Journal of the Brazilian Chemical Society
Print version ISSN 0103-5053
MEDEIROS, Lívia S. de et al. Evaluation of herbicidal potential of depsides from Cladosporium uredinicola, an endophytic fungus found in Guava fruit. J. Braz. Chem. Soc. [online]. 2012, vol.23, n.8, pp. 1551-1557. Epub Aug 16, 2012. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532012005000018.
Two natural products produced by Cladosporium uredinicola, an endophytic fungus isolated from guava fruit, were evaluated for their effects on photosynthesis. Both of them inhibited electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV), acting as Hill reaction inhibitors in freshly lysed spinach thylakoids. These polyketides, belonging to depsides class, inhibited partial reactions of photosystem II (PS II) electron flow from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), from water to sodium silicomolybdate (SiMo Na+), and partially inhibited electron flow from 1,5-diphenylcarbazide (DPC) to 2,6-dichloroindophenol (DCPIP). These results established that the depsides sites of inhibition are located on the donor and acceptor sides of PS II, between P680 and QA. Chlorophyll a fluorescence measurements corroborated this mechanism of action. None of the tested compounds inhibited photosystem I (PS I) electron transport.
Keywords : endophyte; Cladosporium; depsides; Hill reaction inhibitors; photosystem II.