title: Purple top symptoms are associated with reduction of leaf cell death in phytoplasma-infected plants.
abstract: Plants exhibit a wide variety of disease symptoms in response to pathogen attack. In general, most plant symptoms are recognized as harmful effects on host plants, and little is known about positive aspects of symptoms for infected plants. Herein, we report the beneficial role of purple top symptoms, which are characteristic of phytoplasma-infected plants. First, by using plant mutants defective in anthocyanin biosynthesis, we demonstrated that anthocyanin accumulation is directly responsible for the purple top symptoms, and is associated with reduction of leaf cell death caused by phytoplasma infection. Furthermore, we revealed that phytoplasma infection led to significant activation of the anthocyanin biosynthetic pathway and dramatic accumulation of sucrose by about 1000-fold, which can activate the anthocyanin biosynthetic pathway. This is the first study to demonstrate the role and mechanism of the purple top symptoms in plant-phytoplasma interactions.
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Misako
authors: M
authors: Himeno
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Yugo
authors: Y
authors: Kitazawa
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Tetsuya
authors: T
authors: Yoshida
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Kensaku
authors: K
authors: Maejima
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Yasuyuki
authors: Y
authors: Yamaji
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Kenro
authors: K
authors: Oshima
authors: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors: Shigetou
authors: S
authors: Namba
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D004269:DNA, Bacterial / Q000032:analysis; D054884:Host-Pathogen Interactions; D009005:Monosaccharides / Q000378:metabolism; D032306:Petunia / Q000235:genetics / Q000378:metabolism*; D045582:Phytoplasma / Q000235:genetics / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction
chemical_list: D000872:Anthocyanins; D004269:DNA, Bacterial; D009005:Monosaccharides; D010940:Plant Proteins