01942nas a2200145 4500008004100000022001400041245016600055210006900221260001600290300002000306520136300326100001701689700002001706856007001726 2018 eng d a0031-949X00aDistinct Trophic Specializations Affect How Phytophthora ramorum and Clade 6 Phytophthora spp. Colonize and Persist on Umbellularia californica Leaves in Streams0 aDistinct Trophic Specializations Affect How Phytophthora ramorum cJun-05-2018 aPHYTO-06-17-0193 a
Phytophthora spp. are regularly recovered from streams but their ecology in aquatic environments is not well understood. Phytophthora ramorum, invasive in California forests, persists in streams at times when sporulation in the canopy is absent, suggesting that it reproduces in the water. Streams are also inhabited by resident, clade 6 Phytophthora spp., believed to be primarily saprotrophic. We conducted experiments to determine whether differences of trophic specialization exist between these two taxa, and investigated how this may affect their survival and competition on stream leaf litter. P. ramorum effectively colonized fresh (live) rhododendron leaves but not those killed by freezing or drying, whereas clade 6 species colonized all leaf types. However, both taxa were recovered from naturally occurring California bay leaf litter in streams. In stream experiments, P. ramorum colonized bay leaves rapidly at the onset; however, colonization was quickly succeeded by clade 6 species. Nevertheless, both taxa persisted in leaves over 16 weeks. Our results confirm that clade 6 Phytophthora spp. are competent saprotrophs and, though P. ramorum could not colonize dead tissue, early colonization of suitable litter allowed it to survive at a low level in decomposing leaves.
1 aAram, Kamyar1 aRizzo, David, M uhttps://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-06-17-0196-R