3250

3159

كارشناسي ارشد

﴿ بيماري شناسي گياهي ﴾

اصفهان : دانشگاه صنعتي اصفهان ، دانشكده كشاوزي

1384

پانزده ، 115 ، [II] ص : مصور ، جدول

ص . ع : به فارسي و انگليسي

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مهندسي كشاورزي

ID3159

به فارسي و انگليسي : قابل رويت در نسخه ديجيتالي

AbstractAflatoxins are the most serious problem in production and export of pistachio in Iran They are among the most toxic mycotoxins and are produced predominantly byAspergillus flavus and A parasiticus Pistachio is susceptible to invasion byaflatoxicogenic Aspergillus species and subsequent production of aflatoxins duringpreharvesting processing transportation or storage Conventional methods for detectionof these toxins in pistachio are including different methods of chromatography such asTLC and HPLC that are time consuming labor intensive and expensive PCR methodsare more rapid and objective for identification of aflatoxicogenic fungi Equivalentgenes for these fungi are aflatoxin biosynthesis genes that have already been cloned andtheir sequence are known These genes are nearly identical in A flavus and A parasiticus and the same PCR system can be used for detection of both species In thisstudy nuts sample were collected from pistachio orchards in Kerman Rafsanjan andIsfahan AFPA and PDA media were used to isolate Aspergillus species Two hundredand fifty isolates were obtained and used for furthure study These isolates belonged toAspergillus Fusarium Rhizopus Alternaria and Cladosporium species Microscopicand macroscopic characters of Aspergillus species were observed on CYA CY20S andMEA after one week Out of 200 isolates ten Aspergillus species were identified as A alliaceus A candidus A flavus A niger A niveus A ochraceus A parasiticus A tamari A terreus A unguis and A wentii that A alliaceus A candidus A niveus A unguis and A wentii was reported for first time from Iran Isolates No U4 and U11were different from all Aspergillus species described in Klick and Pitt key forAspergillus species identification The target genes namely aflR aflJ and omtB omtBprimer could not amplify in isolates and then a new degenerate primer designed andcalled omtBII This primer could amplify all aflatoxicogenic isolates in this study Application of omtBII primer had the same result with TLC analysis So it is a suitablemarker for detection of aflatoxicogenic isolates Also There was not a directrelationship between sclerote and aflatoxin production in this study By application ofmethylated cyclodextrin in culture media showed that it can be used as rapid methodfor detection of aflatoxicogenic fungi But because of the unknown nature of theproduction of aflatoxin in different situation PCR with specific primers is a reliablemethod for detection of aflatoxicogenic isolates

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