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  • Author or Editor: Yuan Zhang x
  • Journal of the American Society for Horticultural Science x
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The morphological characteristics of chrysanthemum (Chrysanthemum ×morifolium) are rich in variation. However, as a result of the aneuploid polyploidy of the chrysanthemum genome and the lack of proper tools, the genomic information of this crop is limited. Development of microsatellite markers has been an increasing trend in crop genetic studies because of the applicability of these markers in breeding programs. In this study, we reported the development of a simple sequence repeat in chrysanthemums using a magnetic beads enrichment method. An enriched genomic library with AC and GT microsatellite motifs was constructed, and 53 positive clones were detected by a colony polymerase chain reaction (PCR) technique. Of these clones, 35 showed high-quality sequences, and 35 primer pairs were designed accordingly. Twenty-six (74.29%) of the 35 primer pairs revealed polymorphisms on a set of 40 chrysanthemum cultivars. There were 172 alleles amplified over 26 loci with an average of 6.615 alleles per locus. The mean values of gene diversity corrected for the sample size and the inbreeding coefficient were 0.609 and 0.119 over 26 loci, respectively, which indicated that the majority of the microsatellite loci is highly informative. Cluster analysis based on 26 polymorphic loci demonstrated that the selected cultivars were clustered according to geographical origin. This study shows the isolation efficiency of the magnetic beads technique; the abundance of microsatellites in chrysanthemum; and the potential application for the cultivar classification, the studies on genetic diversity, and molecular breeding of chrysanthemums, which is beneficial to promoting the conservation and sustainable use of this crop.

Free access

After nearly a decade of development, the scale of blueberry (Vaccinium sp.) cultivation has increased, particularly in south China; however, this region is becoming increasingly challenged by temperature changes during the flowering phenophase. Understanding the effects of temperature on pollen germination and pollen tube growth in blueberry is thus important. Using the rabbiteye blueberry (V. ashei) ‘Brightwell’, different temperature treatments were carried out during open pollination and cross-pollination with the pollen from rabbiteye blueberry ‘Gardenblue’ in field, greenhouse, and controlled temperature experiments over two consecutive years. The differences in pollen germination, pollen tube dynamics, and ovule viability following different treatments were analyzed, and the critical temperatures were calculated using quadratic and modified bilinear equations to quantify the developmental responses to temperature. The results showed that the fruit set of the artificially pollinated plants inside the greenhouse was significantly higher than that outside the greenhouse. Furthermore, pollen germination and pollen tube growth gradually accelerated under the appropriate high-temperature range, resulting in reduced pollen tube travel time to the ovule. However, the percentage of the style traversed by the pollen tube did not increase at temperatures greater than 30 °C, and a high-temperature range could accelerate ovule degeneration. Therefore, impairment of pollen tube growth in the upper half of the style following pollen germination and ovule degeneration constituted important factors leading to reduced fruit setting under short periods of high temperature during the flowering phenophase in rabbiteye blueberry. This work advances our understanding of the effect of temperature on pollen germination, pollen tube growth, ovule longevity, and fruit setting in rabbiteye blueberry, and provides a foundation for continued cultivation and breeding enhancement. The findings propose that the tolerance of rabbiteye blueberry to a certain high-temperature range in the flowering phenophase should inform breeding strategies for temperature resistance and that temperature range is also an important indicator of suitable environments for cultivation to mitigate potential temperature stress.

Free access

Heterostylous Primula forbesii is an important ornamental flower in China because of its long-lasting flowers and winter bloom. This study aimed to develop markers of expressed sequence tag–simple sequence repeats (EST-SSRs) that are associated with heterostyly and that can be used for molecular-assisted selective breeding in P. forbesii. We investigated 114,474 unigenes and identified 25,095 SSRs in P. forbesii. Dinucleotide repeats (46.14%), mononucleotide repeats (44.65%), and trinucleotide repeats (8.27%) were the most abundant SSRs. Among the 25,095 SSRs, 10,645 SSR primer pairs were successfully designed, of which 130 primer pairs were randomly selected for further amplification validation using eight accessions of P. forbesii; 98 pairs produced clear and stable polymerase chain reaction (PCR) products, and 28 pairs showed polymorphism. Bulked segregant analysis (BSA) was conducted for the F1 population with respect to thrum style and pin style by scanning 28 polymorphic SSR primer combinations. One SSR marker, c64326, linked to the heterostyly trait at a genetic distance of ≈3.70 cM was identified. The marker c64326 was further validated in two populations with an accuracy of 97.92% and 90.63%. The novel and linked EST-SSR markers can be valuable resources for genetic diversity analysis, mapping, and marker-assisted breeding in P. forbesii.

Free access

The mechanism regulating procyanidin (PA) accumulation in banana (Musa acuminata) fruit is not understood. During this study, the effects of PA treatment on the activities of banana PA biosynthetic enzymes and transcriptomic profiles were investigated. The results showed that PA treatment delayed the decreases in leucoanthocyanidin reductase and anthocyanidin reductase activities, which affected the accumulation of PA. Furthermore, the peel samples of the control fruit and the PA-treated fruit on day 1 were selected for transcriptomic analysis. The results revealed that PA treatment induced 1086 differentially expressed genes. Twenty-one key genes, including those encoding biosynthetic enzymes and regulatory factors involved in PA biosynthesis, were validated using a quantitative real-time polymerase chain reaction. The results showed that these genes were upregulated by PA treatment during banana storage. Taken together, our study improves current understanding of the mechanism underlying PA-regulated banana senescence and provide new clues for investigating specific gene functions.

Open Access

Fruit bagging is a popular agricultural practice that has been widely used to physically protect fruit. However, the application of fruit bags usually has various effects on fruit quality. In this study, three kinds of paper bags with different colors and transmittance were applied to investigate their effects on the skin coloration and related gene expression of peach (Prunus persica). Our findings showed that bagging treatment inhibited anthocyanin accumulation and the expression of related structural and regulatory genes in the peach pericarp. To a certain extent, the inhibitory effects were negatively correlated with the light transmittance of these paper bags. The expression of MYB10.1 was also suppressed by fruit bagging and was highly consistent with anthocyanin content in peach pericarps, which indicated that MYB10.1 might have a critical role in the light-mediated regulation of anthocyanin production in peach pericarps. These findings further enrich our theoretical knowledge of the regulation of anthocyanin synthesis in peach fruit and provide a theoretical basis for common horticultural practices.

Open Access