title: Transcriptome and proteome analyses provide insight into laticifer's defense of Euphorbia tirucalli against pests.
abstract: The cytoplasm of laticifers, which are plant cells specialized for rubber production and defense against microbes and herbivores, is a latex. Although laticifers share common functions, the protein constituents of latexes are highly variable among plant species and even among organs. In this study, transcriptomic and proteomic analyses of Euphorbia tirucalli's (Euphorbiaceae) latex were conducted to determine the molecular basis of the laticifer's functions in this plant. The hybrid de novo assembly of Illumina mRNA-seq and expressed sequence tags obtained by Sanger's sequencing revealed 26,447 unigenes. A unigene similar to Arabidopsis embryo-specific protein 3 (AT5G62200), which is a PLAT domain-containing protein, and rubber elongation factor showed the highest expression levels. The proteome analysis, studied by liquid chromatography-mass spectrometry with the de novo assembled unigenes as the database, revealed 161 proteins in the latex, 107 of which were not detected in the stem. A gene ontology analysis indicated that the laticifer's proteome was enriched with proteins related to proteolysis, phosphatase, defense against various environmental stresses and lipid metabolisms. D-mannose-binding lectin, ricin (which lacked the N-terminal conserved ribosome-inactivating protein domain), chitinase and peroxidase were highly accumulated, as confirmed by two-dimensional polyacrylamide gel electrophoresis. Thus, the lectins and chitinase may be the major defensive proteins against pests, and the other defense-related proteins and transcripts detected in latex may work in coordination with them. Highly expressing unigenes with unknown functions are candidate novel defense- or rubber production-related genes.
authors: Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto, 606-8585, Japan; The Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto, 606-8585, Japan. Electronic address: sakito@kit.ac.jp.
authors: Sakihito
authors: S
authors: Kitajima
authors: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8572, Japan. Electronic address: miura.kenji.ga@u.tsukuba.ac.jp.
authors: Kenji
authors: K
authors: Miura
authors: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan; Kyoto Integrated Science & Technology Bio-Analysis Center (KIST-BIC), Shimogyo-ku, Kyoto, 600-8813, Japan.
authors: Wataru
authors: W
authors: Aoki
authors: Department of Biotechnological Science, Kinki University, 930 Nishimitani, Kinokawa, Wakayama, 649-6493, Japan.
authors: Katsuyuki T
authors: KT
authors: Yamato
authors: Department of Bioscience and Biotechnology, University of the Ryukyus, Senbaru, Nishihara-cho, Okinawa, 903-0213, Japan.
authors: Toki
authors: T
authors: Taira
authors: Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto, 606-8585, Japan.
authors: Ryuta
authors: R
authors: Murakami
authors: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors: Shunsuke
authors: S
authors: Aburaya
mesh_terms: D000818:Animals; D029681:Arabidopsis Proteins / Q000235:genetics; D002688:Chitinases / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D028481:Euphorbia / Q000235:genetics / Q000502:physiology*; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D007306:Insecticides / Q000494:pharmacology; D007814:Larva / Q000187:drug effects; D007840:Latex / Q000737:chemistry* / Q000378:metabolism; D037102:Lectins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D040901:Proteomics / Q000379:methods; D059467:Transcriptome
chemical_list: D029681:Arabidopsis Proteins; D007306:Insecticides; D007840:Latex; D037102:Lectins; D010940:Plant Proteins; D002688:Chitinases
keywords: Abiotic stress; Anti-insect activity; Chitinase; Lectin; PLAT domain; Phosphatase; Ricin