Plant Tissue Cult. 9(1) : 35-43, 1999 (June)

Stable Transformation of Jute (Corchorus capsularis L. var CVL-1) Calli and High Efficiency Marker Gene Insertion in Explants

M. Rafiqul Islam, Mahboob H. Khan, Fatema T. Zohra, M. Bakhtiar Hossain and Zeba I. Seraj¹

Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh

Key words: Meristematic zone, ?-glucuronidase, Hygromycin Phosphotransferase, Chimerism, Jute, Transformation

Abastract

Efficiency of foreign gene insertion was found to be high depending upon the infection zone in five-day-old, jute-seedling explants. Average transformation efficiency was found to be 91% in hypocotyls upper-tips and 61% in right or left cotyledonary-petiole tips as judged by transient assay. Regeneration was found to occure from any one of these three explants from the same seedling indicating that the meristematic zone in jute is at the junction between hypocotyls, cotyledonary-petiols and epicotyl. Transfoemed calli were easily obtained from cotyledonary-petiol explants with efficencies of 20-60% depending on the type of vector used. Integration of the hygromycin phosphotransferase (HPT) gene in callus DNA was shown by amplification of HPT-primer specific DNA. However, regenerated plantlets failed to grow in selection medium for longer than two months, either due to chimeric nature of transformed plantlets or poor expression of selectable marker gene in meristematic tissue. Chimerism in transformed plantlets arises because regeneration from explants takes place within 14 days after Agrobacterium infection. Therefore regeneration studies were also done to increase the time required for regeneration and also to obtain regeneration from subcultured calli.

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