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Background: In strawberry cultivation, continuous cropping (CC) obstacles seriously threaten production. A patented soil amendment (SA) can effectively relieve the CC obstacles to strawberry cultivation, but knowledge of the recovery mechanisms underlying this phenomenon is limited. Results: In this study, transcriptomic profiling of strawberry roots in soil with and without the SA was conducted using RNA-Seq technology to reveal gene expression changes in response to SA treatment. In total, 188 differentially expressed genes (DEGs), including 144 upregulated and 44 downregulated DEGs, were identified. SA treatment resulted in genotype-dependent responses, and the response pattern, including an overall increase in the expression of nutrient transport genes and a decrease in the expression of defense response genes, may be a possible mechanism underlying recovery strategies in strawberry roots after the application of the SA to CC soil. We also found that 9 Hsp genes involved in plant defense pathways were all downregulated in the SA-treated roots. Conclusions: This research indicated that strawberry plants reallocated defense resources to development when SA treatment alleviated the stress caused by a CC soil environment. The present study provides an opportunity to reveal the fundamental mechanisms of the tradeoff between growth and defense in strawberry. [ABSTRACT FROM AUTHOR]

Fragaria orientalis Lozinsk. is valuable germplasm material for cross breeding in Fragaria. In this study, we assembled the complete mitochondrial genome of F. orientalis using a combination of Illumina data and Nanopore data. The mitochondrial genome was 275,143 bp in length, including 29 protein-coding genes, 20 tRNA genes, and three rRNA genes, with a total GC content 45.23%. Seven protein-coding genes contained introns, and three were trans-spliced. Phylogenetic analysis indicated that F. orientalis is making a sister clade to the Amygdaloideae species. The complete mitochondrial genome of F. orientalis reported in this study will improve our understanding of Fragaria evolution. [ABSTRACT FROM AUTHOR]

Background: Pink-flowered strawberry is a promising new ornamental flower derived from intergeneric hybridization (Fragaria × Potentilla) with bright color, a prolonged flowering period and edible fruits. Its flower color ranges from light pink to red. Pigment compounds accumulated in its fruits were the same as in cultivated strawberry fruits, but different from that in its flowers. However, the transcriptional events underlying the anthocyanin biosynthetic pathway have not been fully characterized in petal coloration. To gain insights into the regulatory networks related to anthocyanin biosynthesis and identify the key genes, we performed an integrated analysis of the transcriptome and metabolome in petals of pink-flowered strawberry. Results: The main pigments of red and dark pink petals were anthocyanins, among which cyanidins were the main compound. There were no anthocyanins detected in the white-flowered hybrids. A total of 50,285 non-redundant unigenes were obtained from the transcriptome databases involved in red petals of pink-flowered strawberry cultivar Sijihong at three development stages. Amongst the unigenes found to show significant differential expression, 57 were associated with anthocyanin or other flavonoid biosynthesis, in which they were regulated by 241 differentially expressed members of transcription factor families, such as 40 MYBs, 47 bHLHs, and 41 NACs. Based on a comprehensive analysis relating pigment compounds to gene expression profiles, the mechanism of flower coloration was examined in pink-flowered strawberry. A new hypothesis was proposed to explain the lack of color phenotype of the white-flowered strawberry hybrids based on the transcriptome analysis. The expression patterns of FpDFR and FpANS genes corresponded to the accumulation patterns of cyanidin contents in pink-flowered strawberry hybrids with different shades of pink. Moreover, FpANS, FpBZ1 and FpUGT75C1 genes were the major factors that led to the absence of anthocyanins in the white petals of pink-flowered strawberry hybrids. Meanwhile, the competitive effect of FpFLS and FpDFR genes might further inhibit anthocyanin synthesis. Conclusions: The data presented herein are important for understanding the molecular mechanisms underlying the petal pigmentation and will be powerful for integrating novel potential target genes to breed valuable pink-flowered strawberry cultivars. [ABSTRACT FROM AUTHOR]

Soil ecology plays an important role in the growth and health of plants. Research suggests that long-term monocropping may lead to soil ecological disorders. In this study, we aimed to understand the reasons for the decrease in plant productivity stemming from long-term monoculture cropping. Greenhouse studies were conducted to determine the cause of continuous cropping (CC) obstacles in soils under 12 years of continuous strawberry (Fragaria × ananassa Duch.) production. The data suggested that CC led to three phases of changes in abiotic and biotic soil factors. In phase I (CC for 2–6 years), significant changes were observed only in soil physicochemical properties, such as the pH, total nitrogen (TN), ammonium nitrogen (NH 4 +-N), available phosphorus (AP), available potassium (AK) and soil organic matter (SOM), which obviously changed from the second year to the sixth year. In phase II (CC for 6–8 years), two biotic factors, key fungi such as Fusarium , Humicola and Arthrobotrys and soil nematodes, i.e., populations and communities of nematodes, started to change significantly in terms of their abundance. In phase III (CC for >8 years), the accumulation of phenolic acids, i.e., p-hydroxybenzoic acid (p-HBA), ferulic acid (FA), p-coumaric acid (p-CA) and cinnamic acid (CA), significantly inhibited crop growth, and the abundance of key bacteria, including Bacillus , Sphingomonas and Sphingopyxis , started to change significantly from the eighth CC year. The results in this study provide useful information for solving CC obstacles in strawberry production. Unlabelled Image • Continuous cropping led to changes in abiotic and biotic factors in the soil. • This is the first attempt to comprehensively interpret continuous cropping obstacles. • The continuous cropping soil changes could be divided into three main phases: Phase I, Phase II, and Phase III. • This research provides useful information to solve strawberry continuous cropping problems. [ABSTRACT FROM AUTHOR]