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BACKGROUND: Strawberry fruits are perishable with a short post-harvest life. Cinnamyl alcohol dehydrogenase (CAD) is the key enzyme for lignin biosynthesis strengthening plant cell wall. A systematic characterization of strawberry CAD family is absent and their involvement in fruit firmness is largely elusive. OBJECTIVE: Current work aims for a genome-wide identificationof CAD family and its expression correlation with fruit firmness in strawberry varieties. METHODS: A genome-scale identification and molecular characterization for CADs were performed in the commercial strawberry (Fragaria×ananassa) and woodland strawberry (F. vesca). qPCR analysis of CAD homoeologs in three cultivars varying with fruit firmness revealed candidate CAD members positively correlated with lignin content and fruit firmness. RESULTS: A total of 14 and 24 CAD loci were identified in the genomes of F.vesca var. Hawaii4 and F. ×ananassa cv. Camarosa, respectively.Phylogenetic analysis supported a division of this family into three classes. Class I FvCAD each has four homoeologs in commercial strawberry, while those of Class II and Class III have only one or two homoeologs. Except for FvCAD2 and -6, there exits at least one pair of CADs sharing ∼97% or above amino acid identity between F. vesca and F. ×ananassa.The flesh firmness and lignin content varied greatly among strawberry germplasm. Distinct dynamic changes in fruit lignin content were observed before the large green stage, but fruit firmness displayed a similar decrease profile during fruit development in three varieties. Of the eight genes detected in F.×ananassa, FvCAD3 and -12 did not display a F. vesca-biased expression pattern during fruit development.FvCAD4 of Class I was expressed at levels positively correlated with variation in fruit lignin content at white stage.Transcript abundance of five Class IIgenes including FvCAD3, -8, -10, -11, and -12 was positively correlated with lignin content and fruit firmness, with FvCAD10 and -11 (FaCAD in previous publication) reaching an extremely significant correlation with the genetic variation in fruit firmness across three varieties. CONCLUSION: Strawberry Class II CADs were significantly correlated with the genetic variation in fruit firmness, which might expand the potential choices for improving strawberry shelf life.

BACKGROUND: Bet v 1 family identified as one major plant food allergen class, is highly homologous to pathogenesis-related protein 10 (PR-10), but its biological function involved in disease resistance is still unclear. OBJECTIVE: This study aims to investigate whether Bet v 1 potential allergens participate in the resistance of berry crops against fungal pathogen. METHODS: Allergenicity of Bet v 1 proteins in strawberry (Fragaria) was evaluated by bioinformatics methods. Their expression in response to anthracnose and between susceptible and resistance varieties was analyzed. RESULTS: 19 Bet v 1 homologous proteins were identified and 15 of them were considered as allergen candidates. RNA-seq analysis indicated most of these Fra a 1s expressed in fruits could be largely induced by the invasion of anthracnose pathogen Colletotrichum. The mRNA level of fruit major allergen Fra a 1.05 in the resistant variety Shenyang (SY) was 20∼50 fold higher compared with those in the susceptible cultivar and two diploid wild species. Immunoblotting using Birch (Betula pendula) Bet v 1 allergen-specific IgG antibody confirmed the large-scale accumulation of potential cross-reactive antigens in SY fruit. CONCLUSIONS: Strawberry Bet v 1 potential allergens exhibit their correspondence with anthracnose resistance that might be instructive to future breeding strategies.