Cotton plants attacked by herbivorous insects emit large amounts of characteristic volatile terpenoids that are
highly attractive to predatory insects and trigger specific behavioral reactions in these，such as detection and location of the
chemical source． Here，we identified a novel sesquiterpene synthase gene GhTPS1 ( GenBank accession no． JQ365627)
from leaves of Gossypium hirsutum cv． Zhongmian12． GhTPS1 encodes a protein comprised of 545 amino acid residues
with a calculated molecular mass of 63． 3 ku and an isoelectric point of 5． 92． Multiple sequence alignment revealed that
the deduced amino acid sequence has 34% —60% identity with the sesquiterpene synthases of other angiosperm species，
and shared the highest identity with that of ( － ) － germacrene D synthase from Vitis vinifera． Phylogenetic analysis
clustered GhTPS1 into the TPSa subfamily，which is predominantly comprised of angiosperm sesquiterpene synthase genes．
We used real-time quantitative PCR to further investigate the temporal expression of GhTPS1 in G． hirsutum leaves
induced by the feeding activity of Helicoverpa armigera ( Hübner ) larvae． The results indicate that the GhTPS1
transcription level significantly increased after 24 hours of larval feeding activity．
Key words Helicoverpa armigera，terpene synthase，GhTPS1，expression pattern