Tetraose steroidal glycoalkaloids from potato provide resistance against Alternaria solani and Colorado potato beetle

Abstract

Plants with innate disease and pest resistance can contribute to more sustainable agriculture. Plant breeders typically focus on immune receptors or impaired susceptibility genes to develop resistant crops, but these can present challenges in terms of strength, durability or pleotropic effects. Although natural defence compounds produced by plants have the potential to provide a general protective effect against pathogens and pests, they are not a primary target in resistance breeding. The precise contribution of defence metabolites to plant immunity is often unclear and the genetics underlying their biosynthesis is complex. Here, we identified a wild relative of potato, Solanum commersonii, that provides us with unique insight in the role of glycoalkaloids in plant immunity. We cloned two atypical resistance genes that can provide complete resistance to Alternaria solani and Colorado potato beetle through the production of tetraose steroidal glycoalkaloids. Moreover, we show that these compounds are active against a wide variety of fungi. This research provides a direct link between specific modifications to steroidal glycoalkaloids of potato and resistance against diseases and pests. Further research on the biosynthesis of plant defence compounds in different tissues, their toxicity, and the mechanisms for detoxification, can aid the effective use of such compounds to improve sustainability of our food production.

Potato glycoside alkaloids exhibit antifungal activity by regulating the tricarboxylic acid cycle pathway of Fusarium solani

“…The diameter of the colony is of great significance to the growth of pathogenic fungi ( Luo and Tian, 2021 ). PGA could inhibit the colony growth of pathogenic fungi such as A. solani ( Wolters et al, 2023 ) and P. brasiliense ( Joshi et al, 2021 ). PGA inhibited the mycelial growth rate and spore germination of C. trifolii ( Xu et al, 2023 ), and inhibited the growth of F. sulphureum by inhibiting ROS metabolism and destroying cell membrane ( Li et al, 2023 ).…”

Alternaria diseases on potato and tomato

“…are capable of (Hoyos et al., 2023 ), implying the existence of more SGAs and other compounds in MeJA‐treated leaf extracts. Wild solanaceous plants are a veritable wellspring of antifungal SGAs, with broad‐spectrum antifungal tetraose SGAs conferring immunity to Solanum commersonii from EBDC (Wolters et al., 2023 ). This EBDC resistance locus has been successfully backcrossed into potato cultivars and confers broad resistance, also to other pathogens (Wolters et al., 2021 ), but the effects of tetraose SGAs to the environment and human ingestion are currently unknown.…”