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. 2018 May 9;8(1):7429.
doi: 10.1038/s41598-018-24998-5.

Genetic Mapping Identifies Loci That Influence Tomato Resistance Against Colorado Potato Beetles

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Free PMC article

Genetic Mapping Identifies Loci That Influence Tomato Resistance Against Colorado Potato Beetles

Erandi Vargas-Ortiz et al. Sci Rep. .
Free PMC article

Abstract

The Colorado potato beetle (CPB; Leptinotarsa decemlineata Say), the most economically important insect pest on potato (Solanum tuberosum L.), also feeds on other Solanaceae, including cultivated tomato (Solanum lycopersicum L.). We used tomato genetic mapping populations to investigate natural variation in CPB resistance. CPB bioassays with 74 tomato lines carrying introgressions of Solanum pennellii in S. lycopersicum cv. M82 identified introgressions from S. pennellii on chromosomes 1 and 6 conferring CPB susceptibility, whereas introgressions on chromosomes 1, 8 and 10 conferred higher resistance. Mapping of CPB resistance using 113 recombinant inbred lines derived from a cross between S. lycopersicum cv UC-204B and Solanum galapagense identified significant quantitative trait loci on chromosomes 6 and 8. In each case, the S. galapagense alleles were associated with lower leaf damage and reduced larval growth. Results of both genetic mapping approaches converged on the same region of chromosome 6, which may have important functions in tomato defense against CPB herbivory. Although genetic mapping identified quantitative trait loci encompassing known genes for tomato acyl sugar and glycoalkaloid biosynthesis, experiments with acyl sugar near-isogenic lines and transgenic GAME9 glycoalkaloid-deficient and overproducing lines showed no significant effect of these otherwise insect-defensive metabolites on CPB performance.

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Colorado potato beetle performance on parental tomato plants. (a) CPB larval mass and (b) survival on S. lycopersicum (solid line) or S. pennellii (dashed line). Values are means ± SE of 7 and 9 plants, respectively. *P < 0.05 by Student’s t-test.
Figure 2
Figure 2
Colorado potato beetle performance on S. pennellii introgression lines. (a) CPB larval mass and (b) survivorship were recorded 10 days after infestation. Black bars show performance and survival on parental lines. Green bars represent introgression lines where CPB has either significantly better performance than on M82 or greater survival than on S. pennellii (P < 0.05, Dunnetts test). Red bars represent introgression lines where CPB has the same performance or survivorship as on S. pennellii plants and lower than on M82 (P < 0.05, Dunnetts test). All bars represent the mean of 2 or 3 plants. (c) Representation of the chromosomes with introgression lines that affect CPB resistance. Each chromosome is divided into bins based on the classic tomato genetic map (marked with italics, 6 A, 6B, etc.) Horizontal bars are marked with the name of the respective introgression lines carrying segments of S. pennellii introgressed into S. lycopersicum. The approximate position of the flanking markers is shown in centimorgans (Tomato Expen 2000 map, www.solgenomics.net). The most susceptible (IL 6-2, IL 6-2-2, green) and the most resistant (IL 8-1-3, IL 10-2; red) lines are indicated by colored bars.
Figure 3
Figure 3
Variation in Colorado potato beetle performance on Solanum lycopersicum × S. galapagense recombinant inbred lines. (a) Average mass of surviving CPB larvae on each leaflet, ±SE if at least two larvae survived; (b) Percent survival of seven larvae that were placed on each leaflet. (c) Damage in the leaflet was ranked from 0 (no damage) to 5 (50% damage) and the number of RILs per damage level recorded after five days of feeding. Black bars show performance and survival on the parental lines (S. lycopersicum, S.l; S. galapagense, S.g). Green bars represent individuals where CPB performance and survival were the highest, red bars represent recombinant inbred lines where CPB performance and survival were the lowest. Each bar represents an assay conducted with an individual leaflet.
Figure 4
Figure 4
Quantitative trait loci for S. galapagense RILs. (a) Two QTLs for leaf damage (red line) were found, one on chromosome 6 and one on chromosome 8. A larval mass QTL (black line) was found on chromosome 6. A 95% confidence level was used. (b) Representation of the common region between susceptible IL 6-2 and the QTLs on chromosome 6. The dashed line contains the larvae mass QTL on BIN 6D, and part of the leaf damage QTL in BIN 6E. The approximate position of the flanking markers is shown in centimorgans of the S. lycopersicum genetic map (Tomato Expen 2000 map, www.solgenomics.net). (c) Leaf damage in RILs that were grouped on the basis of having the S. lycopersicum (S.l.) or S. galapagense (S.g.) alleles for the QTL on chromosomes 6 or 8. Bars represent means ± SE. Different letters indicate significant differences, p < 0.05, HSD test. (d) Larval mass in RILs separated by having the S. lycopersicum (S.l.) or S. galapagense (S.g.) allele for the QTL on chromosomes 6. Different letters indicate significant differences, p < 0.05, HSD test. (e) Larval mass, percent survival, and damage score from an independent confirmation of recombinant lines that showed high (1 G and 2 G) or low (4 G, 47 G, 53 G, and 64 G) CPB resistance in Fig. 3. The plant genotype, S. lycopersicum (S.l.), S. galapagense (S.g.), or heterozygous (S.g./S.l.) at the site of the identified resistance QTL is indicated.
Figure 5
Figure 5
Colorado potato beetle performance on acyl sugar lines after 10 days of feeding. (a) Larval mass and (b) survival were recorded after 10 days of feeding. Bars represent the mean of ten plants ± SE. * p < 0.05, Dunnett’s test using FA5/AS as a low/negative-acylsugar control.
Figure 6
Figure 6
Effect of tomatine content on CPB performance. (a) Colorado potato beetle larval mass and (b) survival were recorded after 5 days of feeding on S. lycopersicum var. Micro Tom (WT, n = 4), and GAME9 overexpressing (GAME9-OX, n = 5) and silenced (GAME9-RNAi, n = 4) plants. Bars are mean ± SE. There are no significant differences; P > 0.05, ANOVA.

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References

    1. Brown JJ, Jermy T, Butt BA. Influence of an alternate host plant on the fecundity of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera, Chrysomelidae) Ann Entomol Soc Am. 1980;73:197–199. doi: 10.1093/aesa/73.2.197. - DOI
    1. Hare JD. Ecology and managment of the Colorado potato beetle. Annual Review of Entomology. 1990;35:81–100. doi: 10.1146/annurev.en.35.010190.000501. - DOI
    1. Alyokhin A, Baker M, Mota-Sanchez D, Dively G, Grafius E. Colorado potato beetle resistance to insecticides. Am. J. Pot Res. 2008;85:395–413. doi: 10.1007/s12230-008-9052-0. - DOI
    1. Mota-Sanchez D, Hollingworth RM, Grafius EJ, Moyer DD. Resistance and cross-resistance to neonicotinoid insecticides and spinosad in the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) Pest Manag Sci. 2006;62:30–37. doi: 10.1002/ps.1120. - DOI - PubMed
    1. Szendrei Z, Grafius E, Byrne A, Ziegler A. Resistance to neonicotinoid insecticides in field populations of the Colorado potato beetle (Coleoptera: Chrysomelidae) Pest Manag Sci. 2012;68:941–946. doi: 10.1002/ps.3258. - DOI - PubMed

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