Dataset Information

Capsicum annuum proteinase inhibitor ingestion negatively impacts the growth of sorghum pest Chilo partellus and promotes differential protease expression.

ABSTRACT:

Background

Chilo partellus is an important insect pest infesting sorghum and maize. The larvae internalize in the stem, rendering difficulties in pest management. We investigated the effects of Capsicum annuum proteinase inhibitors (CanPIs) on C. partellus larvae by in-vitro and in-vivo experiments.

Methods

Recombinant CanPI-7 (with four-Inhibitory Repeat Domains, IRDs), -22 (two-IRDs) and insect proteinase activities were estimated by proteinase assays, dot blot assays and in gel activity assays. Feeding bioassays of lab reared C. partellus with CanPI-7 and -22 were performed. C. partellus proteinase gene expression was done by RT-PCR. In-silico structure prediction of proteinases and CanPI IRDs was carried out, their validation and molecular docking was done for estimating the interaction strength.

Results

Larval proteinases of C. partellus showed higher activity at alkaline pH and expressed few proteinase isoforms. Both CanPIs showed strong inhibition of C. partellus larval proteinases. Feeding bioassays of C. partellus with CanPIs revealed a dose dependent retardation of larval growth, reduction of pupal mass and fecundity, while larval and pupal periods increased significantly. Ingestion of CanPIs resulted in differential up-regulation of C. partellus proteinase isoforms, which were sensitive to CanPI-7 but were insensitive to CanPI-22. In-silico interaction studies indicated the strong interaction of IRD-9 (of CanPI-22) with Chilo proteinases tested.

Conclusions

Of the two PIs tested, CanPI-7 prevents induction of inhibitor insensitive proteinases in C. partellus so it can be explored for developing C. partellus tolerance in sorghum.

General significance

Ingestion of CanPIs, effectively retards C. partellus growth; while differentially regulating the proteinases.

SUBMITTER: Jadhav AR

PROVIDER: S-EPMC5614469 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Publications

<i>Capsicum annuum</i> proteinase inhibitor ingestion negatively impacts the growth of sorghum pest <i>Chilo partellus</i> and promotes differential protease expression.

Jadhav Abhilash R AR War Abdul R AR Nikam Ashwini N AN Adhav Anmol S AS Gupta Vidya S VS Sharma Hari C HC Giri Ashok P AP Tamhane Vaijayanti A VA

Biochemistry and biophysics reports 20161006

<h4>Background</h4><i>Chilo partellus</i> is an important insect pest infesting sorghum and maize. The larvae internalize in the stem, rendering difficulties in pest management. We investigated the effects of <i>Capsicum annuum</i> proteinase inhibitors (CanPIs) on <i>C. partellus</i> larvae by <i>in-vitro</i> and <i>in-vivo</i> experiments.<h4>Methods</h4>Recombinant CanPI-7 (with four-Inhibitory Repeat Domains, IRDs), -22 (two-IRDs) and insect proteinase activities were estimated by proteinase ...[more]

PMID: 28955969

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Project description:BackgroundWound-inducible Pin-II Proteinase inhibitors (PIs) are one of the important plant serine PIs which have been studied extensively for their structural and functional diversity and relevance in plant defense against insect pests. To explore the functional specialization of an array of Capsicum annuum (L.) proteinase inhibitor (CanPIs) genes, we studied their expression, processing and tissue-specific distribution under steady-state and induced conditions. Inductions were performed by subjecting C. annuum leaves to various treatments, namely aphid infestation or mechanical wounding followed by treatment with either oral secretion (OS) of Helicoverpa armigera or water.ResultsThe elicitation treatments regulated the accumulation of CanPIs corresponding to 4-, 3-, and 2-inhibitory repeat domains (IRDs). Fourty seven different CanPI genes composed of 28 unique IRDs were identified in total along with those reported earlier. The CanPI gene pool either from uninduced or induced leaves was dominated by 3-IRD PIs and trypsin inhibitory domains. Also a major contribution by 4-IRD CanPI genes possessing trypsin and chymotrypsin inhibitor domains was specifically revealed in wounded leaves treated with OS. Wounding displayed the highest number of unique CanPIs while wounding with OS treatment resulted in the high accumulation of specifically CanPI-4, -7 and -10. Characterization of the PI protein activity through two dimensional gel electrophoresis revealed tissue and induction specific patterns. Consistent with transcript abundance, wound plus OS or water treated C. annuum leaves exhibited significantly higher PI activity and isoform diversity contributed by 3- and 4-IRD CanPIs. CanPI accumulation and activity was weakly elicited by aphid infestation yet resulted in the higher expression of CanPI-26, -41 and -43.ConclusionsPlants can differentially perceive various kinds of insect attacks and respond appropriately through activating plant defenses including regulation of PIs at transcriptional and post-translational levels. Based on the differentially elicited CanPI accumulation patterns, it is intriguing to speculate that generating sequence diversity in the form of multi-IRD PIs is a part of elaborative plant defense strategy to obtain a diverse pool of functional units to confine insect attack.