LC-MS/MS analysis was used to identify two new flavonoid phytoalexins induced in response to inoculation of a resistant and susceptible cultivar of sorghum with Colletotrichum sublineolum [64]. Luteolin and apigenin were both present at higher concentrations in these cultivars suggestive of a phytoalexin role. Fungal germination bioassays indeed found luteolin to Inhibitors,research,lifescience,medical strongly inhibit fungal growth and spore germination; effects were similar but less dramatic for apigenin. A number of flavonoid compounds require compartmentalisation in the cell to avoid mutagenic and oxidative effects of the active compounds and intermediates in their synthetic

pathways. In maize, barley and rye a number of different mechanisms of vacuolar import have been identified including a vacuolar ATP-binding cassette (ABC)

transporter, multidrug resistance-associated protein like ABC transporter and pH-dependent vacuolar flavonoid/H+ antiporters [65-68]. The synthesis of the flavone saponarin in mesophyll Inhibitors,research,lifescience,medical protoplasts without vacuoles was inhibited indicating that a functioning vacuole is critical for production of this flavone [69]. Flavonoids have recently been the subject of investigation into metabolic engineering Inhibitors,research,lifescience,medical of crop plants for the http://www.selleckchem.com/products/AZD2281(Olaparib).html purposes of disease resistance to health benefits for humans [70]. Transgenic wheat and barley were constructed expressing a stilbene synthase gene from Vitis vinifera (Common Grape Vine) resulting in the production of the phytoalexin resveratrol (Figure 1) [71]. The authors present results detailing increased

resistance of wheat and barley producing resveratrol to the necrotrophic pathogen Inhibitors,research,lifescience,medical Botrytis cinerea. 5. Cyanogenic Glycosides Cyanogenic glycosides are present in over 2,600 plant species and a number of cereals including wheat, barley, oats, rye, sorghum, millets, sugar cane, maize and rice [72]. These Inhibitors,research,lifescience,medical compounds are derived from the amino acids valine, leucine, isoleucine, phenylalanine or tyrosine and the non-protein amino acid cyclopentenyl-glycine as path of the shikimate pathway (Figure 1) [73]. To avoid toxic release of hydrogen cyanide (HCN) under normal conditions, cyanogenic glycosides are compartmentalised within cells separated from the HCN releasing β-glucosidases. Cyanogenic glycosides are activated by β-glucosidase-dependent www.selleckchem.com/products/carfilzomib-pr-171.html hydrolysis to form the unstable aglycone upon tissue disruption. This cyanohydrin is further enzymatically (hydroxynitrile lyase) Entinostat or spontaneously (at alkaline pH) converted to a ketone or an aldehyde and the toxic constituent of the compound, HCN [74,75]. Cyanide is toxic to cells inhibiting the oxidative function of mitochondria cytochrome oxidase thereby reducing the cells ability to use oxygen for aerobic respiration [76,77]. The cyanogenic glycoside dhurrin (Figure 1) found in Sorghum is only located in the epidermal layers of the leaf while the β-glucosidases and α-hydroxynitrile lyase enzymes capable of activation and release of HCN were located only in mesophyll tissue [78].