Male sterility associated with APRT deficiency in Arabidopsis thaliana results from a mutation in the gene APT1

Abstract

Four mutants of Arabidopsis thaliana that are deficient in adenine phosphoribosyl transferase (APRT) activity have been isolated by selecting for germination of seeds and growth of the plantlets on a medium containing 2,6-diaminopurine (DAP), a toxic analog of adenine. In all mutants, DAP resistance is due to a recessive nuclear mutation at a locus designated apt. The mutants are male sterile due to pollen abortion after meiosis. Furthermore, it has been shown that metabolism of cytokinins is impaired in the mutant BM3, which has the lowest level of APRT activity among the mutants tested. However, three different cDNAs encoding APRT have been isolated in A. thaliana and this raised the question of the nature of the mutation which results in low APRT activity. The mutation was genetically mapped to chromosome I and lies within 6 cM of the phenotypic marker dis2, indicating that the mutation affects the APT1 gene, a result confirmed by sequencing of mutant alleles. The mutation in the allele apt1-3 is located at the 5' splicing site of the third intron, and eliminates a BstNI restriction site, as verified by Southern blotting and PCR fragment length analysis.

In vitro recombination cloning of entire cDNA libraries in Arabidopsis thaliana and its application to the yeast two-hybrid system

“…For the proteins with unknown interaction partners, we tested adenine phosphoribosyl transferase 1 (APRT) and indole-3-glycerol phosphate synthase (IGPS) as bait proteins. APRT is involved in purine and cytokinin metabolism by means of interconverting the corresponding free bases to the phosphorylated ribosyl (Gaillard et al 1998;Mok and Mok 2001). IGPS is a key enzyme of tryptophane biosynthesis which is thought to be an important step in the production of the phytohormone auxin (Ouyang et al 2000).…”

Cytokinins: Biosynthesis metabolism and perception

“…However, affinities for the naturally occurring cytokinins were not reported. It is not known whether the male sterility associated with Apt1 mutations is due to changes in cytokinin composition or adenine salvage (Gaillard et al, 1998). An adenosine kinase gene was isolated from the moss Physcomitrella, but its substrate specificity has not yet been determined (Von Schwartzenberg et al, 1998).…”

Bioengineering of Male Sterility in Rice (Oryza sativa L.)

“…Adenine phosphoribosyl transferase (APRT) is the major enzyme for converting adenine into adenosine-3'-phosphate (AMP) associated with the purine salvage pathway. APRT gene mutation causes the male sterility in Arapidopsis (Gaillard et al 1998). In rice, APRT gene and TGMS phenotype were investigated (Li et al 2003).…”