A pectin glucuronyltransferase gene is essential for intercellular attachment in the plant meristem

  1. Hiroaki Iwai*,
  2. Nobutaka Masaoka*,
  3. Tadashi Ishii†, and
  4. Shinobu Satoh*,‡
  1. *Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan; and †Forestry and Forest Products Research Institute, Ibaraki 305-8687, Japan

  1. Edited by Maarten J. Chrispeels, University of California at San Diego, La Jolla, CA, and approved October 15, 2002 (received for review September 2, 2002)

Abstract

Intercellular attachment is an essential process in the morphogenesis of multicellular organisms. A unique mutant, nolac-H18 (nonorganogenic callus with loosely attached cells), generated by T-DNA transformation using leaf-disk cultures of haploid Nicotiana plumbaginifolia, lost the ability to form tight intercellular attachments and adventitious shoots. The gene tagged with T-DNA, named NpGUT1 (glucuronyltransferase 1), was similar to the gene for the catalytic domains of animal glucuronyltransferases and was expressed predominantly in shoot and root apical meristems. The transformation of NpGUT1 complemented the nolac-H18 mutation, and the expression of antisense NpGUT1 RNA produced crumbled shoots. The mutation caused defects in the glucuronic acid of rhamnogalacturonan II of pectin, which drastically reduced the formation of borate cross-linking of rhamnogalacturonan II. NpGUT1, which encodes a unique glucuronyltransferase, is a glycosyltransferase gene identified in pectin biosynthesis and is essential for intercellular attachment in plant meristems and tissues.

Footnotes

  • ↵ ‡ To whom correspondence should be addressed. E-mail: pdp{at}sakura.cc.tsukuba.ac.jp.

  • This paper was submitted directly (Track II) to the PNAS office.

  • Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. , , and ).

  • See commentary on page 15843.

  • Abbreviations:

    1. HG, homogalacturonan

    2. RG, rhamonogalacturonan

    3. mRG, monomeric RG

    4. dRG, dimeric RG

    5. NpGUT1, glucuronyltransferase 1

    6. nolac, nonorganogenic callus with loosely attached cells

    7. EPG, endo-polygalacturonase

    8. GUS, β-glucuronidase

    9. EXT, exostose

    10. GlcA, glucuronic acid

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  1. Published online before print November 25, 2002, doi: 10.1073/pnas.252530499 PNAS December 10, 2002 vol. 99 no. 25 16319-16324
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