Abstract
Recently, our laboratory has established a novel system for producing mutants by T-DNA transformation called nolac (non-organogenic callus with loosely attached cells), which involves in vitro cultures of leaf disks of haploid Nicotiana plumbaginifolia. A new mutant, nolac-K4 lost the ability to form tight intercellular attachments and adventitious shoots. Three genes tagged with T-DNA were examined with RNA gel blot analysis and homology search. As a result, we selected a candidate gene (L445) responsible for nolac-K4 mutation. The sequence analysis of L445 revealed that this gene has two domains, a receptor-like LRR (leucine-rich repeat) domain, and an extensin domain that presumably functions in the association with cell wall. L445 mRNA was abundant in roots and leaves, and slightly found in flowers. Now, we are verifying that LRR-EXTENSIN participates in the intercellular attachment and communication.
