The oligopeptide-binding protein, OppA, binds and ushers oligopeptide substrates to the membrane-associated oligopeptide permease (Opp), a multi-component ABC-type transporter involved in the uptake of oligopeptides expressed by several bacterial species. In the present study, we report the cloning, purification, refolding and conformational analysis of a recombinant OppA protein derived from X...

A fungal pathogen that killed adult Diaphorina citri Kuwayama (Asian citrus psyllid) (Hemiptera: Psyllidae) in Florida citrus groves during the fall of 2005 was identified and characterized. Investigation of this pathogen is important because D. citri vectors citrus greening disease (Huanglongbing), which was reported in Florida in 2005. The morphological and genetic data generated herein suppo...

In Xanthomonas citri, the bacterium that causes citrus canker, three ATP-binding cassette (ABC) transporters are known to be dedicated to the uptake of sulfur compounds. In this work, using functional, biophysical and structural methods, we showed that NrtT, a periplasmic component of the ABC transporter NrtCB, is an alkanesulfonate-binding protein and that the deletion of the nrtT gene affecte...

The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes...

BACKGROUND Insecticide application is the main way to control Diaphorina citri. However, it causes environmental contamination, has a negative impact on beneficial organisms and leads to psyllid resistance. The essential oil of Piper aduncum has low toxicity towards the environment and contains dillapiol, which has proven to be effective against several crop pests. Here, we studied its efficacy...

Antibodies are known to affect the morphology, growth, and metabolism of mollicutes and thus may serve as candidate molecules for a plantibody-based control strategy for plant-pathogenic spiroplasmas and phytoplasmas. Recombinant single-chain variable fragment (scFv) antibodies are easy to engineer and express in plants, but their inhibitory effects on mollicutes have never been evaluated and c...

Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids in droplets or lines of an emulsified wax formulation in two different arena types in no-choice te...

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is one of the most significant economic pests of citrus worldwide. This insect vectors three phloem-restricted bacteria in the genus Candidatus Liberibacter that cause huanglongbing (citrus greening), the most severe disease limiting citrus production worldwide. We examined the external morphology of the antennal sensil...

The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a serious pest worldwide, transmitting Candidatus Liberibacter spp. (Alphaproteobacteria), the causative agents of a devastating citrus disease known as huanglongbing or greening disease. In a symbiotic organ called the bacteriome, D. citri possesses an organelle-like defensive symbiont, Candidatus Profftella armatura (...

We report the results from surveys conducted in 2013 and 2014 to monitor insecticide susceptibility in Florida field populations of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). These surveys are a component of the insecticide resistance management program for D. citri, which is the vector of ‘Candidatus’ Liberibacter asiaticus. ‘Candidatus’ Liberibacter asiaticus i...