About
The Journal of Citrus Pathology in an international, peer-reviewed, open access, online publication. The Journal of Citrus Pathology welcomes reports on research from all branches of pathology on all diseases of citrus and related fields. The journal accepts original contributions in basic and applied research on citrus diseases, pathogens and disease-associated agents, including graft-transmissible agents, viruses, viroids, bacteria, phytoplasmas and other wall-less bacteria, fungi, oomycetes, and nematodes as well as any agents affecting citrus biology. This on-line IOCV publication by eScholarship ensures the distribution of critical information for citrus health and hosts occasional invited autobiographies and biographies of pioneer leaders of the field of citrus pathology.
Volume 11, Issue 2, 2024
Articles
Whole genome analysis of spontaneous antimicrobial resistance in Liberibacter crescens suggests long-term efficacy for antimicrobial treatment of citrus greening disease
Currently, oxytetracycline and streptomycin are being applied to citrus groves in Florida for the control of citrus greening disease caused by the unculturable bacterium Candidatus Liberibacter asiaticus. Here, the closest cultured relative, L. crescens, was used to estimate the frequency of spontaneous antimicrobial resistance of Liberibacter spp. Results yielded thirteen streptomycin and zero oxytetracycline mutants after exposing 13 billion cells to the antimicrobials. These low rates, alongside the restrictive habitats of the vector and pathogen, suggest resistance may develop very slowly, if at all. Thus, the treatments will likely remain useful long enough before pathogen-resistant or -tolerant genotypes are deployed.
Applying volumetric electron microscopy to visualize xylem tissue impacted by citrus tristeza virus-induced stem pitting
Citrus tristeza virus (CTV) causes several disease syndromes in different citrus hosts; namely quick decline, seedling yellows and stem pitting. CTV-induced stem pitting leads to substantial economic losses in sensitive citrus varieties, including grapefruit. The formation of stem pits has previously been linked to the ability of the virus to colonize xylem tissue outside of its typical phloem limitation, thereby disrupting normal xylem development. The nature of this compromised tissue has not been fully elucidated. In this study, stem pits were characterized at the molecular anatomical level using a combination of techniques to better understand the characteristics of the xylem and phloem tissues impacted by severe pitting. Biological staining was used to visualize CTV-induced stem pitting and was complemented with a novel technology that has not previously been used to study CTV-induced stem pitting, namely serial block-face scanning electron microscopy (SBF-SEM). This proof-of-concept study yielded new insights into the morphology of stem pitting-affected tissue. The utility of SBF-SEM for stem pitting characterization was also demonstrated and an optimized protocol for its application on hard, woody material is presented.