Involvement of a tobacco leucine-rich repeat-extensin in cell morphogenesis
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The unique mutant <i>nolac-K4</i> (<u>n</u>on-<u>o</u>rganogenic callus with <u>l</u>oosely <u>a</u>ttached <u>c</u>ells), which was generated by T-DNA transformation using leaf-disk cultures of haploid <i>Nicotiana plumbaginifolia</i>, has lost the ability to form adventitious shoots and also shows decreased intercellular attachment. The gene tagged with the T-DNA in this line, named <i>NpLRX1</i> (LRR-EXTENSIN 1), is a novel tobacco gene that encodes a cell-wall protein containing chimeric leucine-rich repeat and extensin domains. The gene is highly similar to the <i>Arabidopsis LRX</i> genes, and phylogenetic analysis places it in the vegetative <i>LRX</i> clade. <i>NpLRX1</i> is expressed ubiquitously in vegetative tissues, strongly in the leaf and root vascular bundles, and in emerging lateral roots and root tips. Tobacco leaf disks transformed with an <i>NpLRX1</i>-RNAi construct displayed aberrant adventitious buds and disorganized cell morphogenesis with large intercellular spaces. The shapes of <i>NpLRX1</i>-RNAi-transformed BY-2 cells were irregular, and the cells showed disorganized cortical microtubules. These results suggest that <i>NpLRX1</i>, the lack of which may be responsible for the <i>nolac-K4</i> mutation, is a new tobacco <i>LRX</i> gene that has regulatory roles in cell morphogenesis that are essential for plant tissue development.
- Plant tissue culture letters
Plant tissue culture letters 24(2), 171-177, 2007-03-01
Japanese Society for Plant Cell and Molecular Biology