Published on Fri Jun 18 2021

Introgression of type-IV glandular trichomes from Solanum galapagense to cultivated tomato reveals genetic complexity for the development of acylsugar-based insect resistance

Vendemiatti, E., Therezan, R., Vicente, M. H., de Siqueira Pinto, M., Bergau, N., Yang, L., Bernardi, W. F., Matias de Alencar, S., Zsogon, A., Tissier, A., Benedito, V., Peres, L.

Glandular trichomes are involved in the production of food- and medicine-relevant chemicals in plants. In some wild Solanum species, the presence of type-IV glandulartrichomes leads to high levels of insecticide acylsugars (AS) Low AS production observed in the cultivated tomato is attributed to its incapacity to develop type- IV trich

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Abstract

Glandular trichomes are involved in the production of food- and medicine-relevant chemicals in plants, besides being associated with pest resistance. In some wild Solanum species closely related to the cultivated tomato (S. lycopersicum), the presence of type-IV glandular trichomes leads to the production of high levels of insecticide acylsugars (AS). Conversely, low AS production observed in the cultivated tomato is attributed to its incapacity to develop type-IV trichomes in adult organs. Therefore, we hypothesized that cultivated tomatoes engineered to harbor type-IV trichomes on the leaves of mature plants can be pest resistant. We introgressed into the tomato cultivar Micro-Tom (MT) the capability of S. galapagense to maintain the development of type-IV trichomes throughout all plant stages, thus creating a line named "Galapagos enhanced trichomes" (MT-Get). Mapping-by-sequencing of MT-Get revealed that five chromosomal regions of S. galapagense were present in MT-Get. Further mapping reveled that S. galapagense alleles on chromosomes 1, 2 and 3 are sufficient for the presence of type-IV trichomes, but in lower densities. GC-MS, LC-MS, and gene expression analyses demonstrated that the increased density of type-IV trichomes was accompanied by high AS production and exudation in MT-Get. Moreover, MT-Get did not differ from MT in its susceptibility to whitefly (Bemisia tabaci). Our findings demonstrates that type-IV glandular trichome development along with AS production and exudation are partially uncoupled at the genetic level. The MT-Get genotype represents a valuable resource for further studies involving the biochemical manipulation of type-IV trichome content through either genetic introgression or transgenic approaches.