Comparative Proteomics of Phytase-transgenic Maize Seeds Indicates Environmental Influence is More Important than that of Gene Insertion

Yanhua Tan,Lili Chang,Jiaming Zhang,Xuchu Wang,Zheng Tong,Yong Sun,Cunzhi Peng,Anping Guo

doi:10.1038/s41598-019-44748-5

Yanhua Tan, Lili Chang + Show 6 more

Open Access

https://doi.org/10.1038/s41598-019-44748-5

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Abstract

Proteomic differences were compared between phytase-transgenic (PT) maize seeds and nontransgenic (NT) maize seeds through two-dimensional electrophoresis (2-DE) with mass spectrometry (MS). When maize was grown under field conditions, 30 differentially accumulated proteins (DAPs) were successfully identified in PT seeds (PT/NT). Clusters of Orthologous Groups (COG) functional classification of these proteins showed that the largest group was associated with posttranslational modifications. To investigate the effects of environmental factors, we further compared the seed protein profiles of the same maize planted in a greenhouse or under field conditions. There were 76 DAPs between the greenhouse- and field-grown NT maize seeds and 77 DAPs between the greenhouse- and field-grown PT maize seeds However, under the same planting conditions, there were only 43 DAPs (planted in the greenhouse) or 37 DAPs (planted in the field) between PT and NT maize seeds. The results revealed that DAPs caused by environmental factors were more common than those caused by the insertion of exogenous genes, indicating that the environment has much more important effects on the seed protein profiles. Our maize seed proteomics results also indicated that the occurrence of unintended effects is not specific to genetically modified crops (GMCs); instead, such effects often occur in traditionally bred plants. Our data may be beneficial for biosafety assessments of GMCs at the protein profile level in the future.

Highlights

To detect the potential unintended effects of genetically modified crops (GMCs), a nontargeted approach is needed to survey the plants more broadly
Analysis of the protein profiles of phytase- transgenic (PT) and NT maize seeds revealed a total of 1027 ± 121 spots in NT maize seed gel maps and 1228 ± 284 spots in PT maize seed gel maps (Figs 1; S1)
The 30 identified differentially accumulated proteins (DAPs) were obtained between PT and NT maize seeds, which were www.nature.com/scientificreports

Summary

Introduction

To detect the potential unintended effects of GMCs, a nontargeted approach is needed to survey the plants more broadly. Omics-based global profiling, such as transcriptomics, proteomics and metabolomics, is one of the more informative and cost-efficient analytical methods and may be a useful technique[9,10] Among these profiling approaches, proteomic analysis is a direct method for investigating the unintended effects at protein level. By comparing the entire proteomes of GM crops and control lines, unintended effects can be evaluated at the protein level. With the rapid development of proteomic technology, comparative proteomic approaches coupled directly with tandem mass spectrometry (MS) technology have been widely used to detect the unintended effects of GMCs8. We used both 2-DE-MS/MS and iTRAQ-based methods to identify the quantitative proteomic differences between PT and NT maize seeds grown in a greenhouse[21]. Our results may provide more insights into the unintended effect of environmental factors on protein profiles

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Conclusion