Solanaceae specialized metabolism in a non-model plant: trichome acylinositol biosynthesis

Abstract

One sentence summary: Evidence that the final step in Solanum quitoense acylinositol biosynthesis evolved from an acylsucrose acetyltransferase enzyme. AbstractPlants make hundreds of thousands of biologically active specialized metabolites varying widely in structure, biosynthesis and the processes that they influence. An increasing number of these compounds are documented to protect plants from harmful insects, pathogens, or herbivores, or mediate interactions with beneficial organisms including pollinators and nitrogen fixing microbes. Acylsugars -one class of protective compounds -are made in glandular trichomes of plants across the Solanaceae family. While most described acylsugars are acylsucroses, published examples also include acylsugars with hexose cores. The South American fruit crop Solanum quitoense (Naranjilla) produces acylsugars that contain a myoinositol core. We identified an enzyme that acetylates triacylinositols, a function homologous to the last step in the Solanum lycopersicum acylsucrose biosynthetic pathway. Our analysis reveals parallels between S. lycopersicum acylsucrose and S. quitoense acylinositol biosynthesis, suggesting a common evolutionary origin.

Identification of BAHD acyltransferases associated with acylinositol biosynthesis in Solanum quitoense (naranjilla)

“…Targeting ASAT1H, ASAT3H, and ASAT4H individually caused reductions in the four major acylinositols (Figure 2a,b, Tables S1 and S2). This phenotype is reminiscent of results from CRISPR knockout lines of ASATs in S. lycopersicum and S. pennellii , as well as VIGS of P. axillaris , S. sinuata , S. nigrum (Lou et al, 2021), and S. quitoense ASATs (Fan et al, 2016; Leong, 2019; Moghe et al, 2017; Nadakuduti et al, 2017; Schilmiller et al, 2015). Real‐time quantitative reverse transcription polymerase chain reaction (qRT‐PCR) analysis confirmed reductions in candidate transcript abundance in target plants relative to the controls, with three of six constructs significant at p < .05 (Figures S3 and S4).…”