Maize (Zea mays) genetic transformation by co-cultivating germinating seeds with Agrobacterium tumefaciens

A novel plant genetic transformation method for maize (Zea mays) is reported. Using a scalpel, germinating seeds were wounded in the meristem and co-cultivated with an Agrobacterium tumefaciens strain harbouring a Ti plasmid. Seedlings produced from the treatment were screened by hygromycin selection. Fertile transgenic T(0) and T(1) plants were obtained. PCR amplification, PCR-Southern and Southern-blot analysis showed that the foreign gene had been introduced into the inbreds of maize. About 29% of T(0) seedlings examined were found to be transgenic, although the overall transformation was only 0.6% when total treated seeds were taken into account. The method circumvented tedious and prolonged tissue-culture steps, is simple and can be readily integrated into conventional plant breeding programs.