|WU, QIBIN - Fujian Agricultural & Forestry University|
|GAO, SHIWU - Fujian Agricultural & Forestry University|
|SU, YACHUN - Fujian Agricultural & Forestry University|
|GUO, JINLONG - Fujian Agricultural & Forestry University|
|XI, LIPING - Fujian Agricultural & Forestry University|
|QUE, YOUXIONG - Fujian Agricultural & Forestry University|
Submitted to: PeerJ
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2018
Publication Date: 10/31/2018
Citation: Wu, Q., Gao, S., Pan, Y.-B.., Su, Y., Grisham, M.P., Guo, J., Xi, L., Que, Y. 2018. Heterologous expression of a Glyoxalase I gene from sugarcane confers tolerance to several environmental stresses in bacteria. PeerJ. 6:e5873. https://doi.org/10.7717/peerj.5873.
Interpretive Summary: Sugarcane yields are often influenced by many diseases and various environmental stresses, such as smut, rust and ratoon stunting diseases, salt, heavy mental and drought. The stresses often act on plants by gene expression changes or cytotoxic compounds. The ability of sugarcane to tolerate biotic or abiotic stresses is often associated with its genetic composition and how genes are expressed upon exposure to the stresses. Earlier reports showed that product of glyoxalase I gene detoxifies methylglyoxal, a cytotoxic chemical compound that is rapidly increased in concentration in plants under stress conditions. In this study, a gene called glyoxalase I (ScGlo I) was isolated and characterized from a sugarcane genotype YCE 05-179 through PCR amplification, molecular cloning, and DNA sequencing. The expression level of ScGlo I was assessed by placing the gene inside E. coli bacterial cells and exposing these recombinant E. coli cells to salt and heavy metal compounds. Bacterial cells with ScGlo I grew faster and could tolerated higher concentrations of salt and several heavy metal ions in culture media in comparison to the control cells without ScGlo I. The expression of ScGlo I was also up-regulated in various sugarcane tissues under the stress of salt and several heavy metal ions. These results suggest that the ScGlo I gene plays an important role in sugarcane's response to various biotic and abiotic stresses. The findings opens up a new research avenue for growing sugarcane in polluted or drought environments via genetic engineering and breeding of ScGlo I to enhance host resistance.
Technical Abstract: Glyoxalase I detoxifies methylglyoxal, a rapidly increasing cytotoxic compound under stress conditions. An express sequence tag (EST, GenBank Accession Number: CA140600.1) encoding a glyoxalase I was identified from a transcriptome profiling cDNA library of Sporisorium scitamineum-infected sugarcane buds. This EST was used to search for highly homologous sequences from the GenBank sugarcane database. Through sequence alignment, sequence assembly and RT-PCR, the complete sugarcane glyoxalase I gene, ScGlo I (GenBank Accession Number: KC857628), was successfully cloned. ScGlo I had a size of 1,091 bp with one open reading frame of 885 bp encoding a protein of 294 amino acids. Two typical glyoxalase domains were identified at amino acid sequence positions of 28-149 and 159-283. ScGlo I was cloned into an expression plasmid vector, and the His-tagged ScGlo I protein produced in Escherichia coli was about 51 kDa. The recombinant E. coli cells expressing ScGlo I compared to the control grew faster and tolerated higher concentrations of NaCl, CuCl2, CdCl2 or ZnSO4. ScGlo I expression in various sugarcane tissues was also up-regulated under the stress of NaCl, CuCl2, CdCl2 as well as under simulated pathogen stress conditions by exposure to salicylic acid (SA), methyl jasmonate (MeJA), polyethylene glycol (PEG), or abscisic acid (ABA). ScGlo I activity was also steadily increased when sugarcane was subjected to NaCl or CdCl2 stress. These results suggest that the ScGlo I gene plays an important role in sugarcane's response to various biotic and abiotic stresses.