AbstractCandidatus Liberibacter solanacearum (CLso) transmitted by the carrot psyllid, Bactericera trigonica causes carrot yellows in Israel, and has recently gained much importance due to the excessive economical loss. Understanding the interactions between CLso and the psyllid at the cellular level is fundamental for the disease management. Here, we demonstrate the role of calcium ATPase, cytosolic calcium and most importantly Beclin1 in regulating autophagy and its association with Liberibacter. Presence of CLso generates reactive oxygen species and induces the expression of the detoxification enzymes in the psyllid midguts. CLso also induces the expression of both sarco/endoplasmic reticulum Ca2+ pump (SERCA) and 1,4,5-trisphosphate receptors (ITPR) in the midguts, followed by high levels of calcium in the cytosol. Silencing these proteins individually disrupted the calcium levels in the cytosol leading to direct effects on autophagy and thus on Liberibacter. On the other hand, inhibiting Beclin1-phosphorylation through different calcium induced kinases altered the expression of autophagy and CLso abundance. This study establishes a direct correlation between cytosolic calcium levels, autophagy and CLso in the carrot psyllid midgut.
Plant diseases caused by vector-borne pathogens are responsible for tremendous losses and threaten some of the most important agricultural crops. A good example is the citrus greening disease, which is caused by bacteria of the genus
and is transmitted by psyllids; it has devastated the citrus industry in the United States, China, and Brazil.
Candidatus Liberibacter solanacerum (CLso), transmitted by Bactericera trigonica in a persistent and propagative mode causes carrot yellows disease, inflicting hefty economic losses. Understanding the process of transmission of CLso by psyllids is fundamental to devise sustainable management strategies. Persistent transmission involves critical steps of adhesion, cell invasion, and replication before passage through the midgut barrier. This study uses a transcriptomic approach for the identification of differentially expressed genes with CLso infection in the midguts, adults, and nymphs of B. trigonica and their putative involvement in CLso transmission. Several genes related to focal adhesion and cellular invasion were upregulated after CLso infection. Interestingly, genes involved with proper functionality of the endoplasmic reticulum (ER) were upregulated in CLso infected samples. Notably, genes from the endoplasmic reticulum associated degradation (ERAD) and the unfolded protein response (UPR) pathway were overexpressed after CLso infection. Marker genes of the ERAD and UPR pathways were also upregulated in Diaphorina citri when infected with Candidatus Liberibacter asiaticus (CLas). Upregulation of the ERAD and UPR pathways indicate induction of ER stress by CLso/CLas in their psyllid vector. The role of ER in bacteria–host interactions is well-documented; however, the ER role following pathogenesis of CLso/CLas is unknown and requires further functional validation.
ABSTRACT“CandidatusPortiera aleyrodidarum” is the primary endosymbiont of whiteflies. We report two complete genome sequences of this bacterium from the worldwide invasive B and Q biotypes of the whiteflyBemisia tabaci. Differences in the two genome sequences may add insights into the complex differences in the biology of both biotypes.
Portiera aleyrodidarum” is the obligate primary endosymbiotic bacterium of whiteflies, including the sweet potato whitefly
, and provides essential nutrients to its host. Here we report two complete genome sequences of this bacterium from the B and Q biotypes of