CSIRO Scientists Identify Gene Behind Bt Cotton Resistance Against Bollworms

Researchers from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have identified how insect pests are developing resistance to Bt cotton. Their findings could enhance the monitoring efforts of farmers and scientists in safeguarding the long-term effectiveness of Bt cotton.

The researchers used long-read genomic sequencing to examine two major cotton pests, Helicoverpa armigera and Helicoverpa punctigera. “We knew some insects were showing resistance to the Vip3A protein in Bt cotton,” said Dr. Andy Bachler from CSIRO's Insects as Engineers team. “But we couldn't find the gene or figure out how this mode of resistance worked,” he added. The sequencing revealed two types of mutations affecting the same gene. One was a large insertion and the other was a deletion.

The discovery opens new avenues for molecular pest monitoring in cotton fields. “Now we've found the gene, we can keep an eye out for it in the field,” Dr. Bachler said. While resistance levels in Australia remain low, scientists warn that similar mutations are emerging globally, including in Brazil, China, and the United States. The researchers stressed that molecular testing is essential for tracking resistance, and long-read sequencing plays a vital role in identifying resistance alleles.

For more information, read the article from CSIRO.