Imaginal Disc Growth Factor 6 (Idgf6) Is Involved in Larval and Adult Wing Development in Bactrocera correcta (Bezzi) (Diptera: Tephritidae)

Abstract

In insects, imaginal disk growth factors (IDGFs), an important component of the glycoside hydrolase 18 (GH18) family of chitinases, have been reported to be associated with the maintenance of the cuticle and molting. However, there is little knowledge of their function. In this study, imaginal disk growth factor 6 (<i>Idgf6</i>), which is an <i>Idgf</i>, was first identified and cloned from the guava fruit fly <i>Bactrocera correcta</i> (Bezzi) (Diptera: Tephritidae), one of the most serious pest insects in South China and surrounding Southeast Asian countries. This gene encodes IDGF6 protein with a conserved domain similar to ChiA chitinases, the glycoside hydrolase 18 (GH18) family of chitinases, according to NCBI BLAST. Phylogenetic analysis indicated that all <i>Idgf6s</i> were highly conserved among similar species. Subsequent temporal expression profiling revealed that <i>Idgf6</i> was highly expressed in both the late-pupal and mid-adult stages, suggesting that this gene plays a predominant role in pupal and adult development. Furthermore, RNA interference experiments against <i>Idgf6</i> in <i>B. correcta</i>, which led to the specific decrease in <i>Idgf6</i> expression, resulted in larval death as well as adult wing malformation. The direct effects of <i>Idgf6</i> silencing on <i>B. correcta</i> indicated its important role in development, and <i>Idgf6</i> might be further exploited as a novel insecticide target in the context of pest management.