Abstract
A genome-scale cDNA-AFLP screen identified a number of Lotus japonicus genes transcriptionally activated during AM symbiosis. Among the rapid and symbiosis-specific genes, two serine-protease genes, SbtM and SbtS were identified. Analysis of the genomic sequence of L. japonicus revealed the presence of a gene family for SbtM located in at least two clusters each of which contains one pseudogene. Quantitative real-time PCR revealed that the transcript levels of SbtM genes and SbtS are increased during AM and differentially regulated in symbiosis processes. Analyses of roots transformed with SbtM and SbtS promoter-GUS fusions revealed that SbtM and SbtS are specifically induced around fungus-infected regions.We refine the promoter analysis with the aim to identify cis-element acting in early stages of AM development. Functional genetic studies were also performed using RNAi silencing and TILLING of SbtM genes.
