Spatial distribution characteristics of potato trichomes and their insect resistance mechanism

Trichomes are plant-derived external appendages that play a crucial role in plant stress resistance. This study examined the spatial distribution characteristics of trichomes and conducted insect resistance tests on nine potato varieties (lines) with high, medium, and low trichome densities. Using a comprehensive targeted metabolomics approach, we compared the metabolic profiles between two varieties (lines), ‘Tianshu 15’ and ‘S10-510’, with the greatest differences in trichome density. The results showed that 1) the trichomes on potato leaves exhibited polymorphic distribution patterns, with significantly lower trichome density on the adaxial surface than on the abaxial surface. 2) The percentage of insect-damaged leaves and the number of insects per hundred leaves showed negative correlations with both non-glandular trichomes and glandular trichomes on the adaxial surface and on the abaxial surface. Varieties (lines) with high trichome density exhibited greater insect resistance than those with medium or low trichome density. There was a significant correlation between trichome density and insect resistance. 3) Widely targeted metabolomics detected a total of 1717 distinct metabolites. Among them, phenolic acids, lipids, alkaloids, and flavonoids were most abundant, accounting for 16.70%, 14.91%, 12.75%, and 12.06% of the total detected metabolites, respectively. Significant metabolic differences were observed between ‘Tianshu 15’ and ‘S10-510’, with 446 differential metabolites identified. Among them, 238 metabolites showed significant upregulation, while 208 metabolites exhibited significant downregulation. The top five pathways enriched with the most differential metabolites were secondary metabolites, ABC transporters, tryptophan metabolism, flavone and flavanol biosynthesis, and glycolysis. This study provides valuable insights for research on the mechanisms of pest and disease resistance in potatoes and for the breeding of new varieties (lines).