Comparison of Trichothecene Biosynthetic Gene Expression between Fusarium graminearum and Fusarium asiaticum

Lee, Theresa,Lee, Seung-Ho,Shin, Jean Young,Kim, Hee-Kyoung,Yun, Sung-Hwan,Kim, Hwang-Yong,Lee, Soohyung,Ryu, Jae-Gee The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.1

Nivalenol (NIV) and deoxynivalenol (DON) are predominant Fusarium-producing mycotoxins found in grains, which are mainly produced by Fusarium asiaticum and F. graminearum. NIV is found in most of cereals grown in Korea, but the genetic basis for NIV production by F. asiaticum has not been extensively explored. In this study, 12 genes belonging to the trichothecene biosynthetic gene cluster were compared at the transcriptional level between two NIV-producing F. asiaticum and four DON-producing F. graminearum strains. Chemical analysis revealed that time-course toxin production patterns over 14 days did not differ between NIV and DON strains, excluding F. asiaticum R308, which was a low NIV producer. Both quantitative real-time polymerase chain reaction and Northern analysis revealed that the majority of TRI gene transcripts peaked at day 2 in both NIV and DON producers, which is 2 days earlier than trichothecene accumulation in liquid medium. Comparison of the gene expression profiles identified an NIV-specific pattern in two transcription factor-encoding TRI genes (TRI6 and TRI10) and TRI101, which showed two gene expression peaks during both the early and late incubation periods. In addition, the amount of trichothecenes produced by both DON and NIV producers were correlated with the expression levels of TRI genes, regardless of the trichothecene chemotypes. Therefore, the reduced production of NIV by R308 compared to NIV or DON by the other strains may be attributable to the significantly lower expression levels of the TRI genes, which showed early expression patterns.

Occurrence of Fusarium Mycotoxins in Rice and Its Milling By-Products in Korea

LEE, THERESA,LEE, SOO-HYUNG,LEE, SEUNG-HO,SHIN, JEAN YOUNG,YUN, JONG-CHUL,LEE, YIN-WON,RYU, JAE-GEE International Association for Food Protection 2011 Journal of food protection Vol.74 No.7

<P>A total of 201 samples of brown rice, polished rice, and two types of by-products, blue-tinged rice and discolored rice, were collected from rice stores maintained at 51 rice processing complexes in Korea. These samples were analyzed for the presence of Fusarium mycotoxins such as deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEA). Contaminants (and their ranges) found in discolored rice samples were DON (59 to 1,355 ng g−1), NIV (66 to 4,180 ng g−1), and ZEA (25 to 3,305 ng g−1); those found in blue-tinged (less-ripe) rice were DON (86 to 630 ng g−1), NIV (50 to 3,607 ng g−1), and ZEA (26 to 3,156 ng g−1). Brown rice samples were contaminated mostly with NIV and ZEA (52 to 569 ng g−1 and 47 to 235 ng g−1, respectively). Polished rice samples were largely free from mycotoxins, although one sample was contaminated with NIV (77 ng g−1). When the fungal flora associated with each rice sample was investigated, blue-tinged rice was the most often contaminated with Fusarium graminearum (3.8%), followed by the discolored rice (2.4%) and brown rice (1.6%) samples. Using PCR, toxin genotyping of 266 isolates of F. graminearum revealed that most isolates (96%) were NIV producers. In conclusion, this survey is the first report of the cocontamination of Korean rice and its by-products with trichothecenes and ZEA. Importantly, it also provides new information on the natural contamination of rice by Fusarium mycotoxins.</P>

Population Structure of Fusarium graminearum from Maize and Rice in 2009 in Korea

Lee, Seung-Ho,Lee, Jung-Kwan,Nam, Young-Ju,Lee, Soo-Hyung,Ryu, Jae-Gee,Lee, Theresa The Korean Society of Plant Pathology 2010 Plant Pathology Journal Vol.26 No.4

We performed diagnostic PCR assays and a phylogenetic analysis using partial sequences of TEF1 (translation elongation factor-1) to determine the trichothecene chemotypes and genetic diversity of F. graminearum isolates from maize and rice samples collected in 2009 in Korea. PCR using a species-specific primer set revealed a total of 324 isolates belonging to the putative F. graminearum species complex. PCR with trichothecene chemotypespecific primers revealed that the nivalenol (NIV) chemotype was predominant among the fungal isolates from rice (95%) in all provinces examined. In contrast, the predominant chemotype among the corn isolates varied according to region. The deoxynivalenol (DON) chemotype was found more frequently (66%) than the NIV chemotype in Gangwon Province, whereas the NIV chemotype (70%) was predominant in Chungbuk Province. Phylogenetic analysis showed that all DON isolates examined were clustered into lineage 7, while the NIV isolates resided within lineage 6 (F. asiaticum). Compared with previous studies, the lineage 6 isolates in rice have been predominantly maintained in southern provinces, while the dominance of lineage 7 in maize has been evident in Gangwon at a slightly reduced level.

Occurrence of Toxigenic Fusarium vorosii among Small Grain Cereals in Korea

Lee, Theresa,Paek, Ji-Seon,Lee, Kyung Ah,Lee, Soohyung,Choi, Jung-Hye,Ham, Hyeonheui,Hong, Sung Kee,Ryu, Jae-Gee The Korean Society of Plant Pathology 2016 Plant Pathology Journal Vol.32 No.5

Fusarium graminearum species complex (FGSC) causes Fusarium head blight in small grain cereals. To date, four species (F. graminearum, F. asiaticum, F. boothii, and F. meridionale ) belonging to FGSC frequently occur in Korean cereals. In addition, we first reported the occurrence of additional species (F. vorosii ) within FGSC, which was isolated from barley, corn, and rice in Korea. Phylogenetic analysis of the Fusarium isolates of this group using combined multigene sequences confirmed species identification. Moreover, the macroconidia produced by these isolates were morphologically similar to those of the F. vorosii holotype. Chemical analysis indicated that the F. vorosii isolates produced various trichothecenes such as nivalenol and deoxynivalenol with their acetyl derivatives along with zearalenone. Pathogenicity tests demonstrated that all of the F. vorosii isolates examined were pathogenic on barley, corn, and rice with variation in aggressiveness. This study is the first report of F. vorosii in Korean cereals, their pathogenicity towards barley and corn, and their ability to produce trichothecenes and zearalenone.

Characterization of Bacillus amyloliquefaciens DA12 Showing Potent Antifungal Activity against Mycotoxigenic Fusarium Species

Lee, Theresa,Park, Dami,Kim, Kihyun,Lim, Seong Mi,Yu, Nan Hee,Kim, Sosoo,Kim, Hwang-Yong,Jung, Kyu Seok,Jang, Ja Yeong,Park, Jong-Chul,Ham, Hyeonheui,Lee, Soohyung,Hong, Sung Kee,Kim, Jin-Cheol The Korean Society of Plant Pathology 2017 Plant Pathology Journal Vol.33 No.5

In an attempt to develop a biological control agent against mycotoxigenic Fusarium species, we isolated Bacillus amyloliquefaciens strain DA12 from soil and explored its antimicrobial activities. DA12 was active against the growth of mycotoxigenic F. asiaticum, F. graminearum, F. proliferatum, and F. verticillioides both in vitro and in planta (maize). Further screening using dual culture extended the activity range of strain DA12 against other fungal pathogens including Botrytis cinerea, Colletotrichum coccodes, Endothia parasitica, Fusarium oxysporum, Raffaelea quercus-mongolicae, and Rhizoctonia solani. The butanol extract of the culture filtrate of B. amyloliquefaciens DA12 highly inhibited the germination of F. graminearum macroconidia with inhibition rate 83% at a concentration of $31.3{\mu}g/ml$ and 100% at a concentration of $250{\mu}g/ml$. The antifungal metabolite from the butanol extract was identified as iturin A by thin layer chromatography-bioautography. In addition, volatile organic compounds produced by DA12 were able to inhibit mycelial growth of various phytopathogenic fungi. The volatile compounds were identified as 2-heptanone, 5-methyl heptanone and 6-methyl heptanone by gas chromatography-mass spectrometry (GC-MS) analysis. These results indicate that the antagonistic activity of Bacillus amyloliquefaciens DA12 was attributable to iturin A and volatile heptanones, and the strain could be used as a biocontrol agent to reduce the development of Fusarium diseases and mycotoxin contamination of crops.

Occurrence of Toxigenic Fusarium vorosii among Small Grain Cereals in Korea

Theresa Lee,Ji-Seon Paek,이경아,이수형,Jung-Hye Choi,함현희,홍성기,류재기 한국식물병리학회 2016 Plant Pathology Journal Vol.32 No.5

Fusarium graminearum species complex (FGSC)causes Fusarium head blight in small grain cereals. To date, four species (F. graminearum , F. asiaticum ,F. boothii , and F. meridionale ) belonging to FGSCfrequently occur in Korean cereals. In addition, wefirst reported the occurrence of additional species (F. vorosii ) within FGSC, which was isolated from barley,corn, and rice in Korea. Phylogenetic analysis of theFusarium isolates of this group using combined multigenesequences confirmed species identification. Moreover,the macroconidia produced by these isolateswere morphologically similar to those of the F. vorosiiholotype. Chemical analysis indicated that the F. vorosiiisolates produced various trichothecenes such asnivalenol and deoxynivalenol with their acetyl derivativesalong with zearalenone. Pathogenicity tests demonstratedthat all of the F. vorosii isolates examinedwere pathogenic on barley, corn, and rice with variationin aggressiveness. This study is the first report of F. vorosii in Korean cereals, their pathogenicity towardsbarley and corn, and their ability to produce trichothecenesand zearalenone.

Population Structure of Fusarium graminearum from Maize and Rice in 2009 in Korea

Seung-Ho Lee,이정관,Young Ju Nam,Soohyung Lee,Jae-Gee Ryu,Theresa Lee 한국식물병리학회 2010 Plant Pathology Journal Vol.26 No.4

We performed diagnostic PCR assays and a phylogenetic analysis using partial sequences of TEF1 (translation elongation factor-1) to determine the trichothecene chemotypes and genetic diversity of F. graminearum isolates from maize and rice samples collected in 2009 in Korea. PCR using a species-specific primer set revealed a total of 324 isolates belonging to the putative F. graminearum species complex. PCR with trichothecene chemotypespecific primers revealed that the nivalenol (NIV) chemotype was predominant among the fungal isolates from rice (95%) in all provinces examined. In contrast, the predominant chemotype among the corn isolates varied according to region. The deoxynivalenol (DON) chemotype was found more frequently (66%) than the NIV chemotype in Gangwon Province, whereas the NIV chemotype (70%) was predominant in Chungbuk Province. Phylogenetic analysis showed that all DON isolates examined were clustered into lineage 7, while the NIV isolates resided within lineage 6 (F. asiaticum). Compared with previous studies, the lineage 6 isolates in rice have been predominantly maintained in southern provinces, while the dominance of lineage 7 in maize has been evident in Gangwon at a slightly reduced level.

국내산 생강의 데옥시니발레놀과 니발레놀 발생 및 저감화 저장조건

이미정(Mi Jeong Lee),임수빈(Soo Bin Lim),최정혜(Jung-Hye Choi),김점순(Jeomsoon Kim),이데레사(Theresa Lee),장자영(Ja Yeong Jang) 한국식품저장유통학회 2021 한국식품저장유통학회지 Vol.28 No.7

Two different polyketide synthase genes are required for synthesis of zearalenone in <i>Gibberella zeae</i>

Kim, Yong‐,Tae,Lee, Ye‐,Ryun,Jin, Jianming,Han, Kap‐,Hoon,Kim, Hun,Kim, Jin‐,Cheol,Lee, Theresa,Yun, Sung‐,Hwan,Lee, Yin‐,Won Blackwell Science Ltd 2005 Molecular microbiology Vol.58 No.4

<P><B>Summary</B></P><P>Zearalenone (ZEA) is a polyketide mycotoxin produced by some species of <I>Gibberella/Fusarium</I> and causes hyperestrogenic syndrome in animals. ZEA occurs naturally in cereals infected by <I>Gibberella zeae</I> in temperate regions and threatens animal health. In this study, we report on a set of genes that participate in the biosynthesis of ZEA in <I>G. zeae</I>. Focusing on the non‐reducing polyketide synthase (PKS) genes of the <I>G. zeae</I> genome, we demonstrated that <I>PKS13</I> is required for ZEA production. Subsequent analyses revealed that a continuous, 50 kb segment of DNA carrying <I>PKS13</I> consisted of three additional open reading frames that were coexpressed as a cluster during the condition for ZEA biosynthesis. These genes, in addition to <I>PKS13</I>, were essential for the ZEA biosynthesis. They include another <I>PKS</I> gene (<I>PKS4</I>) encoding a fungal reducing PKS; zearalenone biosynthesis gene 1 (<I>ZEB1</I>), which shows a high similarity to putative isoamyl alcohol oxidase genes; and <I>ZEB2</I> whose deduced product carries a conserved, basic‐region leucine zipper domain. <I>ZEB1</I> is responsible for the chemical conversion of β‐zearalenonol (β‐ZOL) to ZEA in the biosynthetic pathway, and <I>ZEB2</I> controls transcription of the cluster members. Transcription of these genes was strongly influenced by different culture conditions such as nutrient starvations and ambient pH. Furthermore, the same set of genes regulated by <I>ZEB2</I> was dramatically repressed in the transgenic <I>G. zeae</I> strain with the deletion of <I>PKS13</I> or <I>PKS4</I> but not in the <I>ZEB1</I> deletion strain, suggesting that ZEA or β‐ZOL may be involved in transcriptional activation of the gene cluster required for ZEA biosynthesis in <I>G. zeae</I>. This is the first published report on the molecular characterization of genes required for ZEA biosynthesis.</P>

폐에 발생한 원발성 악성 혈관주위세포종

이강문 ( Kang Moon Lee ),안중현 ( Joong Hyun Ahn ),이교영 ( Kyo Young Lee ),장데레사 ( Theresa Jang ),문화식 ( Hwa Sik Moon ),박성학 ( Sung Hak Park ),송정섭 ( Jeong Sup Song ) 대한결핵 및 호흡기학회 1997 Tuberculosis and Respiratory Diseases Vol.44 No.3