Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators

Shuo Yan,Anthony M Shelton,Xiaoxia Liu,Jinjie Cui,Qingwen Zhang,Weilong Zhu,Junyu Luo,Jialin Zhu,Zhen Li

doi:10.1038/srep15917

Abstract

With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant.

Highlights

Cotton (Gossypium hirsutum L.) is primarily grown as an irrigated crop during summer in three major ecological regions of China: the Changjiang River Region, the Yellow River Region and the North-western Region
The agronomic behavior of genetically modified (GM) and non-GM cottons was similar to a standard cultivar in the field
Time of flowering was synchronous between the GM and non-GM cotton throughout the flowering period, ensuring ample opportunity for pollen transfer

Summary

Introduction

Cotton (Gossypium hirsutum L.) is primarily grown as an irrigated crop during summer in three major ecological regions of China: the Changjiang River Region, the Yellow River Region and the North-western Region. Transgenic cotton, producing insecticidal proteins from Bacillus thuringiensis (Bt) has been used since 1997 in China to effectively suppress lepidopteran pests[24,25]. In China where farmers primarily have small units of land on which they grow multiple crops, it is common to have crucifer crops, the host of P. rapae, near cotton. To measure PGF in GM cotton using the combination of molecular techniques and biological assay, we conducted greenhouse experiments with pollinators, including B. ignites, A. mellifera and P. rapae, and without pollinators, using one GM cotton and two non-GM counterparts. Our goals in the study were to: (1) measure PGF with different pollinators, (2) determine the influence of distance between GM pollen donor plants and non-GM pollen receptor plants on PGF, (3) analyze the impact of different non-GM cotton receptor plants on PGF, (4) confirm the insect and glyphosate resistance of hybrids

Methods

Results

Conclusion