AUTHOR=Shabbir Muhammad Zeeshan , Yang Xiangbing , Batool Raufa , Yin Fei , Kendra Paul E. , Li Zhen-Yu 

TITLE=Bacillus thuringiensis and Chlorantraniliprole Trigger the Expression of Detoxification-Related Genes in the Larval Midgut of Plutella xylostella

JOURNAL=Frontiers in Physiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.780255

DOI=10.3389/fphys.2021.780255

ISSN=1664-042X

ABSTRACT=BACKGROUND: Diamondback moth (DBM), Plutella xylostella (L.) has developed resistance to many insecticides. The molecular mechanism of DBM resistance to Bt combined with chlorantraniliprole remains undefined. In this study, a field-original-resistant strain (FOH-DBM) was selected with Bacillus thuringiensis toxin (Bt-G033A), chlorantraniliprole (CL), and a mixture of Bt + chlorantraniliprole (Bt + CL) to evaluate the resistance level. Additionally, transcriptomic profiles of a susceptible (SS-DBM), field original resistant (FOH-DBM), Bt-resistant (Bt-DBM), chlorantraniliprole-resistant (CL-DBM), and Bt + chlorantraniliprole-resistant (BtC-DBM) strains were performed by comparative analysis to identify genes responsible for detoxification. 
RESULTS: The Bt-G033A was the most toxic chemical to all DBM strains among the three insecticides. The comparative analysis identified 25518 differentially expressed genes (DEGs) between pairs/combinations of five strains. DEGs were enriched in pathways related to metabolic and catalytic activity and ABC transporter in resistant strains. In total, 17 metabolic resistance-related candidate genes were identified in resistance to Bt-G033A, CL and Bt + CL by Co-expression network analysis. Within candidate genes, the majority was up-regulated in key genes, including cytochrome P450, glutathione S-transferase (GST), carboxyl-esterase and acetyl-cholinesterase in CL and BtC resistant strains. Furthermore, aminopeptidase (APN), alkaline phosphatase (ALP), cadherin, trypsin, and ABC transporter genes were eminent as Bt-candidate genes. Expression patterns of key genes by qRT-PCR confirmed an association in the detoxification process. 
CONSLUSIONS: To date, the present study is the most comprehensive research presenting functional transcriptome analysis of DBM using Bt toxin and chlorantraniliprole combined insecticidal activity.