The structure and expression of exogenous genes in transgenic crops are critical for the target traits. R7569 was a mutant event identified in this study with deletion at the 3' end of cry1Ac gene compared to the transgenic insect-resistant cotton MON531 event with commercial application. R7569 has the same exogenous insertion structure as MON531, but with a deletion in the 3' end of the cry1Ac gene and the terminator region. R7569 has a truncated cry1Ac gene with the length of 2,554 bp, encoding 881 amino acids. The transcription termination site was mainly concentrated downstream of the truncated position and extended 160-270 bp from the truncated position using rapid-amplification of cDNA ends (RACE). The transcript levels of cry1Ac genes of R7569 and MON531 decreased gradually at seedling, bud and bell stages, and the transcript levels of cry1Ac genes of R7569 were significantly higher than those of MON531 in seedling and bud stages, but there was no significant difference in the boll stage. The content of Cry1Ac protein in R7569 gradually decreased with the seedling, bud and boll stage, and the content of Cry1Ac protein in all three periods was higher than that of MON531. The insect resistance assay showed that the resistance levels of R7569 and MON531 were both at the high level, and the corrected mortality rate against bollworms was 99.5% and 95.2%, respectively, and there was no significant difference between them. The LC50 value of R7569 was 0.732ng/g dw, with a slope of 1.654 indicating a high level of resistance to bollworm. In this study, for the first time, we found a partial deletion of the target gene in commercially applied transgenic crops, and the partial deletion of the 3' end of the cry1Ac gene retained a better transcription, expression level and insecticidal activity, which can provide a specific case for the safety evaluation of transgenic crops.

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which function as regulators of gene expression and contribute in numerous physiological processes. However, little is known referring to miRNAs function in insect chemosensation. In the current study, nine small RNA libraries were constructed and sequenced from the antennae of nymphs, adult males and females of Apolygus lucorum. In total, 399 miRNAs were identified including 275 known and 124 novel miRNAs. Known miRNAs were classified into 71 families, amongst which, 23 families were insect-specific. Expression profile analysis showed that miR-7-5p_1 was the most abundant miRNAs in the antennae of A. lucorum. Altogether, 69708 target genes related to biogenesis, membrane and binding activities were predicted for 399 miRNAs. Particularly, 15 miRNAs were found to target 16 olfactory genes. These miRNAs could be involved in regulation of olfactory-associated genes ex-pression. Comparing the antennae of nymphs, adult males and females, 94 miRNAs were found to be differentially expressed. The expression levels of some differentially expressed miRNAs measured by qPCR were consistent with sequencing results. This study provides a global miRNAs transcriptome in the antennae of A. lucorum and valuable information for further investigation on miRNA-mRNA interactions, especially the functions of miRNAs in regulating chemosensation.