Biochemical and genetic comparison of two nitrate reductase-deficient pea mutants disturbed in the cofactor

✍ Scribed by E. Jacobsen; J. G. Schaart; R. L. Warner

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 460 KB
• Volume: 25
• Category: Article
• ISSN: 0006-2928
• DOI: 10.1007/bf00498957

✦ Synopsis

Two nitrate reductase (NaR)-deficient mutants of pea (Pisum sativurn L. ), E~ and A300, both disturbed in the molybdenum cofactor function and isolated, respectively, from cv Rondo and cv Juneau, were tested for allelism and were compared in biochemical and growth characteristics. The F1 plants of the cross E1 x A300 possessed NaR and xanthine dehydrogenase (XDH) activities comparable to those of the wild types, indicating that these mutants belong to different complementation groups, representing two different loci. Therefore, mutant E~ represents, besides mutant A300 and the allelic mutants A317 and A334, a third locus governing NaR and is assigned the gene destignation nar3. In comparison with the wild types, eytochrome c reductase activity was increased in both mutants. The mutants had different cytochrome c reductase distribution patterns, indicating that mutant A300 could be disturbed in the ability to dimerize NaR apoprotein monomers, and mutant El in the catalytic function of the molybdenum cofactor. In growth characteristics studied, A300 did not differ from the wild types, whereas fully grown leaves of mutant Et became necrotic in soil and in liquid media containing nitrate.