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The T‐DNA integration pattern in Arabidopsis transformants is highly determined by the transformed target cell
Author(s) -
De Buck Sylvie,
Podevin Nancy,
Nolf Jonah,
Jacobs Anni,
Depicker Ann
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2009.03942.x
Subject(s) - transformation (genetics) , biology , agrobacterium tumefaciens , dna , agrobacterium , transfer dna , plasmid , arabidopsis thaliana , genetics , dna replication , gene , microbiology and biotechnology , mutant
Summary Transgenic loci obtained after Agrobacterium tumefaciens ‐mediated transformation can be simple, but fairly often they contain multiple T‐DNA copies integrated into the plant genome. To understand the origin of complex T‐DNA loci, floral‐dip and root transformation experiments were carried out in Arabidopsis thaliana with mixtures of A. tumefaciens strains, each harboring one or two different T‐DNA vectors. Upon floral‐dip transformation, 6–30% of the transformants were co‐transformed by multiple T‐DNAs originating from different bacteria and 20–36% by different T‐DNAs from one strain. However, these co‐transformation frequencies were too low to explain the presence of on average 4–6 T‐DNA copies in these transformants, suggesting that, upon floral‐dip transformation, T‐DNA replication frequently occurs before or during integration after the transfer of single T‐DNA copies. Upon root transformation, the co‐transformation frequencies of T‐DNAs originating from different bacteria were similar or slightly higher (between 10 and 60%) than those obtained after floral‐dip transformation, whereas the co‐transformation frequencies of different T‐DNAs from one strain were comparable (24–31%). Root transformants generally harbor only one to three T‐DNA copies, and thus co‐transformation of different T‐DNAs can explain the T‐DNA copy number in many transformants, but T‐DNA replication is postulated to occur in most multicopy root transformants. In conclusion, the comparable co‐transformation frequencies and differences in complexity of the T‐DNA loci after floral‐dip and root transformations indicate that the T‐DNA copy number is highly determined by the transformation‐competent target cells.