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Identification of potential target genes in mustard aphid (Lipaphis erysimi) for developing RNAi mediated resistance in host plant

KrishiKosh

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Title Identification of potential target genes in mustard aphid (Lipaphis erysimi) for developing RNAi mediated resistance in host plant
M Sc
 
Creator DHIMAN CHAKRAVARTY
 
Contributor R. C. Bhattacharya
 
Subject ---
 
Description T-8422
Mustard (Brassica sp) is one of the most important oilseed crop grown in India. 26%
of edible oil demand in India is met by mustard. Apart from the various abiotic
stresses, mustard aphid (Lipaphis erysimi) is a major biotic stress limiting the
production of mustard crop in India as well as in other countries. According to 2010
annual report published by AICRP on Rapeseed and Mustard, L. erysimi causes about
36% annual yield loss in Brassica juncea. Development of aphid resistant cultivar
through conventional breeding approaches failed to give much success due lack of
resistance genes in the crossable gene pool. Even transgenic strategies expressing
insecticidal proteins such as Bt endotoxin, lectins, protease inhibitors etc. also could
not provide good result. Under this background, new strategies like RNAi, antisence
RNA technology assumes high importance for developing insect resistance. RNAi
requires sequence information for the target organism. But in case of mustard aphid
the sequence resource is very poor. Keeping this in mind, the present study has been
aimed to generate sequence information and to identify suitable RNAi target gene in
L. erysimi. For these purposes firstly cDNA library has been prepared from aphids of
all stages. cDNA clones have been sequenced and from the annotation studies finally
112 genes have been identified. 75% of the genes were found to be homologous with
pea aphid, Acyrthosiphon pisum. From the library sequences, 6 genes were selected
based their role in physiology and metabolism. Semi quantitative reverse transcription
PCR (RT-PCR) was performed to observe stage specific expression of these genes.
Result showed that two out of six genes, cuticle protein and ecdyson receptor A
expresses maximally during nymph stage. So, these two genes can be targeted for
RNAi mediated down regulation. Transgenic Brassica expressing siRNAs specific to
these aphid genes are expected to be aphid resistant.
 
Date 2016-11-03T15:05:49Z
2016-11-03T15:05:49Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/83713
 
Format application/pdf
 
Publisher IARI, NATIONAL RESEARCH CENTRE ON PLANT BIOTECHNOLOGY