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Fruit bagging is a very effective method for study of fruit qualities and anthocyanin synthesis. The characterization of differentially expressed proteins that were isolated from both bagged and normal fruit skin tissue is apparently an essential parameter for understanding the effect of shading on fruit qualities and to understand the mechanism of fruit coloring in Pyrus communis. Proteome maps of both bagged and normal P. communis 'Placer' fruit skin were obtained by performing two-dimensional electrophoresis analysis and compared to assess the extent to which protein distribution differed in pear skin. The comparative analysis showed 38 differentially expressed proteins between the two samples: with three protein spots up-regulated and 35 down-regulated in the bagged fruit. Differentially expressed protein spots were subjected to matrix-assisted laser desorption ionization time of flight (MALDI-TOF) analysis and the data compared to that of known proteins to deduce their possible functions. Of these, 21 protein spots were identified and classified into functional classes. These identified proteins were mainly involved in photosynthesis, signal transduction, energy pathway, protein folding and assembly, and carbohydrate and acidity metabolisms, and were under-expressed in bagged fruit skins. This work provides a first characterization of the proteome changes in response to fruit bagging treatment in red pears. [ABSTRACT FROM AUTHOR]

In tetraploid sour cherry ( Prunus cerasus L.), the accumulation of nonfunctional S-haplotypes with disrupted pistil-component (stylar- S) and/or pollen-component (pollen- S) function leads to a genotype-dependent loss of gametophytic self-incompatibility (GSI). Tetraploid Chinese cherry ( Prunus pseudocerasus L.) exhibits self-compatibility. In this study, we characterized four S-haplotype-specific F-box protein genes ( SFBs) from pollen cDNA of Chinese cherry cv. ‘Taixiaohongying’ with the S-genotype S 1 S 2 S 3 S 4. Of the four SFBs, three showed typical characteristics of SFBs from other Prunus species and functioned as SFB genes; these were termed SFB a (GQ395341), SFB b (GQ395340), and SFB c (EU267943), respectively. The fourth SFB, termed SFB d (GQ395339), has a 100-bp deletion that resulted in the transcript for SFB d lacking the F-box domain. SFB d lost the pollen- S specific function and functioned as the SFB gene mutant. The results of reverse transcription-PCR analysis indicated that the four SFB genes were transcribed at approximately the same intensity. [ABSTRACT FROM AUTHOR]

Skin color is an important factor in pear breeding programs. The degree of red coloration is determined by the content and composition of anthocyanins. In plants, many MYB transcriptional factors are involved in regulating anthocyanin biosynthesis. In this study, a R2R3-MYB transcription factor gene, PyMYB10, was isolated from Asian pear ( Pyrus pyrifolia) cv. ‘Aoguan’. Sequence analysis suggested that the PyMYB10 gene was an ortholog of MdMYB10 gene, which regulates anthocyanin biosynthesis in red fleshed apple ( Malus × domestica) cv. ‘Red Field’. PyMYB10 was identified at the genomic level and had three exons, with its upstream sequence containing core sequences of cis-acting regulatory elements involved in light responsiveness. Fruit bagging showed that light could induce expression of PyMYB10 and anthocyanin biosynthesis. Quantitative real-time PCR revealed that PyMYB10 was predominantly expressed in pear skins, buds, and young leaves, and the level of transcription in buds was higher than in skin and young leaves. In ripening fruits, the transcription of PyMYB10 in the skin was positively correlated with genes in the anthocyanin pathway and with anthocyanin biosynthesis. In addition, the transcription of PyMYB10 and genes of anthocyanin biosynthesis were more abundant in red-skinned pear cultivars compared to blushed cultivars. Transgenic Arabidopsis plants overexpressing PyMYB10 exhibited ectopic pigmentation in immature seeds. The study suggested that PyMYB10 plays a role in regulating anthocyanin biosynthesis and the overexpression of PyMYB10 was sufficient to induce anthocyanin accumulation. [ABSTRACT FROM AUTHOR]

The S-genotypes of 16 apricot ( Prunus armeniaca L.) cultivars native to China were determined by the S-allele PCR approach and the results were confirmed by cross-pollination tests among these cultivars. Primer combination EM-PC2consFD + EM-PC3consR, based on the conserved regions C2 and C3 of Rosaceous S-RNase genes, was the most useful primer combination for identifying Chinese apricot S-alleles. Twelve S-RNase alleles were identified using this primer combination, and they were defined as follows: S 9 was 657 bp, S 10 was 266 bp, S 11 was 464 bp, S 12 was 360 bp, S 13 was 401 bp, S 14 was 492 bp, S 15 was 469 bp, S 16 was 481 bp, S 17 was 487 bp, S 18 was 1337 bp, S 19 was 546 bp and S 20 was 1934 bp. S 11– S 20 were new S-RNase genes deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively. Our findings contribute to a more efficient breeding program of Chinese apricot and further studies on the S-RNase genes. [ABSTRACT FROM AUTHOR]

Abstract??Embryo rescue technique was used successfully to produce interspecific hybrids by crossing peach (P. persica) as a female parent with apricot (P. armeniaca) and plum (P. salicica). In those crosses that had ?Yuhualu? or ?Zhonghuashoutao? as female parents, hybrid embryos aborted from the 7th or 8th week after pollination mainly due to post-pollination incompatibility. An embryo rescue protocol was established to rescue such embryos and recover hybrid plants. Modified half-strength MS medium containing 4?mg?l?16-BA and 0.5?mg?l?1IBA produced up to 90% germination in the embryos. Modified MS medium with 1.0?mg?l?16-BA and 1.0?mg?l?1IBA gave the highest bud induction and multiplication whereas modified MS medium containing 0.5?mg?l?1IAA and 0.2?mg?l?1NAA gave the best rooting percentage. All the hybrids obtained using this embryo rescue technique were verified using simple sequence repeat (SSR) markers. A series of pollen treatments were carried out to partially overcome pre-pollination incompatibility, and it was found accidentally that pollen treatment with electrostatic field not only improved pollen germination but also increased the multiplication coefficient of embryo-induced shoots. [ABSTRACT FROM AUTHOR]

The identity and expression of S-RNase genotypes in the self-compatible (SC) apricot cultivar ‘Katy’ and the self-incompatible (SI) cultivar ‘Xinshiji’ were examined. We used allele specific polymerase chain reaction (AS-PCR) and designated the alleles in ‘Katy’ and ‘Xinshiji’ as S8Sc and S9S10, respectively. The S-RNase gene was expressed in style at the balloon stage in both genotypes. Using real-time fluorescence quantification RT-PCR technology (FQRT-PCR), spatio-temporal expression patterns of S-RNase gene between ‘Katy’ and ‘Xinshiji’ were compared. The results revealed that the expression of the S-RNase gene in ‘Katy’ and ‘Xinshiji’ were different. The transcript abundance was distinctly diverse at the key stage (i.e., at 24 h after self-pollination) in both genotypes, and was greater in ‘Xinshiji’ (SI) than ‘Katy’ (SC). In addition, the abundance of the S-RNase transcript was higher in upper-half of style than in the lower-half of style or in the ovary. In the SI cultivar ‘Xinshiji’, the expression of S-RNase reminded a relatively high level after cross-pollination, but it dropped continuously after self-pollination and un-pollination. [ABSTRACT FROM AUTHOR]

To provide genetic basis for apricot ( Prunus armeniaca Lam.) breeding, inheritance and correlation of yield components including self-compatibility, self-pollinated fruiting rate, fertile flower rate, average fruit weight and fruit number per plant were studied with 5-year-old seedlings of apricot F1 hybrids from ‘Katy’ × (‘Xinshiji’, ‘Katy’ × (‘Hongfeng’ and ‘Katy’ × (‘Taianshuixing’, respectively. Using the criteria that cultivars with self-pollinated fruiting rate ≥6% were self-compatible(SC), we found that the ratios of self-compatible (SC) to self-incompatible (SI) individuals were 27:25, 9:12 and 15:19 in the above three families, respectively, and conformed to the ratio of 1:1 segregation by χ2 test, indicating that the S-locus of ‘Katy’ was heterozygous and self-compatibility was dominant to self-incompatibility. Twenty-seven seedlings from the F1 population of ‘Katy’ × ‘Xinshiji’ were chosen for S-allele-specific PCR. As a result, four S-genotypes with the ratio of 10:6:4:7 were obtained, which was linear to the 1:1:1:1 ratio by χ2 test. Great differences in self-compatibility degree were observed among seedlings even with the same S-genotype. In the F1 populations, a very extensive segregation in self-pollinated fruiting rate, fertile flower rate and average fruit weight was observed, and average values of these traits were lower than that of mid-parent. Therefore, these traits were confirmed to be quantitative. However, significant differences were found in broad heritability (H b 2) of following three characters: the H b 2 of self-pollinated fruiting rate (87.1% – 91.4%) was the greatest, with the variation mainly resulted from inheritance; fertile flower rate (36.8% – 49.1%) was the least and its variation was mainly caused by environmental factors. In addition, self-pollinated fruiting rate and fertile flower rate had very significantly positive correlations with single plant yield, so both may play important roles in the determination of single plant yield. In contrast, correlation between yield and average fruit weight was not significant. [ABSTRACT FROM AUTHOR]