Genetic & Breeding·Germplasm Resources·Molecular Biology

• Comprehensive Evaluation of Fruit Spots in 296 Pear Germplasm Resources
• DUAN Ruiwei, ZHANG Xiangzhan, LI Bo, WANG Mengru, XIE Yarong, LI Pei, WANG Lei, YANG Jian, XUE Huabai
• Acta Horticulturae Sinica. 2023, 50(11): 2305-2322. DOI:10.16420/j.issn.0513-353x.2022-0492
• Abstract ( 445 ) HTML ( 396 ) PDF (4571KB) ( 396 ) 　　　

• In this study，a total of 296 pear germplasms from National Horticulture Germplasm Resources Center Pear Branch Center（Zhengzhou）were collected for fruit spots observation，data collection and photography. During fruit harvesting period，the indicated pear germplasms were sampled and different fruit spot traits，including fruit spots size，fruit spots density，fruit spots height，and the fruit spots area in unit area were comprehensively analyzed. Additionally，sensory evaluation of fruit appearance quality associated with fruit spots in different pear germplasms was performed，and the apperance quality of different pear germplasms was evaluated by grey relation analysis（GRA）and cluster analysis（CA）to establish a comprehensive evaluation model for pear fruit spot traits. The results showed that the relative correlation degree of fruit spots of 296 pear resources ranged from 0.3158 to 0.6526，and the 296 resources were classified into five grades：excellent，good，medium，poor，and extremely poor. Pear varieties including‘Autumn Red’‘Silk Red’‘Red Sensatian’‘Zhongli Meicui’‘Barlett’and‘Dabali’were screened out with excellent fruit spot traits，which have good appearance quality and were consistent with the actual production fruit exterior. On the contrary，pear varieties including‘Puguali’‘Xihuamake’‘Chili’and‘Enli’were screened out with extremely poor fruit spot traits，which have poor appearance quality. Furthermore，the fruit spot traits of 296 pear germplasm resources were divided into five grades by cluster analysis，including excellent，good，medium，poor and extremely poor，which accounted for 7.8%，8.8%，37.1%，34.1% and 12.1% of the tested materials，respectively. Above all，the germplasm resources with excellent fruit spot traits will lay the foundation for the improvement of pear appearance quality，and the germplasm resources with poor fruit traits will be helpful for the investigation of the formation and regulation mechanism underlying pear fruit spots.

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• ABA and Ethylene Enhance the Expression VlMybA1 and VlMybA2 and Promote Pigmentation in the Berry Skin via Their Interaction
• SUN Yushuai, WANG Fei, GUAN Xueqiang, CHI Huiru, YAO Yuxin
• Acta Horticulturae Sinica. 2023, 50(11): 2323-2336. DOI:10.16420/j.issn.0513-353x.2022-0919
• Abstract ( 296 ) HTML ( 254 ) PDF (2320KB) ( 254 ) 　　　

• The patterns of anthocyanin and ABA accumulation and ethylene production as well as the changes in expression of the key genes associated with their synthesis or regulation during berry development were studied using Kyoho grapes（Vitis vinifera × V. labrusca‘Kyoho’）. Analysis of gene expression，promoter response and relative mRNA abundance showed that exogenous ABA treatment upregulated the expression level of VlMybA1 and VlMybA2，in which VlMybA1 was significantly expressed and promoted berry skin pigmentation；In contrast，exogenous ACC treatment increased the VlMybA2 expression and anthocyanin accumulation. The interaction between ABA and ethylene was found，100 μmol · L^-1 ABA largely induced the production of endogenous ethylene，and 500 μmol · L^-1 ACC significantly increased ABA content. Additionally，exogenous ABA treatment increased the relative mRNA abundance of VlMybA2 via ethylene. Collectively，ABA promoted berry skin pigmentation by upregulating the VlMybA1 expression directly and the VlMybA2 expression indirectly via ethylene.

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• Comparative Analysis of Genetic Background of‘Dongshi Zaoyou’，‘Shatianyou’and‘Shuijingyou’Pummelos
• LIU Chenglang, FENG Di, CAO Zonghong, YAN Suyun, ZHANG Yongqing, XU Xiangzeng, GAO Shide, YE Junli, CHAI Lijun, XIE Zongzhou, DENG Xiuxin
• Acta Horticulturae Sinica. 2023, 50(11): 2337-2349. DOI:10.16420/j.issn.0513-353x.2022-0981
• Abstract ( 250 ) HTML ( 169 ) PDF (4165KB) ( 169 ) 　　　

• ‘Dongshi Zaoyou’，a new pummelo cultivar selected from pummelo seedlings，is mainly cultivated in the tropical areas of Yunnan Province. It has good characteristics such as early-maturing，high-yielding，seedless and etc. However，the genetic origin of‘Dongshi Zaoyou’pummelo has not yet been clarified，which was unfavorable to its protection and utilization. In this study，the cross-compatibility test and molecular markers including self-incompatibility S-genotype，SNP and InDels were used to explore the genetic background differences between‘Dongshi Zaoyou’pummelo and its two similar cultivars ‘Shatianyou’，‘Shuijingyou’. The pollination experiments revealed the cross-incompatibility between‘Dongshi Zaoyou’pummelo and‘Shuijingyou’pummelo while the cross-compatibility between‘Dongshi Zaoyou’pummelo and‘Shatianyou’pummelo. Accordingly，S-genotype of‘Dongshi Zaoyou’pummelo was judged to be S₅S₆，the same as that of‘Shuijingyou’pummelo（S₅S₆），while different from that of ‘Shatianyou’pummelo（S₁S₂）. Based on the genome resequencing data，the genome-wide SNP density distribution of three pummelo cultivars were then plotted and compared. The results showed that‘Dongshi Zaoyou’pummelo and‘Shuijingyou’pummelo had highly similar SNP density and clustered into a group，but they both were significantly different from‘Shatianyou’pummelo. In addition，two InDel polymorphic markers could clearly distinguish‘Dongshi Zaoyou’pummelo from‘Shatianyou’pummelo. Collectively，it could be concluded that‘Dongshi Zaoyou’pummelo showed a closer relationship to‘Shuijingyou’pummelo than‘Shatianyou’pummelo.

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• Analysis of Canarium album Transcriptome SSR Information and Molecular Marker Development and Application
• XIE Qian, ZHANG Shiyan, JIANG Lai, DING Mingyue, LIU Lingling, WU Rujian, CHEN Qingxi
• Acta Horticulturae Sinica. 2023, 50(11): 2350-2364. DOI:10.16420/j.issn.0513-353x.2023-0355
• Abstract ( 197 ) HTML ( 97 ) PDF (2686KB) ( 97 ) 　　　

• The mature fruits of different varieties（lines）of Canarium album L. were selected for transcriptome sequencing，and 296 314 sequences were obtained. MISA software was used to analyze SSR loci，and 86 084 SSR loci were obtained，distributed in 70 686 sequences. The frequency of SSR in the detected sequences was 23.86%，of which 54 735 sequences contained two or more SSR loci，accounting for 68.4%. The SSR sequences in the Chinese olive transcriptome were mainly composed of compound nucleotide，single nucleotide and dinucleotide repeats，accounting for 88.88% of the total SSRs. The dominant motifs in mononucleotide and dinucleotide repeat types were A/T and AG/CT/TC/GA，respectively. The effectiveness and polymorphism of 99 pairs of SSR primers randomly selected from six different Chinese olive lines（species）were screened. Finally，53 effective SSR molecular markers and 12 polymorphic SSR molecular markers were developed. The polymorphism evaluation and population structure analysis of 59 Chinese olive germplasm were carried out by using 12 polymorphic EST-SSR markers. A total of 48 polymorphic loci were detected. The average Shannon diversity index was 0.876，and the average polymorphic information content was 0.426. The population structure of 59 Chinese olive germplasms was analyzed by three methods of mixed group model grouping，UPGMA clustering and PCA. The results of mixed group model analysis were crossed with those of UPGMA clustering and principal component analysis，but the number of groups was different. The mixed group model was divided into three groups. UPGMA cluster analysis was divided into two populations at the genetic similarity coefficient of 0.68，which was the same as the PCA method. The results of the study concluded that the 12 pairs of SSR markers developed were genetically diverse and valid，and provided a reliable basic tool for Chinese olive germplasm resource identification.

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• Development of SSR Molecular Markers and Construction of Core Collection of Wild Diploid Strawberry
• ZHANG Yongqi, WANG Chao, XU Linlin, WU E’jiao, LI Tianhong, ZHAO Mizhen, YUAN Huazhao
• Acta Horticulturae Sinica. 2023, 50(11): 2365-2375. DOI:10.16420/j.issn.0513-353x.2022-0985
• Abstract ( 166 ) HTML ( 107 ) PDF (1252KB) ( 107 ) 　　　

• Core collection can reduce the number of resources and maximize the genetic diversity of the population. The 106 829 SSR loci were obtained by searching the genome of Fragaria vesca L. with MISA program，and 5 778 unique and common SSR sequences were obtained by comparing the genome of eight diploid strawberries such as F. vesca L. Among the 26 complex repeats，18 SSR loci were found in F. vesca L，F. chinensis Lozinsk，F. mandshurica Staudt，F. nilgerrensis Schlecht.，F. nubicola Lindl.，F. emeiensis Jia J. Lei，F. pentaphylla Lozinsk and F. viridis Duch. Among them，the single，two，three，four，five，six nucleotide types and complex repeat types were 3 461，1 223，999，57，7，5，26，respectively. Among 26 complex repeat types，18 SSR loci have high coverage in 176 diploid strawberry re-sequencing data，which are used for construction of core collection. The results showed that 444 alleles were obtained from 176 accessions of wild diploid strawberry with 18 pairs of conservative sequence，the average number of effective alleles was 7.899，the Shannon's information index was 0.836-3.362，the observed heterozygosity was 0.006-0.477，the expected heterozygosity was 0.324-0.953，the PIC value was 0.315-0.951，and the average value was 0.756. The core collection of wild diploid strawberry was constructed with 18 pairs of SSR primers selected，and the core collection was evaluated by t-test. The fourty-three accessions were selected，which preserved more than 80% of genetic diversity and were highly representative. They were identified as the core collection of wild diploid strawberry，and at the same time，the molecular ID of two-dimensional code of core collection was constructed. The polymorphic SSR loci developed in this study can provide research tools for identification and molecular marker breeding of wild strawberry in the future.

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• Response to Low Temperature Stress and Screening and Validation of Interaction Protein of CqCHP1 in Chieh-qua
• WANG Min, YANG Songguang, LIU Wei, HE Xiaoming, SHI Shaoqi, LIU Wenrui, CHEN Lin, JIANG Biao, PENG Qingwu
• Acta Horticulturae Sinica. 2023, 50(11): 2376-2386. DOI:10.16420/j.issn.0513-353x.2022-0854
• Abstract ( 129 ) HTML ( 108 ) PDF (3145KB) ( 108 ) 　　　

• In this study，CqCHP1 was cloned from‘Yueguang Chieh-qua’，which encoded cysteine/ histidine-rich C1 domain protein. The gene’s open reading frame was 816 bp with 271 amino acids. The secondary structure indicated that CqCHP1 contained main random curl and 23 serine phosphorylation sites. Phylogenetic tree and amino acid sequence alignment analysis showed that CqCHP1 had the highest homology with cucumber Csa_4G297435. CqCHP1 was expressed in different tissues and specifically induced by low temperature. And at seedling and fruiting stages，CqCHP1 showed higher expression in resistance materials than sensitive materials，while at vegetative growth and flowering periods，it’s the opposite. The protein was located in the nucleus. Analysis of interaction proteins obtained by yeast screening showed that CqCHP1 could interact with bHLH92 in nucleus. And the inteaction was verified by Bimolecular fluorescence complementation（BIFC）and Luciferase complementation imaging assay（LCI）.

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• Analysis of Heat-tolerant Function of Pepper Vesicle Formation Related Gene CaSec16
• YAN Bentao, JIAO Kexin, ZHAO Yue, YANG Qiaomin, CHEN Tao, LU Minghui
• Acta Horticulturae Sinica. 2023, 50(11): 2387-2400. DOI:10.16420/j.issn.0513-353x.2022-0996
• Abstract ( 117 ) HTML ( 76 ) PDF (2808KB) ( 76 ) 　　　

• Vesicle transport plays important roles in plant tolerance to abiotic stress. However，the function of pepper CaSec16（COPII coat assembly protein Sec16-like），a gene related to vesicle formation，remains unclear in heat tolerance. CaSec16 was localized in cytoplasm and nucleus，and was expressed in various tissues of pepper. The expression of CaSec16 was up-regulated during heat stress. Compared with the control plants，the heat tolerance of pepper plants with CaSec16-silenced was compromised，which was shown by the death of growing point，the aggravated leaf wilting，the higher increment in relative electric conductivity，the lower contents of total chlorophyll，the higher accumulation of dead cells，H₂O₂，MDA and proline increased，and the weakened up-regulation of heat-tolerance marker genes. On the contrary，compared with the control plants，the heat tolerance of CaSec16 transient- overexpression pepper plants was improved，which was presented the mitigated leaf wilting，the lower contents of MDA and proline，and the strengthened up-regulation of heat-tolerance marker genes. Taken together，it was speculated that CaSec16 positively regulates the heat tolerance of pepper.

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• Screening and Phenotypic Analysis of EMS Induced Mutants in Watermelon
• YIN Lijuan, WANG Chunxia, LI Chenhao, DING Xiaoling, PAN Xiaona, YU Rong, MA Hanyue, CHEN Xiuhong, YANG Jianqiang, ZHANG Xian, WEI Chunhua
• Acta Horticulturae Sinica. 2023, 50(11): 2401-2416. DOI:10.16420/j.issn.0513-353x.2022-0924
• Abstract ( 155 ) HTML ( 158 ) PDF (8662KB) ( 158 ) 　　　

• The seeds and seedlings of watermelon germplasm M08 were treated with ethyl methane sulfonate（EMS）as a mutagen by seed soaking method and seedling dropping method. Observation，photography，and recording of major agronomic traits such as leaves，flowers，stems，and fruits per plant in M₁ and M₂ generations. In this study，749 individual plants of M₁ generation were obtained by seed soaking method，and 15 mutation types were found，including leaf yellowing，leaf deformity，male flower cluster，and melon embryo shape variation，the total mutation rate reached 20.56%. A total of 689 M₁ generation plants survived through the seedling dropping method，including ten types of variation，with a total variation rate of 19.30%. A total of 443 materials were harvested from the M₂ generation，132 families were randomly selected for phenotypic observation. A total of 13 variation types were obtained，including leaf yellowing，cotyledon junction，leaf deformity，leaf margin involution，stem juxtaposition，pericarp banding variation，plant growth and development retardation，the total mutation rate was 5.21%. Phenotypic observation and photosynthetic characteristics analysis of the M₂ generation population of the M₁-5 family with yellowing to greening leaf color mutant showed that before turning green，the photosynthetic pigment content was low and the leaves were yellow，after turning green，the content of photosynthetic pigments significantly increased，and the leaf color changed from yellow to green，but it was still lower than the normal M08 leaf. With the accumulation of photosynthetic pigments，the photosynthetic ability of the yellowing to greening mutant was restored and it could grow normally.

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• Morphological Characteristics of Pollen from 44 Species of Subgen. Yulania
• WANG Xiaobo, CAO Ying, GUO Wei, MA Lin, LIU Xiuli
• Acta Horticulturae Sinica. 2023, 50(11): 2417-2434. DOI:10.16420/j.issn.0513-353x.2022-0969
• Abstract ( 195 ) HTML ( 107 ) PDF (7004KB) ( 107 ) 　　　

• In order to clarify the morphological characteristics of the pollen and taxonomic relationships of the Subgen. Yulania，the present study observed the morphological characteristics of pollen of 44 Subgen. Yulania（including 8 accessions，36 cultivars）using scanning electron microscopy（SEM）. Pollen of all tested materials is single-grained with one grooves and belong to N₁P₃C₃-type pollen grains，prolate or perprolate，with size medium（36.06-42.81）μm ×（16.39-20.07）μm and symmetrical from left to right. Pollen is subglobose in polar view，oval or long oval in equatorial view，and boat-shaped in lateral view. The extine pattern of pollen is relatively primitive and could be broadly divided into six types：hole-shaped，verrucate shaped，stripe-shaped，brain-shaped，short rod-shaped hole shaped and tuberculate. The results showed that the pollen shape and colpae of different Subgen. Yulania were similar，but the exine varied greatly. Therefore，pollen morphology can be used to distinguish different species. However，due to its low resolution，it is difficult to distinguish Yulania species accurately，and it can only be used as an auxiliary reference index for species classification.

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• Morphological Characteristics and Volatile Component Diversity of the Jasminum Germplasm Resources
• CHEN Meichun, DENG Yingjie, CHEN Zheng, ZHU Yujing, LI Chunniu, WANG Jieping, LIU Bo
• Acta Horticulturae Sinica. 2023, 50(11): 2435-2452. DOI:10.16420/j.issn.0513-353x.2022-0796
• Abstract ( 131 ) HTML ( 64 ) PDF (3876KB) ( 64 ) 　　　

• The flower volatile compounds of Jasminum spp. were detected by using the SPME-GC-MS technique and diversity of flower volatile compounds and aroma quality were also evaluated by the cluster analysis，principal component analysis and aroma quality evaluation. The results showed that the 25 jasmine germplasm resources displayed abundant phenotypic traits：(i) the phyllotaxy of these jasmine germplasm resources was verticillate three-leaves，alternately pinnate compound leaves or opposite single-leaf；(ii) the flower color is white，white-pink bicolor or golden；and (iii) the corollas is single，double or multiple layer (s). Among the 25 germplasm resources，the lightest single flower mass was Jasminum grandiflorum（0.10 g），and the heaviest one was Jasminum sambac Hutou（2.41 g）. Moreover，a total of 107 volatile components were identified from the 25 jasmine germplasm resources，including 43 Terpenoids，24 benzene compounds，28 fatty acid derivatives and 12 N- and NS-containing compounds. The volatile components of 22 germplasm resources were reported for the first time by this study，except for J. grandiflorum，J. multiflorum and Fuzhou double layers J. sambac. According to the results of the principal component and cluster analyses，the 25 jasmine germplasm resources could be clustered into three categories：Group Ⅰ，including J. odoratissimum；Group Ⅱ，including J. seguinii，J. multiflorum and J. dichotomum；and Group Ⅲ，including the remaining 21 germplasms. Furthermore，21 substances including linalool，benzyl alcohol，methyl benzoate，benzyl acetate，α-farnesene，indole，jasmone and butyraldehyde oxime were screened as the differentially representative volatile components. In J. odoratissimum，few volatile components could be identified，but the content of α-farnesene was very high（> 89%）. Butyraldehyde oxime-like substances were volatile components unique to group Ⅱ，and have not been detected in other jasmine germplasm resources. J. grandiflorum had significantly different phenotypic characteristics compared to J. Jasmine，while its volatile compositions were similar to J. Jasmine. The results of aroma quality evaluation indicated that aroma quality of different cultivars of J. sambac was significantly different. It is noteworthy that the aroma quality of Orleans girl，Myanmar double layers，Thailand double layers and Taiwan single layer was not lower than that of Fuzhou’s double layers，therefore，it is worth planting in a large area.

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Cultivation Physiology & Biochemistry

• Effects of Bacillus megaterium on Yield，Quality and Soil Microorganism of Apple
• PAN Jiyuan, DONG Qinglong, WEN Haibin, LIU Yanan, WANG Xiaojie, ZHANG Xuemei, LIU Wenju, LU Xiujun
• Acta Horticulturae Sinica. 2023, 50(11): 2453-2465. DOI:10.16420/j.issn.0513-353x.2022-0965
• Abstract ( 187 ) HTML ( 138 ) PDF (1419KB) ( 138 ) 　　　

• In order to clarify the effects of Bacillus megaterium on the growth of apple（Malus × domestica）trees and the ecological effects of the soil，a field experiment was conducted to explore the effects of B. megaterium application on the growth of new branches，the yield and quality of apple fruits，and the characteristics of soil microbial community using 16 years-old‘Red Fuji’apple trees. The results showed that the growth rate of new branches in 2021 and 2022 were increased by 3.45% and 17.01% within compared with the control 30 d，respectively（P < 0.05），and by 2.58% and 6.71% within 60 d，respectively（P < 0.05），after application of B. megaterium inoculant to apple trees in spring. Moreover，the yield increased by 7.17% and 7.01% respectively（P < 0.05）；the fruits number per plant were increased by 4.95% in 2021（P < 0.05），in the treatment group of 2021 and 2022，but application of B. megaterium inoculant had no significant effect on the fruit shape index，hardness of fruits，and the contents of soluble sugar，soluble solids，and vitamin C in apple fruits. In 2022，the fruit color related indexes of the treatment group，Red-Green Index a^* is lower and Chroma angle h is higher than those of the control group，and there were no significant differences in 2021. Furthermore，the number of fungi in the soil layer of 0-20 cm and 20-40 cm decreased，while the number of bacteria showed the opposite trend. There was no significant difference in α-diversity of soil fungal and bacterial communities in the soil layer of 20-40 cm. For the soil fungal community at genus level，the relative abundances of Trichocladium，Solicocozyma，Naganishia and Ilyoctria in the treatment 1.87，1.92，2.91 and 3.38 times higher than those in the control；The relative abundances of Tausonia and Cephalotrichum were 76.44% and 67.96% of that in the control，respectively（P < 0.05）. For the soil bacterial community at genus level，the relative abundances of Streptomyces and Gemmatimonas in the treatment were 2.65- and 1.33-fold of that in the control，but the relative abundance of Chujaibacter was 48.88% lower than that of the control（P < 0.05）. The number of bacteria and fungi OTU in the rhizosphere of the treatment changed significantly compared with the control；Additionally，the contents of soil available phosphorus and potassium in the rhizosphere of the treatment were 21.87% and 20.81%；5.14% and 5.31%，respectively（P < 0.05），which are higher than those in the control（P < 0.05）. In summary，the application of B. megaterium inoculant to apple trees in spring can inhibit harmful soil fungi，improve the structure and quantity of soil microbial community，mobilize soil phosphorus and potassium，and promote the growth of apple tree and apple fruits yield.

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• Sensory Fuzzy Modeling and Sugar and Acid Analysis Based Evaluation of Fruit Quality Difference in Different‘Ehime Kashi 28’Samples
• CHEN Jiajing, LIU Yuan, WU Yanuo, XU Juan, ZHANG Hongyan
• Acta Horticulturae Sinica. 2023, 50(11): 2466-2476. DOI:10.16420/j.issn.0513-353x.2022-0978
• Abstract ( 257 ) HTML ( 219 ) PDF (4625KB) ( 219 ) 　　　

• To scientifically evaluate the fruit quality of citrus，this study tested the conventional quality，soluble sugar and organic acid content of nine‘Ehime Kashi 28’（‘Beni Madonna’）samples. In addition，panelists were organized to evaluate the favor ability of each sensory attribute and the weight level of each attribute in different samples. Correlation analysis between comprehensive sensory evaluation in six sensory attributes and flavor substances was hence performed. The results showed that the main soluble sugars in the juice sacs of‘Ehime Kashi 28’were fructose，glucose and sucrose，with higher content in sample 3 and 8，and lower content in sample 1 and 9. The main organic acids in the juice sacs of‘Ehime Kashi 28’were citric acid and low level of malic acid，the total acid content in sample 5，3 and 1 were higher，and the content in sample 9 was the lowest. The panelists paid attention to each quality attribute of‘Ehime Kashi 28’as follows：pulp sweetness > pulp acidity > pulp mastication > fruit aroma > fruit color = fruit shape，and the highest sensory comprehensive evaluation scores were in sample 9，3 and 2. In addition，the sensory comprehensive score was significantly correlated with pulp sweetness，pulp mastication and fruit aroma. The sensory evaluation of sugar content was significantly positively correlated with fructose，glucose，total sugar and TSS，and significantly negatively correlated with malic acid.

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Plant Protection

• Determination of Horizontal Transmission Ability of BdCV1 Infecting Botryosphaeria dothidea Strain with Hypovirulence
• GAO Yunjing, WANG Tianhao, HU Wangcheng, HONG Ni, WANG Guoping, WANG Liping
• Acta Horticulturae Sinica. 2023, 50(11): 2477-2488. DOI:10.16420/j.issn.0513-353x.2022-0683
• Abstract ( 83 ) HTML ( 34 ) PDF (3208KB) ( 34 ) 　　　

• Pear ring rot disease，caused by the pathogenic agent of Botryosphaeria dothidea. Botryosphaeria dothidea chrysovirus 1（BdCV1）induced to the hypovirulence of B. dothidea LW-C and LW-1，which will be used as an ideal candidate material for biological control of fruit tree ring rot disease. In order to further clarify whether the BdCV1-mediated hypovirulent strain has potential as a good candidate biocontrol resource，LW-C and LW-1 was confrontly cultured with the B. dothidea strains isolated and collected from different geographical origins and Valsa pyri strain XJ-28，which caused serious harm to pear trees，respectively. The obtained derivate strains were detected to be positive for BdCV1，whose growth rates and pathogenicity were further determined and analyzed. The results showed that BdCV1 could be successfully horizontally transmitted to different B. dothidea and V. pyri strains with certain frequencies，which further inhibited the growth rates and induced to hypovirulence of the strains. The obtained results revealed BdCV1 could be successfully transmitted to the recipient strains at a certain frequency，which could cause the growth rate to decrease and inhibit the growth of the recipient strains to different extent. The formed lesion extension lengths of derivate strains with BdCV1 range from about two to four times longer than that of the recipient strains，when they are inoculated with pear branches or fruits. It further demonstrated that BdCV1 can inhibit the virulence of recipient strains. In summary，BdCV1 could be horizontally transmitted to different recipient strains，revealing that it has wide host range. It is predicted that BdCV1 could be used as a potential biocontrol factor in pear fungal disease biocontrol in practice.

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• The Malus baccata Receptor Like Protein MbRLP7 Negatively Regulates the Resistance of Pyrus betulifolia Bunge to Valsa Canker
• JIANG Daji, WEN Youfu, YU Hongqiang, GUO Zhigang, ZUO Longgang, SUN E, LI Yanyan, ZUO Cunwu, ZHAO Junying
• Acta Horticulturae Sinica. 2023, 50(11): 2489-2498. DOI:10.16420/j.issn.0513-353x.2022-0938
• Abstract ( 75 ) HTML ( 30 ) PDF (1387KB) ( 30 ) 　　　

• Based on bioinformatics analysis，functional verification，and expression measurement，the role of the receptor-like protein MbRLP7 in Valsa pyri resistance，and its potential regulatory mechanisms were explored. The results showed that MbRLP7 had the highest sequence similarity with AtRLP6 and AtRLP7，with 43.0% and 42.8%，respectively. There are several cis-elements in the promoter region of MbRLP7 in response to stress-related signals and Valsa pyri signals. The MbRLP7 was transformed into suspension cells of Pyrus betulifoliaBunge，and three overexpressed cell lines were obtained. After inoculation with the pathogen Valsa pyri（Vp），the growth rate of mycelia on the overexpressing cells was significantly higher than that on the wild-type cells. After Valsa pyri metabolites treatment，the cell activity of all overexpressed cell lines was significantly lower than that of wild-type. In addition，the overexpression of gene MbRLP7 enhanced the induction of Valsa pyrimetabolites on PAMP-triggered immunity（PTI），reactive oxygen species related genes and pathogenesis-related protein PR1. In conclusion，MbRLP7 negatively regulates the resistance of Pyrus betulifoliaBunge to Valsa pyri，and PTI，reactive oxygen species and PR1 are involved in this regulatory process.

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• The Apple Receptor Like Kinase Gene MdLYK1 Positively Regulates Valsa Canker Resistance
• LI Yanyan, GUO Shoujun, CAI Minrui, SUN E, YU Hongqiang, JIANG Daji, ZUO Cunwu, WANG Hai
• Acta Horticulturae Sinica. 2023, 50(11): 2499-2508. DOI:10.16420/j.issn.0513-353x.2022-0922
• Abstract ( 94 ) HTML ( 52 ) PDF (2034KB) ( 52 ) 　　　

• The effect and potential mechanism of receptor like kinase gene MdLYK1（MD09G1111800）on the resistance to Valsa canker were investigated by bioinformatics analysis，functional verification and expression analysis. The results showed that MdLYK1 was homologous to Arabidopsis receptor kinase gene AtLYK1，with 68.1% amino acid sequence similarity. The transient expression of this gene in‘Yanfu 6’fruit significantly improved the fruit Valsa canker resistance. Three overexpressed cell lines were obtained by introducing them into the suspension cells of Pyrus betulifolia Bunge. After inoculation with Valsa pyri，the growth rate of colonies on all overexpressing cell lines was significantly lower than that of wild-type cells. All overexpression cell lines were significantly less sensitive to Valsa pyri metabolites compared to the wild type. In addition，MdLYK1 overexpression significantly enhanced the up-regulated expression of key genes related to signaling such as pathogen-associated molecular patterns triggered immunity，reactive oxygen species，jasmonic acid and other signal-related key genes were up-regulated in the suspension cells of Pyrus betulifolia Bunge. In conclusion，MdLYK1 positively regulates the resistance to apple and pear Valsa canker，and pathogen-associated molecular pattern-triggered immunity，reactive oxygen species and jasmonic acid signals are involved in the regulation of resistance.

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• Screening Proteins of Nicotiana occidentalis That Interact with Coat Protein of Apple Stem Pitting Virus Using Yeast Two-hybrid System
• DING Lei, SUN Pingping, ZHANG Lei, LI Zhengnan
• Acta Horticulturae Sinica. 2023, 50(11): 2509-2515. DOI:10.16420/j.issn.0513-353x.2022-0507
• Abstract ( 110 ) HTML ( 72 ) PDF (2624KB) ( 72 ) 　　　

• Apple stem pitting virus（ASPV）is a latent virus on apple and pear trees worldwide. Nicotiana occidentalis is an important herbaceous host plant for it. In this study，ASPV coat protein（CP）was used as bait to screen a cDNA library of N. occidentalis. Thirty proteins that interact with ASPV CP were obtained by yeast two-hybrid co-transformation and NCBI BLAST. This study could be useful for understanding the molecular mechanism of ASPV infection in N. occidentalis and the function of CP in the process of virus infection.

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Review

• Advances in the Regulation of Anthocyanin Biosynthesis by Hormone Signaling in Fruit Trees
• ZHENG Tianyi, HU Yujie, ZHANG Xuehao, LI Wanping, FANG Yulin, ZHANG Kekun, CHEN Keqin
• Acta Horticulturae Sinica. 2023, 50(11): 2516-2536. DOI:10.16420/j.issn.0513-353x.2022-1038
• Abstract ( 274 ) HTML ( 226 ) PDF (1536KB) ( 226 ) 　　　

• This review summarizes the molecular mechanisms underlying the roles of abscisic acid，jasmonic acid，ethylene，auxin，cytokinin，brassinolide，gibberellin and strigolactone in regulating the anthocyanin accumulation in the fruit trees based on gene expression regulation of the anthocyanin biosynthesis pathway. The review will provide a theoretic basis for enriching the fundamental researches of anthocyanin regulation and biosynthesis in fruit trees，understanding the critical signal transduction pathways of plant hormones，and rationally applying plant hormones to regulate fruits development. The information provides references for the further study of the nthocyanin metabolic pathways in different types of fruit trees.

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New Cultivars

• A New Peach Cultivar‘Zhentao 3’
• WAN Chunyan, HUO Hengzhi, MI Lin, LI Jinfeng, CHEN Xueping, CHEN Bingyi, DI Huatao, YAN Yongqi, YANG Yong, SONG Siyan
• Acta Horticulturae Sinica. 2023, 50(11): 2537-2538. DOI:10.16420/j.issn.0513-353x.2021-0831
• Abstract ( 119 ) HTML ( 85 ) PDF (1067KB) ( 85 ) 　　　

• ‘Zhentao 3’is a new peach cultivar bred by‘Xinbaihua’as female partent and ‘Chiyohime’as male parent. The pollen of‘Zhentao 3’is sterile. The fruit is round. The average fruit weight is 247.6 g and most fruit skin covered by bright red. The flesh is white，hard and clingstone，and sweet flavor，tolerance to storage and transport. It has14.1% soluble solids content，0.185% total acid content. The fruit development period is about 96 days. The cultivar has high and consistent yield，up to 25 000-50 000 kg · hm^-2.

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• A New Anoectochilus roburghii Cultivar‘Jinkang 1’
• WU Mei, ZHOU Xiaojun, KONG Xiangjun, MA Qiaoqun, FANG Li
• Acta Horticulturae Sinica. 2023, 50(11): 2539-2540. DOI:10.16420/j.issn.0513-353x.2021-0434
• Abstract ( 97 ) HTML ( 63 ) PDF (1122KB) ( 63 ) 　　　

• ‘Jinkang 1’was selected from wild Anoectochilus roburghii in Nanjing，Zhangzhou，Fujian Province. The cultivar is erect at early growth stage. The height is 10.5-11.3 cm. The leaves are ovoid，dark green with velvet gloss and golden-red silky lustre reticulate veins. The raceme is with 2-6 white flowers. The fresh weight per plant is 2.6 g and the fresh yield is 1 592 kg · hm^-2 after planting seven months from tissue culture seedlings. The new cultivar grows vigorously and middle resistant to stem rot disease. It is suitable for planting under forests in mountainous areas of Zhejiang Province.

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