Nucleotide-binding leucine-rich repeat （NLR） proteins serve as immune receptors in both plants and animals. To identify components required for NLR-mediated immunity, we designed and carried out a chemical genetics ...Nucleotide-binding leucine-rich repeat （NLR） proteins serve as immune receptors in both plants and animals. To identify components required for NLR-mediated immunity, we designed and carried out a chemical genetics screen to search for small molecules that can alter immune responses in Arabidopsis thaliana. From 13 600 compounds, we identified Ro 8-4304 that was able to specifically suppress the severe autoimmune phenotypes of chs3-2D （chilling sensitive 3, 2D）, including the arrested growth morphology and heightened PR （Pathogenesis Related） gene expression. Further, six Ro 8-4304 insensitive mutants were uncovered from the Ro 8-4304-insensitive mutant （rim） screen using a mutagenized chs3-2D popula- tion. Positional cloning revealed thatriml encodes an allele of AtlCIn （I, currents; CI, chloride; n, nucleotide）. Genetic and biochemical analysis demonstrated that AtlCIn is in the same protein complex with the meth- ylosome components small nuclear ribonucleoprotein D3b （SmD3b） and protein arginine methyltransferase 5 （PRMT5）, which are required for the biogenesis of small nuclear ribonucleoproteins （snRNPs） involved in mRNA splicing. Double mutant analysis revealed that SmD3b is also involved in the sensitivity to Ro 8-4304, and the prmt5-1 chs3-2D double mutant is lethal. Loss of At/C/n, SmD3b, or PRMT5 function results in enhanced disease resistance against the virulent oomycete pathogen Hyaloperonospora arabidopsidis Noco2, suggesting that mRNA splicing plays a previously unknown negative role in plant immunity. The successful implementation of a high-throughput chemical genetic screen and the identification of a small-molecule compound affecting plant immunity indicate that chemical genetics is a powerful tool to study whole-organism plant defense pathways.展开更多
文摘Nucleotide-binding leucine-rich repeat （NLR） proteins serve as immune receptors in both plants and animals. To identify components required for NLR-mediated immunity, we designed and carried out a chemical genetics screen to search for small molecules that can alter immune responses in Arabidopsis thaliana. From 13 600 compounds, we identified Ro 8-4304 that was able to specifically suppress the severe autoimmune phenotypes of chs3-2D （chilling sensitive 3, 2D）, including the arrested growth morphology and heightened PR （Pathogenesis Related） gene expression. Further, six Ro 8-4304 insensitive mutants were uncovered from the Ro 8-4304-insensitive mutant （rim） screen using a mutagenized chs3-2D popula- tion. Positional cloning revealed thatriml encodes an allele of AtlCIn （I, currents; CI, chloride; n, nucleotide）. Genetic and biochemical analysis demonstrated that AtlCIn is in the same protein complex with the meth- ylosome components small nuclear ribonucleoprotein D3b （SmD3b） and protein arginine methyltransferase 5 （PRMT5）, which are required for the biogenesis of small nuclear ribonucleoproteins （snRNPs） involved in mRNA splicing. Double mutant analysis revealed that SmD3b is also involved in the sensitivity to Ro 8-4304, and the prmt5-1 chs3-2D double mutant is lethal. Loss of At/C/n, SmD3b, or PRMT5 function results in enhanced disease resistance against the virulent oomycete pathogen Hyaloperonospora arabidopsidis Noco2, suggesting that mRNA splicing plays a previously unknown negative role in plant immunity. The successful implementation of a high-throughput chemical genetic screen and the identification of a small-molecule compound affecting plant immunity indicate that chemical genetics is a powerful tool to study whole-organism plant defense pathways.
