahsa Modareszadeh, Seongbin Hwang
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Plants
• Subjects: aquaporin; arsenic; Cyc07; NIP; PIP; ROS
• Online Access: https://www.mdpi.com/2223-7747/9/11/1480

Arsenite [As(III)] is a highly toxic chemical to all organisms. Previously, we reported that the overexpression of <i>NtCyc07</i> enhanced As(III) tolerance and reduced As(III) accumulation in yeast (<i>Saccharomyces cerevisiae</i>) and tobacco (<i>Nicotiana tabacum</i>). To understand a mechanism for higher As(III) tolerance and lower As(III) accumulation in <i>NtCyc07</i>-overexpressing tobacco, we examined the expression levels of various putative As(III) transporters (aquaporin). The expressions of putative As(III) exporter <i>NIP1;1</i>, <i>PIP1;1</i>, <i>1;5</i>, <i>2;1</i>, <i>2;2</i>, and <i>2;7</i> were enhanced, while the expressions of putative As(III) importer <i>NIP3;1</i>, <i>4;1</i>, and <i>XIP2;1</i> were decreased, contributing to the reduced accumulation of As(III) in <i>NtCyc07</i>-overexpressing tobacco. In addition, the levels of oxidative stress indicators (H₂O₂, superoxide and malondialdehyde) were lower, and the activities of antioxidant enzymes (catalase, superoxide dismutase and glutathione reductase) were higher in <i>NtCyc07</i>-tobacco than in the control tobacco. This suggests that the lower oxidative stress in transgenic tobacco may be attributed to the higher activities of antioxidant enzymes and lower As(III) levels. Taken together, the overexpression of <i>NtCyc07</i> enhances As(III) tolerance by reducing As(III) accumulation through modulation of expressions of putative As(III) transporters in tobacco.