Soybean sterol composition and utilization by Phytophthora sojae.
The sterol fraction of Glycine max (soybean) was found to contain a mixture of 13 major sterols which differed dramatically in composition between seeds and shoots. Typical C4-desmethyl Delta(5)-sterols, including sitosterol, predominate the sterol mixture of shoots, whereas C4-methyl sterol intermediates, cycloartenol and 24(28)-methylene cycloartanol, accumulate in seeds. The significance of modified sterol profile of shoot compared to seed was relevant to the physiology of Phytophthora sojae, a phytopathogen of soybean shown to be auxotrophic for sterol. Sterols native to the host plant containing a C4-methyl group, such as cycloartenol, were not utilized by the fungus. Alternatively, all Delta(5)-sterols added to the culture media of P. sojae supported normal growth and promoted viable oospore production. The results demonstrate the importance of sterols in plant-fungal interactions and offer the possibility of bioengineering the phytosterol pathway for resistance to phytopathogens which scavenge specific sterols of the host plant to complete the life cycle.
Marshall
J A
JA
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA.
Dennis
A L
AL
Kumazawa
T
T
Haynes
A M
AM
Nes
W D
WD
D015394:Molecular Structure; D010838:Phytophthora / Q000254:growth & development / Q000378:metabolism*; D013025:Glycine max / Q000737:chemistry / Q000378:metabolism* / Q000382:microbiology; D013261:Sterols / Q000378:metabolism*
D013261:Sterols