A novel two T-DNA binary vector allows efficient generation of marker-free transgenic plants in three elite cultivars of rice (Oryza sativa L.)

Transgenic Res. 2004 Jun;13(3):271-87. doi: 10.1023/b:trag.0000034626.22918.0a.

Abstract

A pilot binary vector was constructed to assess the potential of the 2 T-DNA system for generating selectable marker-free progeny plants in three elite rice cultivars (ZhongZuo321, Ariete and Khao Dawk Mali 105) known to exhibit contrasting amenabilities to transformation. The first T-DNA of the vector, delimited by Agrobacterium tumefaciens borders, contains the hygromycin phosphotransferase (hpt) selectable gene and the green fluorescent protein (gfp) reporter gene while the second T-DNA, delimited by Agrobacterium rhizogenes borders, bears the phosphinothricin acetyl transferase (bar) gene, featuring the gene of interest. 82-90% of the hygromycin-resistant primary transformants exhibited tolerance to ammonium glufosinate mediated by the bar gene suggesting very high co-transformation frequency in the three cultivars. All of the regenerated plants were analyzed by Southern blot which confirmed co-integration of the T-DNAs at frequencies consistent with those of co-expression and allowed determination of copy number for each gene as well as detection of two different vector backbone fragments extending between the two T-DNAs. Hygromycin susceptible, ammonium glufosinate tolerant phenotypes represented 14.4, 17.4 and 14.3% of the plants in T1 progenies of ZZ321, Ariete and KDML105 primary transformants, respectively. We developed a statistical model for deducing from the observed copy number of each T-DNA in T0 plants and phenotypic segregations in T1 progenies the most likely constitution and linkage of the T-DNA integration locus. Statistical analysis identified in 40 out of 42 lines a most likely linkage configuration theoretically allowing genetic separation of the two T-DNA types and out segregation of the T-DNA bearing the bar gene. Overall, though improvements of the technology would be beneficial, the 2 T-DNA system appeared to be a useful approach to generate selectable marker-free rice plants with a consistent frequency among cultivars.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / genetics
  • Agriculture / methods
  • Aminobutyrates
  • Blotting, Southern
  • DNA Primers
  • DNA, Bacterial / genetics*
  • Genes, Reporter
  • Genetic Linkage
  • Genetic Vectors / genetics*
  • Green Fluorescent Proteins / genetics
  • Likelihood Functions
  • Models, Statistical
  • Oryza / genetics*
  • Phenotype*
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Plants, Genetically Modified
  • Rhizobium / genetics
  • Species Specificity
  • Transformation, Genetic

Substances

  • Aminobutyrates
  • DNA Primers
  • DNA, Bacterial
  • T-DNA
  • Green Fluorescent Proteins
  • phosphinothricin
  • Acetyltransferases
  • phosphinothricin N-acetyltransferase
  • Phosphotransferases (Alcohol Group Acceptor)
  • hygromycin-B kinase