Proteomic analysis of phytase transgenic and non-transgenic maize seeds

Yanhua Tan,Xuchu Wang,Yong Sun,Xiang Jin,Anping Guo,Cunzhi Peng,Qian Yang,Zheng Tong

doi:10.1038/s41598-017-09557-8

Yanhua Tan, Xuchu Wang + Show 6 more

Open Access

https://doi.org/10.1038/s41598-017-09557-8

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Abstract

Proteomics has become a powerful technique for investigating unintended effects in genetically modified crops. In this study, we performed a comparative proteomics of the seeds of phytase-transgenic (PT) and non-transgenic (NT) maize using 2-DE and iTRAQ techniques. A total of 148 differentially expressed proteins (DEPs), including 106 down-regulated and 42 up-regulated proteins in PT, were identified. Of these proteins, 32 were identified through 2-DE and 116 were generated by iTRAQ. It is noteworthy that only three proteins could be detected via both iTRAQ and 2-DE, and most of the identified DEPs were not newly produced proteins but proteins with altered abundance. These results indicated that many DEPs could be detected in the proteome of PT maize seeds and the corresponding wild type after overexpression of the target gene, but the changes in these proteins were not substantial. Functional classification revealed many DEPs involved in posttranscriptional modifications and some ribosomal proteins and heat-shock proteins that may generate adaptive effects in response to the insertion of exogenous genes. Protein-protein interaction analysis demonstrated that the detected interacting proteins were mainly ribosomal proteins and heat-shock proteins. Our data provided new information on such unintended effects through a proteomic analysis of maize seeds.

Highlights

Modified crops (GMCs) have been globally commercialized since 1996, and the cumulative planting area of Genetically modified crops (GMCs) has reached an unprecedented 2 billion hectares globally in 2015
We used traditional gel-based 2-DE and newly developed gel-free isobaric tags for relative and absolute quantification (iTRAQ) approaches to compare the quantitative differences in the proteomes of maize seeds between PT maize and the NT isogenic variety to investigate any unintended effects in PT maize seeds
Neither the phyA2 nor bar transcript was detected in the NT control seeds of LIYU16. These results suggested that these exogenous genes were successfully expressed in PT maize seeds

Summary

Introduction

Modified crops (GMCs) have been globally commercialized since 1996, and the cumulative planting area of GMCs has reached an unprecedented 2 billion hectares globally in 2015. Determining the potential unintended effects of GMCs is important to understand the benefits of these crops to farmers and consumers. ITRAQ is considered more accurate and reliable than traditional 2-DE gel-based analysis[14,15,16] and is widely used for comparative proteomic analyses. Researches on commercialization of transgenic maize in China have made important potential contributions to maize production for meeting both national and global food and feed needs. We performed a comparative proteomic analysis of leaves from PT maize and the non-transgenic (NT) isogenic variety[22]. We used traditional gel-based 2-DE and newly developed gel-free iTRAQ approaches to compare the quantitative differences in the proteomes of maize seeds between PT maize and the NT isogenic variety to investigate any unintended effects in PT maize seeds

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Conclusion