01739nas a2200193   4500008004100000022001400041245012000055210006900175260002900244300001400273490000700287520111500294100001501409700001901424700001401443700001801457700001501475856005501490       2011                        eng d  a1439-032900aRelationship between field resistance to Phytophthora ramorum and constitutive phenolic chemistry of coast live oak0 aRelationship between field resistance to Phytophthora ramorum an  bBlackwell Publishing Ltd  a464–4690 v413 a<p>Sudden oak death, caused by <em>Phytophthora ramorum</em>, has resulted in high levels of coast live oak (CLO) mortality. However, some CLO survive in areas with high disease pressure and may thus be resistant. We tested the hypothesis that such field-resistant trees contain constitutively higher levels of phenolics than susceptible trees. Phloem was sampled from the trunks of two groups of trees (one previously inoculated, one naturally infected with <em>P. ramorum</em>) categorized over the course of several years as putatively resistant (PR, no symptoms), in remission (IR, showed symptoms but then recovered) and symptomatic (S). Individual and total soluble phenolics from these trees were quantified. There were no significant differences in individual or total soluble phenolics between groups of naturally infected trees. However, inoculated PR and IR trees were characterized by higher constitutive levels of ellagic acid, a tyrosol derivative, and an unidentified phenolic than S trees. Ellagic acid and tyrosol-like compounds in CLO phloem are promising resistance biomarker candidates.</p>1 aNagle, A M1 aMcpherson, B A1 aWood, D L1 aGarbelotto, M1 aBonello, P  uhttp://dx.doi.org/10.1111/j.1439-0329.2010.00703.x