Inheritance and expression of cry1Ac gene in bt eggplant backcross populations in Philippines

Issue Date

12-2012

Abstract

The inheritance and expression of cry1Ac gene, isolated from Bacillus thuringiensis (Bt) in backcross lines derived from hybridization of Bt eggplant even 'EE-1' with two non- Bt Philippine genotype were investigated using event-specific PCR analysis and lateral flow immunoassay or gene strip test. Segregation ratio of the cry1Ac transgene sequences and its expressed protein in majority of backcross F₁ and F₂ lines tested fit the expected 1:1 and 3:1 Mendelian phenotypic ratio, respectively, for a single dominant gene. In addition, the observed segregation ratio remained stable over three successive sexual generations. The PCR analysis and gene strip test results indicated that the cry1Ac gene from 'EE-1' has remained stably integrated in the genome of the backcross progenies and faithfully transmitted and expressed as a single dominant gene through sexual reproduction. Quantitative ELISA was also used to determine the level of Cry1Ac protein expression in different eggplant tissues of Bt-positive BC₃F₁ lines grown under confined field conditions. Higher levels of Cry1Ac protein were detected in the flowers and terminal leaves than in the immature fruits and stem, while the lowest levels were found in the roots. Genotype and parental background effects on the level of Cry1Ac protein expression were also assessed. Cry1Ac concentrations in all eggplant tissue analyzed were significantly different between the two crosses. This study demonstrated that Bt cry1Ac gene from 'EE-1' can be stably inherited and expressed through conventional backcrossing with Philippine varietes.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

37

Issue

3

Page

1-9

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables, graph

Language

English

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