Sun Xudong, Li Hui, Thapa Santosh, Reddy Sangireddy Sasikiran, Pei Xiaobo, Liu Wei, Jiang Yuping, Yang Shaolan, Hui Dafeng, Bhatti Sarabjit, Zhou Suping, Yang Yong, Fish Tara, Thannhauser Theodore W
1Department of Agricultural and Environmental Sciences, College of Agriculture, Tennessee State University, 3500 John A Merritt Blvd, Nashville, TN 37209 USA.
College of Horticulture, Shandong Agricultural University, Taian, Shandong P.R. China.
Hortic Res. 2020 Apr 1;7(1):43. doi: 10.1038/s41438-020-0264-x. eCollection 2020.
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 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, 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 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 root-tip 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 Al-induced DEPs in GlyI associated with tolerance to Al 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 overexpressing tomato plants and PXD009848 under project title '25Dec2017_Suping_XSexp3_ITAG3.2' for positive control ECtr line transformed with empty vector.
乙二醛酶I（Gly I）是谷胱甘肽依赖性乙二醛酶途径中的第一种酶，用于在胁迫条件下解毒甲基乙二醛（MG）。构建了过表达番茄基因（番茄单基因登录号SGN-U582631/Solyc09g082120.3.1）的转基因番茄“Money Maker”植株，并经过四代自花授粉获得了纯合系。在本研究中，过表达系（GlyI）、野生型（WT，阴性对照）和用空载体转化的植株（ECtr，阳性对照），通过在补充有20µM铝离子活性的Magnavaca营养液（pH 4.5）中生长来进行铝处理。处理30天后，与未处理条件相比，所有三个品系经铝处理条件下的植株地上部和根部的鲜重和干重均显著降低。在三个品系之间进行比较时，GlyI的根鲜重和干重显著高于WT和ECtr，而地上部组织没有差异。与两个对照品系相比，GlyI植株基部5mm根尖在未进行铝处理和铝处理条件下均表现出显著更高水平的乙二醛酶活性。在铝处理条件下，ECtr和WT品系中的MG含量显著增加，但GlyI品系中没有。使用串联质量标签质谱法进行的定量蛋白质组学分析在GlyI根尖组织中鉴定出4080种可定量蛋白质和201种铝诱导的差异表达蛋白质（DEP），在ECtr中鉴定出4273种蛋白质和230种DEP。在GlyI和ECtr品系中，铝下调的DEP被分类到基因转录、RNA剪接和蛋白质生物合成的分子途径中。GlyI中与铝和MG毒性耐受性相关的铝诱导DEP参与胼胝质降解、细胞壁成分（木聚糖乙酰化和果胶降解）、氧化应激（抗氧化剂）以及铝损伤表皮细胞的周转、受损DNA的修复、表观遗传学、基因转录和蛋白质翻译。构建了蛋白质-蛋白质关联网络，以帮助选择处于相同途径但在GlyI或ECtr品系中差异调节的蛋白质。蛋白质组学数据可通过ProteomeXchange获得，过表达番茄植株的项目标题为“25Dec2017_Suping_XSexp2_ITAG3.2”，标识符为PXD009456，用空载体转化的阳性对照ECtr品系的项目标题为“25Dec2017_Suping_XSexp3_ITAG3.2”且标识符为PXD009848。
