scholarly journals Bactericera cockerelli resistance in the wild tomato Solanum habrochaites is polygenic and influenced by the presence of Candidatus Liberibacter solanacearum

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carlos A. Avila ◽  
Thiago G. Marconi ◽  
Zenaida Viloria ◽  
Julianna Kurpis ◽  
Sonia Y. Del Rio

Abstract The tomato-potato psyllid (TPP), Bactericera cockerelli, is a vector for the phloem-limited bacterium Candidatus Liberibacter solanacearum (Lso), the causative agent of economically important diseases including tomato vein-greening and potato zebra chip. Here, we screened 11 wild tomato relatives for TPP resistance as potential resources for tomato (Solanum lycopersicum) cultivar development. Six accessions with strong TPP resistance (survival <10%) were identified within S. habrochaites, S. pennelli, S. huaylasense, S. chmielewskii, S. corneliomulleri, and S. galapagense. Two S. pennelli and S. corneliomulleri accessions also showed resistance to Lso. We evaluated recombinant inbred lines (RILs) carrying resistance from S. habrochaites accession LA1777 in the S. lycopersicum background and identified major quantitative trait loci (QTLs) responsible for adult TPP mortality and fecundity in several RILs carrying insertions in different chromosomes, indicating the polygenic nature of these traits. Analysis of a major resistance QTL in RIL LA3952 on chromosome 8 revealed that the presence of Lso is required to increase adult TPP mortality. By contrast, the reduced TPP oviposition trait in LA3952 is independent of Lso. Therefore, resistance traits are available in wild-tomato species, although their complex inheritance and modes of action require further characterisation to optimise their utilisation for tomato improvement.

2021 ◽  
Author(s):  
Parvinderdeep S. Kahlon ◽  
Andrea Förner ◽  
Michael Muser ◽  
Mhaned Oubounyt ◽  
Michael Gigl ◽  
...  

Natural plant populations are highly polymorphic and often show intraspecific quantitative, variation in resistance properties against pathogens. The activation of the underlying defence responses can depend on the perception of conserved pathogen-associated molecular patterns (PAMPs). To dissect and understand such variation, we evaluated the diversity of responses induced by laminarin (representing a general glucan elicitor of plant immune responses) in the wild tomato species Solanum chilense. We confirm considerable overlap of the plant's global transcriptional responses to laminarin and to the oomycete pathogen Phytophthora infestans. We further measured key components of basal defence responses such as reactive oxygen species (ROS) production and levels of diverse phytohormones and their derivatives upon elicitation with laminarin in 83 plants originating from nine natural populations of S. chilense from distinct geographic origin. We found high diversity in these components at basal and elicitor-induced levels. We generated generalised linear mixed models (GLMMs) with these components to explain the observed resistance phenotype against P. infestans in the plants and found that additive effects of multiple components best explain resistance at the species level. For individual components, we observed the strongest positive correlation between the resistance phenotype and ethylene (ET) production upon laminarin elicitation. The strength of this correlation differed between individual populations. Chemical inhibition of ET production in individuals from a population, in which ET production was associated with resistance, provoked more severe disease symptoms. Our findings reveal high diversity in the strength of induced defence responses within a species and in the basal levels of other stress-related phytohormones. We show the involvement of multiple components with a quantitatively different contribution of individual components to resistance in geographically separated populations of S. chilense against P. infestans.


2018 ◽  
Vol 5 (4) ◽  
pp. 174
Author(s):  
Asma Akbar ◽  
Shaukat Hussain ◽  
Gul Shad Ali

Fusarium wilt caused by different Fusarium species is a devastating disease causes heavy loss to tomato plantation worldwide. In this study 13 tomato varieties were screened against F. equiseti to explore the resistance potential of the varieties against the disease. Out of 13 varieties only 2 varieties Roma and Hybrid showed resistance to the disease, while the other 69% were highly susceptible. Based on cluster analysis for genetic diversity it was reported that susceptible varieties are only 8% genetically different and share same genetic pool. We reported that the wild species of tomato Solanum pimpinellifolium (Sp- 2093) showed complete immunity and were remain unaffected having 25% genetic difference with other varieties tested. Thus wild tomato species may provide the source of resistance required to develop resistant variety against the emerging wilt pathogen F. equiseti. The data regarding virluence structure and resisatnt variety that is presented in this study will suport more focused efforts in the management of tomato wilt caused by Fusarium species and that resistant features of wild tomato variety Sp-2093, could be accumulated with other desirable characteristics of different germplasm in one cultivar, which will reduce the chances for new virulent species to evolve.


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