Dataset Information

Adaptation of Spodoptera exigua larvae to plant proteinase inhibitors by induction of gut proteinase activity insensitive to inhibition.

ABSTRACT: Tobacco plants were transformed with a cDNA clone of chymotrypsin/trypsin-specific potato proteinase inhibitor II (PI2) under the control of a constitutive promoter. Although considerable levels of transgene expression could be demonstrated, the growth of Spodoptera exigua larvae fed with detached leaves of PI2-expressing plants was not affected. Analysis of the composition of tryptic gut activity demonstrated that only 18% of the proteinase activity of insects reared on these transgenic plants was sensitive to inhibition by PI2, whereas 78% was sensitive in insects reared on control plants. Larvae had compensated for this loss of tryptic activity by a 2.5-fold induction of new activity that was insensitive to inhibition by PI2. PI2-insensitive proteolytic activity was also induced in response to endogenous proteinase inhibitors of tobacco; therefore, induction of such proteinase activity may represent the mechanism by which insects that feed on plants overcome plant proteinase inhibitor defense.

SUBMITTER: Jongsma MA

PROVIDER: S-EPMC41282 | biostudies-other | 1995 Aug

REPOSITORIES: biostudies-other

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Adaptation of Spodoptera exigua larvae to plant proteinase inhibitors by induction of gut proteinase activity insensitive to inhibition.

Jongsma M A MA Bakker P L PL Peters J J Bosch D D Stiekema W J WJ

Proceedings of the National Academy of Sciences of the United States of America 19950801 17

Tobacco plants were transformed with a cDNA clone of chymotrypsin/trypsin-specific potato proteinase inhibitor II (PI2) under the control of a constitutive promoter. Although considerable levels of transgene expression could be demonstrated, the growth of Spodoptera exigua larvae fed with detached leaves of PI2-expressing plants was not affected. Analysis of the composition of tryptic gut activity demonstrated that only 18% of the proteinase activity of insects reared on these transgenic plants ...[more]

PMID: 7644535

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Project description:BACKGROUND:To understand the genetic mechanisms of insect herbivory, the transcriptional response of insects feeding on different host plant species has to be studied. Here, we generated gene expression data of the generalist herbivore Spodoptera exigua (Hübner) feeding on three selected host plant species and a control (artificial diet). The host plant species used in this study -cabbage (Brassica oleracea), maize (Zea mays) and tobacco (Nicotiana tabacum)- are members of different plant families that each employ specific defence mechanisms and toxins. RESULTS:Spodoptera exigua larvae had a higher growth rate, indicator for herbivore success, when feeding on Z. mays compared to larvae feeding on B. oleracea or N. tabacum. Larvae feeding on the different host plant species showed divergent transcriptional responses. We identified shared and unique gene expression patterns dependent of the host plant species the larvae fed on. Unique gene expression patterns, containing uniquely upregulated transcripts including specific detoxification genes, were found for larvae feeding on either B. oleracea or N. tabacum. No diet-specific gene cluster was identified for larvae feeding on the host for which larvae showed optimal herbivore success, Z. mays, or artificial diet. In contrast, for larvae feeding on hosts for which they showed low herbivore success, specific diet-dependent gene clusters were identified. Functional annotation of these clusters indicates that S. exigua larvae deploy particular host plant-specific genes for digestion and detoxification. CONCLUSIONS:The lack of a host plant-specific gene activity for larvae feeding on Z. mays and the artificial diet suggest a general and non-specific gene activity for host plants with optimal herbivore success. Whereas the finding of specific gene clusters containing particular digestion and detoxifying genes expressed in larvae feeding on B. oleracea and N. tabacum, with low herbivore success, imply a host plant-specific gene activity for larvae feeding on host plants with suboptimal herbivore success. This observation leads to the conclusion that a polyphagous herbivore is able to feed on a large variation of host plants due to the flexibility and diversity of genes involved in digestion and detoxification that are deployed in response to particular host plant species.

Dataset Information

Adaptation of Spodoptera exigua larvae to plant proteinase inhibitors by induction of gut proteinase activity insensitive to inhibition.

Publications

Adaptation of Spodoptera exigua larvae to plant proteinase inhibitors by induction of gut proteinase activity insensitive to inhibition.

Similar Datasets

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