Salt stress-induced production of reactive oxygen- and nitrogen species and cell death in the ethylene receptor mutant Never ripe and wild type tomato roots

Abstract

The salt stress triggered by sublethal, 100 mM and lethal, 250 mM NaCl induced ethylene production as well as rapid accumulation of superoxide radical and H2O2 in the root tips of tomato (Solanum lycopersicum cv. Ailsa Craig) wild type and ethylene receptor mutant, Never ripe (Nr/Nr) plants. In the wild type plants superoxide accumulation confined to lethal salt concentration while H2O2 accumulated more efficiently under sublethal salt stress. However, in Nr roots the superoxide production was higher and unexpectedly, H2O2 level was lower than in the wild type under sublethal salt stress. Nitric oxide production increased significantly under sublethal and lethal salt stress in both genotypes especially in mutant plants, while peroxynitrite accumulated significantly under lethal salt stress. Thus, the nitro-oxidative stress may be stronger in Nr roots, which leads to the programmed death of tissues, characterized by the DNA and protein degradation and loss of cell viability under moderate salt stress. In Nr mutants the cell death was induced in the absence of ethylene perception. Although wild type roots could maintain their potassium content under moderate salt stress, K(+) level significantly declined leading to small K(+)/Na(+) ratio in Nr roots. Thus Nr mutants were more sensitive to salt stress than the wild type and the viability of root cells decreased significantly under moderate salt stress. These changes can be attributed to a stronger ionic stress due to the K(+) loss from the root tissues.

Retracted: Proteomic and physiological responses of Arabidopsis thaliana exposed to salinity stress and N‐acyl‐homoserine lactone

“…NaCl treatments may elevate the production of ROS resulting from photosynthesis, respiration and NADPH oxidase (Poór et al , You and Chan ). Antioxidative enzymes provide plant cells with a highly efficient machinery for scavenging the ROS and tightly control the equilibrium of antioxidant system in plant.…”

Effect of salt stress on ion concentration, proline content, antioxidant enzyme activities and gene expression in tomato cultivars

“…Thus, the mutants were more sensitive to salt stress than the wild type. These changes can be attributed to a stronger ionic stress due to K +  loss from the root tissues (Poóra et al 2015). Villalta et al (2008) suggested that several genes located in chromosome 7 of tolerant tomato plants are responsible for governing the active mechanism of Na + /K  +   regulation.…”

Genome-Wide Identification and Expression Analysis of Two-Component System Genes in Tomato

“…The inconsistent results of SlHK5 , SlRR1 , and SlPRR5 between expression profiles and promoter analyses were also observed in soybean and Chinese cabbage [10,23]. Plant TCS elements were determined to play vital roles in responses to abiotic stresses, particularly drought, high salinity, and high or low temperature in Arabidopsis, rice, tomato, and soybean [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,42,43]. Tomato LE-ETR3 ( Nr ) participated in salt and heat stresses, and reducing expression of LE-ETR4 led to an enhanced hypersensitive response [24,42,43].…”