Project description:Key messageRNAi-based genetically modified maize resistant to Monolepta hieroglyphica (Motschulsky) was demonstrated with negligible transcriptome and metabolome alterations compared to its unmodified equivalent. As one of the most prevalent insect pests afflicting various crops, Monolepta hieroglyphica (Motschulsky) causes severe loss of agricultural and economic productivity for many years in China. In an effort to reduce damages, in this study, an RNA interference (RNAi)-based genetically modified (GM) maize was developed. It was engineered to produce MhSnf7 double-stranded RNAs (dsRNAs), which can suppress the Snf7 gene expression and then lead M. hieroglyphica to death. Field trail analysis confirmed the robustly insecticidal ability of the MhSnf7 GM maize to resist damages by M. hieroglyphica. RNA sequencing analysis identified that only one gene was differentially expressed in the MhSnf7 GM maize compared to non-GM maize, indicating that the transcriptome in MhSnf7 GM maize is principally unaffected by the introduction of the MhSnf7 dsRNA expression vector. Likewise, metabolomics analysis identified that only 8 out of 5787 metabolites were significantly changed. Hence, the integration of transcriptomics and metabolomics demonstrates that there are negligible differences between MhSnf7 GM maize and its unmodified equivalent. This study not only presents a comprehensive assessment of cellular alteration in terms of gene transcription and metabolite abundance in RNAi-based GM maize, but also could be used as a reference for evaluating the unintended effect of GM crops.
Project description:Monolepta hieroglyphica (Motschulsky) (Coleoptera: Chrysomelidae) is an important agricultural insect pest. In this study, the complete mitochondrial genome of M. hieroglyphica (GenBank accession number MW732714) was sequenced using Illumina HiSeq X Ten. The mitogenome was 16,213 bp long and comprised 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs) and a putative control region (CR). The nucleotide composition of the M. hieroglyphica mitochondrial genome was significantly biased (A, G, C and T accounted for 41.04%, 8.01%, 11.76% and 39.18%, respectively) with 80.23% A + T content. Two rRNAs were located between tRNA-Leu and the CR, separated by tRNA-Val. The CR, located between 12 s rRNA and tRNA-Ile, was 1,661 bp long. The length of the 22 tRNAs ranged from 61 to 71 bp. Phylogenetic analyses of 29 Chrysomelidae-Galerucinae species based on 13 mitochondrial protein-coding genes reconstructed using Bayesian 3.2.0 showed that the M. hieroglyphica mitogenome was clustered with the existing three different species of the Monolepta genus mitogenomes in a monophyletic manner. The M. hieroglyphica mitogenome provides an important data resource for further studies and contributes to our understanding of the phylogeny of this group.