Evaluation of transgenic brinjal expressing dsRNA of flp-18 against Meloidogyne incognita
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Date
2014
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DIVISION OF NEMATOLOGY INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
Root knot nematodes (Meloidogyne species) are the most economically
important group of plant parasitic nematodes worldwide attacking nearly more than
2000 host plants. The inadequacy and limitations of current control measures
demand the development and designing of novel management strategies. The most
cost effective and sustainable method for combating their damage is to develop
resistant plants that suppress nematode development and reproduction. Recent
developments in the sequencing of several eukaryotes including M. incognita and
other plant parasitic nematodes provide an invaluable wealth of potential target gene
sequences that can be used for disrupting the nematode life cycle which in turn can
help in their management. RNA interference (RNAi) has proved to be a very
promising tool for understanding the role of these genes in the nematode physiology
and pathogenesis so that they could be the possible targets for designing nematode
resistant crops.
The FMRFamide-like peptides (FLPs) are the most diverse and widely
studied group of nematode neuropeptides. FLPs play a significant role in the
nematode nervous system as a neurotransmitters or neuromodulators and proposed
to be one of the important targets. The present study was undertaken to examine the
stability of transgenic brinjal expressing dsRNA of flp-18 against different
population densities of M. incognita. T1 plants of transgenic brinjal carrying a single
copy of flp-18 were challenged with 1, 2, 4 and 8 second stage juveniles per gram of
soil along with wild type for comparison. Bioefficacy studies performed revealed
40–70% reduction in host invasion compared to wild type plants. Likewise,
reproduction and multiplication was also reduced considerably by 41–50 and 60- 75% respectively irrespective of the population density. Molecular analyses by PCR
and qRT-PCR of the T1 transgenic plants used in the bioefficacy confirmed both for
the presence of transgene and its expression. Comparison of total proteins of
transgenic and wild type plants did not show any difference.
This is a pioneer study to demonstrate the performance of host delivered
RNAi based transgenics against various population densities. Generally, nematode
populations under field conditions are not evenly distributed and quite variable. The
population density in given field could be either at economic threshold level or
ii
below or above these levels (i.e. under ETL, ETL and above ETL). In view of this,
the present study suggests that transgenic brinjal plants expressing dsRNA of flp-18
gene could provide stable resistance to M. incognita at various population densities.
It may prove promising for the management of M. incognita under field conditions
with varying population densities.
Description
t-9026
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