Genetic&Breeding?Germplasm Resources?Molecular Biology

• QTL Mapping and Candidate Gene Identification Related to Ascorbic Acid Content in Tomato
• LIU Genzhong, LI Fangman, GE Pingfei, TAO Jinbao, ZHANG Xingyu, YE Zhibiao, ZHANG Yuyang
• Acta Horticulturae Sinica. 2024, 51(2): 219-228. DOI:10.16420/j.issn.0513-353x.2023-0659
• Abstract ( 323 ) HTML ( 340 ) PDF (1630KB) ( 340 ) 　　　

• The F₂ genetic segregating population was constructed via using high ascorbic acid（AsA）tomato accession TS-226 and low ascorbic acid tomato accession TS-228 as parents. The high-ascorbic acid and low-ascorbic acid pools were constructed respectively. Through bulked segregant analysis sequencing analysis（BSA-seq），the main QTL related to ascorbic acid was found，and the candidate gene related to ascorbic acid was located in the 58.00-60.15 Mb region of tomato chromosome 8. Furthermore，the ∆SNP-index data were analyzed to determine the main candidate gene SlPPO（Polyphenol oxidase）that controls the ascorbic acid content of tomato fruit. Using TS-228 as the background plant，transgenic lines with SlPPO overexpression and silencing were obtained by Agrobacterium-mediated transformation. Compared with the wild type，the total ascorbic acid content in the red ripe fruits of the overexpression lines OE-3 and OE-18 decreased by 18.89% and 26.56%，respectively. The total ascorbic acid content in the red ripe fruits of the silenced lines Ri-9 and Ri-16 increased by 37.53% and 63.93% relative to wild type，respectively. Taken together，SlPPO is the key gene to control the ascorbic acid content of tomato red ripe fruit，and plays a negative role in regulating fruit ascorbic acid content.

• Figure/Table | References | Related Articles | Metrics

• Genome-wide Association Studies of Drought Tolerance in Tomato
• DONG Shuchao, HONG Jun, LING Jiayi, XIE Zixin, ZHANG Shengjun, ZHAO Liping, SONG Liuxia, WANG Yinlei, ZHAO Tongmin
• Acta Horticulturae Sinica. 2024, 51(2): 229-238. DOI:10.16420/j.issn.0513-353x.2023-0694
• Abstract ( 267 ) HTML ( 216 ) PDF (2108KB) ( 216 ) 　　　

• To conduct genome-wide association studies（GWAS）of drought tolerance，the relative water loss of detached leaves was analyzed after 24 h dehydration in 301 tomato（Solanum lycopersicum L.）accessions. A total number of three SNP sites（S02.1158758，S02.1160893，and S05.1426646）significantly associated with the drought tolerance of tomato accessions were identified by GWAS. Each single locus could explain 4.08%-18.97% of the phenotypic variation. Taken together，three SNP sites and seven candidate genes significantly associated with drought tolerance in tomato were identified in this study，which will help unravel the genetic and regulatory mechanisms of tomato drought tolerance，as well as establish a foundation for the genetic improvement of tomato stress tolerance.

• Figure/Table | References | Related Articles | Metrics

• Identification of Genetic Loci and Molecular Marker Development of Salt Tolerance in Tomato Seedlings
• XU Qin, WANG Jiaying, ZHANG Mannan, XIAO Zhihao, ZHENG Hankai, LU Yong'en, WANG Taotao, ZHANG Yuyang, ZHANG Junhong, YE Zhibiao, YE Jie
• Acta Horticulturae Sinica. 2024, 51(2): 239-252. DOI:10.16420/j.issn.0513-353x.2023-0739
• Abstract ( 209 ) HTML ( 171 ) PDF (3898KB) ( 171 ) 　　　

• To identify the genetic components of salt tolerance at the seedling stage of tomato，the contents of sodium（Na⁺）and potassium（K⁺）were determined，and genome-wide association analysis was further performed for shoot Na⁺/K⁺ ratio in a population consisting of 501 tomato accessions. The decrease in salt tolerance from wild tomatoes to large-fruited tomatoes is due to the decrease in Na⁺ content and Na⁺/K⁺ ratio during tomato domestication and improvement. The most significant loci associated with shoot Na⁺ content and Na⁺/K⁺ ratio were identified on chromosome 7，which contained two genes with known function，HKT1;1and HKT1;2. Sequence analysis，and haplotype analysis identified a 6 bp InDel（InDel_6）on the promoter of HKT1;2 showed highly correlated with Na⁺ content and Na⁺/K⁺ ratio，and salt treatment of different genotype accessions based on the InDel_6 confirmed that this mutation was the causative variant associated with Na⁺/K⁺ ratio and confer salt tolerance in tomato. Based on this causative variant，a codominant molecular marker that can quickly and accurately verify the salt tolerance of tomatoes at the seedling stage were developed.

• Figure/Table | References | Related Articles | Metrics

• Creating High Lycopene Fruit Using CRISPR/Cas9 Technology in Tomato
• YANG Liang, LIU Huan, MA Yanqin, LI Ju, WANG Hai'e, ZHOU Yujie, LONG Haicheng, MIAO Mingjun, LI Zhi, CHANG Wei
• Acta Horticulturae Sinica. 2024, 51(2): 253-265. DOI:10.16420/j.issn.0513-353x.2023-0782
• Abstract ( 199 ) HTML ( 190 ) PDF (4585KB) ( 190 ) 　　　

• The large-fruited cultivated tomato resource“T048”was used as the material for targeted editing of the tomato stay-green gene SlSGR1 using CRISPR/Cas9 technology. Sequence analysis of the target sites of 19 positive transgenic plants revealed that a total of ten plants had editing events，with an editing efficiency of 52.6%. The types of editing events involved deletions，insertions and substitutions of bases，most of which occurred 3-4 bp upstream of the PAM sequence. A total of 565 bp of sequence inversion between the two editing sites was also detected. Phenotypic analysis revealed that the homozygous edited plants in the T1 generation showed slower senescence of the leaves and rusty red color fruits，with significantly higher content of lycopene，chlorophyll and β-carotenoid，compared with unedited fruits. Analysis of the key genes for carotenoid synthesis revealed that the expression of the SGR1 in the fruit of the homozygous edited plants was significantly lower than that of the unedited plants，whereas the expression of the PSY1 was significantly higher than that of the unedited one. This study demonstrated that targeted editing of the SlSGR1 gene by CRISPR/Cas9 technology can effectively enhance the content of carotenoids such as lycopene and β-carotene in tomato fruits，and thus provide new germplasm for tomato nutritional quality breeding.

• Figure/Table | References | Related Articles | Metrics

• Identification and Bioinformatics Analysis of 20S Proteasome Gene Family in Tomato
• YAN Chaofan, SUN Xuemei, ZHONG Qiwen, SHAO Dengkui, DENG Changrong, WEN Junqin
• Acta Horticulturae Sinica. 2024, 51(2): 266-280. DOI:10.16420/j.issn.0513-353x.2023-0833
• Abstract ( 282 ) HTML ( 206 ) PDF (5147KB) ( 206 ) 　　　

• 20S proteasome is able to maintain cellular protein homeostasis by specifically degrading proteins in the cytoplasm and nucleus either by itself or by the ubiquitin-proteasome system. In this study，21 members of the 20S proteasome gene family of tomato（Solanum lycopersicum L.）were identified and bioinformatically analyzed. The results showed that most of the genes of the tomato 20S proteasome contain similar promoters and introns，with the genes encoding the α-subunit being better conserved and those encoding the β-subunit being poorly conserved；Subcellular localisation reveals that the majority of genes function in the cytoplasm；Chromosomal localisation and gene duplication analyses revealed that the 21 20S proteasome genes were unevenly distributed across 12 chromosomes，with the presence of two fragment duplication gene pairs；Evolutionary analyses showed that genes encoding the α-subunit and β-subunit were classified in different taxa or subgroups；Multi-species colinearity analysis revealed more homologous gene pairs between chili（Capsicum annuum L.），potato（Solanum tuberosum L.），and tomato. However fewer homologous gene pairs between Arabidopsis，rice（Oryza sativa L.），maize（Zea mays L.），and tomato. SlPRA1-01，SlPRA10-04，SlPRA11-05，and SlPRA16-09 formed gene pairs in three species. Promoter and tissue-specific expression analyses revealed that the 20S proteasome gene family exhibited important role in tomato adversity stress and growth and development.

• Figure/Table | References | Related Articles | Metrics

• Preliminary Transcriptome Analysis in Two Tomato Fruits Materials with Different Sugar Content
• ZHANG Wenhao, ZHANG Hui, LIU Yuting, WANG Yan, ZHANG Yingying, WANG Xinman, WANG Quanhua, ZHU Weimin, YANG Xuedong
• Acta Horticulturae Sinica. 2024, 51(2): 281-294. DOI:10.16420/j.issn.0513-353x.2023-0761
• Abstract ( 211 ) HTML ( 226 ) PDF (6548KB) ( 226 ) 　　　

• High sugar（8%）and common sugar（4.5%）tomatoes were used as the research materials. Fruit samples were collected at the mature green stage，the breaker stage，the pink stage，and the red ripe stage. Transcriptome sequencing was conducted to analyze the differences in gene expression between these two materials. The analysis revealed there 288 differentially expressed genes（DEGs）between common and high sugar tomatoes across these four stages，with 174 down-regulated DEGs and 114 up-regulated DEGs. Notably，the breaker stage showed the highest number of DEGs between these two materials. GO analysis demonstrated significant enrichment of DEGs and GO terms at the breaker stage with the greatest number of GO terms identified at this stage. Furthermore，KEGG analysis showed that the DEGs and related pathways，particularly sugar and acid metabolism pathways，were concentrated at the breaker stage. Clustering analysis of key enzyme genes involved in sugar and acid metabolism identified 30 DEGs.

• Figure/Table | References | Related Articles | Metrics

• Study on the Regulatory Mechanism of SlPL Gene Affecting Tomato Fruit Cracking
• ZHONG Zhaojiang, WU Zhen, ZHOU Rong, ZHU Weimin, YANG Xuedong, YU Xiaowei, XU Yan, GAO Yangyang, JIANG Fangling
• Acta Horticulturae Sinica. 2024, 51(2): 295-308. DOI:10.16420/j.issn.0513-353x.2023-0816
• Abstract ( 354 ) HTML ( 109 ) PDF (3969KB) ( 109 ) 　　　

• Tomato with highly significant differences in fruit cracking rate were used as the materials to analyze the expression differences of the SlPL（Solyc03g111690）gene，which was further functionally validated using genetic transformation. The results showed that the expression of SlPL was significantly higher in crack-susceptible tomato‘NT189’than in crack-resistant tomato‘NT91’；The expression of SlPL in tomato fruit was significantly higher than that in other organs such as roots，stems，leaves and flowers，and the expression was higher in the break ripen and red ripen stages of the fruit. Fruit cracking was further induced by irrigation and ABA treatments，and it was found that the expression of SlPL was overall significantly higher in the fruit of crack-susceptible materials than that of crack-resistant ones in the same treatment period. SlPL overexpression（OEPL）and knockout（pl）lines were then obtained by genetic transformation. OEPL was more susceptible to fruit cracking and had significantly lower fruit firmness and pl had higher fruit firmness than the wild type. OEPL fruit had significantly lower pro-pectin content than the wild type，and significantly higher water-soluble pectin content than the wild type，while pl fruit had significantly higher pro-pectin and total pectin content than the wild type. Pectin cleavage enzyme activity was significantly higher in OEPL fruits than in wild type，and pectin cleavage enzyme activity was significantly lower in pl fruits than in wild type. Gene expression analysis revealed that the relative expression of cell wall metabolism-related genes SlPG2，SlPME2.1，SlCel2，SlGH9C5，and ethylene synthesis pathway-related genes SlACS4 and SlACO1 was significantly higher in OEPL fruits than in wild type，and the opposite was true for pl fruits. pl fruits showed a significantly higher relative expression of the ethylene-responsive factor SlERF2 than in wild type. Observations of the pericarp microstructure revealed that the cells of the epidermal layer and thin-walled cells were more sparsely arranged in OEPL compared with wild type，and those cells were tightly arranged in pl.

• Figure/Table | References | Related Articles | Metrics

• SlMAPKKK43 Regulates Tomato Resistance to Gray Mold
• DONG Xiaonan, LÜ Hongmei, ZHAO Liqun, HE Bingqing, ZHANG Jiaojiao, ZHAO Bing, GUO Yangdong, ZHANG Na
• Acta Horticulturae Sinica. 2024, 51(2): 309-320. DOI:10.16420/j.issn.0513-353x.2023-0757
• Abstract ( 135 ) HTML ( 123 ) PDF (2573KB) ( 123 ) 　　　

• The mitogen-activated protein kinase（MAPK）cascade plays an important role in multiple developmental and physiological processes in plants and in response to various biotic and abiotic stresses. In this study，SlMAPKKK43 overexpressed plants and CRISPR-Cas9-mediated SlMAPKKK43 knockout mutant using Agrobacterium infection genetic transformation were obtained. Through the inoculation of Botrytis cinerea with transgenic lines，we found that SlMAPKKK43 positively regulated the tolerance of tomato to Botrytis cinerea. In order to further elucidate the molecular mechanism of SlMAPKKK43 regulating the resistance of gray mold，the known gray mold regulators SlMKK2 and SlMKK4 were screened by pull down-MS technology，and in vitro phosphorylation assay was used to preliminarily verify that SlMAPKKK43 could phosphorylate SlMKK2 and SlMKK4.

• Figure/Table | References | Related Articles | Metrics

• The Sugar Transporter SlSWEET12c Negatively Regulates Tomato Resistance to Bacterial Leaf Spot Disease
• XING Yanan, CHENG Jie, LIU Xin, LÜ Shuwen, WU Yuanyuan, JIANG Jing
• Acta Horticulturae Sinica. 2024, 51(2): 321-334. DOI:10.16420/j.issn.0513-353x.2023-0611
• Abstract ( 144 ) HTML ( 86 ) PDF (2089KB) ( 86 ) 　　　

• According to the tomato expression database（http://ted.bti.cornell.edu/cgi-bin/）and real-time quantitative analysis，the sugar transporter（sugars will eventually be exported transporter）gene SlSWEET12c showed the most obvious expression difference in tomato susceptible and resistant varieties. Using the tomato（Solanum lycopersicum）plant‘Zhongshu 6’as the test material，stable genetic SlSWEET12c silencing（RNAi）and overexpression（OE）plants were obtained. After further inoculation with Pseudomonas syringae（Pst DC3000），the role of SWEET12c in resisting Pst DC3000 in tomato was clarified through the analysis of bacterial growth，F_v/F_m change，soluble sugar and starch content，reactive oxygen species accumulation，defense enzyme activity and PR protein related gene expression in leaves. Compared with the wild type，the number of bacterial colonies and brown spots were significantly reduced in the leaves of RNAi-SlSWEET12c plants vaccinated with Pst DC3000，and the resistance to Pst DC3000 was enhanced，while OE-SlSWEET12c leaves became more severe，and the number of bacterial colonies and brown spots increased. RNAi-SlSWEET12c plants have significantly higher sucrose and starch content than wild type，reactive oxygen accumulation is less than wild type，the activity of defense enzymes （POD，SOD，APX）and PR protein related genes（NPR1，PR1，PR2，PR5）expression，while the sucrose and starch content of OE-SlSWEET12c plants is lower than wild type，reactive oxygen accumulation is higher than wild type，defense enzyme activity and PR protein related gene expression is significantly lower than wild type. The above results indicate that SlSWEET12c negatively regulates tomato resistance to bacterial leaf spot disease by affecting the composition of sugars in leaves.

• Figure/Table | References | Related Articles | Metrics

Cultivation·Physiology&Biochemistry

• Growth，Development and Transcriptome Analysis of Tomato Cultivars with Different Low Light Tolerances Under Low Light Condition
• WANG Hong, MIAO Chen, DING Xiaotao, SHEN Haibin, ZHU Weimin
• Acta Horticulturae Sinica. 2024, 51(2): 335-345. DOI:10.16420/j.issn.0513-353x.2023-0775
• Abstract ( 173 ) HTML ( 149 ) PDF (2390KB) ( 149 ) 　　　

• In this study，low-light sensitive cultivar‘K20’and low-light tolerant cultivar‘Shenfen 16’were selected as materials. The effects of low light on plant height，stem diameter，internode length，numbers of leaves，antioxidant enzyme activity，MDA content and RNA-seq data were analyzed. The results showed that low light inhibited the growth of tomato plants，accompanied with an increase in MDA content and decreases in antioxidant enzyme activities，but the reductions in ‘Shenfen 16’were smaller than those in‘K20’. Furthermore，898 differentially expressed genes（DEGs）were identified in‘K20’and 2 849 DEGs were obtained in‘Shenfen 16’under low light stress. The up-regulated pathway of Kyoto Encyclopedia of Genes and Genomes（KEGG）enrichments in‘K20’were‘protein processing in endoplasmic reticulum’and‘ribosome biogenesis in eukaryote’，whereas the largest amount of DEGs in‘Shenfen 16’were annotated with‘plant hormone signal transduction’and followed by‘MAPK signaling pathway’. These results suggested that low-light tolerant cultivar may increase its adaptation to low light by regulating the biosynthesis of hormones. In summary，low light inhibited the growth of tomato plants，but low light-tolerant cultivar may increase its adaptability to low light by regulating the synthesis of various hormone such as IAA and increasing the activities of antioxidant enzymes.

• Figure/Table | References | Related Articles | Metrics

• Effects of Humic Acid Treatment on the Composition and Content of Volatile Organic Compounds in Cherry Tomato
• GUAN Sihui, LIU Chenxu, YAO Zhuping, WAN Hongjian, DIAO Ming, CHENG Yuan
• Acta Horticulturae Sinica. 2024, 51(2): 346-360. DOI:10.16420/j.issn.0513-353x.2023-0811
• Abstract ( 193 ) HTML ( 133 ) PDF (2135KB) ( 133 ) 　　　

• The cherry tomato cultivar‘Zheyingfen 1’，known for its abundant fruit flavor，was chosen as the experimental subject. The technique employed in this study involved the utilization of headspace solid phase microextraction coupled with gas chromatography-mass spectrometry. The present study aimed to compare and analyze the compositions，contents，and variations of volatile organic compounds（VOCs）in fruits subjected to humic acid treatment（control）apply water to the root and leaf surface；root and leaf application：humic acid is applied to both root and leaf surface；root application：humic acid on root and water on leaf surface；leaf application：root application of water，leaf surface application of humic acid. A comprehensive analysis revealed the detection of a total of 15 categories and 340 distinct types of VOCs. In comparison to water control，the contents of VOCs in fruits exhibited a relative increase of 49.3%，25.6%，and 14.4% when humic acid was applied to the leaves，roots，and leaves respectively. Moreover，the contents of aldehydes in fruits significantly increased with both root and leaf application of humic acid，whereas the contents of terpenes were significantly elevated solely with root application. The statistical analysis of differential VOCs revealed that，in comparison to the control group，the up-regulated VOCs resulting from the application of humic acid to both roots and leaves，solely to roots，and solely to leaves were 153，147，and 13，respectively. These values accounted for 97.5%，97.4% and 81.3% of the total differential VOCs. Notably，the differential VOCs observed in the combined root and leaf application and the sole root application were significantly greater than those observed in the sole leaf application. The examination of sensory flavor attributes revealed that the application of humic acid to both the root and leaf of tomato plants resulted in an augmentation of the sweet flavor characteristics in the fruits. Conversely，solely applying humic acid to either the root or leaf led to an enhancement of the fruity flavor characteristics. The findings from the principal component analysis indicate that the aroma attributes of tomato fruits following humic acid treatment are not primarily governed by a few VOCs with substantial relative content or high relative odor activity value. Instead，they are influenced by the interplay of multiple VOCs，resulting in distinct aroma profiles. Consequently，the application of humic acid treatment，particularly through root and leaf administration，exerts a significant impact on the composition and relative content of VOCs in tomato fruits，thereby enhancing their flavor quality.

• Figure/Table | References | Related Articles | Metrics

• Change of Sugar in Grafted Tomato Fruit and Correlation Analysis with Nitrogen and Phosphorus Content
• WANG Lei, GAO Fangsheng, ZHANG Zhihuan, LI Weiqiang, CAO Bili, XU Kun
• Acta Horticulturae Sinica. 2024, 51(2): 361-371. DOI:10.16420/j.issn.0513-353x.2023-0850
• Abstract ( 317 ) HTML ( 179 ) PDF (1200KB) ( 179 ) 　　　

• The changes of sugar content，sucrose metabolism related enzyme activities and mineral elements in tomato fruits at different developmental stages were studied. Red fruit tomato‘Davis’(Dv) and pink fruit tomato‘Rolla’(La) were used as scions，and tomato‘Anta-T’(At) and‘Midako’(Md) were used as rootstocks. Regulation of the content of fructose，glucose and sucrose by scion and rootstock in tomato fruits at different developmental stages were found，and there was a significant interaction between scion and rootstock. At 30 d after flowering，sucrose content in fruit of Dv/At was 8.06% higher than that of Dv/Md，but there was no significant difference between La/At and La/Md. Meanwhile fructose content (16.44 mg · g^-1 FW) in Dv/Md was 20.66% lower than Dv/Dv at 110 d after flowering，but there was no significant difference between La/Md and La/La. The difference of sugar content in tomato fruit with different grafting combinations was closely related to the activity of sucrose metabolic enzyme. The difference of sugar content in the early stage of fruit development of grafted tomato was mainly regulated the activity of acid invertase (AI) by scion in fruit. The difference in sugar content at late development stage was mainly due to the influence of rootstock on the activity of sucrose phosphate synthetase (SPS) and neutral invertase (NI). At the same time，nitrogen (N)，phosphorus (P)，potassium (K)，calcium (Ca)，magnesium (Mg) and iron (Fe) in tomato fruits with different grafting combinations were significantly different. Curve estimation analysis showed that N and P content in fruit were significantly negatively correlated with invertase activity (AI and NI)，fructose and glucose，and significantly positively correlated with sucrose content. Therefore，in the process of tomato grafting to promote the quality and yield of tomato，the management of nitrogen and phosphorus nutrients after grafting should be coordinated with the absorption characteristics of rootstocks，so as to avoid the decrease of sugar content and flavor of tomato fruits caused by increase of nitrogen and phosphorus absorption.

• Figure/Table | References | Related Articles | Metrics

New Technologies·New Methods

• Visible Fluorescence Analysis of Cytokinin and Auxin Responses in Tomato
• ZHAO Xiaobing, SUN Keyi, FAN Junmiao, DING Jing
• Acta Horticulturae Sinica. 2024, 51(2): 372-384. DOI:10.16420/j.issn.0513-353x.2023-0715
• Abstract ( 342 ) HTML ( 94 ) PDF (9093KB) ( 94 ) 　　　

• Analysis of dynamic distributions of cytokinin and auxin response signals in tomato plants is of great significance for clarifying the regulatory roles and functional mechanisms of these two hormones at the cytological level. A green fluorescent reporter gene TCSn1::GFP（GFP）with a cytokinin-responsive promoter TCSn1，and a red fluorescent reporter gene DR5v2::tdTomato（tdTomato）with an auxin-responsive promoter DR5v2，were used to perform real-time in-situ analyses of the signals of cytokinin and auxin responses in tomato roots，stems，leaves，flowers，and fruits. It is found that the two types of fluorescence distributed in the tissues/organs including：lateral root cap and columella in root cap，as well as the procambium，ground meristerm and protoderm in root elongation zone at three to seven days after germination，the shoot apical meristem at five to ten days after germination，vascular tissues in stems of plants at 23 and 37 days after planting，young leaves of plants at 32 days after planting，petals and fruit peduncles at anthesis，ovules，the placenta，columella and pericarp of fruits at two to six days after anthesis. Intensities of the two types of fluorescence were both highest in the shoot apical meristem and ovules in fruits，and had a similar variation trend：first decreased and then recovered in the root cap and elongation zone during three to seven days of germination；were weaker in stem segments at 37 days than 23 days after planting；continuously rose in the shoot apical meristem at five to ten days after germination and in the fruits at zero to six days after anthesis. This study provides a sensitive and robust visualization tool for analyzing cytokinin and auxin responses in tomato，and has analyzed their distribution and intensity in different organs of tomato.

• Figure/Table | References | Related Articles | Metrics

• Nondestructive Detection of Soluble Solids Content in Tomatoes Using Electrical Parameters and Machine Learning
• WANG Tingting, TAN Zhanming, CHENG Yunxia, MA Xinchao, WANG Yongming
• Acta Horticulturae Sinica. 2024, 51(2): 385-395. DOI:10.16420/j.issn.0513-353x.2023-0645
• Abstract ( 105 ) HTML ( 63 ) PDF (1826KB) ( 63 ) 　　　

• This study aims to establish a model for predicting the soluble solids content of tomatoes using electrical parameters and machine learning techniques. An LCR meter was employed to measure nine electrical parameters of tomatoes at frequencies of 0.1，1，10，100，and 1 000 kHz，including parallel equivalent capacitance，parallel equivalent resistance，and quality factor. Key electrical characteristic variables were identified through Pearson correlation analysis. Based on these variables，three non-destructive models for predicting the soluble solids content of tomatoes were constructed：a Back Propagation Neural Network（BpNN），Multiple Linear Regression（MLR），and Support Vector Regression （SVR）. The results indicate that at 10 kHz frequency，five electrical parameters-quality factor，loss factor，deflection angle，parallel equivalent capacitance，and parallel equivalent resistance-showed significant correlation with the soluble solids content of tomatoes. By using these five electrical parameters as input variables and the soluble solids content as the output variable，the SVR model exhibited the best predictive performance，coefficient of determination R² equal to 0.951，Root Mean Square Error equal to 0.122，Mean Absolute Error equal to 0.082）. This study provides a new method for the rapid and non-destructive detection of soluble solids content in post-harvest tomatoes.

• Figure/Table | References | Related Articles | Metrics

• Detecting Tomato Fruit Ripeness and Appearance Quality Based on Improved YOLOv5s
• SUN Yuchao, LI Shouhao, XIA Xiubo, YANG Wei, LI Minzan, ZHANG Huanchun
• Acta Horticulturae Sinica. 2024, 51(2): 396-410. DOI:10.16420/j.issn.0513-353x.2023-0859
• Abstract ( 224 ) HTML ( 93 ) PDF (7465KB) ( 93 ) 　　　

• The study was conducted on the detection of tomato fruit maturity and appearance quality based on deep learning methods using pink tomato as the experimental material. Two thousand and thirty-six tomato image data were collected and amplified to 5 316 through preprocessing. Then，the data was annotated and converted into files to construct an experimental dataset. The experiment improves the accuracy of SC-YOLOv5s by adding CA attention mechanism，replacing the Stem block structure，optimizing the detection layer scale based on recognition requirements，and replacing the K-means++ clustering algorithm to improve the model’s feature expression ability. By adding a fire module structure to SC-YOLOv5s for lightweight convolution and reducing the parameter count of the Bottleneck module，the SC-YOLOv5s-lite lightweight design is achieved，improving the detection speed of the model on hardware；Train and optimize the SC-YOLOv5s-lite model on the training set. The results showed that the memory usage of the SC-YOLOv5s-lite model was 7.73 M，with an accuracy rate of 89.04%，a recall rate of 83.35%，an average accuracy of 91.34%，and a detection time of 143 ms. Compared to YOLOv5s，the model parameter quantity is reduced by 54.57%，model size is compressed by 44.86%，with an average accuracy improvement of 3.98%，and the detection time is reduced by 20.99%. It has obvious advantages and is more suitable for hardware deployment.

• Figure/Table | References | Related Articles | Metrics

Plant Protection

• Effect of ToCV and TYLCV Infection on Detoxification Enzymes of Bemisia tabaci
• ZHU Jie, LU Dingyihui, ZHANG Deyong, ZHANG Zhanhong, ZHANG Zhuo, SHI Xiaobin, LIU Yong
• Acta Horticulturae Sinica. 2024, 51(2): 411-422. DOI:10.16420/j.issn.0513-353x.2023-0484
• Abstract ( 106 ) HTML ( 50 ) PDF (1898KB) ( 50 ) 　　　

• Tomato virus disease has become one of the most important diseases in tomato production，resulting in a large reduction in tomato yield or even a failure of the harvest. Tomato chlorosis virus（ToCV） and tomato yellow leaf curl virus（TYLCV）cause severe losses in the field，and co-infection of ToCV and YLCV will also have a series of effects on the B. tabaci feeding，virus acquisition，and virus transmission，causing great difficulties in the prevention of tomato virus diseases. The changes of detoxification enzymes and gene related to physiological defense responses，after B. tabaci feeding on tomatoes co-infected with ToCV and TYLCV was clarified，to control B. tabaci effectively. In this study，the changes of detoxification enzymes in co-infected B. tabaci were studied by enzyme activity determination and real-time fluorescence quantitative PCR technology，and healthy tomatoes were used as the control. The results showed that expect the enzyme activity of glutathione S-transferase（GST）and UDP-glucuro- nosyltransferase（UDPGT）of B. tabaci fed on ToCV infected tomatoes were lower than those fed on healthy B. tabaci，viruliferous B. tabaci’s GST，carboxylesterase（CarE），acetylcholinesterase（AchE），cytochrome P450（CYP450）and UDP enzyme activities and gene expression levels were higher than those of healthy B. tabaci，and there were significant differences in CarE，AchE，P450，UDP enzyme activities and gene expression levels after B. tabaci feeding and infection. The results showed that the detoxification defense of B. tabaci was induced to different degrees after feeding on the co-infected tomato and TYLCV-infected tomato plant，thus helping B. tabaci to transmitt the virus.

• Figure/Table | References | Related Articles | Metrics

Reviews

• Analyzing Flavor and Functional Components in Tomatoes：a Review
• SHEN Heng, WANG Lin, LI Qian, YUAN Shoujuan, ZHENG Wei, WANG Taotao, YE Zhibiao, YANG Changxian
• Acta Horticulturae Sinica. 2024, 51(2): 423-438. DOI:10.16420/j.issn.0513-353x.2023-0315
• Abstract ( 281 ) HTML ( 331 ) PDF (1696KB) ( 331 ) 　　　

• The flavor substances of tomato（Solanum lycopersicum）in tomatoes are mainly composed of soluble sugars（such as glucose and fructose），organic acids（citric acid and malic acid，etc.） and volatile substances（alcohols and esters，etc.）. Tomato also contains various functional components，such as ascorbic acid，lycopene，γ-aminobutyric acid，vitamin D and vitamin E. These components endow tomato fruit with important health functions. In this review，the composition，synthetic pathway and regulatory mechanism of flavor and functional components have been analyzed in tomato to create tomato germplasm that is rich in flavor substances and functional components through gene editing in the future. This lays the groundwork for cultivating functional tomato with good flavor.

• Figure/Table | References | Related Articles | Metrics

• Tomato Brown Rugose Fruit Virus（ToBRFV）Research Progress
• WEI Jianming, HUANG Xin, LI Yunzhou, LIANG Yan
• Acta Horticulturae Sinica. 2024, 51(2): 439-452. DOI:10.16420/j.issn.0513-353x.2023-0853
• Abstract ( 451 ) HTML ( 315 ) PDF (4372KB) ( 315 ) 　　　

• Tomato brown rugose fruit virus（ToBRFV）belongs to the genus of Tobamovirus and the family of Virgaviridae，which is an RNA virus. It can infect plants from various families and genera，including tomato，posing a serious threat to agricultural production. It was first discovered in Israel in 2014 and subsequently spread to many countries and regions around the world. In April 2021，the virus was as a quarantine virus in China. In this article，the genome structure，host range，symptoms，mode of transmission，detection methods，host resistance and defense measures of the virus were summarized，in order to provide reference for the fight against ToBRFV.

• Figure/Table | References | Related Articles | Metrics

New Cultivars

• A New Pineapple Cultivar‘Jintong Boluo’
• HE Yehua, LIU Chaoyang, LUAN Aiping, GONG Xue, LIU Jiarou, Zhang Wei, LIN Shunquan, HU Guibing, LIU Chengming, XIA Jingxian, LIN Wenqiu, CHEN Chengjie, XIE Tao, MA Jun, HE Jianchi, CHEN Shaohua
• Acta Horticulturae Sinica. 2024, 51(2): 453-454. DOI:10.16420/j.issn.0513-353x.2021-0964
• Abstract ( 132 ) HTML ( 87 ) PDF (1146KB) ( 87 ) 　　　

• A new pineapple cultivar‘Jintong Boluo’，is selected from the clonal‘Shenwan’pineapple population in Zhongshan City，Guangdong Province，using the individual selection method. This cultivar has characteristics of high and stable yield. The fruit shape is short cylindrical and the average fruit weight is 720 g. The peel and flesh are both golden yellow，succulent and crispy in flavor，with refreshing fragrance-scented and little fiber in texture. The fruit core is also succulent and crispy in flavor. It can be well cultivated in pineapple-growing regions in Guangdong Province. The yield is about 37 485 kg · hm^-2 in the second year of planting.

• Figure/Table | References | Related Articles | Metrics

• A New Red Pericarp Non-horn Trapa Cultivar‘Nanhu Hongling’
• YAO Xiangtan, SHEN Yaqiang, YUAN Ye, WANG Ruisen, SHEN Meng, QUAN Xinhua
• Acta Horticulturae Sinica. 2024, 51(2): 455-456. DOI:10.16420/j.issn.0513-353x.2021-1048
• Abstract ( 99 ) HTML ( 55 ) PDF (936KB) ( 55 ) 　　　

• ‘Nanhu Hongling’，a new cultivar of water caltrop（Trapa acornis Nakano）with red pericarp and non-horn was selected with local cultivar‘Shuihongling’as female parent and‘Nanhuling’as male parent. The shape of fruit is like the silver ingot Yuanbao（an ancient Chinese coin），the pericarp is light purplish red，the gloss is good，the four corners are degraded，the pulp is milky white，the raw fruit is crisp，and the cooked food is powdery and waxy. The fruit shape and taste are similar to that of‘Nanhuling’. The yield is equivalent to that of‘Nanhuling’，with an average of about 12 000 kg · hm^-2.

• Figure/Table | References | Related Articles | Metrics

• A New Cultivar of Jerusalem Artichoke‘Mengyu 3’
• ZHANG Yu, MEN Guotao, ZHAO Ju, LAN Kailong, ZHANG Ziyi
• Acta Horticulturae Sinica. 2024, 51(2): 457-458. DOI:10.16420/j.issn.0513-353x.2021-0816
• Abstract ( 105 ) HTML ( 92 ) PDF (1218KB) ( 92 ) 　　　

• ‘Mengyu 3’jerusalem artichoke is an excellent descendant obtained by artificial hybridization from the white jerusalem artichoke strain of Nanjing Agricultural University as a female parent and the local red jerusalem artichoke material of Shaanxi Province as a male parent. The plant is late maturing，the growth period is from 125 to 155 days，and its average height is 2.4 m，the number of first-level branches is from two to five. The tuber is pink skin and bud eyes，which with concentrated and regular pattern. The yield of tuber can reach 33 180 to 35 000 kg · hm^-2. It has strong stress resistance，and is suitable to plant in arid and semi-arid and desertified regions where the annual rainfall is above 300 mm.

• Figure/Table | References | Related Articles | Metrics

• New Hemerocallis fulva Cultivars‘Christmas Baby’and‘Bolide’
• BAI Lu, ZHANG Zhiguo, ZHANG Shijie, QIN Qiaoping
• Acta Horticulturae Sinica. 2024, 51(2): 459-460. DOI:10.16420/j.issn.0513-353x.2020-0402
• Abstract ( 95 ) HTML ( 73 ) PDF (1845KB) ( 73 ) 　　　

• ‘Christmas Baby’，a late-blooming Hemerocallis fulva cultivar，is a diploid hybrid that obtained from the breeding of‘Christmas Is’and‘Qian Yi’. Flowering period is from July to August. The floral pedicel is 72 cm. A large amount of flowers with bright color and pleasant fragrance. Furthermore，a new cultivar‘Bolide’with mid-late blooming is obtained from the breeding of‘Sammy Russell’and‘Autumn Red’. Flowering period is from June to July. The floral pedicel is 65 cm.‘Bolide’displays a large amount of flowers with bright color and pentagram petal.

• Figure/Table | References | Related Articles | Metrics

• A New Osmanthus fragrans Cultivar with Colored Leaves‘Hongyun Caigui’
• CHEN Jiyu, XIAO Xia, LI Yuan, YU Xiajun, QIN Haiying, DU Huaping, GUO Hang, WANG Yuanhui
• Acta Horticulturae Sinica. 2024, 51(2): 461-462. DOI:10.16420/j.issn.0513-353x.2022-0047
• Abstract ( 134 ) HTML ( 83 ) PDF (1539KB) ( 83 ) 　　　

• ‘Hongyun Caigui’is a new colorful leaf cultivar bred from the cutting seedlings of Osmanthus fragrans Siji Group. It belongs to shrub or small tree. The edge of leaflet is purple or pink，and the middle is light purple red. With the growth of leaves，the edge becomes yellowish white or yellow，and the middle is green. Each leaf forms mottled leaves，with pretty colorful leaves as purple，pink，green，white，yellow etc. The flowering period is from August to next May，up to 10 months. It has high ornamental value.

• Figure/Table | References | Related Articles | Metrics