Integrative analysis of high temperature-induced transcriptome and metabolome alterations in the leaves of five raspberry (Rubus ideaus L.) cultivars

Raspberry has been widely accepted as a healthy fruit, but its planting in northwest China is restricted due to its heat sensitivity. To make the best use of raspberry and compare the potential for their cultivation in northwest China, five important raspberry cultivars ('Autumn Britten', 'Autumn Bliss', 'Red Autumn', 'Korean Black', 'Heritage') were collected and evaluated for their responses under high temperature stress (HTS, 32.8 ℃, compared to ambient temperature 20.4 ℃). The transcriptome and metabolome profiles are dramatically affected and show different response patterns of different cultivars to HTS. While 'Korean Black' and 'Hertitage' exhibited distinctive responses to HTS when comparing transcriptome and metabolome profiles. After enrichment analysis, we found that HTS mainly affected the amino acids and saccharide metabolism, accumulation of antioxidant metabolites and plant hormone-related MAPK signaling pathways, and alteration of α-linolenic acid metabolism in all five cultivars. Transcription factors were also analyzed and HSF (Heat Shock Transcription Factor) was identified as promising regulatory candidate for heat stress responsive gene expression in raspberry cultivars. Integrative analysis shows that the α-linolenic acid metabolism pathway is greatly altered in 'Korean Black' at both metabolite accumulation and gene expression levels under HTS. Especially for linolenic acid 13(S)-HPOT and jasmonic acid, as well as for genes such as PLA2-ALPHA(Ro04-snap-gene-272.47), DAD1(Ro02-snap-gene-93.71), LOX3(Ro03-snap-gene-410.98), JMT(Ro04-snap-gene-23.45) are critical in HTS responses when comparing 'Hertitage' and 'Korean Black'. Our work provides potential metabolic mechanisms for raspberry stress responses and suggests master genes and transcription factors responsible for stress resistance as potential targets for molecular breeding.