Characterization of the Mamestra configurata (Lepidoptera: Noctuidae) larval midgut protease complement and adaptation to feeding on artificial diet, Brassica species, and protease inhibitor

Abstract

The midgut protease profiles from 5th instar Mamestra configurata larvae fed various diets (standard artificial diet, low protein diet, low protein diet with soybean trypsin inhibitor [SBTI], or Brassica napus) were characterized by one-dimensional enzymography in gelatin gels. The gut protease profile of larvae fed B. napus possessed protease activities of molecular masses of approximately 33 and 55 kDa, which were not present in the guts of larvae fed artificial diet. Similarly, larvae fed artificial diet had protease activities of molecular masses of approximately 21, 30, and 100 kDa that were absent in larvae fed B. napus. Protease profiles changed within 12 to 24 h after switching larvae from artificial diet to plant diet and vice versa. The gut protease profiles from larvae fed various other brassicaceous species and lines having different secondary metabolite profiles did not differ despite significant differences in larval growth rates on the different host plants. Genes encoding putative digestive proteolytic enzymes, including four carboxypeptidases, five aminopeptidases, and 48 serine proteases, were identified in cDNA libraries from 4th instar M. configurata midgut tissue. Many of the protease-encoding genes were expressed at similar levels on all diets; however, three chymoptrypsin-like genes (McSP23, McSP27, and McSP37) were expressed at much higher levels on standard artificial diet and diet containing SBTI as was the trypsin-like gene McSP34. The expression of the trypsin-like gene McSP50 was highest on B. napus. The adaptation of M. configurata digestive biochemistry to different diets is discussed in the context of the flexibility of polyphagous insects to changing diet sources.

Insect intestinal mucins and serine proteases associated with the peritrophic matrix from feeding, starved and moulting Mamestra configurata larvae

“…4), which are within the size ranges reported for M. configurata digestive proteases (Hegedus et al. , 2003; Erlandson et al. , 2009).…”

Characterization of cDNAs Encoding Serine Proteases and Their Transcriptional Responses to Cry1Ab Protoxin in the Gut of Ostrinia nubilalis Larvae

“…The tissue specific expression patterns were further supported by their sensitivity or insensitivity to Kunitz-type soybean trypsin inhibitor [58]. Among the trypsins of A. ipsilon , H. armigera , and H. zea , those in Try-G1 and Try-G3 were sensitive to the PI, whereas trypsins in Try-G2 were insensitive to PIs [13], [29], [59]. The foregut-midgut (Try-G2) trypsins may have developed insensitivity to PIs because they are the first to access and digest food sources containing PIs, thereby protecting the midgut-hindgut (Try-G3) trypsins, which are PI sensitive.…”

“…Lepidopteran gene expansions have been found in Helicoverpa zea [13], Manduca sexta [18], Choristoneura fumiferana [19], Plodia interpunctella [20], Helicoverpa armigera [21], Agrotis ipsilon [14], [22], Sesamia nonagrioides [23], Tineola bisselliella [24], Bombyx mori [25], Spodoptera litura [26], Bombyx mandarina [27], S. frugiperda [28], Mamestra configurata [29], O. nubilalis [30], and Heliothis virescens [31]. Protease gene expansions are proposed to have occurred in response to the evolutionary selection pressure of plant inhibitors [32].…”

Dietary and phylogenetic correlates of digestive trypsin activity in insect pests

“…If duplication is selectively neutral, accumulation of mutations leads to the loss of function or expression of the paralogous genes (Zhang, ). Inactive trypsins with amino acid substitutions or deletions in the catalytic triad have been described in multigene families of phytophagous Lepidoptera (Mazumdar‐Leighton et al., ; Erlandson et al., ) and other insect orders (Oliveira‐Neto et al., ; Marshall et al., ; Bao et al., ; Spit et al., ). A higher number of these catalytically inactive trypsins is related to a relaxed selection for high amounts of trypsin (Bao et al., ).…”