Evalution Of The Unintended Effect Of Transgenic Insect Resistant Maize Based On The Technique Of Omics

Transgenic technology has over the last decade applied successfully in breeding insect resistant corn.There have been more than 100 transgenic corn varieties ever developed contributing greatly to the sustainability of the world agriculture.However,there have since been the public concerns about the potential safety of the genetically modified(GM)crops.For this reason,an international practice of a full range of safety assessments has been conducted among the GM crop developing nations,aiming to ensure endevourly the safety of both environment and food.Corn borer-resisitant GM corn varieties,such as SK12-5,IE034,Bt799,are developed by Chinese scientists of potential farming application.In this study,the traditional practice and the omics technologies for environmental safety assessment of GM corns were conducted,focusing on in paritcular elucidation of the unintended effects of those GM corn varieties over their corn-borer resistant trait.So as to understand those GM corns with respect to their survival competibility and the impact to biodiversity,when they are in field,as well as the proteomic and metabolomic characteristics.The information obtained is expected to provide insights into evaluation of the unintended effects of GM corns.Results achieved may be summarized as follows:1.The GM corn event SK12-5 performed unexceptionally in survival competitiveness assessment upon statistical analyses.Under ruderal field condition,SK12-5 grew significantly weaker than those weeds such as barnyard grass,dayflower,quinoa,amaranth and abutilon weeds etc,which developed into high density quickly seizing most of the light,water and nutrients.Under field trial condition,SK12-5 completed the whole growth cycle,but the plant height,coverage and other morphological traits were apparently disavantagous over those non-corn plants.2.The GM corn event SK12-5 exhibited statistically non-significant impact on biodiversity under the field trail condition.In comparison with the non-GM corn,cultivation of SK12-5 led no significant effects on arthropod community composition and community structure using various approaches such as the direct observation and trap method etc.In addition,no evident impact was observed in the incidence regularity of the main in-field arthropod animal population like,to point a few,aphids in harmonia axyridis,monolepta hieroglyphica,spider,Yinchuan oil hyacinth,earwigs.3.Using a combinative approach of two-dimensional electrophoresis(2-DE)and mass spectrometry technology,we analyzed 4 GM corn events,i.e.SK12-5,IE034,Bt799 z and Bt799 zd,under comparison with their corresponding no-GM background controls of either hybrid lines or inbred lines,for assessment their environmentally unintended effects in aspects of protein differentiality.There were more than 1200 protein spots visualized by 2-DE,of which 61 proteins were identified by mass spectrometry to be exclusively the enzymes for photosynthesis,carbon fixation and energy metabolism etc.The likelihood of peculiar proteins leading to the unintended effects were not detected.Gene ontology(GO)analysis showed that the biochemical functions of the 61 differentially expressed proteins were mainly involved in photosynthesis,assimilate accumulation and energy metabolism.Expression of several key enzymes were found up-regulated significantly in the GM corn,such as ribulose-1,5-bisphosphate carboxylase in photosynthesis,pyruvate kinasein carbon dioxide fixation in photosynthetic pathway of C4 plants and ATP synthase.KEGG analyses of the differentially expressed proteins showed that,in comparison with the hybrid background control ZD958,photosynthetic carbon fixation pathways were enriched in SK12-5,whilst carbon fixation pathway,photosynthesis and carbon metabolism were significantly enriched in Bt799.Taking into account for the inbred control Z58,the differential proteins of IE034 and Bt799 were found significantly enriched in the metabolic pathway of photosynthesis.Protein enrichment and specific metabolites leading to the likelihood of the unintended effects were not detected in all 4 GM corn events tested.4.Using liquid chromatography and mass spectrometry(LC/MS)technology,metabolomes between the GM corn events and their corresponding non-GM controls were compared and analyzed.Results showed that the metabolome of the GM events differed apparently from the non-GM controls and,such difference in the GM events of inbred background Z58 appeared to be less than those of hybrid background ZD958.This is possibly the consequence of foreign gene(s)insertion into corn genome and,the genetic complesity of the hybrid line over the inbred one.