title: Reexamination of chlorophyllase function implies its involvement in defense against chewing herbivores.
abstract: Chlorophyllase (CLH) is a common plant enzyme that catalyzes the hydrolysis of chlorophyll to form chlorophyllide, a more hydrophilic derivative. For more than a century, the biological role of CLH has been controversial, although this enzyme has been often considered to catalyze chlorophyll catabolism during stress-induced chlorophyll breakdown. In this study, we found that the absence of CLH does not affect chlorophyll breakdown in intact leaf tissue in the absence or the presence of methyl-jasmonate, which is known to enhance stress-induced chlorophyll breakdown. Fractionation of cellular membranes shows that Arabidopsis (Arabidopsis thaliana) CLH is located in the endoplasmic reticulum and the tonoplast of intact plant cells. These results indicate that CLH is not involved in endogenous chlorophyll catabolism. Instead, we found that CLH promotes chlorophyllide formation upon disruption of leaf cells, or when it is artificially mistargeted to the chloroplast. These results indicate that CLH is responsible for chlorophyllide formation after the collapse of cells, which led us to hypothesize that chlorophyllide formation might be a process of defense against chewing herbivores. We found that Arabidopsis leaves with genetically enhanced CLH activity exhibit toxicity when fed to Spodoptera litura larvae, an insect herbivore. In addition, purified chlorophyllide partially suppresses the growth of the larvae. Taken together, these results support the presence of a unique binary defense system against insect herbivores involving chlorophyll and CLH. Potential mechanisms of chlorophyllide action for defense are discussed.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Xueyun
authors.initials: X
authors.lastname: Hu
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Satoru
authors.initials: S
authors.lastname: Makita
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Silvia
authors.initials: S
authors.lastname: Schelbert
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Sano
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Masanori
authors.identifier: http://orcid.org/0000-0002-0022-347X
authors.initials: M
authors.lastname: Ochiai
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsuchiya
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Shigeaki F
authors.initials: SF
authors.lastname: Hasegawa
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Stefan
authors.initials: S
authors.lastname: Hörtensteiner
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.).
authors.forename: Ayumi
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan (X.H., M.O., S.F.H., A.T., R.T.);Odawara Research Center, Nippon Soda Co., Ltd., Odawara 250-0280, Japan (S.M., S.Sa.);Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland (S.Sc., S.H.);Graduate School of Global Environmental Studies (T.T.) and Graduate School of Human and Environmental Studies (T.T.), Kyoto University, Kyoto 606-8501, Japan; and Japan Core Research for Evolutionary Science and Technology, Japan Science Technology Agency, Sapporo 060-0819, Japan (A.T., R.T.) rtanaka@lowtem.hokudai.ac.jp.
authors.forename: Ryouichi
authors.identifier: http://orcid.org/0000-0002-5858-5326
authors.initials: R
authors.lastname: Tanaka
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology* / Q000469:parasitology; D012831:Bombyx / Q000502:physiology; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D002735:Chlorophyllides / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism; D060434:Herbivory / Q000187:drug effects; D007814:Larva / Q000502:physiology; D008409:Mastication; D009154:Mutation; D054883:Oxylipins / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000469:parasitology; D021381:Protein Transport / Q000187:drug effects; D018411:Spodoptera / Q000502:physiology; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism
chemical_list: D000085:Acetates; D002735:Chlorophyllides; D003517:Cyclopentanes; D054883:Oxylipins; D002734:Chlorophyll; C072239:methyl jasmonate; D002265:Carboxylic Ester Hydrolases; C019875:chlorophyllase