| Research Abstract |
The object of this research is to elucidate the mechanisms of signal transduction and control of the genes involved in plant active defense responses conferring host-pathogen specificity. We intensively characterized the molecular basis involved in the activation and deactivation of plant active defense genes encoding PAL and CHS in pea, particularly focused on the study of the effects of elicitor and suppressor produced by a pea pathogen, Mycosphaerella pinodes. Details of the current status of the studies are,
1.Artificial reconstruction of a members of PAL gene (PSPAL1) and in a small multigene family of pea demonstrated that the conserved sequence motifs of Box 2 and Box 4 were very important in the activation mediated by the treatment with fungal elicitor by so called Loss of Function and Gain of Function Experiments. However, Box 1 functions in a concerted manner with Box 2 and Box 4, probably forming a transcriptional activation complex.
2.Generation of transgenic tobacco carrying the chimeric PSPAL1 promoter-GUS-Nos terminator construct (same types of the chimeric gene as described in 1 except these construct are connected to GUS reporter gene instead of CAT gene) demonstrated that Boxes1,2, and 4, are prerequisite cis-elements in response to the pathogen attack. These elements are also important in response to the activation mediated by the treatment with fungal elicitor. -1,394 to +140 or to +115 of PSPAL1 (translational fusion type) promoter contributed the tissue-specific expression, particularly in the merismatic tissues of roots, lower part of stems and very high expression in the tissues of flower organs where pink pigment is deposited and lignins are vigorously for med. Chimeric fusion of -1,394 to +5 or to -27 exhibited very little GUS expression, indicating that the exonic sequences are important in the expression if transgenic tobacco.
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