Huanglongbing (HLB) is a devastating citrus disease. In this work, we report an HLB resistance regulatory circuit in Citrus composed of an E3 ubiquitin ligase, PUB21, and its substrate, the MYC2 trans...

Huanglongbing (HLB) is a devastating citrus disease. In this work, we report an HLB resistance regulatory circuit in Citrus composed of an E3 ubiquitin ligase, PUB21, and its substrate, the MYC2 trans...

Nature Biotechnology - A gut-derived peptide protects citrus trees from Huanglongbing

Plants secrete a variety of proteases as a defense response during infection by microbial pathogens. However, the relationship between their catalytic activities and antimicrobial functions remains largely unknown. Particularly, few biologically relevant substrates of these proteases have been identified. Huanglongbing (HLB) has been a major threat to the citrus industry worldwide. The HLB-associated bacterium, "Candidatus Liberibacter asiaticus" (Las), was previously shown to deploy an inhibitor of papain-like cysteine proteases (PLCPs) to promote disease in citrus. In this study, we identified an outer membrane protein (OMP) of Las, LasOMP1, as a substrate of the citrus PLCP CsRD21a. LasOMP1 is one of the most highly expressed genes in Las. CsRD21a cleaves LasOMP1 and produces cleaved peptide products, which could be detected in vitro and in HLB-diseased citrus plants. We found that CsRD21a targets the N-terminal portion of LasOMP1, potentially at an extracellular loop region. Importantly, transgenic sweet orange overexpressing CsRD21a showed reduced Las populations and improved plant growth, highlighting that engineering this protease is a promising strategy to enhance HLB resistance in citrus. Together, our work reveals a pathogen-derived substrate of plant PLCPs and suggests bacterial OMPs may be direct targets of plant defense.

"Huanglongbing (HLB) is a devastating citrus disease. In this work, we report an HLB resistance regulatory circuit in Citrus composed of an E3 ubiquitin ligase, PUB21, and its substrate, the MYC2 transcription factor, which regulates jasmonate-mediated defense responses. A helitron insertion in the PUB21 promoter introduced multiple MYC2-binding cis-elements to create a regulatory circuit linking the PUB21 activity with MYC2 degradation. Ectopic expression of a natural dominant-negative PUB21 paralog discovered in distant Citrus relatives stabilized MYC2 and conferred resistance to HLB. Antiproteolysis peptides (APPs), identified by artificial intelligence, stabilized MYC2 by binding and inhibiting PUB21 activity. A 14–amino acid peptide, APP3-14, molecularly controlled HLB in greenhouse and field trials. This approach represents a strategy to combat uncultivable pathogens through targeted disease resistance protein stabilization".

Huanglongbing (HLB) is a devastating citrus disease. In this work, we report an HLB resistance regulatory circuit in Citrus composed of an E3 ubiquitin ligase, PUB21, and its substrate, the MYC2 trans...

Officials say Huanglongbing, A bacterial disease, is a major threat to the county's $144 million annual citrus crop and residential citrus tree owners

Citrus Huanglongbing (HLB), caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) and considered the most destructive citrus disease worldwide, has long been regarded as a typical bacterial infection. However, recent compelling evidence shows that CLas drives HLB through chronic effector-triggered immunity, not via direct pathogenicity, thereby redefining HLB as an immune-mediated disease (Huang et al.).

The synergistic occurrence of citrus Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (CLas) and root rot severely threatens the global…

Plants secrete a variety of proteases as a defense response during infection by microbial pathogens. However, the relationship between their catalytic activities and antimicrobial functions remains la...

Huanglongbing (HLB) is one of the most destructive diseases threatening global citrus production, yet how citrus plants respond to the pathogen at the cellular level has remained unclear.

Dans le cadre d’une collaboration exemplaire en matière de partage de données entre trois territoires d’outre-mer (Réunion, Guadeloupe et Martinique), un collectif scientifique du Cirad et de l’Anses ...

Huanglongbing (HLB) is a devastating citrus disease. In this work, we report an HLB resistance regulatory circuit in Citrus composed of an E3 ubiquitin ligase, PUB21, and its substrate, the MYC2 trans...

Citrus Huanglongbing (HLB), caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) and considered the most destructive citrus disease worldwide, has long been regarded as a ty...