Persister Cells Form in the Plant Pathogen Xanthomonas citri subsp. citri under Different Stress Conditions

Abstract

Citrus canker disease, caused by the bacterium Xanthomonas citri subsp. citri is a constant threat to citrus-producing areas. Since it has no cure, agricultural practices to restrain its dissemination are essential to reduce the economic damage. Hence, increased knowledge of the basic aspects of X. citri biology could lead to more efficient management practices that can eliminate dormant bacteria in the field. The dormant cells, also referred to as persisters, are phenotypic variants with lowered metabolism, which in turn leads to tolerance to antimicrobials and undermines existing control approaches. We show here that X. citri forms persisters, identifying triggers for this phenotype, including antibiotics, high temperature, and metals (copper and zinc), which increase persistence rates by 10–100 times. The antioxidant N-acetylcysteine reduced copper and zinc-induced persisters, but not those induced by tetracycline, indicating that oxidative stress may be an important inducer of X. citri persistence. In addition, we found that metabolism-independent drugs like cisplatin and mitomycin C are able to eliminate X. citri persistent cells, as well as copper, at high concentrations. Specific amino acids like proline and isoleucine interfered with the physiological balance of the dormancy in X. citri, stimulating or preventing persister resuscitation. Taken together, we discover chemicals that can induce, wake, and kill X. citri persister cells; these results provide insights that should be considered for more efficient integrated control management in the field.

Green Synthesis of Silver Nanoparticles Using Euphorbia wallichii Leaf Extract: Its Antibacterial Action against Citrus Canker Causal Agent and Antioxidant Potential

“…[ 5 ]. The disease is of concern because it has no cure, and most of the control strategies are focused on restraining the dissemination of its causative agent [ 6 ]. It is a very expensive disease and millions of dollars are spent worldwide for its prevention and control [ 5 , 7 ].…”

Predicting the impact of environmental factors on citrus canker through multiple regression

“…Citrus canker is one of the most notorious citrus diseases in Florida, USA, leading towards mass eradication of plants in the entire state [ 12 ]. The disease is still spreading even after spending an estimated 12 million US$ annually on its management [ 13 – 15 ]. The Xcc infestation initially seen as a small lesion on the leaves, which is expanded in later stages and ultimately become necrotic surrounded by water-soaked, oily margins.…”

Overexpression of mqsR in Xylella fastidiosa Leads to a Priming Effect of Cells to Copper Stress Tolerance

“…Copper-containing compounds are among the most used chemicals in agriculture ( Lamichhane et al, 2018 ). The antimicrobial effects of copper were previously attributed to stress-induced responses in many bacterial plant pathogens ( Wright et al, 2019 ; Martins et al, 2021 ), including X. fastidiosa ( Rodrigues et al, 2008 ; Muranaka et al, 2012 ; Merfa et al, 2016 ; Ge et al, 2021 ). In this bacterium, the MqsRA TA system was reported to play a key role when the pathogen is under copper stress.…”