Research Papers

• Temporal and Spatial Expression of Carotenoid Metabolism and Relative Genes in Flowers and Leaves of CN9 Nectarine and Its Yellow-fleshed Mutant
• ZHU Yunqin1,2，ZENG Wenfang1，NIU Liang1，CAI Zuguo1,3，LU Zhenhua1，PAN Lei1，CUI Guochao1，and WANG Zhiqiang1,*
• Acta Horticulturae Sinica. 2018, 45(10): 1869-1880. DOI:10.16420/j.issn.0513-353x.2017-0604
• Abstract ( 465 ) HTML ( 714 ) PDF (1006KB) ( 714 ) 　　　
• Two nectarine cultivars，CN9（white-fleshed）and its yellow-fleshed mutant CN9Y，were used as materials to investigate carotenoids metabolism and genes expression. Qualitative and quantitative levels of carotenoids were analyzed by using HPLC，the expression of genes related to carotenoid accumulation were detected via real-time qPCR method. The results showed that the total carotenoid and β-carotene content of CN9Y nectarine were 5.7 and 19.6 times higher than that of CN9 respectively in calyxes. Carotenoid metabolism genes of both biosynthesis and degradation showed significant higher expression level in CN9Y calyxes than in CN9，except DXS and LCY-E. In petals，the total carotenoid content was similar between CN9 and CN9Y，but their carotenoid composition contents were different. The gene expression levels of DXS，HDR，PDS，LCY-E，CHY-B and CCD1 were higher in CN9Y petals than in CN9，but ZDS，NCED1 and CCD4 were lower in CN9Y than in CN9. In leaves，the carotenoid compositions of CN9 and CN9Y were all dominated by β-carotene，violaxanthin，cis-9-violaxanthin and lutein，the total carotenoid content was similar between CN9 and CN9Y during early fruit development stage，but CN9Y obviously increased after fruits matured，however，CN9 was still stabilized. During 55–80 d after flowering，only the expression level of CCD4 was in accordance with carotenoid accumulation，it is suggested that the difference of CCD4 expression level may lead to the difference of carotenoid accumulation in leaves between the two materials in later stage.
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• RNA-Seq Analysis of the Tissue-specific Expressed Genes of Pyrus betulaefolia in Root，Stem and Leaf
• ZHANG Huan，YANG Yingjie，LI Dingli，SONG Jiankun，MA Chunhui，and WANG Ran*
• Acta Horticulturae Sinica. 2018, 45(10): 1881-1894. DOI:10.16420/j.issn.0513-353x.2017-0783
• Abstract ( 284 ) HTML ( 629 ) PDF (943KB) ( 629 ) 　　　

• The tissue-specific expressed genes of Pyrus betulaefolia in root，stem and leaf were analyzed by RNA-Seq to investigate the molecular mechanism of different growth and development，tissue-specific function in Pyrus plants. With RNA-Seq analysis，19 443，19 567 and 17 876 genes expressed respectively in root，stem，and leaf，were obtained. These genes were classified into 110，110 and 110 categories by GO annotation，and involved in 56，55 and 65 metabolism pathways respectively，by KEGG analysis，including energy metabolism，material transportation，hormone regulation and signal transduction. All of 1 245，971 and 846 differently expressed genes（DEGs）were found respectively in root，stem and leaf，which were involved in 8，8 and 11 significantly enriched pathways，including the metabolism of linolenic acid，fatty acid，sucrose and secondary metabolites，redox reactions and hormone signal transduction. There were 10，6 and 20 of specifically expressed genes related to hormone signal transduction in root，stem，and leaf，respectively. Fifteen genes encoding SAUR protein were specifically expressed in the leaves with a higher expression level in tender leaves and a lower expression level in older leaves. A total of 1 353，1 150 and 1 232 transcription factors were identified in root，stem and leaf，respectively，of which WRKY，MYB and AP2-EREBP had most specifically expressed family members in root. To confirm the reliability of the RNA-Seq data，8 DEGs were selected for qRT-PCR analysis. The results of qRT-PCR were consistent with those of RNA-Seq. Conclusively，specifical expressed genes play a crucial role in tissue-specific function of plants.

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• Meiosis Observation and Fertility Analysis in Natural Tetraploid Loquat of ‘B431’
• LIANG Senlin，DANG Jiangbo，LIANG Guolu，and GUO Qigao*
• Acta Horticulturae Sinica. 2018, 45(10): 1895-1904. DOI:10.16420/j.issn.0513-353x.2018-0222
• Abstract ( 257 ) HTML ( 653 ) PDF (1983KB) ( 653 ) 　　　

• The ploidy of‘B431’loquat was determined by flow cytometry and chromosome production in this study. The meiotic process of Pollen Mother Cells（PMCs）of‘B431’was observed by modified smear method，the fertility was determined by pollen germination in vitro and artificial hybridization，and the chromosome number of hybrid progenies was counted by chromosome production. The results showed that‘B431’had abnormal chromosome behavior during meiosis，such as out-of-plate chromosomes，precocious chromosomes，laggard chromosomes，chromosome bridges，micronuclei，and few triodes. The chromosome association at the diakinesis was mainly bivalents，a small quantity of univalents and patitial multivalents. There were dyads，triads，polyads and micronuclei in the tetrad. The fertility of tetraploid loquat of‘B431’was less than diploid，but with still higher fertility. There was no significant difference in fruit setting rate between‘B431’and diploid，and its pollen in vigor reached 66.29% ± 2.22%. The hybrids of‘B431’hybridized with diploid which was mainly triploid，and it reached 66.67%.‘B431’could be used to create triploid loquat.

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• Isolation，Identification，Optimization of Fermentation Conditions and Biocontrol Effects of Antagonistic Bacterium Strain YJ15
• WANG Chunwei，WANG Yan*，ZHANG Xiqian，DONG Tian，WEN Zhihao，LIU Qianru，LI Tianli，WANG Yihui，WANG Saifeng，ZHANG Zuogang，WANG Jianming，and WANG Meiqin*
• Acta Horticulturae Sinica. 2018, 45(10): 1905-1916. DOI:10.16420/j.issn.0513-353x.2018-0234
• Abstract ( 276 ) HTML ( 646 ) PDF (2339KB) ( 646 ) 　　　

• Sixty-five endophytic bacteria strains were isolated from healthy blueberry fruits. Antagonistic bacterium strain YJ15 was screened with the agar plate diffusion method，and identified as Bacillus siamensis based on the morphological，physiological and biochemical characteristics，and 16S rRNA sequence analysis. Based on single factor tests，three important factors of temperature，pH and nitrogen source were screened by Plackett-Burman experimental design. The optimal fermentation conditions for glucose 20 g · L-1，yeast powder 36.01 g · L-1，FeSO4 1.5 g · L-1，glycerol 1 g · L-1，K2HPO4 1.5 g · L-1，inoculation amount 1 mL，rotational speed 150 r · min-1，temperature 31.35 ℃，pH 7.43 and cultural time 15 hours were determined by steepest ascent experiment and response surface methodology. The antifungal effects of fermentation broth of strain YJ15 on nine pathogenic fungi were obvious with the inhibition rate of 43.42%–92.39%. The fermentation broth of strain YJ15 with lower disease incidence and lesion diameter had better control effects with no significant difference compared with that of carbendazim，and could be useful to effectively control Botrytis cinerea causing blueberry gray mold.

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• Effects of Gibberellin on Nitrogen Metabolism and Uptake of Cucumber Under Suboptimal Root-zone Temperature
• BAI Longqiang1,2,*，LIU Yumei1,3,*，MU Ying1，HE Chaoxing1，YAN Yan1，XIE Bingyan1，YU Xianchang1,**，and LI Yansu1,**
• Acta Horticulturae Sinica. 2018, 45(10): 1917-1928. DOI:10.16420/j.issn.0513-353x.2017-0863
• Abstract ( 354 ) HTML ( 682 ) PDF (760KB) ( 682 ) 　　　

• In the present study，we aimed to investigate the role of exogenous gibberellin（GA）on regulation of nitrate uptake in cucumber（Cucumis sativus L.）under suboptimal root-zone temperature. Cucumber seedlings with two true leaves were exposed to root-zone temperature（16 ℃）in the presence/ absence of 5 μmol · L-1 GA3. The time course of nitrate influx，expression pattern of nitrate transporter（NRT），nitrate reductase（NR），glutamine synthetase（GS），and glutamate synthetase（GOGAT）coding genes，and enzymes activities of NR，GS，and GOGAT，tissue NO3--N and total free amino acid concentration were quantified. The results showed that application of exogenous GA3 increased the 15NO3- influx and CsNRT1 gene expression gradually and simultaneously improved the activity and gene expression of key enzymes in N assimilation. Exogenous GA3 decreased the contents of NO3--N and total free amino acid firstly，but subsequently increased their concentration with time. These results indicate that enhancement of nitrate acquisition capacity of cucumber by GA3 application under suboptimal root-zone temperature may due to its positive effects on N assimilation，which clears the negative feedback signal of N-metabolites.

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• Expression and Function Analysis of CmGAS1 in Melon
• ZHANG Ruiteng1,2，Lü Jianchun1，ZHOU Mengdi1，LIU Jinglin3，LI Ren3，GUO Yangdong3，WANG Huaisong1,*，and FU Qiushi1,*
• Acta Horticulturae Sinica. 2018, 45(10): 1929-1940. DOI:10.16420/j.issn.0513-353x.2017-0766
• Abstract ( 233 ) HTML ( 765 ) PDF (8238KB) ( 765 ) 　　　

• Melon belongs to a group of plants that mainly transport Raffinose Family Oligosac- charides（RFOs）. Galactinol synthase（GAS）is the key enzyme of RFOs synthesis. The aim of this study was to explore the function of CmGAS1 in melon. The full-length cDNA of CmGAS1（accession number：AY077642.1）was 1 903 bp，and the open reading frame（ORF）was 996 bp，encoding 331 amino acids. The molecular weight of CmGAS1 protein was about 38 kD，and the theoretical isoelectric point（pI）was 4.81. Amino acid sequence alignment and phylogenetic analysis showed that the amino acid sequences of CmGAS1 had the closest genetic relationship with cucumber（AAO84915.1），and the homology with cucumber was 98.79%. Homology with watermelon（Cla009222）was 97.58%. RT-qPCR analysis showed that the expression of CmGAS1 gene increased significantly from young leaves（sink）to mature leaves（source）. Expression of the fifth leaf reached the maximum value. Compared with the control，gene expression of the fully expanded functional leaves increased distinctly when 50% leaves were removed. The over expression vector of CmGAS1 was constructed with the specific promoter. The genetic transformation of melon was mediated by Agrobacterium. The positive plants were obtained by PCR identification. The net photosynthetic rates，the content of sucrose，raffinose and stachyose all increased in positive plants compared with the wild type. These results suggested that CmGAS1 played an important role in RFOs synthesis in melon leaves.

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• Studies on the Sugar Metabolism Mechanism of Tomato Fruit Under Red Light Revealed by Proteomic Analysis
• DONG Fei1，WANG Chuanzeng2，SUN Xiudong1，ZHANG Xianzheng1，REN Yuqian1，ZHOU Lijun1，WANG Dan1，and LIU Shiqi1,*
• Acta Horticulturae Sinica. 2018, 45(10): 1941-1951. DOI:10.16420/j.issn.0513-353x.2018-0010
• Abstract ( 188 ) HTML ( 605 ) PDF (1261KB) ( 605 ) 　　　

• We used tomato（Solanum lycopersicum L.）‘Micro-Tom’as the test material，after 30 days of seed germination. The seedlings were transferred to the artificial climate chamber with red and white（the control）lights. The fruits were harvested at the mature green，breaker and ripe stages，then we determined the fruit soluble sugar content and proteomic. The results showed that the soluble sugar content under red-treatment was higher than the control during the development of tomato fruit，and the difference was significant when compared with the control. The proteomic data showed that，compared with the control，46，134 and 65 differentially abundant proteins were identified in the red-treated tomato fruit，and four，four and seven of them were related to sugar metabolism in the mature green，breaker and ripe stages，respectively. Among the fifteen differentially abundant proteins related to sugar metabolism，nine were up-regulated and six were down-regulated. The differential abundances of the fifteen proteins were validated by determining the expression levels of the corresponding mRNAs by qRT-PCR. With two exceptions of glyceraldehyde-3-phosphate dehydrogenase（GAPN）and acetyl-CoA carboxylase（ACACA），the remaining genes exhibited a similar expression pattern between their mRNA and protein levels，confirming the differential gene expression levels and revealing that transcription levels are not always concomitant to the translation level. Based on the comprehensive analysis，the red light treatment can regulate the sugar content of tomato fruit by regulating some genes and proteins related to sugar metabolism.

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• Combining Ability Analysis of the Major Branching Traits in Spray Cut Chrysanthemum
• YANG Xincheng1，SU Jiangshuo1，SUN Wei1，WU Yangyang1，ZHANG Fei1,*，GUAN Zhiyong1，CHEN Fadi1，YAO Jianjun2，and FANG Weimin1,*
• Acta Horticulturae Sinica. 2018, 45(10): 1952-1960. DOI:10.16420/j.issn.0513-353x.2017-0637
• Abstract ( 233 ) HTML ( 517 ) PDF (728KB) ( 517 ) 　　　

• Branching is a major component trait of plant architecture and ornamental quality of spray cut chrysanthemum，and understanding of combining ability of major branching traits offers some references for parental selection in crossbreeding. In the present study，seven branching traits，i.e. total lateral bud number，primary branch number，primary branch length，primary branch angle，total secondary branch number，secondary branch length，and secondary branch angle of the twelve F1 progenies derived from a 4 × 3 diallel design（NCII）were investigated to dissect the combining ability effects and other population genetic parameters. Combining ability analysis showed that total lateral bud number was controlled by non-additive genes；and the primary branch number，total secondary branch number，primary branch length and secondary branch length by both additive and non-additive genes；and the primary branch angle and secondary branch angle by additive genes. A great difference was observed for general combining ability（GCA）effects of parental cultivars and for different branching traits and the hybrid combinations with contrasting special combining ability（SCA）and total combining ability（TCA）effects. Especially，‘Monalisa’exhibiting positive GCA for most branching traits except the primary branch number was capable of breeding cultivar with large plant architecture and loose branching type；whereas ‘Qx-021’（except for secondary branch number）and‘Qx-096’showing negative GCA for all investigated branch traits would be elite parents in crossbreeding targeting for cultivars of compact branching type. The crosses‘Qx-021’בQx-098’and‘Qx-081’בQx-098’showed high TCA for primary and secondary branch number but negative TCA for the other five branching traits，so it was likely to develop new cultivars of compact type from these crosses. In addition，a high level of broad-sense heritability ranging in 73.81%–94.41% was calculated for the seven branching traits，and a moderate high level of narrow-sense heritability larger than 60% was estimated for all the investigated branching traits except total lateral bud number（1.88%）. Findings of the current study reveal the combining abilities and genetic inheritance mode for the investigated branching traits and will be of vital importance for future efficient crossbreeding targeting plant architecture of spray cut chrysanthemum.

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• Overexpression of PhWRIL1 Gene Suppresses Adventitious Shoot Regeneration from Leaf Explants in Petunia
• LIANG Lingge，YANG Xia，WANG Hao，LI Zheng，LI Mingyang，and GUO Yulong*
• Acta Horticulturae Sinica. 2018, 45(10): 1961-1969. DOI:10.16420/j.issn.0513-353x.2017-0868
• Abstract ( 196 ) HTML ( 543 ) PDF (4170KB) ( 543 ) 　　　

• AP2/ERF genes play important roles in plant development and stress responses. A number of studies observed that overexpression of euANT clade genes of the AP2/ERF family can promote plant growth and in vitro regeneration. However，although the basalANT clade is closely related to the euANT，few studies have been done on the influences of overexpression of basalANT genes on de novo organogenesis in tissue culture. In this work，a basalANT gene was cloned from petunia genome，and designated PhWRIL1. Real-time PCR showed that PhWRIL1 mRNA accumulated in various tissues at moderate levels and were more abundant in the aged tissues than the young tissues. Petunia transgenic plants overexpressing PhWRIL1 showed heavily dwarfed phenotype，but the flowering time was not affected significantly. Regeneration capacity assay showed that the induction and growth of callus and shoot were reduced clearly in transgenic plants overexpressing PhWRIL1. These results showed that overexpression of PhWRIL1 suppressed shoot regeneration in plant tissue culture and suggested that basalANT and euANT genes can play opposite effects in plant development.

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• Studies on Compatibility of Interspecific Hybridization Between Michelia crassipes and M. Figo，M. maudiae，M. platypetal
• 1中南林业科技大学风景园林学院，长沙 410004；2University of Georgia，Athens，Georgia，USA 30602
• Acta Horticulturae Sinica. 2018, 45(10): 1970-1978. DOI:10.16420/j.issn.0513-353x.2017-0779
• Abstract ( 176 ) HTML ( 511 ) PDF (2515KB) ( 511 ) 　　　

• To reveal the cross-compatibility of Michelia crassipes and that of other three species（M. figo，M. maudiae and M. platypetala），M. crassipes was used as female parent and M. figo，M. maudiae and M. platypetala as male parent respectively for artificial hybridization. The pollen viability of the species was determined via culture in vitro，and the pollen tube germination after pollination was observed by fluorescence microscope. The fruit setting rate and seed quality of interspecific hybridization were investigated. The results indicated that the pollen viabilities of M. crassipes，M. figo and M. maudiae were above 65%，whereas the pollen viability of M. platypetala was only 29.07%. By fluorescence microscope，pollen germination rate and the pollen tube growth rate of M. crassipes × M. figo and M. crassipes × M. maudiae were higher than those of M. crassipes selfing. Pollen tubes could normally elongate to complete fertilization. The pollen grains of M. crassipes × M. platypetala germinated on the stigma，but the pollen germination and the growth rate of pollen tube were slower than that of the self-pollination，and inflated pollen tube，growth stop，and deposition of callose on stigma and in stylet were observed. The fruit setting rate and seed germination rate in the cross of M. crassipes × M. figo and M. crassipes × M. maudiae were above 80%，indicating that cross-compatibilities of M. crassipes with M. figo and M. maudiae were better. However，the fruit setting rate of M. crassipes × M. platypetala was only 11.1%，and hybrid embryo was abortive. The pre-fertilization barriers caused by the pollen tubes stopping growth could be one of the main barriers of interspecific hybridization between M. crassipes and M. platypetala.

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• Analysis of Stress-resistance of CcCBFs from Cinnamomum camphora Transgenic Tobacco
• WANG Jiange，ZHOU Chan，ZHANG Jiajia，ZHU Fengling，JIAO Xiaolin，and DU Li*
• Acta Horticulturae Sinica. 2018, 45(10): 1979-1988. DOI:10.16420/j.issn.0513-353x.2017-0850
• Abstract ( 224 ) HTML ( 525 ) PDF (1692KB) ( 525 ) 　　　

• In order to explore the function of three CBF genes from Cinnamomum camphora （CcCBFa，CcCBFb and CcCBFc）enhancing plant abiotic stress resistance，the obtained T1 generation of positive transgenic tobacco was subjected to stress treatment under 300 mmol · L-1 mannitol，300 mmol · L-1 NaCl solution and 4 ℃ to simulate drought，high salt and low temperature，respectively. The physiological indexes，such as proline，soluble sugar and malondialdehyde，were measured to reflect the resistance characteristics of transgenic plants. The results showed that CcCBFb and CcCBFc could significantly enhance tobacco drought resistance；CcCBFa and CcCBFc significantly enhanced the salt tolerance of tobacco；CcCBFc significantly enhanced cold tolerance of tobacco. CcCBFc could improve the ability of drought-resistance，salt-tolerance and cold-resistance of transgenic tobacco.

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• Effect of Partial Root-zone Salt Stress on Velvet Ash（Fraxinus velutina）Growth
• DUAN Lijun，LI Guoyuan*，and WANG Dianbei
• Acta Horticulturae Sinica. 2018, 45(10): 1989-1998. DOI:10.16420/j.issn.0513-353x.2018-0052
• Abstract ( 175 ) HTML ( 547 ) PDF (1784KB) ( 547 ) 　　　

• Velvet ash（Fraxinus velutina）is widely planted in the coastal saline land for vegetation construction. Salt distribution in saline soil usually is un-uniform，so velvet is affected by the heterogeneous soil salinity due to its large root system. In this study，the growth character，photosynthesis parameters，root distribution and leaf ion accumulation of velvet ash seedlings were analyzed by the split root pots method under partial root-zone salt stress. The results showed that，growth of velvet ash seedlings under partial low salt stress was significantly higher than that of the uniform salt stress and partial high salt stress. There was no effect of partial high salt stress on the leaf water potential，but leaf stomatal conductance，net photosynthetic rate and transpiration rate were significantly lower than the control. Root biomass，especially the fine root biomass，in the salt-free stressed zone was significantly higher than that of the salt stress zone. Compared with uniform salt stress，partial salt stress had significantly reduced leaf Na+ content and increased the K+/Na+. The growth of velvet ash seedlings was inhibited with partial salt stress，and the higher of salinity in one part，the lower of growth rate，while biomass was significantly higher than the uniform salt stress. Under partial salt stress，the compensatory growth of fine root in the salt-free stress zone could abtain more water，reduce leaf Na+ accumulation and increase leaf K+ content to alleviate the salt stress.

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Research Notes

• Effects of Five Different Dwarfing Interstocks of SH on Growth，Light Distribution，Yield and Fruit Quality in‘Fuji’Apple Trees
• LI Minji，ZHANG Qiang，LI Xingliang，ZHOU Beibei，YANG Yuzhang，ZHOU Jia，ZHANG Junke，and WEI Qinping*
• Acta Horticulturae Sinica. 2018, 45(10): 1999-2007. DOI:10.16420/j.issn.0513-353x.2017-0346
• Abstract ( 198 ) HTML ( 654 ) PDF (1660KB) ( 654 ) 　　　

• Effects of different dwarfing interstocks of SH series on growth，light distribution，yield and fruit quality in‘Fuji’apple trees were in-depth studied to provide the theoretical basis and mentoring programs for the selection of suitable dwarfing interstock. The‘Fuji’apple with different SH dwarf interstocks（SH1，SH3，SH6，SH9 and SH40）planted in spring 2009 was used to investigate the dynamic changes of tree growth，light distribution，yield，single fruit weight and fruit quality in 2016. The spacing is 1.5 m × 5.0 m，spindle pruning. There are big differences in the tree growth，light distribution，yield and fruit sugar and acid constituents between‘Fuji’apple trees with different SH dwarf interstocks. After planting for eight years（2016），there was no significant difference in stem and panicle ratio between‘Fuji’apple trees with different SH dwarf interstocks. The trees with SH1 and SH6 interstocks are the shortest，while the trees with SH40 interstocks are the tallest. The crown of the apple tree with SH40 interstock is the largest. The stem diameter of different dwarf interstocks from big to small is SH40，SH3，SH9，SH6 and SH1. The total number of branches of each interstock tree is more than 1 400 000 per hm2. The ratio of short shoots of the trees with SH6 dwarfing interstock was the highest. The average relative light intensity of each tree canopy was SH3（72.88%），SH6（70.85%），SH9（65.51%），SH1（62.23%）and SH40（61.82%）. The proportion of SH6 tree relative to light intensity less than 30% and 40% is minimum，only 2.08% and 4.17%. The cumulative yield of the tree with SH6 interstock was the highest in four years（2013—2016），and the yield stability was the best. The yield of the tree with SH1 interstock was low，and the yield stability of SH9 tree was bad. The proportion of big fruits from high to low in order is SH40 > SH6 = SH3 > SH9 > SH1. The average fruit weight from high to low in order was SH40 > SH6 > SH9 > SH3 > SH1. The content and ratio of sugars of different interstocks in apple fruit from high to low：fructose，sucrose，glucose and sorbitol. Different sugar content and proportion of fruits of different interstock showed significant difference. There was no significant difference between the total acid content of fruit in different interstocks，content and ratio of different acids of different interstocks from high to low：malic acid，citric acid，oxalic acid，tartaric acid. The content（except oxalic acid）and proportion of different interstock fruit acid had no significant difference. The ratio of sugar to acid in SH6 fruit was the highest，significantly higher than that in SH1，SH3 and SH9. Considering the growth and yield of trees，SH6 as a dwarfing interstock performs better.

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• Effects of Bioorganic Fertilizer SNB-86 Special for Continuous Cropping Apple on Malus hupehensis Seedlings and Soil Environment Under Replant Disease Condition
• LIU Liying1,*，LIU Kexin1,*，CHI Xiaoli1，ZHANG Xiao1，XU Chao1，ZHU Hao1，JIN Xiao1，LIU Weiwei1，SUN Zhongtao1,**，and MAO Zhiquan2,**
• Acta Horticulturae Sinica. 2018, 45(10): 2008-2018. DOI:10.16420/j.issn.0513-353x.2017-0894
• Abstract ( 236 ) HTML ( 574 ) PDF (1158KB) ( 574 ) 　　　

• A biocontrol bacteria SNB-86 isolated from apple continuous cropping soil by confrontation method was identified as Bacillus subtilis. The biofertilizer was prepared by solid-state fermentation using SNB-86，and pot experiment was carried out with apple continuous soil potted Malus hupehensis Rehd. seedlings as the material. Four treatments were set：continuous cropping soil（control），continuous cropping soil fumigated with methyl bromide，biofertilizer carrier and SNB-86 biofertilizer treated soil in pot. The results showed that bioorganic fertilizer SNB-86 significantly increased 171.5% fresh weight and 142.3% dry weight of M. hupehensis seedlings，respectively. The M. hupehensis seedling height increased 97.9% and 25.3% in SNB-86 biofertilizer treated group than that in continuous cropping soil and biofertilizer carrier groups，respectively. The M. hupehensis seedling basal diameter increased 57.6% and 6.2% in SNB-86 biofertilizer treated group than that in continuous cropping soil and biofertilizer carrier groups，respectively. The growth of M. hupehensis seedling in SNB-86 biofertilizer treated group was not good as that in continuous cropping soil fumigated with methyl bromide group. Compared with continuous cropping soil，the number of soil bacteria and actinomycetes in biofertilizer carrier and SNB-86 biofertilizer treated groups increased. The number of soil fungi in SNB-86 biofertilizer treated group decreased significantly to 32.3% of continuous cropping soil，while biofertilizer carrier treatment had less influence on the number of fungi in continuous cropping soil，only 10% lower than that of the continuous cropping soil group. But bromomethane fumigation significantly reduced the number of microbes in soil，resulting in lower soil enzyme activity than continuous cropping soil group. The activities of sucrase，urease，catalase and neutral phosphatase were significantly increased by SNB-86 biofertilizer treatment and biofertilizer carrier treatment. The effect of SNB-86 biofertilizer treatment was most obvious，followed by biofertilizer carrier treatment. While the activities of sucrase，urease，catalase and neutral phosphatase in continuous cropping soil fumigated with methyl bromide were significantly decreased，respectively compared with that in continuous cropping soil group. It is concluded that SNB-86 biofertilizer can significantly promote the growth of M. hupehensis seedlings，increase the activity of soil enzymes，reduce the number of culturable fungi in the soil，and alleviate the obstacle of apple continuous cropping.

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• Identification and Expression Analysis of CR4 in Apple
• Lü Qianqian，LIU Yuxi，LI Jingxuan，MA Zonghuan，JIANG Xuefeng，WANG Baolin，MAO Juan，CHU Mingyu，CHEN Baihong，and ZUO Cunwu*
• Acta Horticulturae Sinica. 2018, 45(10): 2019-2029. DOI:10.16420/j.issn.0513-353x.2017-0883
• Abstract ( 330 ) HTML ( 746 ) PDF (1615KB) ( 746 ) 　　　

• As conserved sequences of Arabidopsis CR4 protein，RCC1（PF00415），TNFR_c6 （PF00020）and Pkinase（PF00069）domains were used to search for the receptor like kinase CRINKLY4（CR4）genes in apple. The physical and chemical characteristics，evolutionary relationship and chromosomal distribution were analyzed for all of the identified CR4 genes. Additionally，tissue-specific expression profiles of CR4s were examined. Stress-specific expression of CR4s was determined in flower buds treated with lower temperature and trunks infected with Valsa mali. In total，eight CR4 genes were identified in the apple（Malus × domestica Borkh.）genome. The size（amino acid，AA），molecular weight and isoelectric point of apple CR4s varied from 668 to 1 690，from 71.73 to 187.61 kD and from 5.69 to 8.66，respectively. The expressed proteins were mainly sublocalized at plasma membrane（PM）. According to the phylogenetic analysis，apple CR4s could be divided into two sub-groups. Gene expression analysis showed that CR4s were distinctly expressed in different tissues and varieties. In addition，expression levels of eight and six CR4s were significantly changed at least in one time point when the flower bud under low temperature or the trunk was infected with Valsa mali，respectively. Among these，expression of MD03G1068800 was up-regulated more than 25 folds after the bud suffering low temperature，while that of MD00G1166500 and MD01G1153100 was up-regulated over 150 folds by Valsa mali，suggesting that these three CR4s can serve as candidate genes for further functional charaterization. This study sheds new light on future functional research of apple CR4s and provides new targets for stress-control and disease resistance regulation in apple industry.

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• Complete Genome Sequence Analysis of Three Citrus psorosis virus Isolates
• LI Min，ZHOU Tianyu，ZHANG Song，YANG Fangyun，ZHOU Yan，ZHOU Changyong，LI Zhongan*，and CAO Mengji*
• Acta Horticulturae Sinica. 2018, 45(10): 2030-2036. DOI:10.16420/j.issn.0513-353x.2018-0172
• Abstract ( 193 ) HTML ( 513 ) PDF (659KB) ( 513 ) 　　　

• Citrus psorosis virus（CPsV）caused a destructive viral disease of citrus，while viral genome information associated with CPsV is still limited to date. In this study，we obtained the complete genome sequences of three CPsV isolates CHN-1，CHN-2 and CHN-3 by using transcriptome sequencing （RNA-Seq），RT-PCR，cloning and Sanger sequencing approaches. Genome sequence analysis showed that the full length sequences of CHN-1，CHN-2 and CHN-3 were 11 282 nucleotides（nt），11 279 nt and 11 278 nt，respectively，and comprised of four open reading frames（ORFs）. Nucleotide sequence similarity between genomic RNAs of the three CPsV isolates ranged from 93.48% to 95.98%，whereas their amino acid（aa）sequence similarities were from 98.18% to 98.86%. Comparing CP genes of the three isolates with six other reported CPsV-isolates，the nucleotide sequence similarities were from 85.83% to 95.23% while amino acid sequence similarities from 94.09% to 99.32%. Phylogenetic analysis indicated that the isolates CHN-1，CHN-2 and CHN-3 clustered together into a branch of evolutionary tree，suggesting they should have the same origin.

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• Identification of a New Pathogen of Citrus Postharvest Disease
• XU Guoliang1，Zhao Feifei1，WANG Qinglian2，WANG Shiling1，JIA Jin1，CHEN Yanling2，HUANG Chuanhong3，LIU Yongzhong2，PENG Shu’ang2，WANG Guoping1，HONG Ni1，and DING Fang1,2,*
• Acta Horticulturae Sinica. 2018, 45(10): 2037-2044. DOI:10.16420/j.issn.0513-353x.2018-0143
• Abstract ( 265 ) HTML ( 576 ) PDF (3371KB) ( 576 ) 　　　

• A new pathogenic strain of Pu. XHz from Citrus sinensis fruit showing symptoms like blue-green mold was identified. Pu. XHz formed white round colonies on PDA medium. Large numbers of blue-gray spores and exudative droplets appeared in the late stage. On CA medium，it showed fireworks-shaped radial colonies. Meanwhile，the colonies of Pu. XHz formed on CYA medium looked like concentric circles. When cultured on G25N medium，white mycelium colonies developed well but did not produce conidia. The size of oval-shaped Pu. XHz conidia was ranging from 4.48–8.37 μm to 2.65–5.24 μm. Pathogenicity test showed，water-soaked ring spots formed 3 days post inoculation（dpi）on Fortunella margarit，Murcott and Citrus sinensis Osbeck‘Newhall’. In about 10 dpi，large quantities of blue-gray conidia and conidiophore with typical character of whisker molds formed in the site of infected lesions. Further analysis by ITS sequencing verified Pu. XHz was a new strain of P. ulaiense. It showed 99% homology with that of P. ulaiense stain SU-9 deposited in GenBank. Our present study verified that Pu. XHz was the causal agent of citrus whisker mold，which laid a basic foundation for further study on the pathogenicity of P. ulaiense.

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• Delphinidin Synthesis Ability in Three Cut Chrysanthemum Cultivars
• YU Kaili，WU Huiying，QU Aiai，WANG Yiguang，FANG Weimin，JIANG Jiafu，CHEN Fadi，and CHEN Sumei*
• Acta Horticulturae Sinica. 2018, 45(10): 2045-2051. DOI:10.16420/j.issn.051-353x.2017-0632
• Abstract ( 238 ) HTML ( 540 ) PDF (1333KB) ( 540 ) 　　　

• To evaluate the delphinidin biosynthesis ability of different chrysanthemum varieties，three varieties of pink flowers were employed，and the petals were fed with 2 mg · mL-1 DHM. The delphinidin content in DHM fed petals was determined. By optimizing the analysis conditions，we established an effective way of quantitative determination of delphinidin via UPLC. The results showed that anthocyanin of chrysanthemum flowers can be extracted by 0.1 mol · L-1 hydrochloric acid methanol，and 10% formic acid in a ratio of 9︰1（v/v），and followed by filtering through 0.22 μm filter membrane. Through the optimization of elution conditions，delphinium can be separated from other anthocynins within nine minutes. Based on optimized UPLC analysis method，delphinium concentration within 2.5–40 mg · L-1 has a good linear relationship with peak area，and the correlation coefficient is 0.997. We found that all the varieties could produce delphinidin when fed with DHM，the contents of delphinidin in three varieties are all over 220 μg · g-1 FW，inferring the tested varieties are promising host varieties for blue flower genetic modification.

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Review

• Mechanisms of NAC Transcription Factor Functions During Fruit Development and Ripening
• ZHANG Qijing1,* and DONG Wenxuan2
• Acta Horticulturae Sinica. 2018, 45(10): 2052-2062. DOI:10.16420/j.issn.0513-353x.2018-0340
• Abstract ( 382 ) HTML ( 676 ) PDF (691KB) ( 676 ) 　　　

• Recent researches on the structure and function of NAC transcription factors（TFs）and their regulating mechanisms during the process of fruit development and ripening are reviewed in this paper. It is suggested that NAC TFs affect fruit ripening through ethylene and multiple hormone pathways. Ethylene pathway includes ethylene induced NAC TFs regulating fruit ripening，NAC TFs regulating the upstream TFs of ethylene signal systems and TFs directly regulating the main ethylene synthesis genes to control fruit maturity. Multiple hormone pathways include TFs affecting fruit maturity via auxin，abscisic acid and gibberellin/brassinolide pathways.

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New Cultivars

• A New Cauliflower Cultivar‘Jinpin 56’
• YAO Xingwei，SUN Deling，NIU Guobao，SHAN Xiaozheng，WEN Zhenghua，JIANG Hanmin，ZHANG Xiaoli，and LIU Lili*
• Acta Horticulturae Sinica. 2018, 45(10): 2063-2064. DOI:10.16420/j.issn.0513-353x.2018-0224
• Abstract ( 287 ) HTML ( 458 ) PDF (858KB) ( 458 ) 　　　

• ‘Jinpin 56’is a new autumn-early maturity cauliflower cultivar developed by the cross of CMS line‘FG-2’× self-incompatible line‘W-53’. The growing period from transplantation to harvest is about 50–55 days in autumn. The plant type is erect. It has light green outer leaves and strong serrated inner leaves，and curds are well protected by leaves. The curd is snow-white colour，smooth，less-tight and tastes sweet and crisp. The average weight of each curd is about 0.95 kg，the mean yield is 45 600 kg · hm-2.

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• A New Iris pallida Cultivar‘Guifei Xianggen Yuanwei’
• HAN Guijun1,2,*，LI Sifeng1,2，and WU Yongpeng1
• Acta Horticulturae Sinica. 2018, 45(10): 2065-2066. DOI:10.16420/j.issn.0513-353x.2018-0454
• Abstract ( 292 ) HTML ( 587 ) PDF (1109KB) ( 587 ) 　　　

• ‘Guifei Xianggen Yuanwei’is a new cultivar derived from Iris pallida which is introduced from Italy. The cultivar is perennial herbs，usually with swollen and branched rhizomes. The corolla color is light blue and the silvery bract is membranous. The cultivar shows good adaptability and superior yield. The rhizome yield of dry weight could be as high as 6 750 kg · hm-2. The content of irone，which is the effective ingredient is above 500 mg · kg-1.

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• ‘Hongfu’，a New Red-flowered Luculia pinceana Cultivar
• MA Hong，WAN Youming，LIU Xiuxian，ZHAO Zhengang，and LI Zhenghong*
• Acta Horticulturae Sinica. 2018, 45(10): 2067-2068. DOI:10.16420/j.issn.0513-353x.2018-0065
• Abstract ( 232 ) HTML ( 509 ) PDF (1195KB) ( 509 ) 　　　

• ‘Hongfu’is a new cultivar selected and bred from the natural variant plants of Luculia pinceana. The cultivar is perennial evergreen shrub with spreading plant type and its plant height can reach 2–3 m. Its leathery leaf is elliptic in shape with leaf index 2.6. The inflorescence type is cyme and the flower type is short-style. The reddish brown sepal is half-spreading in shape at anthesis and its abaxial surface is glabrous. The corolla tube is（3.23 ± 0.35）cm in length. The corolla diameter is（3.86 ± 0.28）cm with deep purplish pink in color. There are flake attachments between corolla lobes. The cultivar has great ornamental value，which can be widely planted for domestic decoration and landscape designment.

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Review

• A New Cultivar of Ornamental Colored Leaf Koelreuteria paniculata ‘Jinluan 3’
• CHEN Zhong1,2,*，GAO Kai3，WANG Guodong4，and AN Xinmin3,*
• Acta Horticulturae Sinica. 2018, 45(10): 2069-2070. DOI:10.16420/j.issn.0513-353x.2017-0838
• Abstract ( 260 ) HTML ( 528 ) PDF (1588KB) ( 528 ) 　　　

• Koelreuteria paniculata‘Jinluan 3’is a new ornamental cultivar bred from a mutant seedling of K. paniculata‘Jinye Luan’. The color of young leaves and new shoots is orange red in spring，then becomes red yellow，the color turns yellow when the leaves mature，and the mature leaves become yellow green in summer，finally turn to isabelline until the leaves fall in autumn. The leaves are relatively small，the bases of leaves are not tilted. The internodes at the apical of the branch are medium. The upper pinnately compound leaves present oblique upward extension. Moreover，propagation of this cultivar mainly depends on grafting，and it is suitable for popularization and application in landscaping in the north and central area in China.

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