Inheritance and expression of transgenes in T-2 and T-3 generations of Lotus corniculatus transformed using Agrobacterium tumefaciens

The inheritance and expression of the reporter gene uidA, encoding beta-glu curonidase (GUS), was previously analysed in the T-1 generation of 25 indep endent transformed lines of Lotus corniculatus cv. Leo. In the work reporte d here, GUS activity in various tissues of seven of these lines was tested in the T-2 generation. Four representative lines were chosen for more detai led study in the T-3 generation. Lines 25 and 38 had multiple, independentl y segregating transgene inserts; lines 24 and 39 appeared to transmit one s egregating transgene insert to their T-1 progeny, although transgene expres sion was low and was detected in fewer seedlings than expected in line 39. The uidA gene was inherited and expressed in seedlings of T-1, T-2 and T-3 generations of all four lines. In all lines, transgene expression varied be tween tissues, with more embryos than seedlings having detectable GUS activ ity. Studies in the T-2 generation showed that use of transgenic plants as female or male parents altered the frequency of expression of the transgene in progeny. By contrast, in the T-3 generation the use of transgenic plant s as female or male parents did not effect either frequency of transmission , or expression of the transgene, in any of the four lines. Transgene inher itance was also similar among individual pods within flower heads and betwe en individual flower heads.