The glutathione synthesis may be regulated by cadmium-induced endogenous ethylene in Lycium chinense, and overexpression of an ethylene responsive transcription factor gene enhances tolerance to cadmium stress in tobacco

Abstract

Glutathione (GSH) plays a pivotal role in heavy metal detoxification. Ethylene is one of the important plant hormones, which plays a critical role in triggering plant responses to different stresses such as cadmium (Cd) stress. Ethylene responsive transcription factor (ERF) belongs to one of the largest plant transcription factor families. ERF is known to be induced by ethylene and thus regulate multiple stress responses through the activation of stressrelated genes. Until now, little has been done to explore the relationship among the accumulation of endogenous ethylene, ERF transcript levels and the GSH content in plants under Cd treatment and we will investigate these link. In this study, the gene transcript level of LchERF, LchGSH1 (gene responsible for the first-step GSH biosynthesis) and LchGSHS (gene responsible for the second-step GSH biosynthesis), endogenous ethylene accumulation, GSH content and Cd concentration in Lycium chinense with or without Cd stress treatment were studied. Furthermore, the transgenic tobacco expressing 35S::LchERF which grown under Cd stress condition was also investigated in this study. Our results showed that endogenous ethylene, LchERF, LchGSH1 and LchGSHS gene expression and GSH content can be induced by Cd treatment in L. chinense, however, reduced by co-treatment with 2-aminoethoxyvinlglycine (AVG), an inhibitor of ethylene biosynthesis. The transgenic tobacco expressing 35S::LchERF showed greater tolerance to Cd stress than non-transgenic plants. The expression of NtGSH1 and NtGSHS genes was increased in transgenic tobacco plants compared with non-transgenic plants, indicating that LchERF is associated with the expression level of GSH synthesis related genes in tobacco. Evidence was presented here that under Cd stress, GSH accumulation occurred at least partially via enhanced LchERF gene expression and the ethylene signal transduction pathways might be involved in this accumulation.

Ethylene and Metal Stress: Small Molecule, Big Impact

“…Similarly, Cao et al ( 2014 ) suggested that Cd tolerance in H. vulgare is related to the induction of ethylene signaling. Transgenic N. tabacum plants overexpressing an ERF gene from Lycium chinense displayed greater tolerance to Cd stress than non-transformed plants (Guan et al, 2015 ). On the other hand, ethylene insensitive etr1-1 and ein3-3 A. thaliana mutants were shown to be less sensitive to Li than WT plants (Bueso et al, 2007 ).…”

“…Therefore, increased ethylene biosynthesis upon Cd exposure seems crucial to mount effective defense responses related to GSH (Schellingen et al, 2015a ). In addition, ethylene signaling is implicated in the accumulation of GSH in Al-exposed A. thaliana (Zhang et al, 2014 ), Cd-exposed L. chinense (Guan et al, 2015 ), and A. thaliana plants (Schellingen et al, 2015b ). The increased Cd tolerance of transgenic tobacco plants overexpressing an ERF gene from L. chinense was related to an enhanced expression level of GSH biosynthesis genes (Guan et al, 2015 ).…”

Ethylene Potentiates Sulfur-Mediated Reversal of Cadmium Inhibited Photosynthetic Responses in Mustard

“…Exogenously applied GSH positively modulates ethylene biosynthetic pathways enzyme and improves stress tolerance in Arabidopsis Col-0 showing that GSH mediated resistance to stresses occurs via an ethylene signaling pathway (Datta et al, 2015). Recent studies showed that ethylene signaling pathways might be involved in the accumulation of GSH under Cd stress (Guan et al, 2015). Recently, Iqbal et al (2015) have shown that ethylene and N interact to regulate photosynthesis of salt stressed Brassica juncea .…”

Ectopic expression of EuWRI1, encoding a transcription factor in E. ulmoides, changes the seeds oil content in transgenic tobacco

“…The T 0 kanamycin‐resistant seedlings were further confirmed by RT‐PCR analysis. To evaluate the integration of transgenes and their copy numbers in the genomes of putative transgenic lines of tobacco, Southern blot was performed following previous method . Transgenic T 1 lines that produced only kanamycin resistant T 2 seedlings were considered to be homozygous for the EuWRI1 gene sequence.…”