Leptosphaeria

Leptosins D-F (258a-c, Scheme 39) [94JCS(P1)1859] were isolated by Takahashi and co-workers from the culture of a strain of Leptosphaeria sp. as cytotoxic substances against the P388 lymphocytic leukemia cell line comparable to that of mitomycin C. Utilizing the nucleophilic substitution reaction of 1-hydroxytryptamines, a simple methodology for the synthesis of core structures of leptosins has been developed (2000H1255). 

Dimeric structures are possible as exemplified by the leptosins, from a strain of Leptosphaeria (a fungus isolated from the marine alga Sargassum tortile). Some of these, e.g. leptosin A 11, may have up to 4 sulfur atoms across the diketopiperazine ring system.23 Various leptosins have antitumor and cytotoxic properties. 

Applications of Fertilizers for Control of Rice Diseases. In general, the application of fertilizers cannot be relied upon to solve all our major rice disease problems however, the application of properly balanced fertilizers reduces the severity of certain major diseases. Work on stem rot (Leptosphaeria salvinii Catt.) in Arkansas (3) and Japan (26) shows that the severity of stem rot can be reduced by increasing the potassium levels of soils in the problem areas. In Arkansas it has been shown that the application of nitrogenous fertilizer significantly increases stem rot severity, whereas the application of potassium fertilizer alone or in combination with nitrogenous fertilizers decreases stem rot severity. Consequently, in Arkansas the application of potassium fertilizer is widely practiced for stem rot control. 

Fig. 9.1 Chemical structures of non-selective phytotoxins 1-6 and host-selective phytotoxin 7 produced by canola virulent isolates of Leptosphaeria maculans. Phytotoxins 1-7 are produced in a chemically defined medium...

Fig. 9.5 Chemical structures of elicitors from Leptosphaeria maculans isolate virulent on canola produced in minimal medium cerebrosides C (13) and D (14)...

Hewlett BJ, Idnurm A, Pedras MSC (2001) Leptosphaeria maculans, the causal agent of blackleg disease of Brassicas. Fungal Gen Biol 33 1-14... 

Chen Y Fernando WGD (2006) Prevalence of pathogenicity groups of Leptosphaeria maculans in western Canada and North Dakota, USA. Can J Plant Pathol 28 533-539... 

Kutcher HR, Keii M, McLaren DL, Rimmer SR (2007) Pathogenic variabihty of Leptosphaeria maculans in western Canada. Can J Plant Pathol 29 388-393... 

Shoemaker RA Brun H (2001) The teleomorph of the weakly aggressive segregate of Leptosphaeria maculans. Can J Plant Bot 79 412-419... 

Taylor JL, Pedras MSC, Morales VM (1995) Horizontal transfer in the phytopathogenic fungal genus Leptosphaeria and host-range expansion. Trends Microbiol 3 202-206... 

Pedras MSC Biesenthal CJ (1998) Production of the host-selective phytotoxin phomalide by isolates of Leptosphaeria maculans and its correlation with sirodesmin PL production. Can J Microbiol 44 547-553... 

Elhott CE, Gardiner DM, Thomas G, Cozijnsen A, De Wouw AV, Hewlett BJ (2007) Production of the toxin sirodesmin PL by Leptosphaeria maculans during infection of Brassica napus. Mol Plant Pathol 8 791-802... 

Pedras MSC Yu Y (2008) Structure and biological activity of maculansin A, a phytotoxin from the phytopathogenic fungus Leptosphaeria maculans. Phytochemistry 69 2966-2971... 

Pedras MSC, Gadagi RS, Jha M, Sarma-MamiUapalle VK (2007) Detoxification of the phytoalexin brassinin by isolates of Leptosphaeria maculans pathogenic on brown mustard involves an inducible hydrolase. Phytochemistry 68 1572-1578... 

The polysulfide leptosins (121-135) belong to a series of epipolythiodioxopiperazines produced by a fungal strain Leptosphaeria sp. OUPS-4, isolated from the marine alga Sargassum tortile [125, 126, 127, 128]. 

A new diketopiperazine (475) and two new epidithiodioxopiperazines (476 and 477), whose structures are very similar to leptosins (e.g. 121) isolated from the fungal strain Leptosphaeria sp. [125-128], were obtained from a marine isolate of the fungus Penicillium and they exhibited cytotoxic activity [362]. 

Andreasson, E., Wretblad, S., Graner, G, Wu, X.M., Zhang, J.M, Dixelius, C., Rask, L., Meijer, J. The myrosinase-glucosinolate system in the interaction between Leptosphaeria maculans and Brassica napus. Mol Plant Pathol 2001 21 281-286. 

Griffiths, K.M., Bacic, A., Howlett, B.J. Sterol composition of mycelia of die plant pathogenic ascomycete Leptosphaeria maculans. Phytochemistry 2003 62 147-153. 

Guerriero, A., D Ambrosio, M., Cuomo, V., and Pietra, F., A novel, degraded polyketidic lactone, leptosphaerolide, and its likely diketone precursor, leptosphaerodione. Isolation from cultures of the marine ascomycete Leptosphaeria oraemaris (Linder), Helv. Chim. Acta, 74, 1445, 1991. 

MITHEN, R.F., LEWIS, B.G., In vitro activity of glucosinolates and their products against Leptosphaeria maculans., Trans. Br. Mycol. Soc., 1986,87,433-440. 

Sexton, A.C. and Howlett, B.J. 2000. Characterization of a cyanide hydratase gene in the phy-topaihog dicfxmgvis Leptosphaeria maculans. Gene, 263 463-470. 

Lucas, M. T. Webster, J. (1967). Conidial states of British species of Leptosphaeria. Transactions of the British Mycological Society, 50, 85-121. 

Liu, J.-Y Liu, C.-H. Zou, W.-X. Tan, R.-X. Leptosphaeric acid, a metaboUte with a novel carbon skeleton from Leptosphaeria Sp. Iv403, an endoph3dic fungus in Artemisia-annua. Helv. Chim. Acta, 2003, 86 657-660. 

Leptosphaeria senegalensis and L. thompkinsii cause mycetoma in Africa [80]. Coniothyrium fuckelii is the anamorph of L. coniothyrium. It is known as a plant pathogen especially on Rosaceae and from human infections [80]. 

Raspberry cane diseases (Didymella applanata, Leptosphaeria coniothyrium, Botrytis cinerea, Elsinoe venta)... 

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