Structure and expression of a tobacco β-1,3-glucanase gene

We determined the primary structure of a tobacco β-1,3-glucanase gene. The β-1,3-glucanase gene has a single large intron, and the intron separates coding regions of the signal peptide and the mature enzyme. Analysis of the 5′-flanking region sequence revealed an 11 bp GC-rich element with perfect homology to the putative regulatory sequence of tobacco chitinase genes. RNA blot analysis showed that levels of mRNAs of β-1,3-glucanase and chitinase are coordinately increased in response to ethylene and salicylic acid. Accumulation of β-1,3-glucanase mRNA in suspension-cultured cells is rapidly induced at late logarithmic growth phase. Members of the tobacco β-1,3-glucanase gene families are classified into two subfamilies. One of the subfamilies appeared to be transcriptionally inactive.