Genetic control of α‐farnesene production in apple fruit and its role in fungal pathogenesis
2019; Wiley; Volume: 100; Issue: 6 Linguagem: Inglês
10.1111/tpj.14504
ISSN1365-313X
AutoresEdwige Souleyre, Joanna K. Bowen, Adam J. Matich, Sumathi Tomes, Xiuyin Chen, Martin Hunt, Mindy Wang, Nadeesha Ileperuma, Kate Richards, Daryl D. Rowan, David Chagné, Ross G. Atkinson,
Tópico(s)Fermentation and Sensory Analysis
ResumoSummary Terpenes are important compounds in plant trophic interactions. A meta‐analysis of GC ‐ MS data from a diverse range of apple ( Malus × domestica ) genotypes revealed that apple fruit produces a range of terpene volatiles, with the predominant terpene being the acyclic branched sesquiterpene ( E,E )‐α‐farnesene. Four quantitative trait loci ( QTL s) for α‐farnesene production in ripe fruit were identified in a segregating ‘Royal Gala’ ( RG ) × ‘Granny Smith’ ( GS ) population with one major QTL on linkage group 10 co‐locating with the Md AFS 1 ( α‐farnesene synthase‐1 ) gene. Three of the four QTL s were derived from the GS parent, which was consistent with GC ‐ MS analysis of headspace and solvent‐extracted terpenes showing that cold‐treated GS apples produced higher levels of ( E,E )‐α‐farnesene than RG . Transgenic RG fruit downregulated for Md AFS 1 expression produced significantly lower levels of ( E,E )‐α‐farnesene. To evaluate the role of ( E,E )‐α‐farnesene in fungal pathogenesis, Md AFS 1 RNA interference transgenic fruit and RG controls were inoculated with three important apple post‐harvest pathogens [ Colletotrichum acutatum , Penicillium expansum and Neofabraea alba (synonym Phlyctema vagabunda )]. From results obtained over four seasons, we demonstrate that reduced ( E,E )‐α‐farnesene is associated with decreased disease initiation rates of all three pathogens. In each case, the infection rate was significantly reduced 7 days post‐inoculation, although the size of successful lesions was comparable with infections on control fruit. These results indicate that ( E,E )‐α‐farnesene production is likely to be an important factor involved in fungal pathogenesis in apple fruit.
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