OsEDR1 negatively regulates rice bacterial resistance via activation of ethylene biosynthesis.
Rice OsEDR1 is a sequence ortholog of Arabidopsis EDR1. However, its molecular function is unknown. We show here that OsEDR1-suppressing/knockout (KO) plants, which developed spontaneous lesions on the leaves, have enhanced resistance to Xanthomonas oryzae pv. oryzae (Xoo) causing bacterial blight disease. This resistance was associated with increased accumulation of salicylic acid (SA) and jasmonic acid (JA), induced expression of SA- and JA-related genes and suppressed accumulation of 1-aminocyclopropane-1-carboxylic acid (ACC), the direct precursor of ethylene, and expression of ethylene-related genes. OsEDR1-KO plants also showed suppressed production of ethylene. Knockout of OsEDR1 suppressed the ACC synthase (ACS) gene family, which encodes the rate-limiting enzymes of ethylene biosynthesis by catalysing the formation of ACC. The lesion phenotype and enhanced bacterial resistance of the OsEDR1-KO plants was partly complemented by the treatment with ACC. ACC treatment was associated with decreased SA and JA biosynthesis in OsEDR1-KO plants. In contrast, aminoethoxyvinylglycine, the inhibitor of ethylene biosynthesis, promoted expression of SA and JA synthesis-related genes in OsEDR1-KO plants. These results suggest that ethylene is a negative signalling molecule in rice bacterial resistance. In the rice-Xoo interaction, OsEDR1 transcriptionally promotes the synthesis of ethylene that, in turn, suppresses SA- and JA-associated defence signalling.
Shen
Xiangling
X
National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
Liu
Hongbo
H
Yuan
Bin
B
Li
Xianghua
X
Xu
Caiguo
C
Wang
Shiping
S
D000598:Amino Acids, Cyclic / Q000032:analysis / Q000378:metabolism; D000890:Anti-Infective Agents / Q000032:analysis / Q000378:metabolism; D003517:Cyclopentanes / Q000032:analysis / Q000378:metabolism; D005030:Ethylenes / Q000032:analysis / Q000096:biosynthesis* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000187:drug effects / Q000235:genetics; D005998:Glycine / Q000031:analogs & derivatives / Q000378:metabolism; D020082:Magnaporthe / Q000472:pathogenicity; D012275:Oryza / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D054883:Oxylipins / Q000032:analysis / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D010937:Plant Growth Regulators / Q000032:analysis / Q000378:metabolism; D057865:Plant Immunity / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D020156:Salicylic Acid / Q000032:analysis / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014974:Xanthomonas / Q000276:immunology / Q000472:pathogenicity
D000598:Amino Acids, Cyclic; D000890:Anti-Infective Agents; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C023863:1-aminocyclopropane-1-carboxylic acid; C011006:jasmonic acid; C036216:ethylene; D020156:Salicylic Acid; C088137:aminoethoxyvinylglycine; D005998:Glycine