Uromyces phaseoli

The methyltransferase that catalyses the formation of 24-ethylidene sterols from 24-methylene precursors in bean rust uredospores (Uromyces phaseoli) can also alkylate lanosterol, 24-methylenecholesterol, zymosterol, and desmosterol to produce C29 sterols.[28- H]-24-Methylenecholesterol was efficiently (ca. 3% yield) incorporated into withaferin A (88) and withanolide D (89) by Withania somnif-era, whereas [28- H]-24-methylcholesterol did not act as a precursor in this system. However, since feeding experiments with [28- H]-24-methylcholesta-5,24-dien-3/8-ol gave ambiguous results it was not possible to rule out other 4-desmethyl sterols (with C28) as intermediates in withanolide biosynthesis. 

Uromyces phaseoli (Germ tube cell walls) SCB 1 13 1 (70)... 

Ethylene treatment of plants increases levels of 1,3-3-glucan hydrolase and chitinase in bean leaves (105, 106) but not in pea epicotyls (97). The effect of increased hydrolase activities is correlated with retardation in the rate of development of bean rust (Uromyces phaseoli) infections (106). Pretreatment of tomato plants with ethylene (5.0 ppm, 48h) induced resistance to Verticillium and lysis of the mycelium was seen in roots and stem internodes (107). 

A review on the stereochemistry of allylic pyrophosphate metabolism includes much information of relevance to the biosynthesis of triterpenoids. Lanosterol and various of its oxidized derivatives are efficiently utilized by Trichoderma viride for the production of the interesting antibiotic viridin (8). Sterol biosynthesis in the fungus Uromyces phaseoli proceeds by way of lanosterol, not cycloartenol. " When bramble [Rubus fruticosus (Rosaceae)] suspension cultures... 

The second methylation step has recently been demonstrated in vitro in preparations from bramble cell cultures (Fonteneau et al., 1977). The enzyme, which is microsomal, is specific for 24-methylene lophenol (5-F) and will not act on substrates with an intact cyclopropane ring such as 24-methylene cycloartanol (2-F) the product of the reaction is 24-ethylidene lophenol (2-C). A similar enzyme which uses lanosterol (1-A) as substrate was reported in the uredospores of Uromyces phaseoli (Liu and Knoche, 1974), which is one of the few fungi which synthesize C29 sterols (Liu and Knoche, 1976). 

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