Profiling Analysis of Volatile and Non-volatile Compounds in Vitis Vinifera Berries (cv. Chardonnay) and Spontaneous Bud Mutation

A novel clonal variety of Vitis vinifera was identified from “Chardonnay” using inter-simple sequence repeat (ISSR) markers and called “bud mutation. ” The metabolomic profiles in Chardonnay and bud mutation berries indicated essential differences in the expression of key genes in the pathways of 2-C-methyl-D-erythritol-4-phosphate (MEP) and lipoxygenase-hydroperoxide lyase (LOX-HPL). Bud mutation fruits also matured 10 days earlier than Chardonnay and have higher carotenoid, sugar, and acidic compound contents. Furthermore, the gene expression was examined in the biosynthetic pathways of two ripening-associated hormones, abscisic acid (ABA) and jasmonic acid (JA), which significantly increased in bud mutation compared with the Chardonnay fruit. The synthesis and metabolism of amino acids, terpenes, fatty acids, volatile components, and specialized metabolites significantly increased in bud mutation. Therefore, in comparison with Chardonnay, bud mutation is considered a highly aroma-producing grape variety for an improvement in the beverage industry.

Effects of Endogenous Hormones and Sugars on Fruit Size Driven by Cell Division between Korla Fragrant Pear and Its Bud Mutation

Large-fruit bud mutations are important factors in fruit tree breeding. However, little is known about the differences between varieties and bud mutations. The ploidy identification of Korla fragrant pear (Pyrus sinkiangensis Yu) and its large bud mutation Zaomeixiang pear showed that the large-fruit characteristic was not caused by chromosome doubling. By counting mesocarp cells at different stages, we found that the number of cells increased continuously after pollination, and the difference was the greatest at 28 days after full bloom (DAFB), and was about 9.4 × 106. After 28 days, the difference in cell volume became bigger and bigger, so both the cell volume and cell number caused the difference in fruit size between Korla fragrant pear and Zaomeixiang pear. To obtain more insights into the differences in fruit size driven by cell division, we analyzed the endogenous hormones [indole ascetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA), and abscisic acid (ABA)], and the main sugars (glucose, fructose, sucrose, and sorbitol). The ZR content of Zaomeixiang pear was always greater than that of Korla fragrant pear at all stages. The ABA content was the opposite except for at 7 DAFB during cell division; the greatest difference was 30.87 ng/g, which appeared at 28 DAFB. ABA and ZR correlated negatively with cell number. After 7 DAFB, the ratio of IAA/ABA, ZR/ABA, and GA/ABA in Zaomeixiang pear was always greater than that for Korla fragrant pear at 28 DAFB. The difference in glucose content at 21 DAFB was the greatest, at 4.80 ng/g. Large amounts of sorbitol accumulated during whole-cell division. Glucose and sorbitol correlated positively with cell numbers. In summary, the data suggest that the different contents of glucose, sorbitol, ZR, and ABA, and the ratio of endogenous hormones might be related to cell division in Korla fragrant pear and Zaomeixiang pear. The result provides a theoretical basis for the large-size fruit’s high-quality production and genetic breeding of Korla fragrant pear and its bud mutation.

Transcriptional reprogramming of the bud-mutation loquat YongLu emerging freezing resistant

Background: Freezing seriously affects loquat, an originally subtropical fruit. Here, a wide-spread cultivar loquat bud mutation ‘Yonglu’ (YL) was found to be more resistant to freezing than the parental ‘Ruantiaobaisha’ (RT), especially the fruits. The freezing resistance mechanism of YL was analyzed by physiological and transcriptomic methods. Results: After freezing treatment, only the fruits of YL showed a significant accumulation of proline (which increased by 1.5-fold). Interestingly, abscisic acid (ABA) accumulation in YL showed no difference after freezing treatment. Moreover, the stomatal density, area, and apertures of YL significantly decreased. All these results suggested that the proline content and stomatal closure contributed to the enhanced freezing tolerance. Further, the transcriptional profiles of freezing tissues were obtained and compared. Functional enrichment analysis showed that aside from basic nutrients and energy metabolisms, such as citrate cycle and oxidative phosphorylation, the fruits and flowers of YL have different systems to enhance freezing tolerance, suggesting a progressive freezing-resistant network. Signaling transduction of nearly all hormones, including ABA, was significantly differentially expressed. Several key genes, such as PP2C and SnRK2, which are crucial for transducing ABA signals, were significantly down- and upregulated, respectively. But the genes of neither ABA biosynthesis nor ABA transduction pathway significantly differentially expressed between two freezing varieties, suggesting they contribute limit in enhancing freezing tolerance of YL. Conclusion: Concludingly, the bud mutation YL loquat has stronger freezing tolerance than its parental RT due to the increasing proline and more effective regulation of stomatal closure. Furthermore, the bud mutation YL loquat reprogrammed its entire transcriptional profiles to enhance their abilities to adapt to freezing stress. However, ABA biosynthesis, ABA transduction pathway and CBF pathway, which are common reasons in cold response, were not the main reason for the increasing freezing tolerance of YL. There must be unknown regulation mechanisms for the bud mutation to freezing resistant.

Identification of ‘Haryejosaeng’ mandarin by multiplex SNP genotyping

BackgroundMost of the satsuma mandarin (Citrus unshiu Marc.) cultivars grown on Jeju Island farms, Korea, are difficult to improve through hybridization because of polyembryony and male sterility. Therefore, their improvement has mostly been based on the selection of nucellar embryo and bud mutation. These cultivars are supplied to breeders and farms at the seedling stage, which renders their identification based only on morphological traits. In addition, because these seedlings originate from nucellar embryo and bud mutation selection, they are genetically very similar. Therefore, the present study was carried out to develop markers that can specifically and rapidly distinguish ‘Haryejosaeng,’ which is generally supplied to breeders, from other satsuma mandarin cultivars that are planted on farms.ResultsPolymerase chain reaction (PCR) was performed to distinguish ‘Haryejosaeng’ from other 8 cultivars (‘Haryejosaeng’- breeder’s stock, ‘Miyagawa wase,’ ‘Okitsu wase,’ ‘Yura wase,’ ‘Miyamoto wase,’ ‘Ueno wase,’ ‘Yonezawa wase,’ and ‘Nichinan 1 gou’) using 6 single nucleotide polymorphism (SNP) markers specific for ‘Haryejosaeng’ and one SNP primer pair, which was used as the negative control. Using a multiplex PCR, SNP markers P1 (HL-SNP-SCAF_2-23997586-F and HL-SNP-SCAF_2-23997586-R), P2 (HL-SNP-SCAF_2-36059523-F and HL-SNP-SCAF_2-36059523-R), and P5 (HL-SNP-SCAF_9-30793978-F and HL-SNP-SCAF_9-30793978-R) simultaneously yielded 165, 150, and 526 bp amplicons, respectively, for Haryejosaeng only. The SNP markers were further validated by high-resolution melting analysis. The multiplex PCR based on P1/P5 and P2/P5 was also used to identify ‘Haryejosaeng’ on a farm growing 17 different cultivars of satsuma mandarin.ConclusionsWe developed specific molecular markers for accurate identification of ‘Haryejosaeng,’ which can be performed by multiplex PCR to save time and cost associated with the supply of ‘Haryejosaeng’ to farms.

Parallel Bud Mutation Sequencing Reveals that Fruit Sugar and Acid Metabolism Potentially Influence Stress in Malus

Apple sugar and acid are the most important traits of apple fruit. Bud sport cultivars can provide abundant research materials for functional gene studies in apple. In this study, using bud sport materials with a rather different sugar and acid flavor, i.e., “Jonathan” and “Sweet Jonathan”, we profiled the whole genome variations and transcriptional regulatory network during fruit developmental stages using whole genome sequencing and RNA-sequencing. Variation analysis identified 4,198,955 SNPs, 319,494 InDels, and 32,434 SVs between the two cultivars. In total, 4313 differentially expressed genes among all of the d 44,399 genes expressed were identified between the two cultivars during fruit development, and functional analysis revealed stress response and signal transduction related genes were enriched. Using 24,047 genes with a more variable expression value, we constructed 28 co-expression modules by weighted correlation network analysis. Deciphering of 14 co-expression modules associated with sugar or acid accumulation during fruit development revealed the hub genes associated with sugar and acid metabolism, e.g., MdDSP4, MdINVE, and MdSTP7. Furthermore, exploration of the intra network of the co-expression module indicated the close relationship between sugar and acid metabolism or sugar and stress. Motif-based sequence analysis of the 17 differentially expressed ATP-binding cassette transporter genes and Yeast one-hybrid assay identified and confirmed a transcription factor, MdBPC6, regulating the ATP-binding cassette (ABC) transporter genes and potentially participating in the apple fruit development or stress response. Collectively, all of the results demonstrated the use of parallel bud mutation sequencing and identified hub genes, and inferred regulatory relationships providing new information about apple fruit sugar and acid accumulation or stress response.