Characterization of volatile organic compounds in grafted tomato plants upon potyvirus necrotic infection

A headspace solid-phase microextraction-gas chromatography-mass spectrometry(HS-SPME/GC-MS)method was used to study the volatile organic compounds(VOCs)associated with the differential immune response of tomato plants infected with the recombinant strain of potato virus Y(PVY^(C)-to),necrogenic to tomato.Analysis was carried out in UC82(UC),a virus susceptible tomato variety,comparing the same UC plants grafted or not onto a virus tolerant tomato ecotype,Manduria(Ma);the three types of samples used for the GC-MS analysis were mock-inoculated UC/Ma plants,UC/Ma+PVY^(C)-to and UC+PVY^(C)-to plants;the VOCs obtained were 111.Results from symptomatic PVY^(C)-to-infected UC plants showed a VOCs composition enriched in alcohols,fatty acid derivates,benzenoids,and salicylic acid derivatives,while in mock-inoculated UC/Ma plants VOCs were mainly characterized by methyl ester compounds.The VOC profile was in line with RNAseq data analyses,denoting that PVY^(C)-to viral RNA accumulation and disease symptoms induce the specific transcriptional activation of genes involved in VOCs biosynthesis.Furthermore,principal component analysis highlighted that VOCs of PVY^(C)-to-infected and mock-inoculated grafted plants were much closer each other than that of symptomatic PVY^(C)-to-infected non-grafted UC plants.These results suggest that VOCs profiles of tomato plants are related to the viral RNA accumulation,disease intensity and graft-derived tolerance to PVY^(C)-to infection.

Plant grafting:Molecular mechanisms and applications

People have grafted plants since antiquity for propagation,to increase yields,and to improve stress tolerance.This cutting and joining of tissues activates an incredible regenerative ability as different plants fuse and grow as one.For over a hundred years,people have studied the scientific basis for how plants graft.Today,new techniques and a deepening knowledge of the molecular basis for graft formation have allowed a range of previously ungraftable combinations to emerge.Here,we review recent developments in our understanding of graft formation,including the attachment and vascular formation steps.We analyze why plants graft and how biotic and abiotic factors influence successful grafting.We also discuss the ability and inability of plants to graft,and how grafting has transformed both horticulture and fundamental plant science.As our knowledge about plant grafting improves,new combinations and techniques will emerge to allow an expanded use of grafting for horticultural applications and to address fundamental research questions.