U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Calluses initiated from thin mature embryo fragments are suitable targets for wheat transformation as assessed by long-term GUS expression studies

Delporte, F., Li, S., Jacquemin, J.M.
Plant cell, tissue, and organ culture 2005 v.80 no.2 pp. 139-149
genetic transformation, dose response, biolistics, transgenic plants, embryo (plant), Agrobacterium radiobacter, explants, wheat, gene expression, Triticum aestivum, 2,4-D, micropropagation, enzyme activity, in vitro regeneration, culture media, beta-glucuronidase, callus
Microprojectile- or Agrobacterium-mediated DNA delivery into calluses initiated from immature embryos has proven to be effective in transforming wheat. Yet, obtaining a large number of high quality immature embryos throughout the year is a laborious and delicate process. To circumvent these limitations, we propose an alternative technique applying the particle bombardment technology to calluses derived from fragmented mature embryos rather than immature tissues. The phosphinothricin acetyl transferase (bar) and beta-glucuronidase (gus) genes were used as selectable and screenable marker genes, respectively, to assess and optimise the performance of the proposed technique. Primary requirement for genetic transformation method development, the regeneration capacity of bombarded calluses was established. A preculture duration of 6 days was identified as optimal for DNA uptake and beta-glucuronidase (GUS) expression. The highest activity was recorded when calluses were selected. Long-term GUS expression studies (1-7 weeks subsequent to bombardment), showed differentiated behaviours for tissues obtained from mature versus immature embryos. Notably, mature embryos exhibited the greatest number of cells stably expressing the reporter gene, thus providing an excellent source material for developing a stable transformation procedure.