Gene transfer via pollen-tube pathway for anti-fusarium wilt in watermelon.

In order to obtain transgenic fusarium wilt resistant watermelon plants, squash DNA was introduced into the ovaries of watermelon plants via the pollen-tube pathway. The introduction of foreign genes into ovaries was accomplished using co-transformation with the CaMV35S-GUS as a marker. Transformed watermelon plants contained integrated copies of the GUS activity and the seeds of transformed progeny produced a blue color when stained with 5-bromo-4-chloro-3-indolyl glucuronide, whereas seeds from untransformed control plants did not. Of 200 transformed seedlings, ten were wilt resistant. The presence of the GUS activity in the genome of stable transgenic seedlings was confirmed by Southern blot analysis. Furthermore, the generation of random amplified polymorphic DNA (RAPD) fingerprints using primers with embedded restriction sites showed amplification products unique to these transgenic plants. Primers OPA-1 and OPA-9 gave distinct band patterns of genomic DNA using the polymerase chain reaction.