• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1995년도 Proceedings of special lectures on Molecular Biological Approaches to Plant Disease National Agricultural Science and Technology Institute Suwon, Korea
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• pp.55-75
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• 1995

Induction of HMG-Co A reductase (HMGR) is essential for the biosynthesis of sesquiterpenoid phytoalexins and steroid derivatives in Solanaceous plants following wounding and pathogen infection. To better understand this complex step in stress-responsive isoprenoid synthesis, three classes of cDNAs for HMGR (hmg1, hmg2, and hmg3) were isolated from a potato tuber library. The potato cDNAs had extensive homology in open reading frames but had low homology in the 3'-untranslated regions. RNA gel blot analysis using gene-specific probes revealed that hmg1 is induced by wounding but wound induction is strongly suppressed by arachidonic acid or by inoculation with Phytophthora infestants. In contrast, hmg2 and hmg3 are slightly induced by wounding and strongly enhanced by arachidonic acid or inoculation. The induction and suppression of HMGR genes parallel the suppression of steroid and stimulation of sesquiterpenoid accumulations observed in earlier investigations. Treatment of the tuber disks with a low concentration of methyl-jasmonate doubled the wound induced accumulation of hmg1 transcripts and steroid-glycoalkaloid accumulation, but did not affect the abundance of transcripts for hmg2 or hmg3 nor induce phytoalexins. High concentration of methyl-jasmonate suppressed hmg1 mRNA and steroid-glycoalkaloid accumulation, induced hmg3 mRNA, and did not elicit phytoalexins. Lipoxygenase inhibitors suppressed the accumulation of of hmg1 transcripts and steroid-glycoalkaloids, which were restored by exogeneous methyl-jasmonate. Methyl-jasmonate applied together with arachidonic acid enhanced the elicitor induced accumulation of sesquiterpenes and sustained steroid-glycoalkaloid levels with transcript levels for the various HMGR mRNAs equal to or greater than wound-only treatment. These results domonstrate that the consequences of wound- and pathogen-responses of plants are different at the levels of gene expression and associated secondary metabolism.

• 한국작물학회지
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• 제47권4호
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• pp.283-285
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• 2002

Momilactones A and B, the major phytotoxins and phytoalexins in rice plants, were quantified by a HPLC-APCI-MS-MS (APCI-MS-MS) system under multiple reaction monitoring conditions. Since MA and MB were found to be easily extracted with water, these phytotoxic compounds may affect germination and growth of other plant species when the rice straws were left in the fields.

• Applied Biological Chemistry
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• 제40권4호
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• pp.352-356
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• 1997

식물배양세포계에서 유용 phytoalexin의 생산여부를 검토하기 위하여 페튜니아 배양세포주에 5종의 naphthoquinone류 화합물을 첨가하였을 때 유도되는 항미생물활성을 조사하였다. 처리한 naphthoquinone류 화합물 중 토양 방선균으로부터 페튜니아 세포생장억제물질로 분리한 2,5,7-trihydroxy-3-(5'-hydroxyhexyl)-1,4-naphthoquinone (3-OH NQ)이 48시간 이내에 90% 이상 효율적으로 배양세포내로 흡수되었다. 3-OH NQ를 처리한 페튜니아 캘러스 추출물은 Aspergillus candidus의 포자발아를 강하게 억제하였다$(MIC:\;32\;{\mu}g/ml)$. 3-OH NQ를 처리한 페튜니아 배양세포로부터 2종의 항미생물 활성물질 4,2',4',${\beta}$-tetrahydroxychalcone과 4',7-dihydroxyflavone을 분리하였다. 주로 유도되는 phytoalexin인 4,2',4',${\beta}$-tetrahydroxychalcone은 A. candidus의 포자발아를 강하게 억제하였다$(MIC:\;16\;{\mu}g/ml)$.

• Journal of Crop Science and Biotechnology
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• 제10권2호
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• pp.112-116
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• 2007

Kinetin(KN) is an inducer of rice(Oryza sativa L.) defense/stress responses, as evidenced by the induction of inducible secondary metabolite and defense/stress protein markers in leaf. We show a novel light-dependent effect of KN-triggered defense stress responses in rice leaf. Leaf segments treated with KN(100 ${\mu}M$) show hypersensitive-like necrotic lesion formation only under continuous light illumination. Potent accumulation of two phytoalexins, sakuranetin and momilactone A(MoA) by KN that peaks at 48 h after treatment under continuous light is completely suppressed by incubation under continuous dark. Using two-dimensional gel electrophoresis we identified KN-induced changes in ribulose-1, 5-bisphosphate carboxylase/oxygenase, energy- and pathogenesis-related proteins(OsPR class 5 and 10 members) by N-terminal amino acid sequencing and mass spectrometry. These changes were light-inducible and could not be observed in the dark(and control). Present results provide a new dimension(light modulation/regulation) to our finding that KN has a potential role in the rice plant self-defense mechanism.

• Archives of Pharmacal Research
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• 제17권1호
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• pp.48-50
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• 1994

Three p-coumaroylamino acids (p-CAAs) were isolated from the yeast-elicited Ephedra distachya cultures by consecutive purification using XAD_2, silicagel and RP-HPLC. Retention times on HPLC as well as their UV, IR, NMR and MS spectral data indicated that the yeast-induced p-CAAs wre p-coumaroyl--D-valine, p-coumaroyl-D-serine and p-coumarouyl-D-threonine, respectively. The structures of p-CAAs were confirmed by the comparison of their physico-chemical properties 3with those of synthetic ones. They were isolated and identified for the first time from natural products and supposed to be accumulated as phytoalexins of Ephedra.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1226-1229
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• 2010

Glyceollins, one of the inducible phytoalexins produced by plants, were induced in a number of varieties of Korean soybean through fungal infection. Of the tested soybean varieties, Tae-Kwang, though not the most productive, was found to be currently the most suitable for the induction of glyceollins. Amongst the fungal species, Rhizopus microsporus var. oligosporus was seen to be the most effective elicitor. Halved soybean seeds produced glyceollins upon fungal infection; however, chopped soybeans and homogenized soybeans did not produce significant quantities of glyceollins.

• The Plant Pathology Journal
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• 제29권1호
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• pp.77-86
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• 2013

Anthracnose development by Colletotrichum musae was observed to be significantly less in the fruits of the banana cultivar 'Embul' (Mysore, AAB) infected with Phyllosticta musarum than in fruits without such infections. Anthracnose disease originates from quiescent C. musae infections in the immature fruit. P. musarum incites minute, scattered spots, referred to as freckles, in the superficial tissues of immature banana peel which do not expand during maturation or ripening. P. musarum does not appear to have a direct suppressive effect on C. musae as conidia of C. musae germinate on both freckled and non-freckled fruit forming quiescent infections. Our investigations have shown that P. musarum infection induced several defence responses in fruit including the accumulation of five phytoalexins, upregulation of chitinase and ${\beta}$-1,3-glucanase, phenylalanine ammonia lyase (PAL) activity and cell wall lignification. $^1H$ and $^{13}C$ NMR spectral data of one purified phytoalexin compared closely with 4'-hydroxyanigorufone. Some of the P. musarum-induced defences that retained during ripening, restrict C. musae development at the ripe stage. This paper examines the potential of P. musarum-induced defences, in the control of anthracnose, the most destructive postharvest disease in banana.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2004년도 추계학술발표회
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• pp.36-41
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• 2004

Postharvest handling of sweetpotatoes is inevitable procedure for the maintenance, storage, management and utilization of high fresh quality of storage roots. It ranges in degree from simple lifting of roots, carrying them from field to storage house and immediate consumption after cooking, to sophisticated methods of curing, and storage under controlled conditions followed by processing into a high quality food products. Postharvest saleability, quality and nutritional value of roots and the presence or absence in roots of bitter, toxic furanoterpenoid phytoalexins or mycotoxins depends greatly on the degree and types of treatment to which produce is subjected. Climatic and soil conditions before harvest and contamination or attack by microorganisms or insect pests in the field may initiate or enhance subsequent postharvest deterioration. Careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. Research has concentrated on the improvement of preharvest conditions to increase yield and lower decrease rates. However, such efforts are wasted unless they go hand in hand with others designed to reduce the high degree of loss associated with careless postharvest handling.

• 한국작물학회지
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• 제47권
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• pp.124-134
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• 2002

The sweetpotato, Ipomoea batatas L. (Lam.), is one of the important summer upland crops in Korea and has been used as human food, industrial yaw material and vegetable. Sweetpotato has been consumed for human foods such as boiled, roasted, fried or salad etc. It should be developed for higher quality as a snack or health food, primarily through improving the eating and marketing qualities as well as nutritional value. Its quality after cooking or processing is a complex one combining the aroma, taste, texture and fiber content. The other important qualities for consumers are root shape, size, skin color, flesh color, insect and disease resistance, nutritional components and safety from phytoalexins(toxic stress metabolites) etc. Korean people generally prefer to red skin color, round or elliptic shape and dry texture, yellow flesh color of sweetpotato which is high in starch content including vitamins and nutrients. The almost factors of quality components of sweetpotato are genetically controlled by breeder, but postharvest handlings and marketing management for making high quality goods should be done thoroughly according to the quality evaluation criteria of sweetpotato from the moment of harvest until shipping them to the market by farmers and the other users. This paper describes current status and prospects of the quality evaluations and researches in sweetpotato roots in Korea.

• 대한화장품학회지
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• 제38권3호
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• pp.237-245
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• 2012

쿠메스트롤은 식물이 스트레스에 대항해 합성하는 phytoalexins의 일종으로, 알팔파 새싹, 클로버, 콩나물에서 일반적으로 발견된다. 본 연구에서는 쿠메스트롤의 자외선에 의해 유도되는 피부 진피세포 광노화 예방 효능에 관한 연구를 실시하였다. 쿠메스트롤 전처리는 자외선 B 조사에 의해 감소된 Sirt1 단백질 발현 및 활성과 하위 미토콘드리아 생합성 관련 유전자인 PGC-$1{\alpha}$, NRF1, TFAM의 발현 변화를 감소시켰다. 또한, ATP 및 ROS 생성량을 정상화시키고 피부 노화를 유도하는 최종당화산물 생성을 억제하였다. 이상의 결과에서 쿠메스트롤은 자외선 조사에 의해 발생하는 진피 세포 내 미토콘드리아 손상 및 이에 따른 당화 단백질 생성을 감소시킴으로써 피부 광노화 현상으로부터 보호할 수 있음을 확인하였다.