Only a minority of broad-range detoxification genes respond to a variety of phytotoxins in generalist Bemisia tabaci species

Abstract

Generalist insect can utilize two different modes for regulating their detoxification genes, the constitutive mode and the induced mode. Here, we used the Bemisia tabaci sibling species MEAM1 and MED, as a model system for studying constitutive and induced detoxification resistance and their associated tradeoffs. B. tabaci adults were allowed to feed through membranes for 24 h on diet containing only sucrose or sucrose with various phytotoxins. Quantitative real-time PCR analyses of 18 detoxification genes, indicated that relatively few transcripts were changed in both the MEAM1 and MED species, in response to the addition of phytotoxins to the diet. Induced transcription of detoxification genes only in the MED species, in response to the presence of indole-3-carbinol in the insect’s diet, was correlated with maintenance of reproductive performance in comparison to significant reduction in performance of the MEAM1 species. Three genes, COE2, CYP6-like 5 and BtGST2, responded to more than one compound and were highly transcribed in the insect gut. Furthermore, functional assays showed that the BtGST2 gene encodes a protein capable of interacting with both flavonoids and glucosinolates. In conclusion, several detoxification genes were identified that could potentially be involved in the adaptation of B. tabaci to its host plants.

Transcription and Activity of Digestive Enzymes of Nezara viridula Maintained on Different Plant Diets

“…However, diet-dependent changes in transcription in hemipteran species may not be as pronounced or even involve digestive enzymes. Feeding on diets with different phytotoxins only induced changes in a few detoxification enzymes in Bemisia tabaci (Halon et al, 2015). For the scale insect Paratachardina pseudolobata, feeding on different host plants induced transcriptional changes, yet only a fraction of the genes was related to detoxification, being otherwise enriched for primary metabolism functions (Christodoulides et al, 2017).…”

“…Some corn varieties produce cysteine proteases that damage the peritrophic membrane lining the insect gut (Pechan et al, 2000), but insects can upregulate inhibitors of these enzymes (Li et al, 2009). Changes in protease activities or gene transcription profiles have been noted in several insects including in response to phytotoxins (Halon et al, 2015), diet source (Coudron et al, 2007;Huang et al, 2017;Rivera-Vega et al, 2017), or adaptation to the presence of plant protease inhibitors (Lara et al, 2000;Oppert et al, 2005;Brioschi et al, 2007). Key proteases or defense mechanisms are potential targets for disruption for stink bug management through the application of protease inhibitors (Schlüter et al, 2010) or gene knockdown (Joga et al, 2016;Ghosh et al, 2017).…”

Transcriptional profile and differential fitness in a specialist milkweed insect across host plants varying in toxicity

“…Furthermore, the expression of multiple P450s and differential expression of specific CYP genes in A. nerii feeding on more toxic host plants parallel the role of P450s in xenobiotic resistance and host plant adaptation in other insects (Berenbaum, Favret, & Schuler, ; Puinean et al., ; Tao, Xue, Huang, Chen, & Mao, ; Wybouw et al., ; Zhu, Moural, Nelson, & Palli, ). P450s were classically described in the adaptive radiation of Papilionidae lepidopteran species (Berenbaum et al., ; Schuler & Berenbaum, ), and specific CYP6 genes have since been identified in phytotoxin resistance in the whitefly, Bemisia tabaci , and in aphid species (Halon et al., ; Peng et al., ; Ramsey, Elzinga, Sarkar, Xin, & Jander, ). Two different CYP6 genes were differentially regulated in opposite directions in A. nerii feeding on G. physocarpus , suggesting a role for specific P450s in mediating milkweed toxicity.…”

Toxicity of Plant Secondary Metabolites Modulating Detoxification Genes Expression for Natural Red Palm Weevil Pesticide Development

“…However, their expression remained significantly lower compared to GST expression ( Figure 2 ). In the past, the expression of GST, cytochrome P450 , and esterase against toxicants in other pest species is well documented [ 37 , 38 , 39 ]. The high expression of GST and cytochrome P450 directly related with the detoxification of host against the tested compounds.…”