RRC ID 12010
Author Taketa S, Matsuki K, Amano S, Saisho D, Himi E, Shitsukawa N, Yuo T, Noda K, Takeda K.
Title Duplicate polyphenol oxidase genes on barley chromosome 2H and their functional differentiation in the phenol reaction of spikes and grains.
Journal J. Exp. Bot.
Abstract Polyphenol oxidases (PPOs) are copper-containing metalloenzymes encoded in the nucleus and transported into the plastids. Reportedly, PPOs cause time-dependent discoloration (browning) of end-products of wheat and barley, which impairs their appearance quality. For this study, two barley PPO homologues were amplified using PCR with a primer pair designed in the copper binding domains of the wheat PPO genes. The full-lengths of the respective PPO genes were cloned using a BAC library, inverse-PCR, and 3'-RACE. Linkage analysis showed that the polymorphisms in PPO1 and PPO2 co-segregated with the phenol reaction phenotype of awns. Subsequent RT-PCR experiments showed that PPO1 was expressed in hulls and awns, and that PPO2 was expressed in the caryopses. Allelic variation of PPO1 and PPO2 was analysed in 51 barley accessions with the negative phenol reaction of awns. In PPO1, amino acid substitutions of five types affecting functionally important motif(s) or C-terminal region(s) were identified in 40 of the 51 accessions tested. In PPO2, only one mutant allele with a precocious stop codon resulting from an 8 bp insertion in the first exon was found in three of the 51 accessions tested. These observations demonstrate that PPO1 is the major determinant controlling the phenol reaction of awns. Comparisons of PPO1 single mutants and the PPO1PPO2 double mutant indicate that PPO2 controls the phenol reaction in the crease on the ventral side of caryopses. An insertion of a hAT-family transposon in the promoter region of PPO2 may be responsible for different expression patterns of the duplicate PPO genes in barley.
Volume 61(14)
Pages 3983-93
Published 2010-9
DOI 10.1093/jxb/erq211
PII erq211
PMID 20616156
PMC PMC2935872
MeSH Alleles Catechol Oxidase / genetics* Catechol Oxidase / metabolism Chromosomes, Plant / genetics* Edible Grain / enzymology Edible Grain / genetics Gene Library Hordeum / enzymology Hordeum / genetics* Phenols / chemistry* Plant Proteins / genetics* Plant Proteins / metabolism Polymerase Chain Reaction
IF 5.36
Times Cited 16
WOS Category PLANT SCIENCES
Resource
Barley Haruna Nijo