Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis

Journal Article · Mon Nov 28 00:00:00 EST 2016 · Plant Cell

DOI:https://doi.org/10.1105/tpc.16.00186· OSTI ID:1379600

Fang, Lin  ^[1]; Ishikawa, Toshiki ^[2]; Rennie, Emilie A. ^[1]; Murawska, Gosia M.  ^[1]; Lao, Jeemeng ^[1]; Yan, Jingwei ^[1]; Tsai, Alex Yi-Lin ^[1]; Baidoo, Edward E. K. ^[1]; Xu, Jun  ^[3]; Keasling, Jay D.  ^[4]; Demura, Taku ^[5]; Kawai-Yamada, Maki ^[2]; Scheller, Henrik V.  ^[6]; Mortimer, Jenny C.  ^[4]

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1. Joint BioEnergy Inst., Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division
2. Saitama Univ. (Japan). Graduate School of Science and Engineering
3. Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
4. Joint BioEnergy Inst., Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
5. RIKEN, Yokohama (Japan). Center for Sustainable Resource Science, Biomass Engineering Program; Nara Inst. of Science and Technology, Nara (Japan). Graduate School of Biological Sciences
6. Joint BioEnergy Inst., Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology

Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ~25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologous expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1379600
• Journal Information: Plant Cell, Vol. 28, Issue 12; ISSN 1040-4651
• Publisher: American Society of Plant Biologists
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES