Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Meloidogyne Graminicola Down Regulated the Expression of Gibberellin Related Gene to Establish Infection in Rice Root

Mohammad Hossain
Senior Scientific Officer
Plant Pathology Division, Bangladesh Rice Research Institute, Gazipur-1701, Bangladesh

Abstract/ Executive Summary:

The down regulation of OsGA20ox indicated that nematode infection resulted in inhibition of GA biosynthesis in the leaves of Taichung 65. The basic helix-loop-helix transcription factor AK073385 is highly responsive to GA which could be a good indicator for the presence of GA in rice; indirectly, the gene could serve as indicator of GA biosynthesis. The PR10/PBZ1 (probenazole inducible 1) is a GA inducible gene which has been shown to be regulated after blast fungus infection in rice. They were upregulated in leaves at 2 dpi which is contradictory to the downregulation of OsGA20ox. They were not differentially expressed in leaves at 6 dpi. The gene Osgid1-7and PR10/PBZ1 were significantly higher expressed in whole roots at 2 and 6 dpi, indicating that those genes were triggered by nematode infection. Expression of PR10/PBZ1 and AK073385 genes were inhibited in the root tip at 2 dpi and 6 dpi. However, PR10/PBZ1 was upregulated later after infection (at 6 dpi) in root tissue. Systemic expression of PR10/PBZ1 was downregulated at early stage of infection in root tissue but higher expressed at later stage (6 dpi) of infection indicating that it might be late responsive gene. PR10/PBZ1 is also responsive to other hormones. Jwa et al. (2006) reported that PR10/PBZ1 was potently up-regulated by JA, ET, KN (kinetin), CN (cantharidin), EN (endothall) and fungal pathogen M. grisea in rice. Genes encoding for PR-proteins, products of secondary plant metabolism and phytoalexins, that are known as defence genes are induced during nematode attack. The transcripts of the GA responsive basic-helix-loop-helix gene AK073385 were 44 times upregulated in root tissues 24 h of GA foliar application (data not shown) but downregulated in root tissues both at 2 dpi and 6dpi when infected with M. graminicola. This confirms that the gene is indeed upregulated by GA and that nematode infection might inhibit this. There was no difference in the expression of GA signalling gene Osgid1-3 after infection, neither in root tip nor leaf tissue. This indicates that Taichung 65 plants do not try or is not able to induce Osgid1-3 expression after infection of M. graminicola. The expression of GA signalling gene Osgid1-7 was significantly higher only in whole root at 2 dpi but not in leaves or root tips. Even this gene was not differentially expressed in root and leaf tissues at later stage (6 dpi) of infection. The nematode inhibited biosynthesis of OsGA20ox in leaves at 2 dpi and, in both of leaves and roots at 6 dpi. The GA response gene AK073385 was also less expressed in root tip at 6 dpi. These might help M. graminicola to continue their infection in Taichung 65.

Keywords: Meloidogyne graminicola, Down regulated expression, Gibberellin, Rroot

Location: Plant Pathology Division, BRRI HQ

Start Date: 01-07-2010

End Date: 30-06-2011

Program Area: Pest Management

Commodity: Rice

Objectives:

To know the expression of gene in rice during nematode infection

Methodology:

Total RNA extraction from plant tissue: Non-infected (control) and M. graminicola infected Taichung 65 plants were used to analyse the expression of selected genes. Whole root, root tip and shoot RNA was extracted at 2 dpi (day post inoculation) and 6 dpi using TRIzol (Invitrogen, Carlsbad, USA) following the manufacturer’s instructions and this RNA was subsequently used for first strand cDNA synthesis with the aid of Superscript ΙΙ (Invitrogen) using oligo dT primers. Quantitative real-time RT-PCR (qRT-PCR): The qRT-PCR with 3 replicates of each sample was performed to compare the quantitative expression of genes between samples involved in plant defense. Quantification of rice gene expression in response to infection with M. graminicola: The difference in relative expression of a target gene (gene of interest) normalized to a reference gene index between a sample of interest and a control sample (calibrator, C) was statistically determined by relative expression software tool, REST-384© based on Ct (Threshold cycle or Crossing Point) deviation and real-time PCR efficiency. The decision on significance was determined on α = 0.05 level.

Source of Information: Proceedings of BRRI Annual Internal Review for 2010-11

Article Link (Online Journal):

Funding Source:

1. Government

Budget:

Total Budget (Tk.) :

Achievement/Findings:

The expression of GA signalling gene Osgid1-7 was significantly higher only in whole root at 2 dpi but not in leaves or root tips. Even this gene was not differentially expressed in root and leaf tissues at later stage (6 dpi) of infection. The nematode inhibited biosynthesis of OsGA20ox in leaves at 2 dpi and, in both of leaves and roots at 6 dpi. The GA response gene AK073385 was also less expressed in root tip at 6 dpi. These might help M. graminicola to continue their infection in Taichung 65.

Knowledge Management: Report/Proceedings