title: Differential gene expression in gall midge susceptible rice genotypes revealed by suppressive subtraction hybridization (SSH) cDNA libraries and microarray analysis.
abstract: BACKGROUND
  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. 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.
  
  
  RESULTS
  Results 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.
  
  
  CONCLUSIONS
  These 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.
authors.affiliation: Directorate of Rice Research, Rajendranagar, Hyderabad, 500 030, AP, India.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Rawat
authors.affiliation: Directorate of Rice Research, Rajendranagar, Hyderabad, 500 030, AP, India.
authors.forename: Chiruvuri Naga
authors.initials: CN
authors.lastname: Neeraja
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India. suresh@icgeb.res.in.
authors.forename: Suresh
authors.initials: S
authors.lastname: Nair
authors.affiliation: Directorate of Rice Research, Rajendranagar, Hyderabad, 500 030, AP, India. jbentur@yahoo.com.
authors.forename: Jagadish S
authors.initials: JS
authors.lastname: Bentur
keywords: Compatible interaction; Gall midge biotypes; Metabolic pathways; Real-time PCR; Susceptibility