title: Yeast nitrogen utilization in the phyllosphere during plant lifespan under regulation of autophagy.
abstract: Recently, microbe-plant interactions at the above-ground parts have attracted great attention. Here we describe nitrogen metabolism and regulation of autophagy in the methylotrophic yeast Candida boidinii, proliferating and surviving on the leaves of Arabidopsis thaliana. After quantitative analyses of yeast growth on the leaves of A. thaliana with the wild-type and several mutant yeast strains, we showed that on young leaves, nitrate reductase (Ynr1) was necessary for yeast proliferation, and the yeast utilized nitrate as nitrogen source. On the other hand, a newly developed methylamine sensor revealed appearance of methylamine on older leaves, and methylamine metabolism was induced in C. boidinii, and Ynr1 was subjected to degradation. Biochemical and microscopic analysis of Ynr1 in vitro during a shift of nitrogen source from nitrate to methylamine revealed that Ynr1 was transported to the vacuole being the cargo for biosynthetic cytoplasm-to-vacuole targeting (Cvt) pathway, and degraded. Our results reveal changes in the nitrogen source composition for phyllospheric yeasts during plant aging, and subsequent adaptation of the yeasts to this environmental change mediated by regulation of autophagy.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Shiraishi
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Masahide
authors.initials: M
authors.lastname: Oku
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kawaguchi
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Uchida
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Yurimoto
authors.affiliation: 1] Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan [2] Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan [3] Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency, K's Gobancho, 7 Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Sakai
mesh_terms: D017360:Arabidopsis / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects; D000071183:Autophagy-Related Proteins; D002175:Candida / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D008136:Longevity; D008744:Methylamines / Q000494:pharmacology; D018613:Microscopy, Confocal; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D021381:Protein Transport / Q000187:drug effects; D014617:Vacuoles / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: C000592959:AUTOPHAGY-RELATED11 protein, Arabidopsis; D029681:Arabidopsis Proteins; D000071183:Autophagy-Related Proteins; D008744:Methylamines; D033921:Vesicular Transport Proteins; C027451:methylamine; D050901:Nitrate Reductase; D009584:Nitrogen