Inheritance and expression of Cry2Aa gene in transgenic chickpea (Cicer arietinum L.)

Abstract

The transmission and expression of Cry2Aa gene driven by Arabidopsis Rubisco small sub unit gene (atsA1) promoter (AraSSU) in chickpea was previously analysed in the T1 generation of 13 independent transgenic lines. It is desirable that transmission of transgene(s) by maternal and paternal parents be consistent and predictable. We selected three representative lines, BS5A, BS6H, and BS6L to study transgene transmission and expression up to the T6 generation. The line BS5A has tightly linked multiple transgene inserts, while lines BS6H and BS6L appeared to transmit one segregating transgenic insert to their progeny. The Cry2Aa gene was inherited up to the T6 generation in all three lines tested. In the case of line BS5A, the level of expression of Cry2Aa protein varied within the T1 progeny. The expression of the Cry2Aa protein was found high in progeny of the lines, BS6H and BS6L and the lines showed stable and predictable expression of Cry2Aa protein up to T6 generation. Surprisingly, we have been able to identify homozygous progeny in line BS5A, while lines BS6H and BS6L are segregating even in the T6 generation. Loss or silencing of Cry2Aa gene under the control of AraSSU promoter was not observed and the transgene inherited and expressed stably in chickpea.