Glycoalkaloid Composition and Flavonoid Content as Driving Forces of Phytotoxicity in Diploid Potato

Despite their advantages, biotechnological and omic techniques have not been applied often to characterize phytotoxicity in depth. Here, we show the distribution of phytotoxicity and glycoalkaloid content in a diploid potato population and try to clarify the source of variability of phytotoxicity among plants whose leaf extracts have a high glycoalkaloid content against the test plant species, mustard. Six glycoalkaloids were recognized in the potato leaf extracts: solasonine, solamargine, alpha-solanine, alpha-chaconine, leptinine I, and leptine II. The glycoalkaloid profiles of the progeny of the group with high phytotoxicity differed from those of the progeny of the group with low phytotoxicity, which stimulated mustard growth. RNA sequencing analysis revealed that the upregulated flavonol synthase/flavonone 3-hydroxylase-like gene was expressed in the progeny of the low phytotoxicity group, stimulating plant growth. We concluded that the metabolic shift among potato progeny may be a source of different physiological responses in mustard. The composition of glycoalkaloids, rather than the total glycoalkaloid content itself, in potato leaf extracts, may be a driving force of phytotoxicity. We suggest that, in addition to glycoalkaloids, other metabolites may shape phytotoxicity, and we assume that these metabolites may be flavonoids.

Automated summary

In this study, we investigated the relationship between plant phytotoxicity and glycoalkaloid content in potato leaf extracts. We found that potato progeny with high glycoalkaloid content showed phytotoxicity against mustard, while progeny with low glycoalkaloid content stimulated mustard growth. RNA sequencing analysis revealed that the upregulation of a flavonol synthase/flavonone 3-hydroxylase-like gene in low phytotoxicity progeny stimulated plant growth. These findings suggest that metabolic shifts and specific compositions of glycoalkaloids in potato leaf extracts may be responsible for different physiological responses in mustard.