scholarly journals Exogenous Application of Polycationic Nanobactericide on Tomato Plants Reduces the Candidatus Liberibacter Solanacearum Infection

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2096
Author(s):  
Adela Nazareth García-Sánchez ◽  
Roberto Yáñez-Macias ◽  
José Luis Hernández-Flores ◽  
Ariel Álvarez-Morales ◽  
José Humberto Valenzuela-Soto ◽  
...  

Candidatus Liberibacter solanacearum (CaLso) is associated with diseases in tomato crops and transmitted by the tomato psyllid Bactericera cockerelli. A polymeric water-dispersible nanobactericide (PNB) was evaluated against CaLso as a different alternative. PNB is a well-defined polycationic diblock copolymer designed to permeate into the vascular system of plants. Its assessment under greenhouse conditions was carried out with tomato plants previously infected with CaLso. Using a concentration as low as 1.0 mg L−1, a small but significant reduction in the bacterial load was observed by real-time qPCR. Thus, to achieve an ecologically friendly dosage and set an optimum treatment protocol, we performed experiments to determine the effective concentration of PNB to reduce ~65% of the initial bacterial load. In a first bioassay, a 40- or 70-fold increase was used to reach that objective. At this concentration level, other bioassays were explored to determine the effect as a function of time. Surprisingly, a real reduction in the symptoms was observed after three weeks, and there was a significant decrease in the bacterial load level (~98%) compared to the untreated control plants. During this period, flowering and formation of tomato fruits were observed in plants treated with PNB.

Plant Disease ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 2009-2015 ◽  
Author(s):  
Azucena Mendoza-Herrera ◽  
Julien Levy ◽  
Kyle Harrison ◽  
Jianxiu Yao ◽  
Freddy Ibanez ◽  
...  

‘Candidatus Liberibacter solanacearum’ is a plant pathogen associated with diseases affecting several crops of the Solanaceae and Apiaceae families. Two ‘Ca. L. solanacearum’ haplotypes (LsoA and LsoB) infect solanaceous crops in North America and are transmitted by the tomato psyllid Bactericera cockerelli. Although both ‘Ca. L. solanacearum’ haplotypes cause zebra chip in potato, the diseases associated with each haplotype in tomato (Solanum lycopersicum) have not been described. ‘Ca. L. solanacearum’-infected tomato plants exhibit symptoms resembling those of permanent yellowing disease (known in Mexico as “permanente del tomate”) and sometimes called psyllid yellows. In this study, the symptoms associated with each ‘Ca. L. solanacearum’ haplotype in tomato were compared, and the bacterial abundance in different nodes of the plants was measured by quantitative polymerase chain reaction. Surprisingly, both plant phenotype and bacterium distribution were different between LsoA- and LsoB-infected plants. Plants infected with LsoB died prematurely, whereas those infected with LsoA did not. Across the measured time points, LsoB abundance in infected plants was consistent with previous reports describing a sink to source gradient, while such gradient was only observed in LsoA-infected plants early after infection. This is the first report describing the differences in symptoms in tomato associated with two ‘Ca. L. solanacearum’ haplotypes, LsoA and LsoB.


Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1073
Author(s):  
Xiao-Tian Tang ◽  
Cecilia Tamborindeguy

Autophagy, also known as type II programmed cell death, is a cellular mechanism of “self-eating”. Autophagy plays an important role against pathogen infection in numerous organisms. Recently, it has been demonstrated that autophagy can be activated and even manipulated by plant viruses to facilitate their transmission within insect vectors. However, little is known about the role of autophagy in the interactions of insect vectors with plant bacterial pathogens. ‘Candidatus Liberibacter solanacearum’ (Lso) is a phloem-limited Gram-negative bacterium that infects crops worldwide. Two Lso haplotypes, LsoA and LsoB, are transmitted by the potato psyllid, Bactericera cockerelli and cause damaging diseases in solanaceous plants (e.g., zebra chip in potatoes). Both LsoA and LsoB are transmitted by the potato psyllid in a persistent circulative manner: they colonize and replicate within psyllid tissues. Following acquisition, the gut is the first organ Lso encounters and could be a barrier for transmission. In this study, we annotated autophagy-related genes (ATGs) from the potato psyllid transcriptome and evaluated their expression in response to Lso infection at the gut interface. In total, 19 ATGs belonging to 17 different families were identified. The comprehensive expression profile analysis revealed that the majority of the ATGs were regulated in the psyllid gut following the exposure or infection to each Lso haplotype, LsoA and LsoB, suggesting a potential role of autophagy in response to Lso at the psyllid gut interface.


Plant Disease ◽  
2021 ◽  
Author(s):  
Cesar Alejandro Reyes Corral ◽  
W. Rodney Cooper ◽  
Alexander V Karasev ◽  
Carolina Delgado-Luna ◽  
SERGIO R. Sanchez-PENA

The potato psyllid, Bactericera cockerelli (Šulc), (Hemiptera: Triozidae) is a pest of Solanaceous crops (Solanales) including potato (Solanum tuberosum L.) and tomato (Solanum lycopersicum L.). Feeding by high populations of nymphs causes psyllid yellows while adults and nymphs are vectors of the plant pathogen, “Candidatus Liberibacter solanacearum” (Lso). Foliar symptoms that were consistent with either Lso-infection or psyllid yellows were observed in 2019 on tomatillo (Physalis ixocarpa Brot.; Solanaceae) grown within an experimental plot located near Saltillo, Mexico. This study had three primary objectives: 1) determine whether the foliar symptoms observed on tomatillo were associated with Lso infection, 2) identify the haplotypes of Lso and potato psyllids present in the symptomatic plot, and 3) use gut content analysis to infer the plant sources of Lso-infected psyllids. Results confirmed that 71% of symptomatic plants and 71% of psyllids collected from the plants were infected with Lso. The detection of Lso in plants and psyllids, and the lack of nymphal populations associated with psyllid yellows strongly suggests that the observed foliar symptoms were caused by Lso infection. All infected plants and insects harbored the more virulent Lso haplotype B, but one psyllid was also co-infected with haplotype A. The potato psyllids were predominantly of the central haplotype, but one psyllid was identified as the western haplotype. Molecular gut content analysis of psyllids confirmed the movement of psyllids between non-crop habitats and tomatillo and indicated that Lso infection of psyllids was associated with increased plant diversity in their diet.


Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 298
Author(s):  
Jing Wan ◽  
Rui Wang ◽  
Yonglin Ren ◽  
Simon McKirdy

The tomato potato psyllid (TPP), Bactericera cockerelli, is a psyllid native to North America that has recently invaded New Zealand and Australia. The potential for economic losses accompanying invasions of TPP and its associated bacterial plant pathogen Candidatus Liberibacter solanacearum (CLso), has caused much concern. Here, we employed ecological niche models to predict environments suitable for TPP/CLso on a global scale and then evaluated the extent to which global potato cultivation is at risk. In addition, at a finer scale the risk to the Australian potato acreage was evaluated. A total of 86 MaxEnt models were built using various combinations of settings and climatic predictors, and the best model based on model evaluation metrics was selected. Climatically suitable habitats were identified in Eurasia, Africa, South America, and Australasia. Intersecting the predicted suitability map with land use data showed that 79.06% of the global potato cultivation acreage, 96.14% of the potato production acreage in South America and Eurasia, and all the Australian potato cropping areas are at risk. The information generated by this study increases knowledge of the ecology of TPP/CLso and can be used by government agencies to make decisions about preventing the spread of TPP and CLso across the globe.


2011 ◽  
Vol 101 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
Julien Levy ◽  
Aravind Ravindran ◽  
Dennis Gross ◽  
Cecilia Tamborindeguy ◽  
Elizabeth Pierson

Zebra Chip disease is a serious threat to potato production. The pathogen, the phloem-limited bacterium ‘Candidatus Liberibacter solanacearum,’ is vectored by the potato and tomato psyllid Bactericerca cockerelli to potato and tomato. Patterns of pathogen translocation through phloem in potato and tomato plants were examined to determine whether rate or direction of translocation vary by host species or potato cultivars. Two insects were given a 7-day inoculation access period on a single leaf. Weekly, leaves from upper-, middle-, and lower-tier branches were tested for the presence of ‘Ca. L. solanacearum’ by polymerase chain reaction (PCR). In tomato and potato, ‘Ca. L. solanacearum’ was detected 2 to 3 weeks after infestation, most frequently in upper- and middle-tier leaves. In potato, the pathogen was detected in leaves on a second, noninfested stem when the stems remained joined via the tuber. Although rates of pathogen movement were similar among potato cultivars, symptoms developed earlier in more susceptible cultivars. Quantitative PCR indicated that bacterial titers were frequently low in tomato and potato samples (<20 genome units per nanogram of DNA). Results establish that, for improved detection, samples should include newly developing leaves and consider that, under low insect pressure, the pathogen may be undetectable by PCR until 3 weeks after infestation.


2020 ◽  
Vol 113 (6) ◽  
pp. 2595-2603
Author(s):  
Cesar A Reyes Corral ◽  
W Rodney Cooper ◽  
David R Horton ◽  
Alexander V Karasev

Abstract The potato psyllid, Bactericera cockerelli (Šulc), is a major pest of potato (Solanum tuberosum L.; Solanales: Solanaceae) as a vector of ‘Candidatus Liberibacter solanacearum’, the pathogen that causes zebra chip. Management of zebra chip is challenging in part because the noncrop sources of Liberibacter-infected psyllids arriving in potato remain unknown. Adding to this challenge is the occurrence of distinct genetic haplotypes of both potato psyllid and Liberibacter that differ in host range. Longleaf groundcherry (Physalis longifolia Nutt.) has been substantially overlooked in prior research as a potential noncrop source of Liberibacter-infected B. cockerelli colonizing fields of potato. The objective of this study was to assess the suitability of P. longifolia to the three common haplotypes of B. cockerelli (central, western, and northwestern haplotypes), and to two haplotypes of ‘Ca. L. solanacearum’ (Liberibacter A and B haplotypes). Greenhouse bioassays indicated that B. cockerelli of all three haplotypes produced more offspring on P. longifolia than on potato and preferred P. longifolia over potato during settling and egg-laying activities. Greenhouse and field trials showed that P. longifolia was also highly susceptible to Liberibacter. Additionally, we discovered that infected rhizomes survived winter and produced infected plants in late spring that could then be available for psyllid colonization and pathogen acquisition. Results show that P. longifolia is susceptible to both B. cockerelli and ‘Ca. L. solanacearum’ and must be considered as a potentially important source of infective B. cockerelli colonizing potato fields in the western United States.


Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2587-2591 ◽  
Author(s):  
Jennifer Dahan ◽  
Erik J. Wenninger ◽  
Brandon D. Thompson ◽  
Sahar Eid ◽  
Nora Olsen ◽  
...  

‘Candidatus Liberibacter solanacearum’ (Lso) is an uncultured, phloem-associated bacterium causing a severe tuber disease in potato called zebra chip (ZC). Seven haplotypes of Lso have been described in different hosts, with haplotypes A and B found associated with infections in potato and tomato. In the field, Lso is transmitted by the potato psyllid (Bactericera cockerelli), and between 2011 and 2015, a significant change in Lso haplotype prevalence was previously reported in Idaho: from exclusively A haplotype found in tested psyllids in 2012 to mainly B haplotype found in collected psyllids in 2015. However, prevalence of Lso haplotypes in Idaho was not analyzed in potato tubers exhibiting symptoms of ZC. To fill in this knowledge gap, prevalence of Lso haplotypes was investigated in potato tubers harvested in southern Idaho between 2012 and 2018, and it was found to change from exclusively A haplotype in the 2012 season to an almost equal A and B haplotype distribution during the 2016 season. During the same period, haplotype distribution of Lso in psyllid vectors collected using yellow sticky traps also changed, but in psyllids, the shift from A haplotype of Lso to B haplotype was complete, with no A haplotype detected in 2016 to 2018. The changes in the haplotype prevalence of the Lso circulating in potato fields in southern Idaho may be, among other factors, responsible for a decrease in the ZC incidence in Idaho potato fields between an outbreak of the disease in 2012 and a very low level of ZC afterward.


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