| Full text | |
| Author(s): |
Brioschi, Daniela
;
Nadalini, Larissa D.
;
Bengtson, Mario H.
;
Sogayar, Mari Cleide
;
Moura, Daniel S.
;
Silva Filho, Marcio C.
[6]
Total Authors: 6
|
| Document type: | Journal article |
| Source: | Insect Biochemistry and Molecular Biology; v. 37, n. 12, p. 1283-1290, Dec. 2007. |
| Field of knowledge: | Biological Sciences - Biochemistry |
| Abstract | |
The existence of a diverse serine proteinase gene family in lepidopteran insects suggests they play a significant role in the insect adaptation to plant proteinase inhibitors. These proteinases have been shown to be involved in the process of proteolytic digestion in insect larvae. We carried out a selective transcriptome study of midguts from Spodoptera frugiperda larvae fed on a diet supplemented with soybean proteinase inhibitor (SPI). Using subtracted cDNA libraries made of gut-expressed transcripts, a total of 2100 partial sequences were obtained, of those 38% were related to digestive process. Two large and diverse groups of chymotrypsins and trypsins were obtained, and some of these proteinase-encoding genes were further characterized by quantitative RT-PCR. The transcription analyses revealed two groups: one group of genes constitutively expressed in the control larvae that is up regulated by introducing SPI to the diet, and a second group that is absent in the control but is induced by the SPI-rich diet. This observation suggests that adaptation of S. frugiperda to SPI involves de novo synthesis and also up regulation of existing enzymes. Proteases from intestines of larvae reared on a diet with SPI showed insensitivity to the inhibitor. The proteases were also insensitive to a broad-spectrum potato proteinase inhibitor preparation. We propose that adaptation of S. frugiperda to SPI follows a "shotgun" approach, based on a general up regulation of a large set of endoproteinases. (AU) | |