Differential gene expression in gall midge susceptible rice genotypes revealed by suppressive subtraction hybridization (SSH) cDNA libraries and microarray analysis.

Nidhi Rawat,Jagadish S Bentur,Suresh Nair,Chiruvuri Naga Neeraja

doi:10.1186/1939-8433-5-8

Abstract

BackgroundA major pest of rice, the Asian rice gall midge (Orseolia oryzae Wood-Mason), causes significant yield losses in the rice growing regions throughout Asia. Feeding by the larvae induces susceptible plants to produce nutritive tissue to support growth and development. In order to identify molecular signatures during compatible interactions, genome wide transcriptional profiling was performed using SSH library and microarray technology.ResultsResults revealed up-regulation of genes related to primary metabolism, nutrient relocation, cell organization and DNA synthesis. Concomitantly, defense, secondary metabolism and signaling genes were suppressed. Further, real-time PCR validation of a selected set of 20 genes, in three susceptible rice varieties (TN1, Kavya and Suraksha) during the interaction with the respective virulent gall midge biotypes, also revealed variation in gene expression in Kavya as compared to TN1 and Suraksha.ConclusionsThese studies showed that virulent insects induced the plants to step up metabolism and transport nutrients to their feeding site and suppressed defense responses. But Kavya rice mounted an elevated defense response during early hours of virulent gall midge infestation, which was over-powered later, resulting in host plant susceptibility.Electronic supplementary materialThe online version of this article (doi:10.1186/1939-8433-5-8) contains supplementary material, which is available to authorized users.

Highlights

A major pest of rice, the Asian rice gall midge (Orseolia oryzae Wood-Mason), causes significant yield losses in the rice growing regions throughout Asia
Characterization of gall midge induced ESTs from the TN1 Suppressive Subtraction Hybridization (SSH) library We began the investigation by comparing gene expression in un-infested and infested TN1 plants using SSH
After removing low quality sequences and short sequence reads, 552 ESTs were considered for sequence assembly to reveal 309 singletons and the remaining 243 sequences were assembled in 131 contigs [Additional file 1: Table S1, Rawat et al] using the MacVector program

Summary

Introduction

A major pest of rice, the Asian rice gall midge (Orseolia oryzae Wood-Mason), causes significant yield losses in the rice growing regions throughout Asia. Gall-forming insects are known to manipulate their host plants and induce changes in source-sink relationships in a way that is beneficial to larval development Since insects derive their nutrition from gall tissue, the gall becomes a sink for different nutrients and energy that is vital for the insect’s growth Even vascular tissues may be modified by gall induction, ensuring a supply of nutrients and water for the inducing insect (Meyer 1969) These insects, through feeding or oviposition, cause differentiation of a special nutritive tissue that is rich in sugars, proteins, and lipids, as well as a range hydrolyzing enzymes These insects, through feeding or oviposition, cause differentiation of a special nutritive tissue that is rich in sugars, proteins, and lipids, as well as a range hydrolyzing enzymes (Raman 2003; Raman and Ananthakrishnan. 1983)

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