Haemoglobin modulates salicylate and jasmonate/ethylene-mediated resistance mechanisms against pathogens.
Nitric oxide (NO) plays a role in defence against hemibiotrophic pathogens mediated by salicylate (SA) and also necrotrophic pathogens influenced by jasmonate/ethylene (JA/Et). This study examined how NO-oxidizing haemoglobins (Hb) encoded by GLB1, GLB2, and GLB3 in Arabidopsis could influence both defence pathways. The impact of Hb on responses to the hemibiotrophic Pseudomonas syringae pathovar tomato (Pst) AvrRpm1 and the necrotrophic Botrytis cinerea were investigated using glb1, glb2, and glb3 mutant lines and also CaMV 35S GLB1 and GLB2 overexpression lines. In glb1, but not glb2 and glb3, increased resistance was observed to both pathogens but was compromised in the 35S-GLB1. A quantum cascade laser-based sensor measured elevated NO production in glb1 infected with Pst AvrRpm1 and B. cinerea, which was reduced in 35S-GLB1 compared to Col-0. SA accumulation was increased in glb1 and reduced in 35S-GLB1 compared to controls following attack by Pst AvrRpm1. Similarly, JA and Et levels were increased in glb1 but decreased in 35S-GLB1 in response to attack by B. cinerea. Quantitative PCR assays indicated reduced GLB1 expression during challenge with either pathogen, thus this may elevate NO concentration and promote a wide-ranging defence against pathogens.
Aberystwyth University, Institute of Biological, Environmental and Rural Sciences, Aberystwyth, Wales, SY23 3DA, UK. lum@aber.ac.uk
Luis A J
LA
Mur
Anushen
A
Sivakumaran
Julien
J
Mandon
Simona M
SM
Cristescu
Frans J M
FJ
Harren
Kim H
KH
Hebelstrup
D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D020171:Botrytis / Q000254:growth & development / Q000502:physiology; D003517:Cyclopentanes / Q000032:analysis / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D005030:Ethylenes / Q000032:analysis / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D006454:Hemoglobins / Q000235:genetics* / Q000378:metabolism; D054884:Host-Pathogen Interactions; D009154:Mutation; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism; D054883:Oxylipins / Q000032:analysis / Q000378:metabolism; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000032:analysis / Q000378:metabolism*; D057865:Plant Immunity / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000502:physiology; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000254:growth & development / Q000502:physiology; D020156:Salicylic Acid / Q000032:analysis / Q000378:metabolism
C470347:AHB1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005030:Ethylenes; D006454:Hemoglobins; D054883:Oxylipins; D010937:Plant Growth Regulators; D009569:Nitric Oxide; C011006:jasmonic acid; C036216:ethylene; D020156:Salicylic Acid