Salicylic acid mediated immune response of Citrus sinensis to varying frequencies of herbivory and pathogen inoculation

BMC Plant Biology

Lukasz L. Stelinski¹  Freddy Ibanez²  Monique Rivera³  Yu Wang⁴  Joon Hyuk Suh⁴  Mamoudou Setamou⁵ 

[1] Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, 33850, Florida, USA;Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, 33850, Florida, USA;Present address: Texas A&M University-AgriLife Research, 2415 E Highway 83 –, 78596, Weslaco, TX, USA;Department of Entomology, University of California Riverside, Riverside, 92521, California, USA;Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, 33850, Florida, USA;Texas A&M University-Kingsville Citrus Center, 312 N International Blvd, 78599, Weslaco, TX, USA;

关键词: Salicylic acid;    Diaphorina citri;    Plant defense;    Metabolomics;    Gene expression;    Vector-host-pathogen interactions;    Huanglongbing;   

DOI  :  10.1186/s12870-021-03389-5

来源: Springer

【 摘 要 】

BackgroundPlant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CaLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease.ResultsA one-time (7 days) inoculation access period with CaLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response after a long period of infection without herbivory (270 and 360 days). In contrast, while repeated (monthly) ‘pulses’ of 7 day feeding injury by psyllids stimulated immunity in CaLas-infected citrus by increasing SA in leaves initially (up to 120 days), long-term (270 and 360 days) repeated herbivory caused SA to decrease coincident with upregulation of genes associated with SA metabolism (BMST and DMR6). Similarly, transcriptional responses and metabolite (SA and its analytes) accumulation in citrus leaves exposed to a continuously reproducing population of D. citri exhibited a transitory upregulation of genes associated with SA signaling at 120 days and a posterior downregulation after long-term psyllid (adults and nymphs) feeding (270 and 360 days).ConclusionsHerbivory played an important role in regulation of SA accumulation in mature leaves of C. sinensis, whether or not those trees were coincidentally infected with CaLas. Our results indicate that prevention of feeding injury inflicted by D. citri from the tritrophic interaction may allow citrus plants to better cope with the consequences of CaLas infection, highlighting the importance of vector suppression as a component of managing this cosmopolitan disease.

【 授权许可】

CC BY