Effect of Transgenesis on mRNA and miRNA Profiles in Cucumber Fruits Expressing Thaumatin II.

Magdalena Ewa Pawełkowicz,Tomasz Pniewski,Małgorzata Sroka,Wojciech Pląder,Maria Szwacka,Agnieszka Skarzyńska

doi:10.3390/genes11030334

Magdalena Ewa Pawełkowicz, Tomasz Pniewski + Show 4 more

Open Access

https://doi.org/10.3390/genes11030334

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Abstract

Transgenic plants are commonly used in breeding programs because of the various features that can be introduced. However, unintended effects caused by genetic transformation are still a topic of concern. This makes research on the nutritional safety of transgenic crop plants extremely interesting. Cucumber (Cucumis sativus L.) is a crop that is grown worldwide. The aim of this study was to identify and characterize differentially expressed genes and regulatory miRNAs in transgenic cucumber fruits that contain the thaumatin II gene, which encodes the sweet-tasting protein thaumatin II, by NGS sequencing. We compared the fruit transcriptomes and miRNomes of three transgenic cucumber lines with wild-type cucumber. In total, we found 47 differentially expressed genes between control and all three transgenic lines. We performed the bioinformatic functional analysis and gene ontology classification. We also identified 12 differentially regulated miRNAs, from which three can influence the two targets (assigned as DEGs) in one of the studied transgenic lines (line 224). We found that the transformation of cucumber with thaumatin II and expression of the transgene had minimal impact on gene expression and epigenetic regulation by miRNA, in the cucumber fruits.

Highlights

Cucumber is a plant of great economic importance
We investigated the fruits of transgenic cucumbers with the thaumatin II gene to detect transcriptomic changes that may indicate unintended effects at the molecular level and show the influence of the transgene on the other genes in the commercial product which is cucumber fruit
We sequenced the transcriptomes from small fruits of three transgenic cucumber lines (212, 224, and 225) and their wild-type B10 line to detect differentially expressed genes (DEGs) and to check whether unintended effects of transformation may occur at the molecular level in cucumber

Summary

Introduction

Cucumber is a plant of great economic importance. It has been widely bred using modern biotechnology methods to create varieties with new features. University of Life Sciences, Poland) since 1996, when transgenic cucumber plants with the thaumatin II gene were obtained [1]. The fruit is pyramidal shaped and is filled with a colorless gel that contains thaumatin [2]. Thaumatin is about 100,000 times sweeter than sucrose. It has a high affinity for the receptors responsible for the sweet taste sensation, which makes its perception much higher than that for sugars [3]. Thaumatin is non-caloric, non-toxic, and is accepted by nutrition authorities [2]

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