Research Data Downregulation of α-farnesene synthase-1 reduces apple fruit fungal susceptibility, alongside defence gene upregulation and phytohormone changes

Description

Data sets underlying analyses and results as summarised in the manuscript. ABSTRACT Plant terpenes play a vital role in general metabolism and in mediating biological interactions, both between plants and with other organisms. We explored the physiological and molecular features driving reduced susceptibility to the fungus Colletotrichum acutatum, typically classified as a necrotrophic pathogen, but which may initiate infection via a transient biotrophic phase, in two independent transgenic ‘Royal Gala’ apple lines (AFS1_kd). These lines are downregulated for α-farnesene synthase-1 (MdAFS1), responsible for synthesising the major apple sesquiterpene, α-farnesene. Cuticle integrity is required for enhanced defence in AFS1_kd fruit as its removal increased infection rates to that of wild-type (wt). However, microscopy revealed no significant structural differences in the skin of AFS1_kd compared to wt fruit. Similarly, whilst subtle differences in surface wax composition were observed in AFS1_kd fruit compared to wt (likely linked to altered farnesyl diphosphate levels), these chemical differences appear insufficient to explain resistance. Subsequent transcriptome profiling showed constitutive upregulation of defence-related genes in AFS1_kd fruit relative to wt before inoculation, suggesting an activated defence response. Phytohormone analysis uncovered a reduction in jasmonic acid (JA) before inoculation compared with wt fruit. Downregulation of the JA-pathway was not observed in AFS1_kd lines, except for genes encoding omega-3-fatty acid desaturases, suggesting linoleic acid diversion into dihydrojasmonic acid might have reduced precursor availability for JA production. Regularised canonical correlation analysis linked MdAFS1 expression to JA biosynthesis and crosstalk with abscisic acid and gibberellin metabolism. Collectively, these findings highlight a complex interplay between secondary metabolism, constitutive defence and hormonal signalling in fruit pathogenesis.

Steps to reproduce

As outlined in the Materials and Methods section of the manuscript.

Institutions

• Bioeconomy Science Institute

  Auckland, Lincoln

Categories

Funders

• Ministry of Business, Innovation and Employment

  Wellington

  Grant ID: Growing Futures-Horticulture Goes Urban

Related Links

Licence