Effects of abiotic stresses on the expression of chitinase-like genes in Acyrthosiphon pisum

Abstract

Insect chitinases play a crucial part to digest chitin in the exoskeleton during the molting process. However, research on insect chitinase related to the environmental stress response is very limited. This study was the first conducted to expression analysis of chitinase- related genes in A. pisum under abiotic stresses. Here, we identified five chitinase-like proteins (ApIDGF, ApCht3, ApCht7, ApCht10 and ApENGase), and clustered them into five groups (group II, III, V, Ⅹ, and ENGase). Developmental expression analysis revealed that the five A. pisum chitinase-related genes were expressed at whole developmental stages with different relative expression patterns. When aphids were exposed to various abiotic stresses including temperature, insecticide and the stress 20-hydroxyecdysone (20E), all five chitinase genes were differentially expressed in A. pisum. The results showed that insecticide such as imidacloprid down-regulated the expression of these five Cht-related genes. Analysis of temperature stress of A. pisum chitinase suggested that ApCht7 expression was high at 10°C, which demonstrates its important role in pea aphids under low temperature. Conversely, ApCht10 was more active under high temperature stress, as it was significantly up-regulated at 30°C. Besides, 20E enhanced ApCht3 and ApCht10 expression in A. pisum, but reduced ApCht7 expression. These findings provide basic information and insights for the study of the role of these genes under abiotic stress, which advances our knowledge in the management of pea aphids under multiple stresses.

Chitinase inhibition induces transcriptional dysregulation altering ecdysteroid-mediated control of Spodoptera frugiperda development

“…Crude enzyme extract of 5 th instar S. frugiperda larvae fed on an artificial diet was prepared as mentioned earlier. 11 Briefly, 500 mg finely powdered tissue of 5 th instar larvae was homogenized in 50 mM sodium phosphate buffer (pH 7) in 1:1 ratio (w/v) and kept at 4°C for 2 h. The suspension was centrifuged at 13,000 ˣ g, 4°C for 20 min and the resulting supernatant was used as a source of chitinase. Total endochitinases activity inhibition from S.frugiperda was carried out using 4-Methylumbelliferyl ß-D-N, N',N''-triacetylchitotrioside as substrate, endochinase cleaves the substrate to release fluorescent 4-Methylumbelliferone.…”

“… 7 In the case of Spodoptera frugiperda , chitinase silencing affects the molting and eclosion. 11 , 12 Moreover, natural molecules like shikonin, wogonin, quercetin, kaempferol, and berberine are known insect chitinase inhibitors. Shikonin and wogonin treatment caused larval growth retardation and increased mortality in S .…”

A-to-I RNA editing of CYP18A1 mediates transgenerational wing dimorphism in aphids

“…In brief, 20E (Cayman Chemicals, USA) was dissolved in 95% ethanol as the stock solution, then diluted to 12 mg/mL with ultrapure water, and used as the working solution (84). The wheat seedlings treated with 20E were used to feed the fourth-instar nymphs, and the treatment method was the same as above.…”