title: Cyclic nucleotide-gated channel 18 is an essential Ca2+ channel in pollen tube tips for pollen tube guidance to ovules in Arabidopsis.
abstract: In flowering plants, pollen tubes are guided into ovules by multiple attractants from female gametophytes to release paired sperm cells for double fertilization. It has been well-established that Ca(2+) gradients in the pollen tube tips are essential for pollen tube guidance and that plasma membrane Ca(2+) channels in pollen tube tips are core components that regulate Ca(2+) gradients by mediating and regulating external Ca(2+) influx. Therefore, Ca(2+) channels are the core components for pollen tube guidance. However, there is still no genetic evidence for the identification of the putative Ca(2+) channels essential for pollen tube guidance. Here, we report that the point mutations R491Q or R578K in cyclic nucleotide-gated channel 18 (CNGC18) resulted in abnormal Ca(2+) gradients and strong pollen tube guidance defects by impairing the activation of CNGC18 in Arabidopsis. The pollen tube guidance defects of cngc18-17 (R491Q) and of the transfer DNA (T-DNA) insertion mutant cngc18-1 (+/-) were completely rescued by CNGC18. Furthermore, domain-swapping experiments showed that CNGC18's transmembrane domains are indispensable for pollen tube guidance. Additionally, we found that, among eight Ca(2+) channels (including six CNGCs and two glutamate receptor-like channels), CNGC18 was the only one essential for pollen tube guidance. Thus, CNGC18 is the long-sought essential Ca(2+) channel for pollen tube guidance in Arabidopsis.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Qi-Fei
authors.initials: QF
authors.lastname: Gao
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Gu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Hui-Qin
authors.initials: HQ
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Cui-Fang
authors.initials: CF
authors.lastname: Fei
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information Technology, Abbottabad 22060, Pakistan.
authors.forename: Jamshaid
authors.initials: J
authors.lastname: Hussain
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Shu-Jing
authors.initials: SJ
authors.lastname: Sun
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Jing-Yun
authors.initials: JY
authors.lastname: Dong
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Hongtao
authors.initials: H
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; wangyongfei@sibs.ac.cn.
authors.forename: Yong-Fei
authors.initials: YF
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D057809:HEK293 Cells; D006801:Humans; D008564:Membrane Potentials; D020125:Mutation, Missense; D056771:Ovule; D018408:Patch-Clamp Techniques; D051479:Plant Infertility / Q000235:genetics; D030821:Plants, Genetically Modified; D017354:Point Mutation; D053205:Pollen Tube / Q000254:growth & development*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015290:Second Messenger Systems
chemical_list: D029681:Arabidopsis Proteins; C000589714:CNGC18 protein, Arabidopsis; D015220:Calcium Channels; D054815:Cyclic Nucleotide-Gated Cation Channels; D011993:Recombinant Fusion Proteins; C016276:8-bromocyclic GMP; D006152:Cyclic GMP; D002118:Calcium
keywords: Arabidopsis; CNGC18; Ca2+ channel; Ca2+ gradient; pollen tube guidance