What is it about?
We took insects that were found to be resistant to Vip3Aa from field surveys and carried out a variety of genetic approaches (such as crossing, transcriptomics and long-read sequencing) to identify a gene which is involved in Vip3Aa resistance. We then used CRISPR-Cas9 to disrupt this gene in another sub-species of Helicoverpa armigera which led to the same Vip3Aa resistance phenotype.
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Photo by Eka P. Amdela on Unsplash
Why is it important?
Bt crops are grown world-wide and are effective at controlling specific insect pests. Resistance to Bt toxins is important to manage. One of the most recent Bt toxins (Vip3Aa) has had only very few candidate resistance genes identified in Lepidopteran pests. We add to the small handful of genes involved in Vip3Aa toxicity, which aids both molecular monitoring of resistance as well as an understanding of the function of Vip3Aa.
Perspectives
For me, the most interesting part of this publication is the demonstration of long-read sequencing for identification of the genetic disruption in the second colony derived from the field. This was a major block for this work previously, and only recently were we able to identify the genomic disruption in this line - a massive transposable element in the first intron. We knew this gene was disrupted (from genetic crossing) but short-read sequencing wasn't able to provide any insight into the disruption present in the intron. The transposable element is huge - bigger than the whole gene - and we had no idea it was there from the short-read sequencing data we had available.
Andreas Bachler
CSIRO
Read the Original
This page is a summary of: Disruption of HaVipR1 confers Vip3Aa resistance in the moth crop pest Helicoverpa armigera, PLoS Biology, May 2025, PLOS,
DOI: 10.1371/journal.pbio.3003165.
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