Transfer from model to crop plants: the Vlot lab confirms a role of volatile organic compounds in systemic immunity of barley and identifies two volatiles with a possible causative role in barley defense against pathogens.
Immunity-associated volatile emissions of beta-ionone and nonanal propagate defence responses in neighbouring barley plants.
Alessandro Brambilla, Anna Sommer, Andrea Ghirardo, Marion Wenig, Claudia Knappe, Baris Weber, Melissa Amesmaier, Miriam Lenk, Jörg-Peter Schnitzler, A Corina Vlot
Journal of Experimental Botany, Volume 73, Issue 2, 13 January 2022, Pages 615–630
Plants activate biochemical responses to combat stress. (Hemi-)biotrophic pathogens are fended off by systemic acquired resistance (SAR), a primed state allowing plants to respond faster and more strongly upon subsequent infection. Here, we show that SAR-like defences in barley (Hordeum vulgare) are propagated between neighbouring plants, which respond with enhanced resistance to the volatile cues from infected senders. The emissions of the sender plants contained 15 volatile organic compounds (VOCs) associated with infection. Two of these, beta-ionone and nonanal, elicited resistance upon plant exposure. Whole-genome transcriptomics analysis confirmed that interplant propagation of defence in barley is established as a form of priming. Although gene expression changes were more pronounced after challenge infection of the receiver plants with Blumeria graminis f. sp. hordei, differential gene expression in response to the volatile cues of the sender plants included an induction of HISTONE DEACETYLASE 2 (HvHDA2) and priming of TETRATRICOPEPTIDE REPEAT-LIKE superfamily protein (HvTPL). Because HvHDA2 and HvTPLtranscript accumulation was also enhanced by exposure of barley to beta-ionone and nonanal, our data identify both genes as possible defence/priming markers in barley. Our results suggest that VOCs and plant–plant interactions are relevant for possible crop protection strategies priming defence responses in barley.
