CaDHN5, a Dehydrin Gene from Pepper, Plays an Important Role in Salt and Osmotic Stress Responses

Abstract

Dehydrins (DHNs), as a sub-family of group two late embryogenesis-abundant (LEA) proteins, have attracted considerable interest owing to their functions in enhancing abiotic stress tolerance in plants. Our previous study showed that the expression of CaDHN5 (a dehydrin gene from pepper) is strongly induced by salt and osmotic stresses, but its function was not clear. To understand the function of CaDHN5 in the abiotic stress responses, we produced pepper (Capsicum annuum L.) plants, in which CaDHN5 expression was down-regulated using VIGS (Virus-induced Gene Silencing), and transgenic Arabidopsis plants overexpressing CaDHN5. We found that knock-down of CaDHN5 suppressed the expression of manganese superoxide dismutase (MnSOD) and peroxidase (POD) genes. These changes caused more reactive oxygen species accumulation in the VIGS lines than control pepper plants under stress conditions. CaDHN5-overexpressing plants exhibited enhanced tolerance to salt and osmotic stresses as compared to the wild type and also showed increased expression of salt and osmotic stress-related genes. Interestingly, our results showed that many salt-related genes were upregulated in our transgenic Arabidopsis lines under salt or osmotic stress. Taken together, our results suggest that CaDHN5 functions as a positive regulator in the salt and osmotic stress signaling pathways.

Salinity Tolerance in Plants: Trends and Perspectives

“…Luo et al [26] showed that Arabidopsis plants overexpressing a SKn-type dehydrin from Capsicum annuum L. ( CaDHN5 ) resulted an increased tolerance to salt and osmotic stress, suggesting an important role for CaDHN5 in response to the mentioned abiotic stresses [26]. In addition, using VIGS (virus-induced gene silencing) technique, the authors reported that knockdown of the CaDHN5 gen suppressed the expression of manganese superoxide dismutase ( MnSOD ) and peroxidase ( POD ) genes in transformed pepper plants [26]. These changes caused a higher oxidative stress in the VIGS lines than in control pepper plants under NaCl or osmotic stress conditions, as observed by the data of some stress-oxidative parameters (superoxide accumulation, lipid peroxidation, and electrolyte leakage), chlorophyll levels, and the rate of water loss.…”

“…These changes caused a higher oxidative stress in the VIGS lines than in control pepper plants under NaCl or osmotic stress conditions, as observed by the data of some stress-oxidative parameters (superoxide accumulation, lipid peroxidation, and electrolyte leakage), chlorophyll levels, and the rate of water loss. The results demonstrated an important role for the CaDHN5 gene in the tolerance of plants to salt and osmotic stresses as well as in the salt and osmotic stress signalling pathways [26]. The results also indicated that CaDHN5 positively regulates the expression of the MnSOD and POD genes, but also other stress-related genes, including AtSOD1 (encoding a H + /Na + plasma membrane antiporter), AtDREB2A (a transcription factor in the ABA signalling pathway), and AtRSA1 and AtRITF1 genes that regulate the transcription of several ROS scavenging-related genes and the AtSOS1 gene [26].…”

Dehydration Sensitivity at the Early Seedling Establishment Stages of the European Beech (Fagus sylvatica L.)

“…Dehydrins are involved in protection against oxidative stress by reducing H 2 O 2 levels and enhancing the expression of ROS scavenging enzymes [70]. Conversely, suppressed expression of ROS scavenging enzymes, including superoxide dismutase and peroxidase, leading to ROS accumulation was reported in dehydrin-silenced pepper plants [71]. In this context, the link between dehydrins and ROS warrants further research.…”

Functional Characteristics Analysis of Dehydrins in Larix kaempferi under Osmotic Stress

“…Dehydrins were reported to have the function of binding DNA to protect DNA from damage caused by environmental stress. Thus far, some studies have reported that DHN proteins can bind to DNA, the Vitis riparia dehydrin locates in the nucleus and binds to DNA to protect it from hydrogen peroxide [ 24 ]. Given that the four LkDHNs could bind the dsDNAs and present in both the nucleus and cytoplasm, it is possible that these LkDHNs were located in the nucleus to protect the DNA from oxidative stress.…”