Bacillus thuringiensis and Chlorantraniliprole trigger the expression of detoxification-related genes in the larval midgut of Plutella xylostella

Authors: SHABBIR, MUHAMMAD ZEESHA - Guangdong Academy Of Agricultural Sciences; Yang, Xiangbing; YIN, FEI - Guangdong Academy Of Agricultural Sciences; BATOOL, RAUFA - Guangdong Academy Of Agricultural Sciences; Kendra, Paul; LI, ZHEN-YU - Guangdong Academy Of Agricultural Sciences

Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2021
Publication Date: 12/13/2021
Citation: Shabbir, M.N., Yang, X., Yin, F., Batool, R., Kendra, P.E., Li, Z. 2021. Bacillus thuringiensis and Chlorantraniliprole trigger the expression of detoxification-related genes in the larval midgut of Plutella xylostella. Frontiers in Physiology. 12:780255. https://doi.org/10.3389/fphys.2021.780255.
DOI: https://doi.org/10.3389/fphys.2021.780255

Interpretive Summary: Diamondback moth (DBM), Plutella xylostella, a destructive pest of many crops throughout the world, has developed resistance to many classes of insecticides which poses a major challenge for DBM management. To date, the molecular mechanism of DBM resistance to Bt (Bt-GO33A) and chlorantraniliprole (CL) remains unclear. To understand the resistance mechanism of DBM, scientists from Guangdong Academy of Agricultural Science (China) and USDA-ARS in Miami Florida (USA) evaluated five DBM strains under greenhouse conditions for their resistance level to Bt-GO33A, CL, and their mixture (BtC). Overall, the resistance level of DBM to insecticides from highest to lowest was: Bt-GO33A > BtC > CL. Also, the comparative analysis identified 25,518 differentially expressed genes (DEGs) between pairs/combinations of five strains and those DEGs were enriched in pathways related to metabolic, catalytic activity, and ABC transporter in resistant strains. In total, 17 candidate genes were identified in relation to resistance to CL or Bt-GO33A, and the majority was up-regulated, including cytochrome P450, glutathione S-transferase, GST, carboxyl-esterase, and acetyl-cholinesterase in the CL resistant strain, and aminopeptidase (APN), alkaline phosphatase (ALP), cadherin, trypsin, and ABC transporter genes in the Bt resistant strain. The study elucidated a comprehensive transcriptomic resource in resistance mechanisms of DBM and will be helpful for designing new combinations of insecticides to better manage resistance in DBM.

Technical Abstract: Diamondback moth (DBM), Plutella xylostella (L.) has developed resistance to many insecticides. The molecular mechanism of DBM resistance to Bt and chlorantraniliprole remains undefined. In this study, a field-original-resistant strain (FOH-DBM) was se-lected with Bacillus thuringiensis toxin (Bt-GO33A), chlorantraniliprole (CL), and a mixture of Bt + chlorantraniliprole (BtC) to evaluate the resistance level. DBM exhibited the highest resistance to Bt-GO33A, followed by BtC, and CL. Additionally, tran-scriptomic 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 analyzed by comparative analysis to identify genes responsible for detoxification. The comparative analysis identified 25,518 differentially expressed genes (DEGs) among pairs/combinations of five strains. DEGs were enriched in pathways related to metabolic and catalytic activity as well as ABC transporter in re-sistant strains. In total, 17 candidate genes were identified in resistance to CL and Bt-GO33A, and the majority was up-regulated including cytochrome P450, glutathione S-transferase, GST, carboxyl-esterase, and acetyl-cholinesterase in CL resistant strain. Fur-thermore, 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 with the detoxification process. These data entail a comprehensive transcriptomic resource for further designing new combinations of insecticides to delay resistance in Plutella xylostella.