Development of a Novel Plant Transformation Method for Selected Crops

Abstract

Genetic transformation of crops is a straight forward method in crop improvement. Agrobacterium is the unique cellular organism which is capable of transferring genetic material to plants. Callus or explant transformation followed by transgenic plant regeneration is the most common Agrobacterium mediated transformation method. We introduced an alternative novel Agrobacterium mediated transformation method through seedling transformation. Flowering locus T [FT) and VlmybA2 for induction of early flowering and purple pigmentation respectively were used to check the effectiveness of seedling transformation method for selected monocot and dicot crops (rice, anthurium and 3 Citrussp.) byAgrobacterium. Rice seedlings of 10cm, Citrus seedlings less than 1cm and anthurium seedlings of 2cm height were used for transformation. A few albino plants were observed in putative chimeric rice seedlings of 35S: FT and 35S: VlmybA2. Purple pigmentation was clearly visible only on base of the stem of putative VImybA2 rice seedlings in contrast to controls. Putative VlmybA2 Citrus seedlings produced purple pigmentation after 2 weeks of transformation. They could not survive due to contamination. During the limited experimental period of 2 months, signs of early flowering (shortened internodes and early axillary buds) were observed in Citrus plants. Significant growth retardation was observed in putative chimeric anthurium seedlings transformed by 35S: FT and 35S \VlmybA2 after one month of transformation. Soil isolates of above plants did not reveal the Agrobacterium indicating the potential of this method for bio safety. Based on the above results, seedling transformation could be effective for Citrus and rice. This experiment is continued with further testing for development of the seedling transformation method as an alternative novel method.