• Mycobiology
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• v.49 no.3
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• pp.267-274
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• 2021

Two Diaporthe species isolated from fruit of Citrus sinensis in China were characterized based on morphology and multilocus phylogeny of ITS, tef1, and tub2 gene sequences. The phylogeny indicated that the two species match Diaporthe taoicola and D. siamensis. A critical examination of phenotypic characteristics confirmed the phylogenetic results. Diaporthe taoicola was morphologically characterized by producing Alpha conidia with tapering toward both ends. Meanwhile, D. siamensis produced cylindrical or ellipsoidal Alpha conidia with two oil drops. Pathogenicity tests revealed that both species were pathogenic to fruit of C. sinensis. To our knowledge, the two species were firstly reported on Citrus sinensis in China.

• Journal of Microbiology
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• v.45 no.1
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• pp.11-14
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• 2007

Over the last few years, the endophytic bacterial community associated with citrus has been studied as an important component interacting with Xylella fastidiosa, the causal agent of citrus variegated chlorosis(CVC). This bacterium may also colonize some model plants, such as Catharanthus roseus and Nicotiana clevelandii. In the present study, we compared the endophytic colonization of Citrus sinensis and Catharanthus rose us using the endophytic bacteria Klebsiella pneumoniae. We chose an appropriate strain, K. pneumoniae 342 (Kp342), labeled with the GFP gene. This strain was inoculated onto seedlings of C. sinensis and C. roseus. The isolation frequency was determined one week after the inoculation and the endophytic colonization of K. pneumoniae was observed using fluorescence microscopy. Although the endophytic bacterium was more frequently isolated from C. roseus than from C. sinensis, the colonization profiles for both host plants were similar, suggesting that C. roseus could be used as a model plant to study the interaction between endophytic bacteria and X. fastidiosa.

• The Plant Pathology Journal
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• v.15 no.6
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• pp.335-339
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• 1999

Citrus tristeza virus(CTV), an aphid-borne closterovirus, is one of the most destructive pathogens of citrus. It has caused rapid decline in growth, stem pitting and death in citrus trees. A reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed for detection of CTV and investigation of the CTV infection status of citrus and its related cultivars in Cheju island. For RT-PCR based CTV detection, primers were designed to amplify 670bp of coat protein gene. A screening test for CTV in citrus cultivars was conducted from March to July in 1999. Seventy individual citrus trees representing 9 species of 3 genera were tested. The infection rates of CTV for leaves from the years or older trees of late maturing citrus varieties such as Yuzu (C. junos Sieb. ex Tanaka), Navel orange (C.sinensis Osbeck), Kiyomitanger (C. unshiu x C. sinensis), and Shiranuhi ((C. unshiu x C. sinensis) x C. reticulata) were 100%, 80%, 60%, and 60% respectively. The CTV infection rates in Early satsuma mandarins such as 'Miyagawa Early' Satsuma mandarins (C. unshiu Marc. var. Miyagawa) and 'Okitsu Early' Satsuma mandarins (C. unshiu Marc. var. Okitsu) were 100%, and 60%, respectively. CTV was not detected in Cheju native Dangyooja (C. unshiu Marc. var. Osbeck), Trifoliate orange (Poncirus trifoliata) and Kumquat (Fortunella margarita Swingle). In conclusion, RT-PCR assay can be successfully applied to the detection of CTV in citrus trees.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.120.3-121
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• 2003

Relative degree of resistance of citrus to Xanthomonas axonopodis pv. citri, the causal bacterium of canker, was investigated. Growth rate of a bacterium in leaf tissues after infiltration, disease incidence, and percent of lesion area were compared. By using growth rate[(GR=(At - A$\sub$t-1/)/A$\sub$t-1] host plants were differentiated into susceptible and resistant. Growth rates reached to peak at 40 hrs after inoculation and then declined. The growth rate in leaf tissues of a moderately susceptible cultivar, Citrus sinensis vu. Lane late(sweet orange), was the highest, and those of C. unshiu ${\times}$ C. sinensis(kiyomi), C. junos(yuzu), [(Citrus. unshiu x C. sinensis) x C. reticulata] (shiranuhi), and C. unshiu(satuma mandarin) were similar. This result indicates that the growth rate of the bacterium in leaf tissues can be effectively used for evaluation of disease resistance for citrus plants to X. axonopodis pv. citri. The disease on sweet orange occurred earlier than relatively resistant citrus plants tested. The percent of lesion area on leaf was also higher in sweet orange than those of satsuma mandarin, shiranuhi and kiyomi, and yuzu. The disease severity was highest on sweet orange and followed by kiyomi, shiranuhi, satsuma mandarin, and yuzu.

• The Korea Journal of Herbology
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• v.20 no.4
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• pp.113-119
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• 2005

Objectives : The purpose of this study is to determine new source of Jisil(枳實). Methods : Find out the source of Jisil in the history of herbal medicine. Results : 1. The source of jisil(枳實) is known as the immature fruit of Poncirus trifoliata Rafinesqul(Rutaceae) in the Korean Pharmacopoeia Eight Edition, the dried young fruit of Citrus aurantium L. and its cultivars or Citrus sinensis Osbeck(Fam. Rutaceae) in Pharmacopeia of the people's republic of china(English edition 2000). 2. Until Song dynasty, Jisil is the pericarp of the ripe fruit of Poncirus trifoliata 3. From Myeong dynasty the source of jisil(枳實) turn to the immature fruit of C. wilsonii, C. junos, C. aurantiun var. amara Conclusions : The source of Jisil(枳實) is the ripe fruit of Poncirus trifoliata.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.69-77
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• 2007

We examined the depigmentation effect on Korean traditional citrus 17 species. With B16 melanoma cells, we have seen inhibition of the tyrosinase and melanin formation, which eventually were dose dependently decreased by three citrus fruits, immature Citrus unshiu, Citrus hassaku, and Citrus sinensis ${\times}$ reticulata as compared with positive control. Also, we examined expression of tyrosinase, DOPAchrome tautomerase (TRP-2), and DHICA oxidase (TRP-1) which affect melanin synthesis. Especially, immature Citrus unshiu decreased the protein levels of tyrosinase and TRP-1. In conclusion, immature Citrus unshue showed the strongest activity in all the experiments mentioned above and we expect that it can be used for preventing UV-induced pigmentation.

• Journal of Microbiology
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• v.45 no.5
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• pp.388-393
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• 2007

Citrus variegated chlorosis (CVC) is a disease of the sweet orange [Citrus sinensis (L.)], which is caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that has been shown to infect all sweet orange cultivars. Sweet orange trees have been occasionally observed to be infected by Xylella fastidiosa without evidencing severe disease symptoms, whereas other trees in the same grove may exhibit severe disease symptoms. The principal endophytic bacterial species isolated from such CVC-asymptomatic citrus plants is Curtobacterium flaccumfaciens. The Madagascar periwinkle [Citrus sinensis (L.)] is a model plant which has been used to study X. fastidiosa in greenhouse environments. In order to characterize the interactions of X. fastidiosa and C. flaccumfaciens, periwinkle plants were inoculated separately with C. flaccumfaciens, X. fastidiosa, and both bacteria together. The number of flowers produced by the plants, the heights of the plants, and the exhibited disease symptoms were evaluated. PCR-primers for C. flaccumfaciens were designed in order to verify the presence of this endophytic bacterium in plant tissue, and to complement an existing assay for X. fastidiosa. These primers were capable of detecting C. flaccumfaciens in the periwinkle in the presence of X. fastidiosa. X. fastidiosa induced stunting and reduced the number of flowers produced by the periwinkle. When C. flaccumfaciens was inoculated together with X. fastidiosa, no stunting was observed. The number of flowers produced by our doubly- inoculated plants was an intermediate between the number produced by the plants inoculated with either of the bacteria separately. Our data indicate that C. flaccumfaciens interacted with X. fastidiosa in C. roseus, and reduced the severity of the disease symptoms induced by X. fastidiosa. Periwinkle is considered to be an excellent experimental system by which the interaction of C. flaccumfaciens and other endophytic bacteria with X. fastidiosa can be studied.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.390-395
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• 2015

The synthesis of chimeras is a breeding approach for horticultural crops. In our breeding program, a new diploid citrus chimera, named 'Hongrou Taoye' (Citrus sinensis [L.] Osbeck + Citrus unshiu Marc.), was found arising at the junction where a 'Taoye' sweet orange (C. sinensis) scion was grafted onto Satsuma mandarin (C. unshiu). As an artificial chimera, its fruit traits derived from the L1 cell layer, with juice color and carotenoid complement, in which ${\beta}$-cryptoxanthin accumulated predominantly, similar to those of Satsuma mandarin. By contrast, traits originating from the L2/L3 cell layer, including pollen, seed, and rind aroma characteristics, were the same as those of 'Taoye' sweet orange (the scion). SSR and cpSSR analyses showed that both nuclear and chloroplast genomes of the chimera were a combination of both donor parents. 'Hongrou Taoye' thus combined the valuable traits of both donor plants, and therefore has good potential in citrus fresh market.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.136-142
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• 1992

The crude bioflavonoids were obtained by methanol and butanol extraction from Iyophilized orange (Citrus sinensis) peel. And then, its yield was about 0.26% in dry base. Two bioflavonoids were purified by gel filtration and HPLC, and could be identified narirutin and hesperidin through TLC, HPLC, UV spertrum and NMR analysis. The yields of narirutin and hesperidin from a gram of crude bioflavonoids were 42mg and 530mg respectively, and the main fraction of bioflavonoid from orange peel was supposed to be hesperidin. Each component was intravenously injected into Sprague-Dawley rats (1mg/100g body weight) and hesperidin was found to lower their blood pressure significantly (p < 0.001).

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1237-1242
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• 2009

Polymethoxylated flavones (PMFs) extracted from Citrus sinensis 'Jincheng' peel were characterized by chromatographic and spectroscopic techniques. Seven individual PMF were identified. 3, 3', 4', 5, 6, 7-hexamethoxyflavone (HEX), nobiletin (NOB), heptamethoxyflavone (HEP), 5-demethylnobiletin (DN), and tangeretin (TAN) were characterized through electrospray ionization mass spectrometry (ESI-MS) in positive mode of protonated molecular ions $[M+H]^+$, the diagnostic fragment ions, together with the UV-Vis spectra and high performance liquid chromatography (HPLC) elution order from literature data. Sinensetin (SIN) and tetramethyl-O-scutellarein (SCU) were isolated and identified through their MS, $^1H$ nuclear magnetic resonance (NMR) and UV-Vis spectral studies. The levels of PMFs in peels from different cultivars of citrus fruits grown in China were determined for the first time. The results showed that C. aurantium 'Bitter orange' peel was the most promising variety for HEP. C. sinensis peel was a good source for SIN and SCU.