Articles
STABLE INTEGRATION AND EXPRESSION OF CHITINASE GENE IN TRANSGENIC TOMATO
Article number
929_53
Pages
373 – 379
Language
English
Abstract
Early blight caused by Alternaria solani is a major production constraint in the cultivation of tomato.
Conventional breeding has met with limited success.
Therefore the transformation of tomato with gene encoding pathogen cell wall degrading enzyme chitinase isolated from Trichoderma harzianum was carried out for expression of resistance against A. solani. The present study was done to identify homozygous lines with stable and high transgene expression from the progeny of primary transformants (T1) of tomato cultivar Arka vikas. T1 plants were screened by PCR using gene specific primer. 15 T1 plants were selected based on percent disease index (PDI) and similarity to parent phenotype for advancing to T2 generation and two homozygous lines were identified.
Gene expression analysis for chitinase gene was carried out in randomly chosen plants from the progeny of two T1 homozygous lines and one T1 hemizygous line through quantitative RT PCR. The chitinase gene expression in plants of two homozygous lines was 2.5-4.0× higher than that of hemizygous lines.
The seedlings of homozygous plants in T2 and T3 generation were also screened for disease expression by in vitro leaf bioassay as well as challenge inoculation with Alternaria solani.
Conventional breeding has met with limited success.
Therefore the transformation of tomato with gene encoding pathogen cell wall degrading enzyme chitinase isolated from Trichoderma harzianum was carried out for expression of resistance against A. solani. The present study was done to identify homozygous lines with stable and high transgene expression from the progeny of primary transformants (T1) of tomato cultivar Arka vikas. T1 plants were screened by PCR using gene specific primer. 15 T1 plants were selected based on percent disease index (PDI) and similarity to parent phenotype for advancing to T2 generation and two homozygous lines were identified.
Gene expression analysis for chitinase gene was carried out in randomly chosen plants from the progeny of two T1 homozygous lines and one T1 hemizygous line through quantitative RT PCR. The chitinase gene expression in plants of two homozygous lines was 2.5-4.0× higher than that of hemizygous lines.
The seedlings of homozygous plants in T2 and T3 generation were also screened for disease expression by in vitro leaf bioassay as well as challenge inoculation with Alternaria solani.
Authors
J.B. Mythili, P.R. Rajeev, G. Ganeshan, P. Chowdappa, S. Yadav , P.H. Ramanjini Gowda
Keywords
transgenic tomato, early blight, Trichoderma harzianum, chitinase
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