Development of Methods to Distinguish between Durum/Common Wheat and Common Wheat in Blended Flour Using PCR

摘要

A PCR-based method was developed to distinguish between durum/common wheat and com-mon wheat by leveraging slight differences of DNA sequence in Starch Synthase II (SS II) coded on wheat A, B and D genomes. A primer pair, SS II ex7-U/L, was designed to hybridize with a con-served DNA sequence region found in SS II-A, B and D genes. Another primer pair, SS II-D 1769U/1889L, was constructed to recognize a unique sequence in the SS II-D gene. The target re-gion of SS II ex7-U/L with the size of 114 bp was amplified from durum and common wheat DNA, while no amplification was observed from any cereals other than those in the wheat genus. A DNA fragment with the size of 121 bp was specifically amplified from common wheat with SS II-D 1769U/1889L. In blended flour prepared from wheat and other cereals, the developed PCR system composed of two primer pairs effectively detected durum/common wheat and common wheat. These results suggested that PCR using two primer pairs is useful for detecting common and/or durum wheat in blended flour and could be utilized to ensure accurate food labeling.%PCRを活用した4および6倍体と6倍体コムギとの識別法を開発した．A，BおよびDゲノムで構成される普通コムギは6倍体コムギに，AおよびBゲノムで構成されるデュラムコムギは4倍体コムギに分類される．SS II遺伝子は各コムギA，BおよびDゲノムにコードされ，それらのDNA塩基配列はわずかに異なる．この差異を識別する2種の異なるプライマー対を設計した．プライマー対SS IIex7-U/LはSS II-A，B，Dに共通の配列を認識し，4および6倍体コムギDNAから114bpのPCR増幅産物を生じた．一方，プライマー対SS II-D1769U/1889LはSS II-D上の特異的な配列を認識し，6倍体コムギからのみ121bpの増幅産物を生じた，コムギと他の穀物からなるコムギ混合物を本PCRに供したところ，4および6倍体コムギと6倍体コムギを効果的に識別することができた．以上のことから，本PCRは食品原料粉中の普通およびデュラムコムギの識別を可能とし，コムギの正確な表示に有用であることが示された．