Affiliations: [a] Ecological Technique and Engineering College, Shanghai Institute of Technology, Shanghai, China
| [b] Shanghai Key Laboratory of Protected Horticultural Technology, Forestry and Fruit Tree Research Institute, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, China
Note: [1] This article received a correction notice (Erratum) with the reference: 10.3233/JBR-220950, available at https://content.iospress.com/articles/journal-of-berry-research/jbr220950.
Abstract: 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.
