Expression in Escherichia coli of Three Different Soybean Late Embryogenesis Abundant (LEA) Genes to Investigate Enhanced Stress Tolerance

Abstract

In order to identify the function of late embryogenesis abundant (LEA) genes, in vitro functional analyses were performed using an Escherichia coli heterologous expression system. Three soybean late embryogenesis abundant (LEA) genes, PM11 (GenBank accession No. AF004805; group 1), PM30 (AF117884; group 3), and ZLDE-2 (AY351918; group 2), were cloned and expressed in a pET-28a system. The gene products were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified by mass spectrometry. E. coli cells containing the recombinant plasmids or empty vector as controls were treated by salt and low temperature stress. Compared with control cells, the E. coli cells expressing either PM11 or PM30 showed a shorter lag period and improved growth when transferred to LB (Luria-Bertani) liquid media containing 800 mmol/L NaCl or 700 mmol/L KCl or after 4 °C treatment. E. coli cells expressing ZLDE-2 did not show obvious growth improvement both in either high KCl medium or after 4 °C treatment. The results indicate that the E. coli expression system is a simple, useful method to identify the functions of some stress-tolerant genes from plants.

Improved tolerance to salt and water stress in Drosophila melanogaster cells conferred by late embryogenesis abundant protein

“…A similar conclusion can be reached for the ability of AfLEA1.3 to ameliorate the impact of salt stress on mitochondrial function in Figure 5. Protection against salt and osmotic stress by transgenic expression of plant LEA proteins has also been demonstrated in yeast and bacteria (Lan et al, 2005;Yu, 2005). Furthermore, the glucose starvation-inducible protein B (GsiB; Bacillus subtilis) shows high similarities with group 1 LEA proteins (Stacy and Aalen, 1998) and GsiB domain carrying proteins are involved in high-salt tolerant Escherichia coli strains (Kapardar et al, 2010).…”

The continuing conundrum of the LEA proteins

“…E. coli expressing a modified recombinant PM2 with a duplicated 22-mer repeat region (a variant of the 11-mer motif typical of group 3 proteins) exhibited higher salt tolerance levels than bacteria containing proteins with a single repeat region, implicating the repeat region as the functional domain of the LEA protein. This approach was extended to analyse the protective effect of soybean LEA proteins from all three major groups: group 1 (PM11; Em homologue) and group 3 (PM30) proteins offered protection against both salt stress and cold stress, but the group 2 protein, ZLDE-2, was ineffective (Lan et al 2005). Intriguingly, Campos et al (2006) have presented evidence suggesting that certain LEA proteins are growth inhibitory in E. coli.…”

Molecular Characterization of a MYB Protein from Oryza sativa for its Role in Abiotic Stress Tolerance

“…Guo et al 21 observed the drought tolerance in E.coli cells transformed with the ThPOD3 from Tamarix hispida. LEA proteins from soybean improved tolerance to E. coli cells against salt stress 22 . In order to examine the function of proteins against diverse abiotic stresses, recombinant plasmid was expressed in E. coli.…”