PCR法によるクワズイモの同定

摘要

Kuwazuimo (Alocasia odora) and shimakuwazuimo (Alocasia cucullata) are evergreen perennial plants that originated in East Asia. Although inedible, they are occasionally eaten by mistake because they resemble satoimo (Colocasia esculenta), and this has caused food poisoning in Japan. It is not easy to determine the cause of a food poisoning outbreak from the shape or chemical composition when the available sample is small. Therefore, we developed a new primer pair for PCR to identify kuwazuimo and shimakuwazuimo in small samples, based on the internal transcribed spacer (ITS) region of ribosomal DNA. Using PCR with the developed primer pair, we detected all samples of kuwazuimo obtained from the market, while excluding 17 other kinds of crops. The samples were identified as shimakuwazuimo by DNA sequencing of the PCR products. The present PCR method showed high specincity and was confirmed to be applicable to the identification of kuwazuimo and shimakuwazuimo from various crops.%クワズイモ(Alocasia odora)は東アジア原産のサトイモ科クワズイモ属の常緑性多年草で，食用であるサトイモ(Colocasia esculenta)に外観が類似しており(Fig.1)，誤認による摂食のため，食中毒を引き起こすことが報告されている.クワズイモ属は，20℃以上の高温を好み，多くは温室観葉植物として栽培されている.植物組織中に水に難溶性のシュウ酸カルシウム(C_aC_2O_4)を含有し，誤って摂食すると，針状結晶による物理的な刺激により，唇のしびれ，口腔内のはれ，胃痛を起こすことが知られている.日本では，クワズイモは四国南部，九州南部以南に，シマクワズイモ(Alocasia cucullata)は琉球列島，小笠原諸島に，ヤエヤマクワズイモ(Alocasia atropur-purea)は西表島に自生しており，このうちクワズイモおよびシマクワズイモの耐寒性は比較的高い.