Showing papers by "Michael R. Sussman published in 2000"

Genetic evidence for the in planta role of phloem-specific plasma membrane sucrose transporters

Abstract: A major question in plant physiology is how the large amount of sucrose made in leaves is transported to the rest of the plant. Although physiological, biochemical, and anatomical investigations have been performed in this field, to date there have been very few genetic studies. Using a reverse genetic screen, we have identified mutant Arabidopsis plants containing transferred DNA insertions in the gene encoding a phloem-specific sucrose transporter, SUC2. SUC2 is thought to function in loading sugar from the apoplast into the conducting sieve tubes. In the homozygous state, these mutations resulted in stunted growth, retarded development, and sterility. The source leaves of mutant plants contained a great excess of starch, and radiolabeled sugar failed to be transported efficiently to roots and inflorescences. These data provide genetic proof that apoplastic phloem loading is critical for growth, development, and reproduction in Arabidopsis and that SUC2 is at least partially responsible for this step.

The Arabidopsis knockout facility at the University of Wisconsin-Madison

Abstract: As of this writing the Arabidopsis genome is 97% sequenced with only small portions of the highly repetitive regions within centromeres and telomeres remaining. The identification of approximately 25,000 plant genes will give plant biologists an opportunity to identify and understand the function of

Method for rapidly identifying deletion mutations

Abstract: A method is described for the detection of a rare deletion mutant allele in a population of wild-type individuals. DNA samples from the individuals are subjected to a modified form of polymerase chain reaction (PCR) which favors the replication of truncated DNA strands over the synthesis of wild-type full length strands. The preferred way to bias the process toward the synthesis of truncated DNA strands is by limiting the extension step in the PCR reaction protocol. This process permits the convenient detection of a deletion mutant allele from a population of 1000 wild type individuals with the full length allele.