Overlapping sets of transcripts from host and non-host interactions of tomato are expressed early during non-host resistance

TLDR: This is the first report of transcriptome profile in tomato during non-host interactions against M. grisea, and it is identified that the pathway involved in synthesis of volatile compounds like 2-phenylethanol was induced during NHR in tomato.

Abstract: Natural immunity present in all the plants against most of the pathogens is called as non-host resistance (NHR). Although NHR is most durable form of resistance, it was less studied compared to other forms of resistance. We compared transcriptional changes in tomato during non-host ('Magnaporthe grisea') and compatible ('Alternaria alternata' f. sp. 'lycopersici') interactions using Agilent microarray GeneChip containing 44,000 probe sets. The experiment was designed to understand the early and late responses of tomato leaves inoculated with non-host and compatible pathogens. Microarray data revealed that the expression profiles in the non- host and compatible interactions at 6 h post inoculation (hpi) and 24 hpi largely overlapped indicating that a set of genes are activated during plant-pathogen interaction. However, these genes were expressed much earlier in NHR compared to a compatible interaction. NHR is, therefore, an accelerated and amplified basal defense response. Transcripts involved in energy production (carbohydrate metabolism and photosynthesis) were down-regulated, whereas transcripts associated with catabolic processes (starch and sucrose hydrolysis) were up-regulated in both the interactions at 6 and 24 hpi. We have also identified that the pathway involved in synthesis of volatile compounds like 2-phenylethanol was induced during NHR in tomato. This is the first report of transcriptome profile in tomato during non-host interactions against M. grisea.