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ABSTRACT Alternaria citri, a postharvest pathogen, produces endopolygalacturonase (endoPG) and causes black rot on citrus fruit. We previously described that an endoPG-disrupted mutant of Alternaria citri was significantly reduced in its ability to macerate plant tissue and cause black rot symptoms on citrus. In order to investigate colonization of citrus fruit tissues by Alternaria citri, pTEFEGFP carrying a green fluorescent protein (GFP) gene was introduced into wild-type Alternaria citri and its endoPG-disrupted mutant (M60). Green fluorescence was observed in spores, germ tubes, appressoria, and infection hyphae of transformants G1 (derived from wild type) and GM4 (derived from M60). Hyphae of G1 but not GM4 vertically penetrated the peel, but the hyphae of both G1 and GM4 spread equally in the juice sac area of citrus fruit. Green fluorescence of Alternaria citri transformant EPG7 carrying a GFP gene under control of the endoPG gene promoter of Alternaria citri was induced by pectin in the peel during the infection stage, but repressed completely in the juice sac area, likely by carbon catabolite repression by sugars in the juice. 相似文献
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Masaki Kiryu Miho Hamanaka Kayo Yoshitomi Susumu Mochizuki Kazuya Akimitsu Kenji Gomi 《Journal of General Plant Pathology》2018,84(3):221-229
Plant volatile compounds, including terpenes, are known to be involved in the rice defense system. In the present analysis of a terpene synthase, OsTPS18, in rice, we found that OsTPS18 was localized in the cytoplasm and synthesized the sesquiterpenes (E)-nerolidol and (E)-β-farnesene. The amounts of (E)-nerolidol and (E)-β-farnesene increased after jasmonic acid (JA) treatment. (E)-Nerolidol had significant antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo). These results suggest that (E)-nerolidol plays an important role in JA-induced resistance against Xoo and that it functions as an antibacterial compound in rice. 相似文献
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ABSTRACT A gene (AcCreA) encoding a catabolite repression element (CreA) with (two zinc fingers of the Cys(2)His(2) type was isolated from the postharvest fungal pathogen Alternaria citri. The AcCreA overexpression mutant AcOEC2 of A. citri showed normal growth on pectin medium and on segments of peel or the juice sac area from citrus fruit. Production of endopolygalacturonase, an essential virulence factor of this pathogen, was similar in AcOEC2 and the wild type in pectin-containing media. However, addition of glucose to the medium showed that carbon catabolite repression of endopolygalacturonase gene (Acpg1) expression, as well as endopolygalacturonase production, was lost in AcOEC2. The wild-type strain of A. citri causes rot mainly in the central axis of citrus fruit without development of rotting in the juice sac area; however, AcOEC2 caused severe black rot symptoms in both the central axis and juice sac areas. These results indicate that AcCreA-mediated catabolite repression controls the virulence or infection of this pathogen, and that the wild-type A. citri does not cause symptoms in the juice sac area due to carbon catabolite repression by sugars in the juice of the juice sac area. 相似文献
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Yumiko Yamasaki Hitoshi Kunoh Hiroyuki Yamamoto Kazuya Akimitsu 《Journal of General Plant Pathology》2007,73(3):168-179
Volatile compounds of plants, including monoterpenes, are a possible source of signal molecules that induce defense systems
to protect plants from tissue damage. Volatile compounds from rough lemon leaves were trapped by solid-phase microextraction
fibers in sealed vials, and subsequent gas chromatography–mass spectrometry and gas chromatography analyses identified the
profile of the major components, mainly various monoterpenes. Among several monoterpenes examined, citral, citronellal, and
linalool significantly inhibited the spore germination and hyphal growth of Alternaria alternata. The effect of linalool was fungistatic, while the effects of citral and citronellal were partially fungicidal. Wounding
of rough lemon leaves induced a significant increase in release of monoterpenes. The release of linalool was the most abundant
and was 14.5 times that of unwounded rough lemon leaves. Unlike the wounding treatment, microbe attack did not significantly
change monoterpene releases, and there was statistically no difference found in the peak areas from microbe-treated and untreated
leaves. Linalool, limonene, and β-pinene also had insect-repellant effects on wild-type Drosophila melanogaster. Expression patterns of defense-related genes in rough lemon and rice significantly changed after treatment with vapors of
monoterpene volatiles. Taking these results together, monoterpene volatiles are likely to play roles in the defense of rough
lemon against microbe and insect pathogens. 相似文献
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Kaji Ryoma Yariuchi Rina Fujii Yumi Taniguchi Shiduku Uji Yuya Suzuki Go Kashihara Keita Kisaki Gan Suezawa Katsuhiko Ohtani Mamoru Kataoka Ikuo Akimitsu Kazuya Gomi Kenji 《Journal of General Plant Pathology》2021,87(6):361-365
Journal of General Plant Pathology - Kiwifruit bacterial canker, which is caused by Pseudomonas syringae pv. actinidiae biovar 3 (Psa3), is found throughout kiwifruit-growing countries. Here, we... 相似文献
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Takabatake N Okamura M Yokoyama N Ikehara Y Akimitsu N Arimitsu N Hamamoto H Sekimizu K Suzuki H Igarashi I 《Veterinary parasitology》2007,148(2):93-101
Recent in vitro-based studies using several Babesia spp. have suggested that sialic acids and/or sialoglycoproteins on host red blood cells (RBCs) play an important role in their invasion of RBCs. In the present study, we analyzed the RBC characteristics of glycophorin A (GPA)-knockout mice and studied their in vivo susceptibility to lethal infection of Babesia rodhaini for the first time. In immunoblot and lectin blot analyses, glycoproteins containing O-linked oligosaccharides terminated with alpha2-3-linked sialic acids disappeared from the RBCs of GPA homozygous ((-/-)) mice. Flow cytometric analysis showed a remarkable reduction of Maackia amurensis lectin II binding to the surface of GPA(-/-) RBCs relative to control RBCs, indicating an appreciable loss of alpha2-3-linked sialic acids on the RBC surface of GPA(-/-) mice. Importantly, while B. rodhaini caused lethal infection in wild-type mice, the infected GPA(-/-) mice showed inhibition of parasite growth and eventually survived. These results indicate that RBC sialoglycoproteins lost in GPA(-/-) mice are involved in the in vivo growth of B. rodhaini, probably functioning as essential molecule(s) for the parasite invasion of host RBCs in the blood circulation. 相似文献
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Atsushi Furuta Kazi Abdus Salam Idam Hermawan Nobuyoshi Akimitsu Junichi Tanaka Hidenori Tani Atsuya Yamashita Kohji Moriishi Masamichi Nakakoshi Masayoshi Tsubuki Poh Wee Peng Youichi Suzuki Naoki Yamamoto Yuji Sekiguchi Satoshi Tsuneda Naohiro Noda 《Marine drugs》2014,12(1):462-476
Hepatitis C virus (HCV) is an important etiological agent that is responsible for the development of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV nonstructural protein 3 (NS3) helicase is a possible target for novel drug development due to its essential role in viral replication. In this study, we identified halisulfate 3 (hal3) and suvanine as novel NS3 helicase inhibitors, with IC50 values of 4 and 3 µM, respectively, from a marine sponge by screening extracts of marine organisms. Both hal3 and suvanine inhibited the ATPase, RNA binding, and serine protease activities of NS3 helicase with IC50 values of 8, 8, and 14 µM, and 7, 3, and 34 µM, respectively. However, the dengue virus (DENV) NS3 helicase, which shares a catalytic core (consisting mainly of ATPase and RNA binding sites) with HCV NS3 helicase, was not inhibited by hal3 and suvanine, even at concentrations of 100 µM. Therefore, we conclude that hal3 and suvanine specifically inhibit HCV NS3 helicase via an interaction with an allosteric site in NS3 rather than binding to the catalytic core. This led to the inhibition of all NS3 activities, presumably by inducing conformational changes. 相似文献