Molecular analysis of a null mutant for pea (Pisum sativum L.) seed lipoxygenase-2.
A mutant line of Pisum fulvum was identified that lacked seed lipoxygenase-2 (LOX-2). The mutant phenotype was introgressed into a standard Pisum sativum cv. Birte to provide near-isogenic lines with or without seed LOX-2. Genetic analyses showed the mutation to behave as a single, recessive Mendelian gene. Northern and dot-blot analyses showed a large reduction in LOX-2 mRNA from developing seeds of the LOX-2-null mutant. A restriction fragment length polymorphism associated with the 5' end of the LOX-2 gene(s) co-segregated with the null phenotype, indicating that the reduction of LOX-2 mRNA was neither a consequence of deletion of the LOX genes nor a consequence of the action of a genetically distant regulatory gene. Analysis of the 5'-flanking sequences of LOX-2 genes from Birte and the near-isogenic LOX-2-null mutant revealed a number of insertions, deletions and substitutions within the promoter from the LOX-2-null mutant that could be responsible for the null phenotype. Incubation of crude seed LOX preparations from Birte and the LOX-2-null mutant showed that the latter generated relatively less 13-hydroperoxides and also produced relatively more hydroxy- and ketoacid compounds that have implications for the fresh-frozen pea industry.
Forster
C
C
John Innes Centre, Norwich Research Park, UK.
North
H
H
Afzal
N
N
Domoney
C
C
Hornostaj
A
A
Robinson
D S
DS
Casey
R
R
D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002460:Cell Line; D003433:Crosses, Genetic; D004252:DNA Mutational Analysis; D017343:Genes, Plant / Q000235:genetics; D005808:Genes, Recessive / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D006880:Hydroxy Acids / Q000378:metabolism; D019787:Linoleic Acid / Q000378:metabolism; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D018532:Pisum sativum / Q000166:cytology / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000166:cytology / Q000201:enzymology / Q000235:genetics
D006880:Hydroxy Acids; D012333:RNA, Messenger; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; C117433:13-lipoxygenase; D008084:Lipoxygenase