An international team of researchers led by University of Arizona (UA) and
the U.S. Department of Agriculture (USDA) unveiled the molecular basis in
insects that evolved resistance to biotech cotton plants. The results of the
study are published in PLOS ONE on May 19.

"Many mechanisms of resistance to Bt proteins have been proposed and studied
in the lab, but this is the first analysis of the molecular genetic basis of
severe pest resistance to a Bt crop in the field," said Bruce Tabashnik, one
of the authors of the study and the head of the Department of Entomology in
the UA College of Agriculture and Life Sciences.

The researchers compared cadherin gene in the pink bollworms from Arizona
and India. They found an astounding diversity of cadherin in pink bollworms
from India caused by alternative splicing, a novel mechanism of resistance
that allows a single DNA sequence to code for many variants of a protein.
This is the first report of alternative splicing linked with field-evolved
Bt resistance.

[uanews.org]