화학유전체학을 이용한 뿌리 발달 조절 기작의 연구

Genetic variation can produce natural phenotypic diversity within a species. Understanding the molecular basis of how natural genetic variation is translated into specific phenotypic variation has been one of the central questions in genetics. Many single nucleotide polymorphisms (SNPs) are found in plant NB-LRR (Nucleotide Binding-Leucine Rich Repeat) genes, which are proposed to provide diversification in race-specific disease responses. However, a possible role of various SNPs other than for immune signaling remains to be investigated.  Here we report that Arabidopsis Columbia strain-specific amino acid substitutions in a TIR (Toll-Interleukin1 Receptor)-NB-LRR protein cause root meristem arrest in response to a specific compound, DFPM, via plant immune signal transduction.

Using chemical genetics, we have identified this novel DFPM compound that generates a strain-specific root development arrest phenotype. The genetic locus responsible for this natural variation, VICTR (Variation In Chemically Triggered Root development response) was isolated and encodes a NB-LRR protein expressed specifically in the root meristem. Disruption of the root arrest response in victr null alleles and recapitulation of the chemical response in the Landsberg, Bayreuth, and C24 strains by expression of VICTR-Col demonstrates that VICTR causes the chemically-induced root meristem arrest. Furthermore, major regulators of race-specific disease signaling pathways are required for this developmental response. These findings show that a previously unexplored function of plant immune signaling lies in the control of root growth and development. Data suggest that the recent evolution or retention of the ancient VICTR locus in the Columbia strain provides a specific chemical perception mechanism that triggers disruption of primary root growth.