Al-induced proteomics changes in tomato plants over-expressing a glyoxalase I gene

Abstract

Glyoxalase I (Gly I) is the first enzyme in the glutathionine-dependent glyoxalase pathway for detoxification of methylglyoxal (MG) under stress conditions. Transgenic tomato 'Money Maker' plants overexpressing tomato SlGlyI gene (tomato unigene accession SGN-U582631/Solyc09g082120.3.1) were generated and homozygous lines were obtained after four generations of self-pollination. In this study, SlGlyI-overepxressing line (GlyI), wild type (WT, negative control) and plants transformed with empty vector (ECtr, positive control), were subjected to Al-treatment by growing in Magnavaca's nutrient solution (pH 4.5) supplemented with 20 µM Al 3+ ion activity. After 30 days of treatments, the fresh and dry weight of shoots and roots of plants from Al-treated conditions decreased significantly compared to the non-treated conditions for all the three lines. When compared across the three lines, root fresh and dry weight of GlyI was significant higher than WT and ECtr, whereas there was no difference in shoot tissues. The basal 5 mm root-tips of GlyI plants expressed a significantly higher level of glyoxalase activity under both non-Al-treated and Al-treated conditions compared to the two control lines. Under Al-treated condition, there was a significant increase in MG content in ECtr and WT lines, but not in GlyI line. Quantitative proteomics analysis using tandem mass tags mass spectrometry identified 4080 quantifiable proteins and 201 Al-induced differentially expressed proteins (DEPs) in roottip tissues from GlyI, and 4273 proteins and 230 DEPs from ECtr. The Al-down-regulated DEPs were classified into molecular pathways of gene transcription, RNA splicing and protein biosynthesis in both GlyI and ECtr lines. The Alinduced DEPs in GlyI associated with tolerance to Al 3+ and MG toxicity are involved in callose degradation, cell wall components (xylan acetylation and pectin degradation), oxidative stress (antioxidants) and turnover of Al-damaged epidermal cells, repair of damaged DNA, epigenetics, gene transcription, and protein translation. A protein-protein association network was constructed to aid the selection of proteins in the same pathway but differentially regulated in GlyI or ECtr lines. Proteomics data are available via ProteomeXchange with identifiers PXD009456 under project title '25Dec2017_Suping_XSexp2_ITAG3.2' for SlGlyI-overexpressing tomato plants and PXD009848 under project title '25Dec2017_Suping_XSexp3_ITAG3.2' for positive control ECtr line transformed with empty vector.

Salt-Tolerant Phenomena, Sequencing and Characterization of a Glyoxalase I (Jojo-Gly I) Gene from Jojoba in Comparison with Other Glyoxalase I Genes

“…The stress done via salinity with Na salts not only reduces Ca availability, it also reduces the move of Ca and its mobility for growing parts in the plant. This action reverts to the plant in the quality and vegetative organs [ 20 , 38 ]. Spinach tomato affected with high concentrations of NaCl induced K defiance [ 39 , 40 ].…”

“…Although different workers have achieved different levels of overexpression of glyoxalase I , all the overexpressing cells, except the yeast cells expressing tomato Gly I , tolerate methylglyoxal. Moreover, the tolerance level to methylglyoxal depended on the level of glyoxalase I [ 20 ]. Further experiments will be needed to understand the relationship between gene identification with plant metabolism and physiology by determining some metabolites.…”

“…The tomato glyoxalase I gene in the yeast expression system using the pYEX4 vector led to a 20-fold increase in the specific activity of the glyoxalase I enzyme. However, the sensitivity to methylglyoxal was similar to that of control cells [ 20 ].…”

“…In an early attempt, the screening of the Arabidopsis expression library with glyoxalase I antibodies raised against B. juncea resulted in isolation of the Gst gene. The isolation of the Gst clone by immunological screening of the library with glyoxalase I antibodies in their study indicated a presence of common epitopes in both glyoxalase I and glutathione S-transferase proteins [ 8 , 19 , 20 ]. When the available sequences of Gly I from different organisms were used to generate a dendrogram, a segregation of glyoxalase I sequences into prokaryotic and eukaryotic types was obvious.…”

Proteomics of Reproductive Development, Fruit Ripening, and Stress Responses in Tomato

“…Transgenic tomato lines overexpressing the glyoxylase I gene ( Gly I ) have been assessed under Al stress to identify the role of proteins involved in callose degradation, cell wall-related proteins (xylan acetylation and pectin degradation), the role of antioxidants, and nuclear proteins, especially those involved in transcription and epigenetic and chromatin modifications. The root proteome of a cherry tomato under Al stress exhibited an abundance of ROS detoxification enzymes, cell wall remodeling, and proteasomal activity …”