Loss of a Conserved tRNA Anticodon Modification Perturbs Plant Immunity.
tRNA is the most highly modified class of RNA species, and modifications are found in tRNAs from all organisms that have been examined. Despite their vastly different chemical structures and their presence in different tRNAs, occurring in different locations in tRNA, the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent discoveries have revealed unprecedented complexity in the modification patterns of tRNA, their regulation and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge on the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance and activation of defenses in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2´-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance during the course of infection with the bacterial pathogen Pseudomonas syringae DC3000, and lack of such tRNA modification, as observed in scs9 mutants, severely compromise plant immunity against the same pathogen without affecting the salicylic acid (SA) signaling pathway which regulates plant immune responses. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective immune response in Arabidopsis, and therefore expands the repertoire of molecular components essential for an efficient disease resistance response.
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
Vicente
V
Ramírez
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
Beatriz
B
Gonzalez
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
Ana
A
López
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
María José
MJ
Castelló
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
María José
MJ
Gil
Graham J
GJ
Etherington
College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.
Bo
B
Zheng
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, HuaZhong Agricultural University, Wuhan, China.
Peng
P
Chen
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain.
Pablo
P
Vera
D000926:Anticodon / Q000235:genetics / Q000276:immunology; D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D008745:Methylation; D057865:Plant Immunity / Q000235:genetics*; D044224:Pseudomonas syringae / Q000276:immunology / Q000472:pathogenicity; D012343:RNA, Transfer / Q000235:genetics* / Q000276:immunology; D012266:Ribose / Q000378:metabolism; D012359:tRNA Methyltransferases / Q000235:genetics* / Q000378:metabolism
D000926:Anticodon; D029681:Arabidopsis Proteins; D012266:Ribose; D012343:RNA, Transfer; C000607994:SCS9 protein, Arabidopsis; D012359:tRNA Methyltransferases