Superoxide anion regulates plant growth and tuber development of potato

Abstract

A higher concentration of H2O2 was detected in the sense transgenic potato plant (SS4) with the lily chCu,ZnSOD sequence, whereas higher levels of O2(-) was detected in the antisense transgenic plant (SA1) than the WT plant. The elongation growth in SA1 was significantly inhibited by treatment with diphenyleneiodonium, an inhibitor of O2(-) generation, and promoted in the SS4 on treatment with herbicide methyl viologen, a generator of apoplastic O2(-) . Higher concentrations of GAs were detected during plant growth and the early stage of tuberization in SA1. Complete recovery of the above elongation growth and microtuberization pattern in transgenic plants following treatment of GA(3) or an inhibitor of gibberellin synthesis, paclobutrazol, indicate that these changes were mainly caused by active GA levels. In conclusion, a specific ROS (O2(-) ) acts as a signal transducer via GA biosynthetic pathways for the regulation of plant growth and tuber development of potato.

Differential Expression in Response to Biotic and Abiotic Stress from Three Potato Glutaredoxins Induced during Suberization

“…Because plants appear to control various physiological processes by regulating the amount of ROS, its role as a signal transducer have been extensively studied. Those processes include pathogen defense (Levine et al, 1994;Alvarez et al, 1998), tolerance to abiotic stresses (Prasad et al, 1994), root development 0oo et al, 2001), senescence (Zimmermann and Zentgraf, 2005), stomatal behavior (McAinsh et al, 1996), and growth and tuberization (Kim et al, 2007). To regulate the level of ROS, the plant employs efficient redox and antioxidant systems, including the glutathione redox cycle, which is essential to the maintenance of the thio-redox state.…”

“…Here, StGRX2 transcript levels were up-regulated by treatments with gibberellin (GA3) or cytokinin (zeatin), while StGRXl was constitutively expressed, regardless of hormones being applied. We have recently proposed that ROS regulate potato stem growth and tuber development by modulating the GA biosynthetic pathway (Kim et al, 2007). If this is the case, StGRX2 likely plays a role in GAmediated tuber development.…”

“…These results indicate that StGRX2 is induced in reproductive organs and is involved in their development. Because ROS is associated with tuberization in potatoes (Kim et al, 2007), StGRX2 might be related to redox regulation during tuberization 'via the modulation of hormone biosynthesis. For example, that gene may alter the redox state of specific proteins in the biosynthetic pathway.…”

Systematic Analysis of Superoxide‐Dependent Signaling in Plant Cells: Usefulness and Specificity of Methyl Viologen Application

“…Knowledge on the role of O 2 À in this context is just slowly emerging. Results from sense and antisense transgenic potato plants with modified chloroplastidic Cu/Zn-SOD activities indicate that O 2 À displays a regulatory role in plant growth and tuber development by interference with gibberellins [113]. O 2 À affects the expression of genes within their biosynthetic pathways.…”

“…O 2 À affects the expression of genes within their biosynthetic pathways. As overexpression and suppression of chloroplastidic SOD affected the production of ROS and allowed for their modulation, this approach is unique for studying the physiological role of ROS in relation to various concentrations of O 2 À and H 2 O 2 [113].…”