Comparative transcriptome and metabolome analyses of two strawberry cultivars with different storability

Abstract

Postharvest storability is an important trait for breeding strawberry (Fragaria × ananassa Duch.). We evaluated the postharvest fruit quality of five strawberry cultivars (‘Durihyang’, ‘Kingsberry’, ‘Maehyang’, ‘Seolhyang’, and ‘Sunnyberry’) and identified differences in their fruit ripening during the transition from the big-green to fully-red stage between two cultivars with the highest (‘Sunnyberry’) and lowest (‘Kingsberry’) storability, using comparative transcriptome and -metabolome analysis. The differentially expressed genes revealed transcriptome changes related to anthocyanin biosynthesis and cell walls. Consistently, the metabolites of both cultivars showed general changes during ripening along with cultivar-specific characteristics in sugar and amino acid profiles. To identify the genes responsible for storability differences, we surveyed the expression of transcription factors, and found that the expression levels of WRKY31, WRKY70, and NAC83 correlated with delayed senescence and increased storability. Among them, the expression levels of NAC83, and its downstream target genes, in the five cultivars suggested that NAC83 expression can be used to predict postharvest strawberry fruit storability.

Expanded transcriptomic view of strawberry fruit ripening through meta-analysis

“…stage compared to the FR stage, as determined from the distribution of samples on the PCA score plot (Fig 1A), and as observed in a previous study using 'Kingsberry' and 'Sunnyberry' [30].…”

“…During the BG to FR stages, strawberry fruit undergoes de-greening and red coloration among other physiological changes [5]. The two stages are visually separated from the other developmental stages and have been selected in many previous studies investigating the ripening process [29,30]. More DEGs are generated from BG vs. FR than from sub-stages between BG and FR [29].…”

Transcriptome Analysis of the Fruit of Two Strawberry Cultivars “Sunnyberry” and “Kingsberry” That Show Different Susceptibility to Botrytis cinerea after Harvest

“…qPCR analysis was conducted as described by Min et al [ 3 ]. The cDNA was diluted to 100 ng μL −1 and combined with 5 μL of 2 × Real-Time PCR Master Mix containing SYBR Green 1 (BioFACT, Daejeon, Korea).…”

“…However, postharvest strawberry fruit is perishable and susceptible to mechanical damage, fungal decay, and rapid metabolism. Severe deterioration of postharvest fruit quality and economic loss may be the consequences of small scratches and bruises during packaging and shipping [ 2 , 3 ]. Strawberry fruit readily senesces after harvest and has a short shelf life because it is highly sensitive to biotic and abiotic stress [ 4 ].…”

“…Studies on various B. cinerea -resistant strawberry cultivars have been conducted. An earlier work assessed postharvest storability in five different strawberry cultivars developed in Korea [ 3 ]. The “Sunnyberry” and “Kingsberry” varieties were the most resistant and susceptible to postharvest fungal decay, respectively.…”