Research Papers

• Identification and Expression Analysis of the Vacuolar Iron Transporter Gene Family in Apple
• YANG Yaming, DING Yuduan, CHEN Lijuan, TIAN Xueting, YIN Weijie, PENG Honghui, DU Wei, LIANG Liping, REN Xiaolin
• Acta Horticulturae Sinica. 2021, 48(2): 205-218. DOI:10.16420/j.issn.0513-353x.2020-0272
• Abstract ( 700 ) HTML ( 619 ) PDF (2976KB) ( 619 ) 　　　

• Vacuolar iron transporter（VIT）is involved in iron storage and transport,it plays important roles in plant photosynthesis,nitrogen fixation,respiration,DNA and hormone synthesis. In this study,nine apple VIT genes were identified,and the phylogenetic relationship of these genes was analyzed by phylogeny,the results showed that the VIT protein of apple was closely related to the evolution of Arabidopsis thaliana. Chromosome mapping showed that nine VIT genes are distributed on seven chromosomes,bioinformatic analysis of VIT genes promoter region showed many cis-elements related to environmental stresses,photoresponse and plant hormone response. Expression profile analysis showed that the expression of VIT gene was relatively high in flowers and fruits. In addition,the physical and chemical properties,protein interaction network and gene structure of MdVIT family were analyzed,the results showed that the main factors for VIT family amplification in apple were tandem duplication and segmental duplication,cationic co-transporters（XP_008372221.1 and XP_008383418.1）were mainly involved in the interaction of VIT proteins in apple. The qRT-PCR analysis showed that the expression levels of MdVIT1 and MdVIT2 in leaves of‘M26’apple rootstock seedlings treated with 2 000 μmol · L^-1 FeSO₄ · 7H₂O for 24 h were 6.6 and 12 times higher than those of the control. After 6 h treatment with 2 000 μmol · L^-1 FeSO₄ · 7H₂O,the relative expression level of MdVIT4 showed in the stem was the highest,which was 237 times higher than that of the control. Taken together,among the characterized apple VIT genes MdVIT1,MdVIT2 and MdVIT4 were speculated closely related to iron stress in apple,which provide useful information for further study the mechanisms of metal iron caused stress in apple.

• Figure/Table | References | Related Articles | Metrics

• Effects of Nitrogen Application Position on Fine Root Distribution,Nitrogen Absorption,Yield and Quality of Dwarfing Interstock Apple Trees
• LIU Zhaoxia, XING Yue, WU Xiaoxian, TIAN Ge, ZHU Zhanling, GE Shunfeng, JIANG Yuanmao
• Acta Horticulturae Sinica. 2021, 48(2): 219-232. DOI:10.16420/j.issn.0513-353x.2020-0289
• Abstract ( 672 ) HTML ( 645 ) PDF (1083KB) ( 645 ) 　　　

• In order to clarify the reasonable fertilization position of dwarfing interstock apple trees, reduce the waste of nitrogen fertilizer. In 2018 and 2019,we studied the effects of nitrogen application in three horizontal distance of inner ring,middle ring and outer ring of the apple crown projected on soil ¹⁵N distribution,apple tree ¹⁵N absorption and utilization,and yield and quality on 8-year-old‘Yanfu 3’/SH6/Malus robusta using the ¹⁵N isotope tracer technique. The results showed that the root length density of apple fine roots（diameter ≤ 2 mm）in all treatments presented attenuation rules in both horizontal and vertical directions,and it was mainly distributed in the range of 0-100 cm from the horizontal direction of the trunk and 0-40 cm from the vertical direction. Compared with the control group,the fine root length density of the treated area increased significantly. Judging from the increase in fine root length density in the nitrogen application zone of the 0-20 cm soil layer in the vertical direction,nitrogen application in inner ring had the largest increase,1.33 to 1.36 times of the control,followed by nitrogen application in middle ring. Under different treatments,the peak of soil ¹⁵N content in the horizontal direction appeared in the area where the fertilization area was located,and in the vertical direction in 0-20 cm soil layer. The spatial concordance index between the density of apple fine root length and soil ¹⁵N content（RLD-¹⁵N）showed significant differences among different treatments,and the nitrogen application in inner ring was significantly higher than that in middle and outer ring. The application of nitrogen in the inner ring significantly increased the that of the new organs of the tree during the new shoot growing stage. The ¹⁵N utilization rate of the tree was nitrogen application in inner ring > nitrogen application in middle ring > nitrogen application in outer ring. There was no significant difference in ¹⁵N residue rate between nitrogen application in inner ring and in outer ring,but both were higher than that in outer ring. Compared with nitrogen application in outer ring,nitrogen application in inner ring significantly improved fruit yield,soluble sugar content and sugar acid ratio,but there was no significant difference in hardness and titratable acid content. It can be seen that the application of nitrogen in the inner layer of dwarfing interstock apple was conducive to improving the spatial concordance index between the density of apple fine root length and soil ¹⁵N content,increasing the nitrogen content of new-born organs in the early growth period,improving the ¹⁵N utilization efficiency of the tree,and increasing the fruit yield and soluble sugar content. Therefore,in actual production,it is recommended to apply nitrogen fertilizer at the 1/3 crown projection area close to the trunk of adult dwarfing interstock apple trees,that is,approximately 0-75 cm from the horizontal distance of the trunk.

• Figure/Table | References | Related Articles | Metrics

• Identification of TIFY Family in Apple and Their Expression Analysis Under Insect Stress
• MEI Chuang, ZHANG Xiaoyan, YAN Peng, Aisajan Mamat, FENG Beibei, MA Kai, HAN Liqun, DONG Lianxin, WANG Jixun
• Acta Horticulturae Sinica. 2021, 48(2): 233-242. DOI:10.16420/j.issn.0513-353x.2020-0350
• Abstract ( 547 ) HTML ( 447 ) PDF (2362KB) ( 447 ) 　　　

• The TIFY transcription factors in the apple were identified using bioinformatics methods. The gene structure,conserved motifs and evolutionary relationship were analyzed. Meanwhile,the differential expression of apple TIFY family member genes under insect Agrilus mari stress conditions was determined based on Malus sieversii transcriptome data analysis. A total of 16 TIFY transcription factors were identified through analysis,which encodes proteins between 209-449 aa. The 16 MdTIFY genes are located on the 8 chromosomes of apples,and all MdTIFY proteins have conserved TIFY domains. Among them,eight MdTIFY correspond to the spliced transcripts of M. sieversii transcriptome sequencing. These genes all contain conserved TIFY functional domains. Multi-species phylogeny analyses showed that these proteins can be clustered into 7 groups. The expression levels of the seven TIFY genes showed significant differences among different treatments. After pest infestation,the expression of MsTIFY10B-a increased by 34-fold in insect-resistant plants,and the expression of MsTIFY9-c increased by 5.2-fold. Meanwhile the contents of jasmonic acid-isoleucine（JA-Ile）in insect-resistant plants were significantly higher than that of sensitive plants. The important insect-resistance response genes,MsTIFY10B-a and MsTIFY9-c,are located in the key nodes of association network in M. sieversii,being as important regulators during the plant responses tobiotic stresses.

• Figure/Table | References | Related Articles | Metrics

• Analysis of Proliferation Abilities and Telomere Lengths of Apple Plantlets in Vitro Preserved for Eight to Thirty-three Years
• LIU Yajie, LIANG Chen, WANG Li, DU Guoqiang, SHI Xiaoxin
• Acta Horticulturae Sinica. 2021, 48(2): 243-253. DOI:10.16420/j.issn.0513-353x.2020-0305
• Abstract ( 597 ) HTML ( 269 ) PDF (2227KB) ( 269 ) 　　　

• In order to examine the relationship between telomere lengths and their propagation ability or aging,and to explore the relationship between the telomer lengths and the preservation time limit in apple plantlets in vitro,the phenotypes,proliferation characteristics,and telomere lengths of apple plantlets preserved in vitro and consecutively subcultured for years were studied in three apple cultivars. The results showed that there were no changes in the proliferation abilities and no significant changes in phenotypes in most apple shoot plantlets in vitro from 8 to 33-year‘Fuji’preserved,8 to 27-year‘Golden Delicious’preserved,and 8 to 25-year‘Gala’preserved,respectively. No significant change in telomere lengths was found in leaves of the plantlets at 30-day plantlet age with different subculture times in three cultivars. The telomere lengths in the 73th subculture time plantlets could change during the given subculture periods, such as 10,30,50,and 90 days,which showed cultivar specificity. For example,there was no significant difference of telomere lengths in plantlet leaves of‘Fuji’and‘Gala’,while the telomere lengths in plantlet leaves of‘Golden Delicious’were the longest at 50-day and the shortest at 90-day. The telomere lengths in the 71th subculture time plantlet stems cultured for 30 days of‘Golden Delicious’,were significantly higher than that in leaves,and no significant difference was found either between those in stems and calli or in leaves and calli;while in‘Gala’,the telomere lengths in calli were the longest,followed by that in leaves and stems. The changes of the telomere lengths in apple plantlets in vitro coincided with their proliferation abilities,phenotypes,and aging during the same subculture time.

• Figure/Table | References | Related Articles | Metrics

• Studies on the Regreening Mechanism of the Iron-deficiency Chlorosis Leaves induced by GA₃ in‘Whangkeumbae’（Pyrus pyrifolia Nakai）
• JIA Bing, GUO Guoling, WANG Youyu, YE Zhenfeng, LIU Li, LIU Pu, HENG Wei, ZHU Liwu
• Acta Horticulturae Sinica. 2021, 48(2): 254-264. DOI:10.16420/j.issn.0513-353x.2020-0285
• Abstract ( 647 ) HTML ( 271 ) PDF (2577KB) ( 271 ) 　　　

• In order to reveal the regreening effect and physiological mechanism of the iron-deficiency chlorosis leaves induced by GA₃,the iron-deficiency chlorosis and normal plants of‘Whangkeumbae’（Pyrus pyrifolia Nakai）were used as the experiment materials,and GA₃ solutions of 50,100,200 and 400 mg · L^-1 was sprayed on chlorosis leaves during the growth period. The contents of Fe,GA₃,GA₄,IAA and JA in leaves were determined,the chloroplast ultrastructure was observed and photographed under an electron microscope,and the expression levels of genes related to Fe metabolism or GA signal transduction were analyzed by fluorescence quantitative PCR. The results showed that on the 9th day after treatment with exogenous GA₃,the chlorosis leaves showed different degrees of regreening,with obvious vein regreening and partial body regreening. On the 12th day of treatment with 400 mg · L^-1 GA₃,the regreening of chlorosis leaves were the most obvious. The Fe content in regreening leaves were significantly higher than that in control with water on the 9th and 12th day after GA₃ treatment. Exogenous GA₃ could induce the expressions of FER1,FER2,FER3,FRO2,IRT1 and FD1 in chlorosis leaves. On the 12th day,the expression levels of FER2 and IRT1 in each treatment were more than 10 and 40 times higher than that in the control group,indicating that exogenous GA₃ promoted the expression of genes related to iron storage,reduction and transport in leaves. Exogenous GA₃ treatment significantly increased the contents of endogenous GA₃ and GA₄ in leaves and rapidly induced the expression of GID11 and GID13. Among them,the expression level of GID11 was 76.45 times higher than that of the control group on the 3rd day after the treatment with 50 mg · L^-1 GA₃. On the 12th day after treatment with 400 mg · L^-1 GA₃,the thylakoid granule lamellae in leaves were clearer than that of chlorosis leaves,with fewer fractured lamellae. The results preliminarily revealed regreening mechanism of chlorosis leaves induced by GA₃ in‘Whangkeumbae’.

• Figure/Table | References | Related Articles | Metrics

• Cloning and Functional Analysis of the CDS and Promoter of VpPR4b Gene Response to Downy Mildew in Chinese Wild Grape
• LIU Bing, LI Mengyuan, ZHANG Na, SHANG Boxing, LIU Guotian, XU Yan
• Acta Horticulturae Sinica. 2021, 48(2): 265-275. DOI:10.16420/j.issn.0513-353x.2020-0343
• Abstract ( 538 ) HTML ( 412 ) PDF (4089KB) ( 412 ) 　　　

• VpPR4b and VvPR4b were cloned form Vitis piasezkii‘Liuba-8’（resistant to downy mildew）and V. vinifera‘Pinot Noir’（susceptible to downy mildew）. Sequence analysis showed that the identity between VpPR4b and VvPR4b nucleotide was 98.61%. The coding region of VpPR4b is 432 bp,which encodes 143 amino acids and contains the BARWIN conserved domain,indicating it is a typical typeⅡPR4 protein. Both VpPR4b and VvPR4b are highly expressed after inoculation with Plasmopara viticola. Subcellular localization analysis indicated that VpPR4b was localized in the membrane. The promoters of VpPR4b and VvPR4b were cloned from‘Liuba-8’and‘Pinot Noir’,respectively. It showed that VpPR4b and VvPR4b promoter sequence similarity is as high as 95.65%,and contains similar cis-acting elements. It has been verified that the transcription factors WRKY40 and WRKY75 can bind the VpPR4b promoter in yeast. This study showed that PR4b may play a role in the resistance to downy mildew in grape.

• Figure/Table | References | Related Articles | Metrics

• Preliminary Analysis of CsCalS5 and Callose Deposition in Citrus sinensis Infected with Candidatus Liberibacter asiaticus
• ZHANG Qingwen, QI Jingjing, XIE Yu, XIE Zhu, PENG Yun, LI Qiang, PENG Aihong, ZOU Xiuping, HE Yongrui, CHEN Shanchun, YAO Lixiao
• Acta Horticulturae Sinica. 2021, 48(2): 276-288. DOI:10.16420/j.issn.0513-353x.2020-0282
• Abstract ( 586 ) HTML ( 281 ) PDF (3192KB) ( 281 ) 　　　

• Callose synthase is a key enzyme to control callose synthesis and plays an important role in plant growth and stress resistance. The CsCalS5 gene and promoter sequence of Citrus sinensis‘Jincheng’ were cloned and analyzed. Its tissue expression and induced expression with exogenous phytohormones,Candidatus Liberibacter asiaticus（CLas）and Xanthomonas citri subsp. Citri（Xcc）were detected by real-time fluorescent quantitative PCR. The callose deposition in vein of CLas-infected or Xcc-infected C. sinensis was observed by tissue section staining. The CsCalS5 promoter sequence contained abscisic acid （ABA）and pathogen response elements. The CsCalS5 gene encoded a transmembrane protein composed of 1 952 amino acids containing the conserved domains FKS1 and β-1,3-glucan synthetase functional domain. CsCalS5 was highly expressed in the stem of C. sinensis,and could be induced by ABA. The expression of CsCalS5 in CLas-infected leaves was 4.02 times of that in the healthy control,and the callose was obviously deposited in the phloem of vein of CLas-infected leaves. After Xcc infection,callose deposition was not significantly increased in the veins phloem,the expression of CsCalS5 was not significantly different from healthy controls. In conclusion,CLas might promote the deposition of callose in the phloem by up-regulating the expression of CsCalS5 in C. sinensis,which could be regulated by ABA.

• Figure/Table | References | Related Articles | Metrics

• The Relationship Between Changes of Endogenous Hormones and Cell Wall Metabolism of Common Bean During Bean Development
• XIE Guofang, LIU Na, SONG Yi, GUAN Chunhua, ZHANG Mingsheng
• Acta Horticulturae Sinica. 2021, 48(2): 289-299. DOI:10.16420/j.issn.0513-353x.2020-0388
• Abstract ( 406 ) HTML ( 334 ) PDF (1458KB) ( 334 ) 　　　

• The cell wall metabolism of fresh common bean（Phaseolus vulgaris L.）seriously affects the edible quality. The contents of endogenous hormones,the main components and enzymes related to cell wall metabolism were analyzed in four developmental stages in beans‘Dabaibang’,and the relationship between endogenous hormones and cell wall metabolism was analyzed. The results showed that the content of GA₃ and 6-BA decreased,the content of ethylene（ET）and JA decreased firstly and then increased during the development of pods. The pods was mainly in elongation growth before the 10th day after anthesis,and the pods was mainly in thickening growth after the 10th day after anthesis. Sucrose synthetase（SuSy）promoted sucrose synthesis before 10 days after anthesis. Sucrose content decreased and cellulose content increased with the decrease of SuSy and cellulase（Cx）activity. G-lignin deposition in xylem at 5 days after anthesis,G-lignin and S-lignin were deposited in phloem,gradually deepened and diffused to both sides after the 10th day after anthersis. S-lignin was only deposited in phloem. The high phenylalanine ammonia lyase（PAL）activity provided the substrate for lignin biosynthesis at the 5th day after anthesis,and then the increase of cinnamyl alcohol dehydrogenase（CAD）activity promoted lignin synthesis,the increase of superoxide dismutase（SOD）activity promoted the conversion of $\mathrm{O}_{2}^{\overline{·}}$ to H₂O₂,and the polymerization of lignin with peroxidase（POD）activity. Polygalacturonase（PG）activity,sodium-carbonate-soluble-pectin（SSP）and water-soluble-pectin（WSP）content increased firstly and then decreased,pectin methylesterase（PME）activity decreased,chelator-soluble-pectin（CSP）content decreased firstly and then increased. The correlation analysis showed that JA positively regulated pod development and cellulose metabolism,while ET,GA₃,6-BA and ABA were the opposite. JA regulates lignin polymerization by inhibiting the conversion of $\mathrm{O}_{2}^{\overline{·}}$ to H₂O₂ and POD activity. ET,GA₃,6-BA and ABA promoted lignin synthesis by enhancing PAL and POD activity. IAA and SA were involved in regulation of pectin metabolism.

• Figure/Table | References | Related Articles | Metrics

• Isolation of Three Types of Invertase Genes from Hemerocallis fulva and Their Responses to Low Temperature and Osmotic Stress
• BAI Lu, ZHANG Zhiguo, ZHANG Shijie, HUANG Dongmei, QIN Qiaoping
• Acta Horticulturae Sinica. 2021, 48(2): 300-312. DOI:10.16420/j.issn.0513-353x.2020-0346
• Abstract ( 547 ) HTML ( 267 ) PDF (3352KB) ( 267 ) 　　　

• In this study,three invertase genes were cloned from Hemerocallis fulva‘Athlone’,named HfCIN3,HfCWIN1 and HfVIN1. The ORFs of the three invertase genes were 1 941,1 701,1 920 bp,encoding 646,566 and 639 amino acids,respectively,with the similarity of 18.81%-41.86%. The amino acid sequence of HfCIN3 was 75.16%-82.79% similar to those of dendrobium and wild banana,HfCWIN1 was 58.95%-68.88% similar to asparagus and oil palm,and HfVIN1 was 73.4% similar to agave. HfCIN3 had a signal peptide and typical glycoside hydrolases family 100 domain,HfCWIN1 and HfVIN1 had glycosyl hydrolases family 32 domain. HfCWIN1 also contained a 72 amino acid Malectin domain related to cell wall sugar recognition. HfVIN1 contained a possible vacuolar motif“ILPD”and had a typical transmembrane domain at the N terminus. Both HfCWIN1 and HfVIN1 possessed the N-glycosylation and O-β-GlcNAc sites,whereas HfCIN3 only had the O-β-GlcNAc sites. Phylogenetic analysis showed that monocotyledons and dicotyledons could clearly be distinguished regarding different types of invertase;CWIN and VIN were closely related,and HfCIN3,HfCWIN1 and HfVIN1 were clustered in monocots. Transient expression analysis showed 35S:HfCIN3-GFP was expressed in chloroplasts;35S:HfVIN1-GFP was expressed in vacuoles;and 35S:HfCWIN1-YFP was detected in cell walls and guard cells. The expression levels of HfCIN3,HfCWIN1 and HfVIN1 were significantly higher in leaves than that of the root and flower tissues;the expression levels in leaves were HfVIN1 > HfCWIN1 > HfCIN3. After 24 h treatment at 0 ℃,the expression of HfVIN1 was increased by 2.2 times compared with 5 ℃,and the expression level of HfCWIN1 was increased significantly at 0 ℃ compared with the other temperatures. The highest expression of HfVIN3 was recorded at 0 ℃. After 24 h treatment with 5% or 10% PEG,the expression levels of HfCIN3 and HfVIN1 were not significantly different from the control,but that of HfCWIN1 was significantly lower than the control. The CIN activity and gene expression were similar in different tissues,but CWIN and VIN were not consistent with the gene expression. As temperature decreased,CIN declined,CWIN increased at first and then decreased,and VIN decreased at first then increased,and then decreased;PEG induced VIN activity. The enzyme activity and gene expression were not synchronized after the low temperature and osmotic stress treatment,possibly because the gene post-transcriptional modifications played an important role in invertase activity. The results of this study established the differences in subcellular localizations,gene expression patterns and the responses to abiotic stresses among the three various types of Hemerocallis fulva invertase,HfVIN1 responded to low temperature,whereas HfCWIN1 responded to osmotic stress.

• Figure/Table | References | Related Articles | Metrics

• Cloning and Characterization of Key Synthase FAS Gene Involved in Terpenoids Pathway of Chrysanthemum morifolium
• HU Hao, YANG Ting, GAO Liping, Maarten A. Jongsma, WANG Caiyun
• Acta Horticulturae Sinica. 2021, 48(2): 313-324. DOI:10.16420/j.issn.0513-353x.2020-0232
• Abstract ( 610 ) HTML ( 412 ) PDF (1516KB) ( 412 ) 　　　

• The secondary metabolite composition and relative abundance in leaves and ovaries of the Chrysanthemum morifolium model cultivar‘1581’were analyzed by SPME extraction and GC-MS analysis. The terpenoids represented the dominant group of volatiles. Based on conserved sequences FDS-like genes identified in a transcriptome database derived from chrysanthemum,a farnesol synthase gene（CmFAS）was cloned with an 1 197 bp open reading frame（ORF）,encoding 398 amino acids and putatively located in the plastids. Phylogenetic analysis showed that CmFAS belongs to the FDS gene family in Asteraceae and has higher sequence similarity with the monoterpene CDS genes of pyrethrum （Tanacetum cinerariifolium）and Artemisia. Multiple alignment of FDS proteins of several different plant species demonstrated that CmFAS had the five typical conserved regions of chain elongation prenyltransferases. The gene expression of CmFAS was the highest in young leaves and lower in ovaries and mature leaves. The expression level of CmFAS was lower than that of CmFDS1 and CmFDS2 in chrysanthemum. By enzyme assay,it showed that CmFAS not only catalyzed DMAPP and IPP to farnesol but also converted CPP to chrysanthemol. CmFAS is a bifunctional enzyme generating both monoterpene and sesquiterpene products. CmFAS is the first sesquiterpene synthase located in plastids of chrysanthemum.

• Figure/Table | References | Related Articles | Metrics

Research Notes

• Association Analysis of SCoT Markers and Leaf Phenotypic Traits in Cherry Germplasm
• PENG Fangfang, LONG Zhijian, WEI Zhaoxin, LI Xunlan, LUO Youjin, HAN Guohui
• Acta Horticulturae Sinica. 2021, 48(2): 325-335. DOI:10.16420/j.issn.0513-353x.2020-0262
• Abstract ( 411 ) HTML ( 293 ) PDF (1057KB) ( 293 ) 　　　

• Based on the established SCoT analysis system,the suitable primers were screened,and then SCoT molecular markers,genetic diversity of leaf traits and their correlation were analyzed in 12 cherry varieties. The results showed that 46 marker primers being suitable for cherry genetic analysis were selected from 102 SCoT marker primers,with a screening rate of 45.1%. A total of 77 allele points were obtained from 18 SCoT primers,including 65 polymorphic loci,with a polymorphism rate of 84.4%. The variation coefficient of leaf traits of 12 varieties was 11.49%-36.93%,which was basically consistent with the results of SCoT marker clustering analysis. Pearson’s correlation analysis showed that a total of 54 marker sites were significantly or extremely significantly correlated with 12 leaf traits. Through the multiple linear stepwise regression analysis,eight specific marker sites related to leaf traits were obtained, which explained the change of 47.8%-100.0% of leaf traits. Sequence analysis of eight association marker sites showed that five markers could find homologous sequences in cherry genome;the similarity was more than 75%;and their chromosome positions could be identified. Among them,four markers could find homologous sequences with functional annotation in NCBI,and three markers could not find homologous sequences.

• Figure/Table | References | Related Articles | Metrics

• Characteristic and Relative Expression Pattern Analysis of FWL/PLAC8 Family in Blueberry
• YU Lei, ZHOU Ya, ZONG Yu, ZHANG Ying, QIU Jiaqi, LI Yongqiang, YANG Li, GUO Weidong
• Acta Horticulturae Sinica. 2021, 48(2): 336-346. DOI:10.16420/j.issn.0513-353x.2020-0151
• Abstract ( 590 ) HTML ( 387 ) PDF (2526KB) ( 387 ) 　　　

• Fruit size and weight are the most vital agronomic characters for consumers,breeders and researchers,and fruit weight（FW）was reported as an important quantitative trait locus affecting tomato and other fruit weight and size remarkably. In this study,the growth curves during Vaccinium corymbosum ‘O’Neal’（large-size fruit）and‘Bluerain’（small-size fruit）flower bud enlargement and fruit development,and conventionally physical indexes of mature fruits were measured and analyzed. The FWL family with conserved domain PLAC8 in the blueberry genome was identified,and the gene structure, chromosome location,conserved motifs of VcFWL/PLAC8 were analyzed. The relative expression level of VcFWL/PLAC8 genes during‘O’Neal’and‘Bluerain’flower bud enlargement and fruit development was detected by real-time fluorescence quantitative PCR. The results showed that the fruit weight of‘O’Neal’was dramatically higher than that of‘Bluerain’from stage S2,and the locule number,seed number and weight per fruit of‘O’Neal’mature fruits were also notably higher than those of‘Bluerain’. The VcFWL/PLAC8 family contained 11 members with highly conserved motifs in the‘Draper’genome,which can be divided into three clusters. qRT-PCR analysis showed that the expression patterns of A and C subfamilies were consistant with opposite to the cell proliferation trend,while the expression level of B subfamily was relatively low. These results suggested that VcFWL/PLAC8 genes might be involved in fruit growth and development through different regulatory mechanisms and pathways.

• Figure/Table | References | Related Articles | Metrics

• Detection and Sequence Analyses of Grapevine Leafroll-associated Virus 7 Isolates in China
• FAN Xudong, DONG Yafeng, ZHANG Zunping, REN Fang, HU Guojun, ZHANG Mengyan, LI Chen
• Acta Horticulturae Sinica. 2021, 48(2): 347-354. DOI:10.16420/j.issn.0513-353x.2020-0241
• Abstract ( 281 ) HTML ( 283 ) PDF (760KB) ( 283 ) 　　　

• Grapevine leafroll disease（GLD）is a virus disease widely distributed in the world and causes great damage on grapevine. Grapevine leafroll-associated virus 7（GLRaV-7） is one of its pathogens. To investigate the genetic variation of GLRaV-7 isolates,42 positive samples were screened out by reverse transcription-PCR（RT-PCR）from 188 grapevine samples which were collected from 15 Chinese provinces and regions. The detection rate of GLRaV-7 was 24.5%. The coat protein（CP）genes of 42 isolates and heat-shock protein 70（HSP70）genes of 15 isolates were sequenced and analyzed respectively,and the results showed identities ranging 89.12%-100.00% and 88.94%-100.00%,85.33%-100.00% and 88.97%-100.00% at the nucleotide and amino acid sequences respectively. Phylogenetic analysis of CP and HSP70 gene sequences showed that all of GLRaV-7 isolates can be divided into six and five groups,respectively. Gp3,Gp4 and Gp5 only included GLRaV-7 Chinese isolates obtained in this study. This is the first report on the genetic variation of CP and HSP70 genes of GLRaV-7 isolates in China,and this study will be helpful for pathogenicity studies and development of reliable diagnostic methods.

• Figure/Table | References | Related Articles | Metrics

• Cloning and Spatiotemporal Expression Analysis of PgWUS and PgBEL1 in Punica granatum
• ZHAO Yujie, LIU Cuiyu, ZHAO Xueqing, WANG Yuying, YAN Ming, YUAN Zhaohe
• Acta Horticulturae Sinica. 2021, 48(2): 355-366. DOI:10.16420/j.issn.0513-353x.2020-0377
• Abstract ( 459 ) HTML ( 1148 ) PDF (1149KB) ( 1148 ) 　　　

• Based on the pomegranate genome database,PgWUS and PgBEL1,the homolog of WUS and BEL1 were identified and cloned by homologous cloning. The full-length CDS sequences of PgBEL1 and PgWUS were 1 851 bp and 936 bp,encoding 616 and 311 amino acids,respectively. The protein sequence multiple alignment and phylogenetic analysis suggested that PgWUS had the highest evolution relationship with WUS in Cucumis melo var. makuwa and C. sativus. There was high similarity of amino acid sequences in PgBEL1 and BEL1 of Eucatyptus grandis. Subcellular localization results showed that both PgBEL1 and PgWUS were located in the nucleus. Real-time quantitative PCR analysis suggested that the expression level of PgBEL1 in bisexual flowers was higher than that in functional male flowers at P1 P4 periods（bud vertical diameter < 12.0 mm）. PgBEL1 was highly expressed in leaf,it was 3.2 times than that in calyx while 1.2 times than that in stem,respectively. PgBEL1 expression was low in shoot apex. The expression level of PgBEL1 in pistil was 1.16 times than that in stamen. At the P2 and P3 periods of pomegranate flower development that bud vertical diameter was 5.1-10.0 mm,the expression level of PgWUS in bisexual flowers was higher than that in functional male flowers. PgWUS expression was the lowest in calyx and was the highest in stem. The expression level of PgWUS in pistil was 1.5 times than that in stamen and 1.8 times than that in shoot apex. There was a significant difference in the expression levels of PgWUS in pistil and stamen.

• Figure/Table | References | Related Articles | Metrics

• Cloning and Expression of a Pathogenesis Related Protein Gene EjPR1 from Loquat Induced by Colletotrichum gloeosporioides
• ZOU Hui, ZHAO Liang, YUAN Ting, GUO Qigao, WU Di, LIANG Guolu
• Acta Horticulturae Sinica. 2021, 48(2): 367-376. DOI:10.16420/j.issn.0513-353x.2020-0141
• Abstract ( 358 ) HTML ( 329 ) PDF (3354KB) ( 329 ) 　　　

• A full length cDNA of pathogenesis-related protein 1 gene named EjPR1 was obtained from the leaves of‘Peluches’which was a loquat cultivar with high resistance to anthracnose treated by Colletotrichum gloeosporioides using RT-PCR and RACE technology. Bioinformatics analysis indicated that the full length of EjPR1 was 731 bp（GenBank number：MN92775）,the length of 5′ UTR and 3′ UTR were 79 bp and 91 bp,respectively. The length of open reading frame（ORF）was 561 bp encoding 186 amino acids with isoelectric point 5.63 and molecular weight 21 485.34 D which was consistent with the results of prokaryotic expression. Multiple alignment analysis based on the amino acids encoded by different PR1 genes from six other species of Rosaceae showed that EjPR1 was conserved among them with the similarity of 76.41%-94.36%. The results of time series expression analysis after inoculation with anthrax indicated that EjPR1 expression was up-regulated by infection and the highest expression was observed 96 h after inoculation in highly resistant cultivar while there was no significant difference in highly susceptible cultivar. It was speculated that EjPR1 might be involved in disease defense of loquat.

• Figure/Table | References | Related Articles | Metrics

• Selection and Validation of Reference Genes for qRT-PCR Analysis of the Correlated Genes in Flower Pigments Biosynthesis Pathway of Anemone obtusiloba
• MA Lulin, DUAN Qing, CUI Guangfen, DU Wenwen, JIA Wenjie, WANG Xiangning, WANG Jihua, CHEN Fadi
• Acta Horticulturae Sinica. 2021, 48(2): 377-388. DOI:10.16420/j.issn.0513-353x.2020-0306
• Abstract ( 463 ) HTML ( 365 ) PDF (1501KB) ( 365 ) 　　　

• In order to screen the appropriate reference genes for qRT-PCR analysis of the flavonoids/anthocyanins biosynthetic pathway related genes of Anemone obtusiloba,eight traditional reference genes including polyubiquitin（UBQ）,β-tubulin（β-TUB）,aquaporin（AQP）,actin（ACT）,glyceraldehyde-3-phosphate dehydrogenase（GAPDH）,histone（HIS）,elongation factor 1-β（EF-1β）and 60S ribosomal protein L13-1（RPL13）were selected as candidate reference genes based on the RNA-seq data of A. obtusiloba blue/white flowers. The expression of eight candidate reference genes were assessed by qRT-PCR in different tissues such as leaves,stems and blue/white different color flowers of A. obtusiloba,and the stability of them were analyzed by geNorm,NormFinder and BestKeeper programs. The relative expression of some pigments synthesis related genes in the biosynthetic pathway of flavonoids/anthocyanins were assessed to confirm the utility of the most stable reference gene. The results showed that UBQ was the most stable reference gene,while the stability of β-TUB was the lowest among all candidate reference genes. The qRT-PCR results of several pigments synthesis related genes using UBQ as the reference gene were in accordance with the results of RNA-seq. Thus,it was concluded that UBQ was the most suitable reference gene for gene expression analysis of flower pigments biosynthetic pathway in A. obtusiloba.

• Figure/Table | References | Related Articles | Metrics

New Technology and New Mathod

• Multiplex PCR Detection for Late Blight Resistant Genes R8,RB and Virus Resistant Genes Rx1,Ry_adg in Potato
• LIU Cheng, WANG Shiyao, SHI Weiling, SONG Yuhao, JIANG Rui, ZHAO Yong, MO Shichun, LÜ Dianqiu, WANG Jichun, LIU Xun
• Acta Horticulturae Sinica. 2021, 48(2): 389-396. DOI:10.16420/j.issn.0513-353x.2020-0318
• Abstract ( 697 ) HTML ( 240 ) PDF (1288KB) ( 240 ) 　　　

• Based on defined RB and R8 genes for late blight resistance in 218 germplasm resources,Rx1 and Ry_adg for potato virus X（PVX）and potato virus Y（PVY）extreme resistance were screened in the present study,respectively. The mixed DNA from two screened potato genotypes containing Rx1,RB and Ry_adg,R8 was used as templates. The multiplex PCR system was developed with the reported markers for Rx1 and Ry_adg and designed markers for RB and R8. In addition,the amplification of the PCR reaction system was monitored by the potato GBSS gene markers. The crucial factors of multiplex PCR system including extension temperature and primers concentration were optimized. Five specific fragments were simultaneously amplified in one PCR reaction. This detection method was used to detect these R genes from advanced breeding lines. The results revealed that four breeding lines containing four above mentioned R genes were screened. In conclusion,the established multiplex PCR detection system will be used for molecular marker-assisted selection,providing a simple and efficient technical method for late blight and viral diseases multi-R genes aggregation breeding,and new resources for the new varieties selection with four R genes in potato.

• Figure/Table | References | Related Articles | Metrics

New Cultivar

• A New Pear Cultivar‘Jixiang’
• WANG Qiang, ZHANG Maojun, LU Mingyan, YAN Xingkai, WU Chunhao, LI Honglian, DING Lihua
• Acta Horticulturae Sinica. 2021, 48(2): 397-398. DOI:10.16420/j.issn.0513-353x.2019-0811
• Abstract ( 613 ) HTML ( 182 ) PDF (1053KB) ( 182 ) 　　　

• ‘Jixiang’pear is a new cultivor with strong resistance to cold and disease selected from the‘Pingguo’pear seedling. The fruit is green-yellow;sunny slope has a flush;the fruit shape is neat,round;the average fruit weight is about 145 g;and the maximum fruit is 195 g. The flesh is white and crispy at the beginning of ripening,then it becomes soft juicy,sweet and sour,fragrant after ripening 7 d. The core of Jixiang pear is small,with few the stone cells. The quality is excellent;the soluble solids content is 14.2%,and the soluble sugar is 8.54%. The titratable acid content is 0.69%. The five-year plants have strong resistance to cold disease with high yield of 20 000 kg · hm^-2.

• Figure/Table | References | Related Articles | Metrics

• A New Nai Plum Cultivar‘Wanhuangjin’
• LIAO Ruyu, ZENG Zhifang, JIN Guang, YIN Lanxiang, LIU Tianfeng, LUO Shuixin
• Acta Horticulturae Sinica. 2021, 48(2): 399-400. DOI:10.16420/j.issn.0513-353x.2019-0893
• Abstract ( 690 ) HTML ( 204 ) PDF (1209KB) ( 204 ) 　　　

• The novel cultivar‘Wanhuangjin’is a late-ripening bud mutation from common Nai plum. The fruit has a heart shape with small cavity,and its skin is yellow-green with partial yellow. The fruit flesh is orange;the total soluble sugar content is 10.5%;the titratable acid content is 0.79%;the soluble solids content is 13.5% and the edible rate is 98.1%. The average fruit weight is 125.0 g and the largest is 168.0 g. The fruit harvest time is in late August. The yield of four-year old single tree is 86.24 kg. The fruit is resistant to fruit cracking and falling before harvest.

• Figure/Table | References | Related Articles | Metrics

• A New Mid-ripening Table Grape Cultivar‘Huapu Heifeng’
• WANG Haibo, WANG Baoliang, JI Xiaohao, WANG Xiaodi, SHI Xiangbin, WANG Zhiqiang, WANG Xiaolong, LIU Fengzhi
• Acta Horticulturae Sinica. 2021, 48(2): 401-402. DOI:10.16420/j.issn.0513-353x.2019-0891
• Abstract ( 758 ) HTML ( 338 ) PDF (1298KB) ( 338 ) 　　　

• ‘Huapu Heifeng’is a mid-ripening table grape cultivar derived from‘Takatsuma’seedling selection. Its average fruit cluster weight is 553.3 g,and the average single berry weight is 10.8 g. The berry is oval,purple-black,soft and juicy with strawberry flavor. The soluble solids content is 19.6%,the titratable acid content is 0.46%. Berrys mature in late August in Xingcheng. It has high yield,early bearing,strong tolerance to cold and dry,and moderate resistance to salt and alkali. Depending on the region,the yield should be controlled in 11 250-30 000 kg · hm^-2.

• Figure/Table | References | Related Articles | Metrics

• A New Early Ripening Chestnut Cultivar‘Xinzaoli’
• JI Zhiping, LÜ Pinghui, HE Jialin
• Acta Horticulturae Sinica. 2021, 48(2): 403-404. DOI:10.16420/j.issn.0513-353x.2019-0866
• Abstract ( 560 ) HTML ( 209 ) PDF (1276KB) ( 209 ) 　　　

• The new early maturing chestnut cultivar‘Xinzaoli’was selected from natural seedlings. Its mother tree was found in Anping Village,Pingtou Town,Baoji City,Shaanxi Province. The cultivar mature in middle and late August in Northern foot of the Qinling Mountains,at least 20 days earlier than the local main cultivar. The flesh is yellow and the texture is fine,waxy and sweet. The endocarp is easy to peel,and the nut is perfect for stir-fry. The average yield of 4-year-old single tree is 3.42 kg. It has strong stress resistance and could be cultivated in hills,beaches and barren mountains.

• Figure/Table | References | Related Articles | Metrics

• A New Bitter Gourd Cultivar‘Ruyu 118’
• LAI Zhengfeng, LIAN Dongmei, HONG Jianji, ZHANG Yucan, YAO Yunfa, LIN Yongsheng
• Acta Horticulturae Sinica. 2021, 48(2): 405-406. DOI:10.16420/j.issn.0513-353x.2019-0929
• Abstract ( 357 ) HTML ( 243 ) PDF (1333KB) ( 243 ) 　　　

• ‘Ruyu 118’is a new bitter gourd mid-late ripening hybrid developed by crossing BY-2-6-24 as female parent and YH-7-19 as male parent. Its fruit is longconic with white green skin,short longitudinal stripe and large round tumor,about 24-28 cm in length,7-8 cm in diameter,1.2 cm in flesh thickness. The fruit weight is 500-600 g. Its yield is about 52 500 kg · hm^-2.‘Ruyu 118’has good commercial appearance,high temperature tolerance and strong disease resistance. It is suitable to be cultivated in tropical,subtropical and temperate regions of China.

• Figure/Table | References | Related Articles | Metrics

• A New Ornamental Lotus Cultivar‘Shicheng Jinxiu’
• LIU Xiaojing, DU Fengfeng, YANG Dan, DING Yuesheng, CHANG Yajun, CUI Jian, YAO Dongrui
• Acta Horticulturae Sinica. 2021, 48(2): 407-408. DOI:10.16420/j.issn.0513-353x.2019-0834
• Abstract ( 556 ) HTML ( 282 ) PDF (1432KB) ( 282 ) 　　　

• The ornamental lotus‘Shicheng Jinxiu’is a double-layered cultivar. It was selected from the progeny of natural hybrid of‘Jinxia’.‘Shicheng Jinxiu’is a big size lotus;leaf height is 57-82 cm;leaf diameter is 33-43 cm × 27-39 cm;flower height is 75-96 cm;flower diameter is 15-21 cm;petal number is 91-110. The flower is multicolored;tip is purple-red;the middle is pink;and base is yellow. The flower is bowl-shaped at first,and plate-shaped later.

• Figure/Table | References | Related Articles | Metrics