Application of insulin signaling to predict insect growth rate in Maruca vitrata (Lepidoptera: Crambidae)

Abstract

Insect growth is influenced by two major environmental factors: temperature and nutrient. These environmental factors are internally mediated by insulin/insulin-like growth factor signal (IIS) to coordinate tissue or organ growth. Maruca vitrata, a subtropical lepidopteran insect, migrates to different climate regions and feeds on various crops. The objective of this study was to determine molecular tools to predict growth rate of M. vitrata using IIS components. Four genes [insulin receptor (InR), Forkhead Box O (FOXO), Target of Rapamycin (TOR), and serine-threonine protein kinase (Akt)] were used to correlate their expression levels with larval growth rates under different environmental conditions. The functional association of IIS and larval growth was confirmed because RNA interference of these genes significantly decreased larval growth rate and pupal weight. Different rearing temperatures altered expression levels of these four IIS genes and changed their growth rate. Different nutrient conditions also significantly changed larval growth and altered expression levels of IIS components. Different local populations of M. vitrata exhibited significantly different larval growth rates under the same nutrient and temperature conditions along with different expression levels of IIS components. Under a constant temperature (25°C), larval growth rates showed significant correlations with IIS gene expression levels. Subsequent regression formulas of expression levels of four IIS components against larval growth rate were applied to predict growth patterns of M. vitrata larvae reared on different natural hosts and natural local populations reared on the same diet. All four formulas well predicted larval growth rates with some deviations. These results indicate that the IIS expression analysis explains the growth variation at the same temperature due to nutrient and genetic background.

Alteration of insulin signaling to control insect pest by using transformed bacteria expressing dsRNA

“…On dsRNA injection, RNAi was achieved in M. vitrata in our previous studies . In the current study, RNAi efficiency was quantified.…”

“…On dsRNA injection, RNAi was achieved in M. vitrata in our previous studies. 23,26 In the current study, RNAi efficiency was quantified. When dsRNA was injected to the hemocoel of L4 larvae, it resulted in 80-100% RNAi efficiencies for four different IIS component genes ( Fig.…”

Insulin‐like peptides of the legume pod borer, Maruca vitrata, and their mediation effects on hemolymph trehalose level, larval development, and adult reproduction

“…Transcriptome analysis of M. vitrata larvae provides IIS components that are conserved with vertebrate insulin and other invertebrate ILP signaling components (Al Baki, Jung, & Kim, ). IIS is required for downregulation of hemolymph trehalose level and larval growth of M. vitrata (Al Baki, Jung, & Kim, ; Al Baki, Jung, Maharjan et al, ). However, ILPs in M. vitrata have not been reported yet.…”

“…IIS mediates regulation of hemolymph trehalose level of M. vitrata (Al Baki, Jung, & Kim, ). In addition, larval growth is mediated by IIS (Al Baki, Jung, Maharjan et al, ). However, ILP in M. vitrata has not been reported yet.…”

Insights into plant-beneficial traits of probiotic Pseudomonas chlororaphis isolates

“…Next, microbial survival mechanisms are addressed with a focus on biofilm formation and microbial nutrition. Although P. chlororaphis isolates are deemed nonpathogenic [6], isolates have the potential to kill plant-associated organisms such as nematodes and insects. Further, these isolates can be denitrifiers; therefore, their potential effects on ecosystem function should be carefully considered before their widespread use in the field.…”