Pears carry a gametophytic self-incompatibility(SI)system.In this system,S-RNase is the SI pistil determinant,and S-locus F-box brothers(SFBBs)are candidate pollen determinants.However,compared with apple,fewer SFBB g...Pears carry a gametophytic self-incompatibility(SI)system.In this system,S-RNase is the SI pistil determinant,and S-locus F-box brothers(SFBBs)are candidate pollen determinants.However,compared with apple,fewer SFBB genes were identified from pear,possibly caused by the lack of economic and effective methods.Here,we used transcriptome sequencing on‘Yali’(Pyrus bretschneideri)to obtain sequence fragments of SFBB genes and then used polymerase chain reaction(PCR)to amplify the whole sequence of SFBB genes.Twenty-seven SFBB genes,including22 full-length and five nonfull-length SFBB genes,were identified in‘Yali’(P.bretschneideri).SFBBs linkage analysis by PCR-enzyme-linked immunoassay(ELISA)showed that 12 SFBB genes belong to the S21 locus,and 15 SFBB genes belong to the S34 locus.Phylogenetic analysis showed that SFBB genes from Pyrus were divided into 26 types,more than the original eight types.The intrahaplotypic divergence of SFBBs is high and comparable to the allelic diversity of S-RNase,which is consistent with a nonself-recognition SI system.In addition,the expression level of PbrSFBBs in‘Jinzhui’,the only known haploid pollen of a self-compatible mutant,was mostly approximately two times higher than in‘Yali’,which may be the reason for the self-compatible mutant.展开更多
Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (...Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit.展开更多
This study used 40-year-old Pyrus bretschneideri cv. Dangshan Su pear trees in Dangshan County, Anhui Province as experimental materials. Four positions at the crown of the pear tree with different light intensity wer...This study used 40-year-old Pyrus bretschneideri cv. Dangshan Su pear trees in Dangshan County, Anhui Province as experimental materials. Four positions at the crown of the pear tree with different light intensity were observed, including the south exterior and interior and the north exterior and interior of the middle crown. The ZD-ZA illumination meter was adopted to measure the light intensity, the anthracene ketone method to survey the soluble sugar, the standard acid-soda to measure the organic acid, and the 2,6-dichloropheonlinolphenol to survey the Vc. Sampling began in the first week after the anthesis, following a time schedule of one times every two weeks within two months of the prophase of the fruit development, and one times every four weeks of the later period until the fruit ripens. Correlation analyses, variance analyses and multiple comparison were applied to process the data.The results showed that: 1) the soluble sugar level increased with the growth of the fruit, slowly in the initial 7 weeks after the blooming, but rapidly from the 7th week on, and the positive correlation was found between the sugar level and the number of weeks after the anthesis (r=0.961), and between the sugar level and light intensity (r=0.95); 2) the organic acid level presented the trend of falling with the growth of the fruit, and the correlation between the organic acid level (not apparently related to the light intensity) and the number of weeks after the anthesis was negative (r=-0.814); 3) the sugar-acid ratio rose with the growth of the fruit, in positive correlation with the soluble sugar level and not significant correlation with the organic acid level; 4) the variation of Vc content indicated a low-high-low pattern, with the value of 25.76 mg·kg -1 in the first week after the blooming, and a rise to 68.32 mg·kg -1 in the 5th week, then a decline with the fruit growth to 18.82 mg·kg -1 in the 7th week, and the significant correlation was not found with the number of weeks after the anthesis and the light intensity; 5) the light intensity was positively correlated with the soluble sugar, while not significantly correlated with the organic acid and Vc. The quality of fruit was improved with the increase of light intensity.The result suggests that different measures need to be taken to adjust the nutrition of the pear tree in the different fruit-growth phases. When the tree is properly trimmed, sunlight can be fully utilized to achieve a perfect photosynthesis which contributes to a better inner physiological system, and thus the fruit quality will be improved.展开更多
A new selfincompatibility gene was isolated and identified from Pyrus bretschneideri cultivars of Yingzhiqing and Daaoao via PCR amplification, DNA sequence analysis and cross pollination tests. DNA sequence analysis ...A new selfincompatibility gene was isolated and identified from Pyrus bretschneideri cultivars of Yingzhiqing and Daaoao via PCR amplification, DNA sequence analysis and cross pollination tests. DNA sequence analysis revealed that the isolated fragment displayed a high homology with S 1 ～S 11 allele, and the identity to S 1 ～S 11 allele at the deduced amino level ranged from 56% to 72%; the high degree of variances in the hypervariable （HV） region resulted from the presence of substitution, deletion and insertion of 9 to 15 amino acids. The new Sallele was named S 12 RNase and its accession number was AY250987 in GeneBank. The sizes of HV region, intron, signal peptide, C1 region, C2 region were 39 AA, 341 bp, 27 AA, 11 AA and 10 AA, respectively. The cross pollination tests were carried out using Pyrus pyrifolia cultivars that contained S 1 ～S9RNase genes as female parents, and the cultivars of Daaoao and Yingzhiqing as male parents, respectively. The results showed that all of {%P.pyrifolia%} cultivars were compatible with Daaoao and Yingzhiqing, whereas the cross pollination between Daaoao and Yingzhiqing were incompatible, further confirming that the DNA fragment isolated was a new Sgene.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000107)National Natural Science Foundation of China(Grant No.32001983)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190896)。
文摘Pears carry a gametophytic self-incompatibility(SI)system.In this system,S-RNase is the SI pistil determinant,and S-locus F-box brothers(SFBBs)are candidate pollen determinants.However,compared with apple,fewer SFBB genes were identified from pear,possibly caused by the lack of economic and effective methods.Here,we used transcriptome sequencing on‘Yali’(Pyrus bretschneideri)to obtain sequence fragments of SFBB genes and then used polymerase chain reaction(PCR)to amplify the whole sequence of SFBB genes.Twenty-seven SFBB genes,including22 full-length and five nonfull-length SFBB genes,were identified in‘Yali’(P.bretschneideri).SFBBs linkage analysis by PCR-enzyme-linked immunoassay(ELISA)showed that 12 SFBB genes belong to the S21 locus,and 15 SFBB genes belong to the S34 locus.Phylogenetic analysis showed that SFBB genes from Pyrus were divided into 26 types,more than the original eight types.The intrahaplotypic divergence of SFBBs is high and comparable to the allelic diversity of S-RNase,which is consistent with a nonself-recognition SI system.In addition,the expression level of PbrSFBBs in‘Jinzhui’,the only known haploid pollen of a self-compatible mutant,was mostly approximately two times higher than in‘Yali’,which may be the reason for the self-compatible mutant.
基金supported by the China Agriculture Research System (Grant No.CARS-28-14)。
文摘Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit.
文摘This study used 40-year-old Pyrus bretschneideri cv. Dangshan Su pear trees in Dangshan County, Anhui Province as experimental materials. Four positions at the crown of the pear tree with different light intensity were observed, including the south exterior and interior and the north exterior and interior of the middle crown. The ZD-ZA illumination meter was adopted to measure the light intensity, the anthracene ketone method to survey the soluble sugar, the standard acid-soda to measure the organic acid, and the 2,6-dichloropheonlinolphenol to survey the Vc. Sampling began in the first week after the anthesis, following a time schedule of one times every two weeks within two months of the prophase of the fruit development, and one times every four weeks of the later period until the fruit ripens. Correlation analyses, variance analyses and multiple comparison were applied to process the data.The results showed that: 1) the soluble sugar level increased with the growth of the fruit, slowly in the initial 7 weeks after the blooming, but rapidly from the 7th week on, and the positive correlation was found between the sugar level and the number of weeks after the anthesis (r=0.961), and between the sugar level and light intensity (r=0.95); 2) the organic acid level presented the trend of falling with the growth of the fruit, and the correlation between the organic acid level (not apparently related to the light intensity) and the number of weeks after the anthesis was negative (r=-0.814); 3) the sugar-acid ratio rose with the growth of the fruit, in positive correlation with the soluble sugar level and not significant correlation with the organic acid level; 4) the variation of Vc content indicated a low-high-low pattern, with the value of 25.76 mg·kg -1 in the first week after the blooming, and a rise to 68.32 mg·kg -1 in the 5th week, then a decline with the fruit growth to 18.82 mg·kg -1 in the 7th week, and the significant correlation was not found with the number of weeks after the anthesis and the light intensity; 5) the light intensity was positively correlated with the soluble sugar, while not significantly correlated with the organic acid and Vc. The quality of fruit was improved with the increase of light intensity.The result suggests that different measures need to be taken to adjust the nutrition of the pear tree in the different fruit-growth phases. When the tree is properly trimmed, sunlight can be fully utilized to achieve a perfect photosynthesis which contributes to a better inner physiological system, and thus the fruit quality will be improved.
文摘A new selfincompatibility gene was isolated and identified from Pyrus bretschneideri cultivars of Yingzhiqing and Daaoao via PCR amplification, DNA sequence analysis and cross pollination tests. DNA sequence analysis revealed that the isolated fragment displayed a high homology with S 1 ～S 11 allele, and the identity to S 1 ～S 11 allele at the deduced amino level ranged from 56% to 72%; the high degree of variances in the hypervariable （HV） region resulted from the presence of substitution, deletion and insertion of 9 to 15 amino acids. The new Sallele was named S 12 RNase and its accession number was AY250987 in GeneBank. The sizes of HV region, intron, signal peptide, C1 region, C2 region were 39 AA, 341 bp, 27 AA, 11 AA and 10 AA, respectively. The cross pollination tests were carried out using Pyrus pyrifolia cultivars that contained S 1 ～S9RNase genes as female parents, and the cultivars of Daaoao and Yingzhiqing as male parents, respectively. The results showed that all of {%P.pyrifolia%} cultivars were compatible with Daaoao and Yingzhiqing, whereas the cross pollination between Daaoao and Yingzhiqing were incompatible, further confirming that the DNA fragment isolated was a new Sgene.
