scholarly journals β-1,4-Glucanase-like protein from the cyanobacterium Synechocystis PCC6803 is a β-1,3-1,4-glucanase and functions in salt stress tolerance

2007 ◽  
Vol 405 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Masahiro Tamoi ◽  
Hideki Kurotaki ◽  
Tamo Fukamizo

In the present study, we characterized the gene (Cyanobase accession number slr0897) designated Ssglc encoding a β-1,4-glucanase-like protein (SsGlc) from Synechocystis PCC6803. The deduced amino acid sequence for Ssglc showed a high degree of similarity to sequences of GH (glycoside hydrolase) family 9 β-1,4-glucanases (cellulases) from various sources. Surprisingly, the recombinant protein obtained from the Escherichia coli expression system was able to hydrolyse barley β-glucan and lichenan (β-1,3-1,4-glucan), but not cellulose (β-1,4-glucan), curdlan (β-1,3-glucan), or laminarin (β-1,3-1,6-glucan). A 1H-NMR analysis of the enzymatic products revealed that the enzyme hydrolyses the β-1,4-glycosidic linkage of barley β-glucan through an inverting mechanism. The data indicated that SsGlc was a novel type of GH9 glucanase which could specifically hydrolyse the β-1,3-1,4-linkage of glucan. The growth of mutant Synechocystis cells in which the Ssglc gene was disrupted by a kanamycin-resistance cartridge gene was almost the same as that of the wild-type cells under continuous light (40 μmol of photons/m2 per s), a 12 h light (40 μmol of photons/m2 per s)/12 h dark cycle, cold stress (4 °C), and high light stress (200 μmol of photons/m2 per s). However, under salt stress (300–450 mM NaCl), growth of the Ssglc-disrupted mutant cells was significantly inhibited as compared with that of the wild-type cells. The Ssglc-disrupted mutant cells showed a decreased rate of O2 consumption and NaHCO3-dependent O2 evolution as compared with the wild-type cells under salt stress. Under osmotic stress (100–400 mM sorbitol), there was no difference in growth between the wild-type and the Ssglc-disrupted mutant cells. These results suggest that SsGlc functions in salt stress tolerance in Synechocystis PCC6803.

2021 ◽  
Vol 22 (16) ◽  
pp. 8625
Author(s):  
Shuangzhan Huang ◽  
Lanjuan Hu ◽  
Shihan Zhang ◽  
Mingxing Zhang ◽  
Wenzhu Jiang ◽  
...  

Plant WRKY transcription factors play crucial roles in plant growth and development, as well as plant responses to biotic and abiotic stresses. In this study, we identified and characterized a WRKY transcription factor in rice, OsWRKY50. OsWRKY50 functions as a transcriptional repressor in the nucleus. The transcription of OsWRKY50 was repressed under salt stress conditions, but activated after abscisic acid (ABA) treatment. OsWRKY50-overexpression (OsWRKY50-OX) plants displayed increased tolerance to salt stress compared to wild type and control plants. The expression of OsLEA3, OsRAB21, OsHKT1;5, and OsP5CS1 in OsWRKY50-OX were much higher than wild type and control plants under salt stress. Furthermore, OsWRKY50-OX displayed hyposensitivity to ABA-regulated seed germination and seedling establishment. The protoplast-based transient expression system and yeast hybrid assay demonstrated that OsWRKY50 directly binds to the promoter of OsNCED5, and thus further inhibits its transcription. Taken together, our results demonstrate that rice transcription repressor OsWRKY50 mediates ABA-dependent seed germination and seedling growth and enhances salt stress tolerance via an ABA-independent pathway.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ximena Alvarez-Gerding ◽  
Rowena Cortés-Bullemore ◽  
Consuelo Medina ◽  
Jesús L. Romero-Romero ◽  
Claudio Inostroza-Blancheteau ◽  
...  

Citrus plants are widely cultivated around the world and, however, are one of the most salt stress sensitive crops. To improve salinity tolerance, transgenic Carrizo citrange rootstocks that overexpress glyoxalase I and glyoxalase II genes were obtained and their salt stress tolerance was evaluated. Molecular analysis showed high expression for both glyoxalase genes (BjGlyIandPgGlyII) in 5H03 and 5H04 lines. Under control conditions, transgenic and wild type plants presented normal morphology. In salinity treatments, the transgenic plants showed less yellowing, marginal burn in lower leaves and showed less than 40% of leaf damage compared with wild type plants. The transgenic plants showed a significant increase in the dry weight of shoot but there are no differences in the root and complete plant dry weight. In addition, a higher accumulation of chlorine is observed in the roots in transgenic line 5H03 but in shoot it was lower. Also, the wild type plant accumulated around 20% more chlorine in the shoot compared to roots. These results suggest that heterologous expression of glyoxalase system genes could enhance salt stress tolerance in Carrizo citrange rootstock and could be a good biotechnological approach to improve the abiotic stress tolerance in woody plant species.


2019 ◽  
Vol 20 (21) ◽  
pp. 5244 ◽  
Author(s):  
Qi Guo ◽  
Liang Zhao ◽  
Xinqi Fan ◽  
Peng Xu ◽  
Zhenzhen Xu ◽  
...  

Cotton is one of the most economically important crops in the world, and it is exposed to various abiotic stresses during its lifecycle, especially salt stress. However, the molecular mechanisms underlying cotton tolerance to salt stress are still not fully understood due to the complex nature of salt response. Therefore, identification of salt stress tolerance-related functional genes will help us understand key components involved in stress response and provide valuable genes for improving salt stress tolerance via genetic engineering in cotton. In the present study, virus-induced gene silencing of GhWRKY5 in cotton showed enhanced salt sensitivity compared to wild-type plants under salt stress. Overexpression of GarWRKY5 in Arabidopsis positively regulated salt tolerance at the stages of seed germination and vegetative growth. Additionally, GarWRKY5-overexpressing plants exhibited higher activities of superoxide dismutase (SOD) and peroxidase (POD) under salt stress. The transcriptome sequencing analysis of transgenic Arabidopsis plants and wild-type plants revealed that there was enriched coexpression of genes involved in reactive oxygen species (ROS) scavenging (including glutamine S-transferases (GSTs) and SODs) and altered response to jasmonic acid and salicylic acid in the GarWRKY5-OE lines. GarWRKY5 is involved in salt stress response by the jasmonic acid- or salicylic acid-mediated signaling pathway based on overexpression of GarWRKY5 in Arabidopsis and virus-induced gene silencing of GarWRKY5 in cotton.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 173
Author(s):  
Abeer F. Desouky ◽  
Ahmed H. Ahmed ◽  
Hartmut Stützel ◽  
Hans-Jörg Jacobsen ◽  
Yi-Chen Pao ◽  
...  

Pathogenesis-related (PR) proteins are known to play relevant roles in plant defense against biotic and abiotic stresses. In the present study, we characterize the response of transgenic faba bean (Vicia faba L.) plants encoding a PR10a gene from potato (Solanum tuberosum L.) to salinity and drought. The transgene was under the mannopine synthetase (pMAS) promoter. PR10a-overexpressing faba bean plants showed better growth than the wild-type plants after 14 days of drought stress and 30 days of salt stress under hydroponic growth conditions. After removing the stress, the PR10a-plants returned to a normal state, while the wild-type plants could not be restored. Most importantly, there was no phenotypic difference between transgenic and non-transgenic faba bean plants under well-watered conditions. Evaluation of physiological parameters during salt stress showed lower Na+-content in the leaves of the transgenic plants, which would reduce the toxic effect. In addition, PR10a-plants were able to maintain vegetative growth and experienced fewer photosystem changes under both stresses and a lower level of osmotic stress injury under salt stress compared to wild-type plants. Taken together, our findings suggest that the PR10a gene from potato plays an important role in abiotic stress tolerance, probably by activation of stress-related physiological processes.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 782
Author(s):  
Joon-Yung Cha ◽  
Sang-Ho Kang ◽  
Myung Geun Ji ◽  
Gyeong-Im Shin ◽  
Song Yi Jeong ◽  
...  

Humic acid (HA) is a principal component of humic substances, which make up the complex organic matter that broadly exists in soil environments. HA promotes plant development as well as stress tolerance, however the precise molecular mechanism for these is little known. Here we conducted transcriptome analysis to elucidate the molecular mechanisms by which HA enhances salt stress tolerance. Gene Ontology Enrichment Analysis pointed to the involvement of diverse abiotic stress-related genes encoding HEAT-SHOCK PROTEINs and redox proteins, which were up-regulated by HA regardless of salt stress. Genes related to biotic stress and secondary metabolic process were mainly down-regulated by HA. In addition, HA up-regulated genes encoding transcription factors (TFs) involved in plant development as well as abiotic stress tolerance, and down-regulated TF genes involved in secondary metabolic processes. Our transcriptome information provided here provides molecular evidences and improves our understanding of how HA confers tolerance to salinity stress in plants.


2020 ◽  
Vol 21 (6) ◽  
pp. 2177 ◽  
Author(s):  
Bo Li ◽  
Jia-Cheng Zheng ◽  
Ting-Ting Wang ◽  
Dong-Hong Min ◽  
Wen-Liang Wei ◽  
...  

Vascular plant one-zinc-finger (VOZ) transcription factor, a plant specific one-zinc-finger-type transcriptional activator, is involved in regulating numerous biological processes such as floral induction and development, defense against pathogens, and response to multiple types of abiotic stress. Six VOZ transcription factor-encoding genes (GmVOZs) have been reported to exist in the soybean (Glycine max) genome. In spite of this, little information is currently available regarding GmVOZs. In this study, GmVOZs were cloned and characterized. GmVOZ genes encode proteins possessing transcriptional activation activity in yeast cells. GmVOZ1E, GmVOZ2B, and GmVOZ2D gene products were widely dispersed in the cytosol, while GmVOZ1G was primarily located in the nucleus. GmVOZs displayed a differential expression profile under dehydration, salt, and salicylic acid (SA) stress conditions. Among them, GmVOZ1G showed a significantly induced expression in response to all stress treatments. Overexpression of GmVOZ1G in soybean hairy roots resulted in a greater tolerance to drought and salt stress. In contrast, RNA interference (RNAi) soybean hairy roots suppressing GmVOZ1G were more sensitive to both of these stresses. Under drought treatment, soybean composite plants with an overexpression of hairy roots had higher relative water content (RWC). In response to drought and salt stress, lower malondialdehyde (MDA) accumulation and higher peroxidase (POD) and superoxide dismutase (SOD) activities were observed in soybean composite seedlings with an overexpression of hairy roots. The opposite results for each physiological parameter were obtained in RNAi lines. In conclusion, GmVOZ1G positively regulates drought and salt stress tolerance in soybean hairy roots. Our results will be valuable for the functional characterization of soybean VOZ transcription factors under abiotic stress.


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