Impact of macrocidins, produced by Phoma macrostoma, on carotenoid profiles of plants

Publication date: Available online 2 May 2015 Source:Biological Control Author(s): M. Hubbard , R.K. Hynes , K.L. Bailey Phoma macrostoma (Montagne) is a bioherbicide that controls broadleaf weeds such as Canada thistle (Cirsium arvense L. (Scop.)) and dandelion (Taraxacum officinale Weber ex F.H. Wigg.), while leaving crop plants, such as wheat (Triticum aestivum L.) and pumpkin (Cucurbita L. spp), unharmed. The bioherbicidal activity of P. macrostoma is largely due to the production of phytotoxic secondary metabolites, macrocidins. While macrocidins produce photobleaching symptoms in susceptible plants, the mechanism(s) by which this occurs are not known. The hypothesis that macrocidins inhibit carotenoid biosynthesis was tested by comparing the carotenoid profiles and other physiological parameters of macrocidin-treated Canada thistle, dandelion, pumpkin and wheat with control plants and plants treated with the known carotenoid biosynthesis inhibitor, diflufenican. Only in susceptible plants, macrocidins induced photobleaching symptoms, lowered total chlorophyll content and reduced photosynthetic gas exchange while increasing the percentage of the carotenoid precursor phytoene. While diflufenican also led to chlorosis in dandelion and thistles, its impacts differed from those of macrocidins in that diflufenican-treated dandelion, thistle and pumpkin had increased total carotenoid and carotenoid precursor content compared to the control. Diflufenican-treated dandeli...

Source: Biological Control - May 7, 2015 Category: Biology Source Type: research