ARS | Publication request: ASSOCIATION OF REVERSIBLE INACTIVATION OF MAIZE TRANSPOSABLE ELEMENT, DS, WITH TISSUE-SPECIFIC PROCESSING OF THE 35S:TPASE TRANSCRIPT IN CARROT (DAUCUS CAROTA L.)

Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2006
Publication Date: November 19, 2006
Citation: Ipek, A., Ipek, M., Simon, P.W. 2006. Association of reversible inactivation of maize transposable element, Ds, with tissue-specific processing of the 35s:TPase transcript in carrot (Daucus carota l.)[abstract]. Journal of Horticultural Science and Biotechnology. 81:819-826.

Technical Abstract: An Ac/Ds based two-element transposon tagging system has been introduced into carrot. F1 progeny containing both 35S:TPase and the Ds element were derived from crosses between 35S:TPase and Ds bearing parents. While excision of Ds was not detected in any F1 plants carrying both 35S:TPase and the Ds element, calli initiated from these F1 plants had the Ds element excised, indicating Ds transposition. Reverse transcriptase PCR analysis revealed that the 35S:TPase gene was expressed in both F1 plants and calli, and introns 1, 2, and 3 were spliced correctly. Although intron 4 was also spliced correctly in calli, imprecisely spliced intron 4 was detected in F1 plants. Sequence analysis of incorrectly spliced reverse transcriptase PCR products demonstrated the presence of a cryptic intron donor site within intron 4 of the 35S:TPase transcript, likely competing with proposed intron donor site during the maturation of the major 35S:TPase transcript. These results suggested that the major transcript of 35S:TPase was incorrectly processed and consequently the Ds element was reversibly inactivated in the somatic tissues of carrot plants whereas this inactive Ds element was remobilized by tissue culture where the 35S:TPase was spliced correctly. These observations point to an important role of tissue-specific 35S:TPase transcript processing for successful transposition of Ds in carrot. Therefore, the successful processing of the 35S:TPase transcript in carrot callus may point to strategies for increasing Ac transposition in other tissues.