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Title: TOMATO (LYCOPERSICON ESCULENTUM MILL.) TRANSFORMANTS CARRYING IPT GENE FUSED TO HEAT-SHOCK (HSP 70) PROMOTER

Author
item FEDOROWICZ, O - WARSAW AGRIC UNIV, POLAND
item BARTOSZEWSKI, GREGORY - WARSAW AGRIC UNIV, POLAND
item Smigocki, Anna
item MALINOWSKI, R - WARSAW AGRIC UNIV, POLAND
item NIEMIROWICZ-SZCYT, K - WARSAW AGRIC UNIV, POLAND

Submitted to: Proceedings of Food Biotechnology Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/13/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: A thorough understanding of how plant growth regulators control many of the physiological processes associated with normal plant growth and development is lacking. Cytokinin is a major plant growth hormone associated with such processes as shoot development and onset of senescence. In order to gain a better understanding of cytokinin's role in these processes, a gene for production of cytokinin was introduced into a mutant tomato line ls. Low levels of cytokinins, abnormal flowers without petals and reduced fertility, and suppressed lateral shoots (no formation of axillary buds) characterize the ls tomato line. The ls mutant was transformed with the cytokinin biosynthesis gene that was fused to a switch that is turned on by elevated temperatures. In regenerated transgenic plants, the expression of the cytokinin gene was shown to be upregulated after a 2 hour, 42 degree C heat treatment. Appearances of the transgenic ls mutant plants carrying the cytokinin gene were mostly normal before and after the heat treatment. Further research will be conducted to study whether increased cytokinin levels can cause reversion of the ls mutation. This research will help scientists determine how cytokinins regulate plant growth and lead to development of commercial tomato lines that produce better quality fruits and higher yields.

Technical Abstract: Tomato ls mutant, characterised by suppressed lateral shoots, abnormal flowers and low level of endogenous cytokinins, was transformed with Agrobacterium tumefaciens strain ACS101 carrying an ipt gene under a heat shock promoter. Of the 62 rooted shoots that were obtained, most exhibited unchanged ploidy levels. PCR analysis confirmed that 76% of the plants were transgenic. Segregation of the selectable marker gene, nptII, in majority of the progeny was 3:1 on kanamycin-containing medium. Heat shock treatment at 42 degree C for 2 hr increased ipt gene transcripts as analyzed by RT PCR. Transcript levels decreased over time and after six hours could not be detected.