Transposon tagging of disease resistance genes

Technical Report · Sun Jan 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/6038413· OSTI ID:6038413

Michelmore, R W ^[1]

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1. California Univ., Davis, CA (USA). Dept. of Physics

We are developing a transposon mutagenesis system for lettuce to clone genes for resistance to the fungal pathogen, Bremia lactucae. Activity of heterologous transposons is being studied in transgenic plants. Southern analysis of T{sub 1} and T{sub 2} plants containing Tam3 from Antirrhinum provided ambiguous results. Multiple endonuclease digests indicated that transposition had occurred; however, in no plant were all endonuclease digests consistent with a simple excision event. Southern or PCR analysis of over 50 plans containing Ac from maize have also failed to reveal clear evidence of transposition; this is contrast to experiments by others with the same constructs who have observed high rates of Ac excision in other plant species. Nearly all of 65 T{sub 2} families containing Ac interrupting a chimeric streptomycin resistance gene (Courtesy J. Jones, Sainsbury Lab., UK) clearly segregated for streptomycin resistance. Southern analyses, however, showed no evidence of transposition, indicating restoration of a functional message by other mechanisms, possibly mRNA processing. Transgenic plants have also been generated containing CaMV 35S or hsp70 promoters fused to transposase coding sequences or a Ds element interrupting a chimeric GUS gene (Courtesy M. Lassner, UC Davis). F{sub 1} plants containing both constructs were analyzed for transposition. Only two plants containing both constructs were obtained from 48 progeny, far fewer than expected, and neither showed evidence of transposition in Southerns and GUS assays. We are currently constructing further chimeric transposase fusions. To test for the stability of the targeted disease resistance genes, 50,000 F{sub 1} plants heterozygous for three resistance genes were generated; no mutants have been identified in the 5000 so far screened.

• Research Organization: California Univ., Davis, CA (USA). Dept. of Physics; Commonwealth Scientific and Industrial Research Organization, Canberra (Australia). Div. of Plant Industry
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG03-88ER13904
• OSTI ID: 6038413
• Report Number(s): DOE/ER/13904-T1; ON: DE91007308
• Country of Publication: United States
• Language: English

Related Subjects

550400* -- Genetics
553003 -- Agriculture & Food Technology-- Pest & Disease Control-- (1987-)
59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
CLONING
DISEASE RESISTANCE
DISEASES
DNA HYBRIDIZATION
DNA-CLONING
DOCUMENT TYPES
FOOD
FUNGAL DISEASES
HYBRIDIZATION
INFECTIOUS DISEASES
LETTUCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MUTAGENESIS
MUTANTS
PATHOGENS
PLANTS
PROGRESS REPORT
TRANSPOSONS
VEGETABLES