Genetic & Breeding·Germplasm Resources·Molecular Biology

• Mechanism of PpMADS2 and PpMADS3 Synergistically Regulating Carotenoids Accumulation in Peach Fruit
• XIAO Xiang, ZHOU Chujiang, JIN Shuwan, SHI Liyu, YANG Zhenfeng, CAO Shifeng, CHEN Wei
• Acta Horticulturae Sinica. 2023, 50(6): 1173-1186. DOI:10.16420/j.issn.0513-353x.2022-0221
• Abstract ( 415 ) HTML ( 340 ) PDF (2536KB) ( 340 ) 　　　

• To explore the regulation of MADS-box family transcription factors on carotenoid metabolism in yellow fleshed peach, two MADS genes named as PpMADS2（PRUPE_5G208500）and PpMADS3（PRUPE_5G208400）were cloned. The open reading frames of PpMADS2 and PpMADS3 were 768 bp and 756 bp，encoding 255 and 251 amino acids, respectively. Bioinformatics analysis revealed that the N-terminus of both proteins contained typical characteristic domains of MADS-box family. Subcellular localization showed that both PpMADS2 and PpMADS3 were located at the nucleus. The results showed the gene expression levels of PpMADS2，PpMADS3 as well as carotenoid biosynthetic genes such as PpPSY and PpCHYB increased during fruit ripening，which was consistent with the carotenoid accumulation in yellow fleshed peach. Furthermore, the results demonstrated that PpMADS2 could interact with PpMADS3 then synergistically activate the promoters of PpPSY and PpCHYB genes. Therefore，it is speculated that PpMADS2 and PpMADS3 promoted the accumulation of carotenoids in yellow fleshed peach fruit cooperatively through transcriptional activation of PpPSY and PpCHYB. These research provided a theoretical basis for further exploring the regulatory mechanism of MADS-box transcription factors on carotenoid accumulation in peach fruit.

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• Transcriptome Analysis of Flower Buds of Sweet Cherry Cultivars with Different Chilling Requirements During Dormancy Stages in Hangzhou
• RUAN Ruoxin, LUO Huifeng, ZHANG Chen, HUANG Kangkang, XI Dujun, PEI Jiabo, XING Mengyun, LIU Hui
• Acta Horticulturae Sinica. 2023, 50(6): 1187-1202. DOI:10.16420/j.issn.0513-353x.2022-0297
• Abstract ( 419 ) HTML ( 180 ) PDF (3081KB) ( 180 ) 　　　

• This study aims to explore the molecular regulation mechanism of flower bud dormancy in sweet cherry cultivars that are suitable for growing in South China. Two sweet cherry cultivars（‘Brooks’and‘Summit’）planted in Hangzhou with different chilling requirements were used as materials. Flower buds were collected at three different dormancy stages，namely pre-dormancy stage（S1），endodormancy stage（S2），and pre-budbreak stage（S3）. Transcriptome sequencing was performed to analyze the gene expression differences between these two cultivars. 343，671，and 1 588 differentially expressed genes （DEGs）were obtained in S1，S2，and S3，respectively，and the number of DEGs in S3 was the largest. GO analysis revealed that the DEGs between the two cultivars were mainly enriched in the processes related to cellular component organization，cellular metabolism，response to stimulus，and transporter activity in the dormancy stages. KEGG analysis showed that the DEGs concentrated in S3，which involved sugar metabolism，protein processing，plant-pathogen interaction，and plant hormone signal transduction. The expression trends of some DEGs suggested their roles in regulating the transition of dormancy state of flower buds in sweet cherry. Forty-two differentially expressed transcription factors including nine families were obtained by predictive analysis of transcription factors. The expression levels of 13 transcription factors belonging to AP2/ERF，MYB，WRKY，C2H2，C3H，and MADS-box family in S2 were significantly higher than those in S1 and S3，suggesting that these transcription factors may be involved in the regulation of flower bud dormancy.

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• Genetic Analysis of Sugar and Acid Quality Traits in Mango Hybrid Population
• WAN Jiaxin, DAI Tao, LUO Guoliang, LI Li, WU Hongxia, XU Wentian, ZHENG Bin, WANG Songbiao, LUO Cong, LIANG Qingzhi
• Acta Horticulturae Sinica. 2023, 50(6): 1203-1214. DOI:10.16420/j.issn.0513-353x.2022-0416
• Abstract ( 311 ) HTML ( 100 ) PDF (1026KB) ( 100 ) 　　　

• To analyze the genetic variation of sugar and acid contents in mango F₁ population in order to provide a basis for selecting parents in cross breeding of mango. A hybrid population of 95 F₁ plants with‘Jinhuang’as the female parent and‘Irwin’as the male parent was constructed. Descriptive statistical analysis，correlation analysis，analysis of variance and broad-sense heritability analysis were carried out for the sugar and acid quality traits of mango fruits. Current results indicated that the major individual sugars were glucose，fructose and sucrose；the main organic acids were malic acid，citric acid，ascorbic acid，lactic acid，succinic acid and α-ketoglutaric acid in mango fruits. These fruit quality traits such as individual sugar and organic acid showed normally or nearly normally distribution in hybrid population；fructose was highly significantly correlated with glucose and sucrose；citric acid was significantly positively correlated with α-ketoglutaric acidand titratable acid，malic acid was significantly positively correlated with succinic acid and ascorbic acid；fructose and sucrose showed a mid-parental heterosis；and most of organic acids showed neither a mid-parental nor a super-parental heterosis.

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• Construction and Application of a CRISPR/Cas9 System for Multiplex Gene Editing in Tomato
• YANG Mengxia, LIU Xiaolin, CAO Xue, WEI Kai, NING Yu, YANG Pei, LI Shanshan, CHEN Ziyue, WANG Xiaoxuan, GUO Yanmei, DU Yongchen, LI Junming, LIU Lei, LI Xin, HUANG Zejun
• Acta Horticulturae Sinica. 2023, 50(6): 1215-1229. DOI:10.16420/j.issn.0513-353x.2022-0339
• Abstract ( 452 ) HTML ( 193 ) PDF (5594KB) ( 193 ) 　　　

• In order to construct a CRISPR/Cas9 system for multiplex gene editing in tomato，Arabidopsis U6 promoters in pKSE401 and pCBC-DT1T2 vectors were replaced with SlU6-2p，SlU6-3p，SlU6-7p，SlU3-5p，SlU3-9p and SlU6-5p，respectively. Accordingly，a binary vector（pMGET），two intermediate vectors（pKC-S2M and pKC-S3M），and three gRNA module vectors（pCBC-S1，pCBC-S2 and pCBC-S3）were constructed. In order to test the system for multiplex gene editing in tomato，multiplex gene editing vectors pMGET-OYGTULC and pMGET-TULCOYG were constructed by aggregating sgRNA expression cassettes containing the target sequences of six tomato fruit trait-related genes Green flesh（GF），Ovate（O），Locule number（LC），SlMYB12（Y），Tangerine（T）and Uniform ripening（U），through PCR amplification，Golden gate cloning and isocaudamer technique，and the editing efficiency of six genes at the same time of the two vectors was 44.00% and 11.76%，respectively. The tomato material was transformed by Agrobacterium tumefaciens carrying pMGET-OYGTULC vector to obtain two plants with six genes edited. The sequence variations were in the form of single base insertion，single or multiple base deletion and large fragment deletion. In this study，the CRISPR/Cas9 system can be efficiently used for multiplex gene editing in tomato，and stable genetic mutants can be obtained，which can provide a versatile toolbox for basic research and genetic improvement in tomato.

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• Identification and Expression Analysis of HMA Gene Family in Brassica juncea Under Cadmium Stress
• HUANG Zhihao, LIU Tingting, DONG Xujie, YAN Mingli, LIUZhixiang , ZENG Chaozhen
• Acta Horticulturae Sinica. 2023, 50(6): 1230-1242. DOI:10.16420/j.issn.0513-353x.2022-0509
• Abstract ( 383 ) HTML ( 156 ) PDF (3193KB) ( 156 ) 　　　

• Brassica juncea can enrich a variety of heavy metals. Heavy metal transporting ATPase（HMA）plays an important role in the process of transporting heavy metals in plants. Based on genomic and transcriptomic data，the HMA gene family members in B. juncea were identified. A total of 27 HMA genes were found in B. juncea genome. Six of these HMA proteins have instability indexes greater than 40. Twenty-two members are hydrophobic proteins. These genes cluster into three subfamilies，P-1B-1，P-1B-2，and P-1B-4. All the HMAs are membrane proteins containing the E1-E2 ATPase and hydrolase domains. Each HMA protein contains 1-8 motifs. Different subfamilies have unique conserved motifs according to the types of heavy metals transported by them. In the promoter regions of the HMA genes，the cis-acting element TGA related to the regulation of growth and development，the cis-acting elements ABRE，MBS，LTR，and TC related to the regulation of stress response are widely distributed. Under cadmium（Cd）stress，BjuA033764，BjuB019118，BjuB035256，and BjuB045293 were up-regulated in leaves，and BjuA003596，BjuB040613，and BjuA025022 were up-regulated in roots，indicating their involvement in the response to Cd stress.

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• Preliminary Study on the Mechanism of Signal Molecule H₂O₂ Regulating the Formation of Pleurotus ostreatus Cap Color
• HOU Ludan, YAN Kexing, DONG Shuai, LIU Xingyu, CHANG Mingchang, MENG Junlong
• Acta Horticulturae Sinica. 2023, 50(6): 1243-1254. DOI:10.16420/j.issn.0513-353x.2022-0546
• Abstract ( 258 ) HTML ( 53 ) PDF (2049KB) ( 53 ) 　　　

• By spraying H₂O₂ and its scavenger N，N'-dimethylthiourea（DMTU）externally，it was clarified that H₂O₂ can participate in regulating the formation of Pleurotus ostreatus cap color. Using the reported Agaricus bisporus as a reference，28 genes involved in the melanin synthesis pathways were identified through sequence alignment，and the effect of exogenous H₂O₂ on the relative expression of key enzyme genes in different pathways was analyzed by qPCR. The results showed that H₂O₂ signaling molecule can change the proportion of different types of melanin in P. ostreatus and affecting the color of the cap by regulating the expression of key enzyme genes in different melanin synthesis pathways. On the other hand，it can promote the high expression of copper transcription factor genes mac，copper transporter genes ctr and polyphenol oxidase gene ppo1，and finally affect the formation of cap color.

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• Identification of the MYB Gene Family and Functional Analysis of Key Genes Related to Blue Flower Coloration in Agapanthus praecox
• HE Weizhi, LEI Weiqi, GUO Xiangxin, LI Ruilian, CHEN Guanqun
• Acta Horticulturae Sinica. 2023, 50(6): 1255-1268. DOI:10.16420/j.issn.0513-353x.2022-0226
• Abstract ( 400 ) HTML ( 165 ) PDF (3495KB) ( 165 ) 　　　

• MYB gene family members of Agapanthus praecox were identified by bioinformatics methods and the function of key genes that regulate blue flower coloration was verified. In total，123 ApMYBs were identified based on full-length transcriptome sequencing data，including 60 R2R3-MYBs，four 3R-MYBs，two 4R-MYBs and 57 1R-MYBs. Then，the R2R3-MYBs that regulate flavonoid biosynthesis were further analyzed. R2R3-MYBs were divided into 22 subgroups（A1-A22），together with A18（S4），A17（S5）and A16（S7）subgroups were all related to flower coloration，except for S6 subgroup. ApMYB4，ApMYB6，ApMYB7，ApMYB12，ApMYB111 and ApMYB123 were all localized in the nuclei. Whereas，ApMYB123 was especially concentrated in the nucleolus. During blue flower coloration，ApMYB12 was significantly up-regulated，while ApMYB111 was opposite. White flowers showed increased expression of ApMYB4，ApMYB6 and ApMYB7 compared to blue flowers，indicating them as the negative regulators of coloration. A specific expression peak of ApMYB123 was arisen in bloom stage of white flowers，suggesting biosynthesis of proanthocyanidins. Further ectopic expression of ApMYB12 in tobacco found that the petal color turned lighter than wild type plants. In addition，the anthocyanin content reduced by 54.55%-62.50% while the flavonols content increased by 125%-170%. These results demonstrated that ApMYB12 regulated the biosynthesis of auxiliary pigment flavonols，thereby regulating the coloration of blue flower.

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• Cloning and Cd-resistant Analysis of PsWRKY40 in Potentilla sericea
• GAO Pengfei, GAO Bing, FENG Zhenghong, WU Jianhui
• Acta Horticulturae Sinica. 2023, 50(6): 1269-1283. DOI:10.16420/j.issn.0513-353x.2022-0213
• Abstract ( 173 ) HTML ( 93 ) PDF (3982KB) ( 93 ) 　　　

• The full-length cDNA sequence of PsWRKY40 was cloned from Potentilla sericea. The open reading frame of this gene was 978 bp in length，which encoded 325 amino acids，and belonged to the GroupⅡsubfamily of the WRKY family. The expression level of PsWRKY40 significantly increased by NaCl，CdCl₂ and mannitol treatments. PsWRKY40 was transformed into Arabidopsis thaliana heterologously，and transgenic plant was obtained. Under the treatment of Cd²⁺，it was found that the resistance of the transgenic lines was significantly higher than that of the wild type，and transgenic lines had a significantly higher expression level of AtSOD，AtPOD and AtCAT. The results showed that PsWRKY40 can be induced by Cd²⁺，so it may participate in the regulation of Cd²⁺ resistance in Potentilla sericea.

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• Ectopic Overexpression of OfNCED3 Regulates the Synthesis of Carotenoids and Chlorophylls in Transgenic Tobacco Leaves
• DU Yanxia, WANG Yiguang, XIAO Zheng, DONG Bin, FANG Qiu, ZHONG Shiwei, YANG Liyuan, ZHAO Hongbo
• Acta Horticulturae Sinica. 2023, 50(6): 1284-1294. DOI:10.16420/j.issn.0513-353x.2022-0330
• Abstract ( 321 ) HTML ( 124 ) PDF (3810KB) ( 124 ) 　　　

• In this study，the OfNCED3 cDNA sequence were acquired based on the transcriptional data of Osmanthus fragrans‘Yanhong Gui’. The multiple sequence alignment analysis showed that OfNCED3 had two conservative domain（MIAHPKxDP and HDFAITE）characteristics of the NCED family and four conserved histidine residues. Phylogenetic analysis indicated that OfNCED3 is grouped together with SlNCED1. The results of real-time quantitative PCR showed that the expression of OfNCED3 in the petals of‘Yanhong Gui’with higher carotenoid content was significantly lower than that of‘Yu Linglong’with lower carotenoid content during flower opening process. It is speculated that OfNCED3 may be related to the difference of carotenoid contents between‘Yanhong Gui’and‘Yu Linglong’petals. Transgenic tobacco lines overexpressing OfNCED3 were obtained by an Agrobacterium-mediated method. The contents of chlorophyll，carotenoid and ABA were determined by using spectrophotometer and ultra high performance liquid chromatography（UPLC），and the expression levels of genes related to carotenoid pathway were analyzed via real-time quantitative PCR. The overexpression of OfNCED3 gene expression resulted in a significant decrease of chlorophyll and carotenoid contents and a increase of endogenous ABA content. The expression of carotenoid synthesis genes was significantly up-regulated，and the downstream synthesis genes were more up-regulated than the upstream synthesis genes. This research suggests OfNCED3 can promote the synthesis of ABA by degrading carotenoids in plants.

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Cultivation Physiology & Biochemistry

• Effects of Exogenous Glucose on Soil Active Organic Carbon Pool in Apple Root Zone and Plant Growth and Development
• QIN Sijun, ZHANG Kuo, QI Bianbin, YU Bo, LÜ Deguo
• Acta Horticulturae Sinica. 2023, 50(6): 1295-1304. DOI:10.16420/j.issn.0513-353x.2022-0368
• Abstract ( 273 ) HTML ( 125 ) PDF (746KB) ( 125 ) 　　　

• In this study，the seedlings of Malus × domesica ‘Hanfu’/M. baccata were planted on a typical low-carbon sandy soil in the apple orchard of Liaoning Province. Glucose which is one of the final products of decomposition of various organic substances and is easily absorbed and utilized is used as a carbon source. The method of adding glucose and soil sterilization treatment is designed to study the effect of exogenous carbon on the components of soil active organic carbon pool in apple root zone and plant growth and development. The results showed that adding glucose and adding glucose treatment after sterilization can significantly increase the content of low-carbon sandy soil organic carbon，microbial biomass carbon，water-soluble organic carbon and particulate organic carbon while the soil sterilization treatment alone reduced the soil organic carbon，microbial biomass carbon and particulate organic carbon content. Adding glucose and adding glucose after sterilization treatments significantly increased the soil cellulase and β-glucosidase activity. And adding glucose and adding glucose after sterilization treatments increase the key enzymes involved in respiratory metabolism pathways，phosphoenolpyruvate carboxylase（PEPC），isoforms citrate dehydrogenase（IDH）and malate dehydrogenase（MDH）activities. Adding glucose and adding glucose after sterilization treatments enhance apple plant photosynthesis，promote biomass accumulation and plant growth. In summary，adding five times the amount of easily decomposable carbon source to low-carbon sandy soil according to the soil microbial background level can significantly increase soil organic carbon content and active organic carbon pool components，increase soil enzyme activity and the key enzymes involved in respiration metabolism activities，enhance the photosynthetic capacity of plants，and promote plant growth and development.

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Cultivation Physiology & Biochemistry

• The Relationship Between Membrane Lipid Metabolism and Chilling Injury of Postharvest Peach Fruit Induced by Low Temperature
• ZHOU Cheng, FANG Yi, ZHOU Jinyang, HUANG Qihao, PAN Yongjian, SHI Qianqian, NI Huixian, YANG Zhenfeng, SONG Chunbo
• Acta Horticulturae Sinica. 2023, 50(6): 1305-1317. DOI:10.16420/j.issn.0513-353x.2022-0427
• Abstract ( 185 ) HTML ( 103 ) PDF (1045KB) ( 103 ) 　　　

• Based on membrane lipid metabolomics，the study aimed to reveal the relationship between membrane lipid metabolism and chilling injury（CI）of postharvest peach fruit induced by low temperature. Compared with 4 ℃，8 ℃ delayed the increase of the genes expression level of phospholipids degradation，phosphatidic acid（PA）biosynthesis and fatty acid desaturase in peach fruit，thereby reducing the process of PA accumulation and fatty acid desaturation，maintaining the high level of phosphatidylcholine（PC），phosphatidylethanolamine（PE）components and fatty acid unsaturation，ultimately delayed the occurrence of CI in peach fruit. In addition，8 ℃ induced a significant increase in the number of differential lipid metabolites in peach fruit，and maintained a higher level of diglyceride（DAG）and a lower level of triglyceride（TAG）components in the late storage period，which might be the result of the normal post-ripening softening process and CI of postharvest peach fruit induced by 8 ℃. Taken together，the dynamic changes of membrane lipid metabolism induced by 8 ℃ were beneficial to the delay of CI during postharvest peach fruit softening.

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• The Accumulation Dynamics of Biomass and N，P，K Nutrient in the Aboveground Newborn Organs of‘Guanximiyou’Pomelo Tree
• ZHANG Lijun, HOU Kaijie, WU Wenyuan, SONG Biao, MAI Xiaofeng, WANG Yuwen, LIAO Wenqiang, LI Wei, WU Liangquan, LI Yan, GUO Jiuxin
• Acta Horticulturae Sinica. 2023, 50(6): 1318-1331. DOI:10.16420/j.issn.0513-353x.2022-0392
• Abstract ( 127 ) HTML ( 82 ) PDF (2460KB) ( 82 ) 　　　

• The present study investigated the biomass and nutrient accumulation characteristics of nitrogen（N），phosphorus（P）and potassium（K）in the aboveground newborn organs of‘Guanximiyou’pomelo（Citrus grandis），so as to provide a theoretical and practical basis for targeted scientific fertilization in pomelo production. A field experiment was carried out in Pinghe County of Fujian Province in 2019 and 2020，the ten-year-old pomelo tree was used as the material，and samples were measured for five times during the whole growth period to dynamically determine the biomass of the aboveground tree organ，including fallen flowers and fruits，leaf（leaf with fruit，L + F；leaf without fruit，L-F），branch（branch with fruit，B + F；branch without fruit，B-F）and fruit（peel and pulp）. Also，the contents and accumulations of the N，P and K in various organs or parts were measured, and that nutrient balance was calculated in the pomelo tree. The biomass of aboveground newborn organs of pomelo tree increased gradually with the growth process, and the total biomass was 16.70 kg · plant^-1 at the harvest，the biomass of fruit，leaf，branch and fallen flowers and fruits accounted for 69.45%，23.59%，3.77% and 3.19%，respectively，in which the biomass was mainly distributed in pulp（43.99%）and shoot without fruit organs（including 22.55% in L-F and 3.55% in B-F）. In general，the contents of N，P and K in the leaf，branch and fruit organs were decreased with increasing growth stages of the pomelo tree，in which the N content in L + F and branch while the P content in B + F and pulp organs showed that the first decreased and then increased，by contrast in the N content in pulp and K content in leaf and pulp organs. Based on the characteristics of biomass and nutrient content，the cumulative amounts of N，P and K in the newborn organs of pomelo tree were 235.51，27.58 and 196.40 g · plant^-1，respectively. Among them，the nutrient taken away by the fruit harvest was 123.55，18.31 and 140.17 g · plant^-1 for N，P and K，in which the nutrient loss of fallen flowers and fruits only accounted for 8.44%，5.55% and 3.50%. Except K decreased at the harvest stage，the aboveground apparent accumulations of N，P and K were increased gradually in the newborn organs of pomelo tree during the growth process，in which their distribution in leaf and branch decreased while that in fruit increased gradually，and they were mainly distributed in the pulp and L-F organs. Moreover，the apparent balance of aboveground nutrients showed that farmers’ fertilizer practices led to about 83.7% N，94.8% P and 80.5% K being enriched in soil or lost in the environment.

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• Effects of Different Potassium Fertilizers on Growth and Absorption and Accumulation of Mineral Elements and Cadmium in Potato
• GONG Danmin, CAI Linzhi, DING Ren, MA Yanyan, WANG Wanxin, XIONG Xingyao, HU Xinxi
• Acta Horticulturae Sinica. 2023, 50(6): 1332-1342. DOI:10.16420/j.issn.0513-353x.2022-0626
• Abstract ( 199 ) HTML ( 126 ) PDF (994KB) ( 126 ) 　　　

• The effects of potassium sulfate-type compound fertilizer（K₂SO₄），potassium chloride-type compound fertilizer（KCl）and the same amount of different forms of potassium fertilizer（K₂SO₄ + KCl）on the growth，yield，quality，absorption of mineral elements and cadmium of two potato varieties‘Xingjia 2’and‘Jizhangshu 12’were studied in winter paddy fields. The results showed that at 60 days after emergence，plant heights，stem diameters，the leaf SPAD values and biomasses of K₂SO₄ treatment were significantly higher than those of KCl treatment，and those of K₂SO₄ + KCl treatment were between the two treatments. The contents of sulfur，nitrogen and phosphorus in the plants of K₂SO₄ treatment were the highest，while the contents of KCl treatment were the lowest. The content of chlorine and cadmium in plants treated with KCl was the highest，and that of K₂SO₄ treatment was the lowest.‘Xingjia 2’and‘Jizhangshu 12’of K₂SO₄ treatment had the highest yields，which were 31 442 kg · hm^-2 and 30 512 kg · hm^-2 respectively，and followed by K₂SO₄ + KCl treatment，and the KCl treatment had the lowest yields. The contents of protein，vitamin C and cadmium in tubers were significantly affected by the types of potassium fertilizers. The contents of protein and vitamin C of K₂SO₄ treatment were the highest，and those of KCl treatment were the lowest. However，the contents of cadmium in the tubers of KCl treatment were the highest，and those of K₂SO₄ treatment were the lowest. Therefore，compared with the KCl，and the K₂SO₄ can promote the absorption of nitrogen and phosphorus by plants，reduces the absorption of cadmium，promotes plant growth，increases tuber yield，and improves tuber quality.

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• Effect of Branch Light Treatment on Prolonging the Vase Life of Cut Rose
• MA Mengyu, HU Yaofang, GU Lin, LI Zhenjian, QIAN Yongqiang, JU Guansheng, LIU Junxiang, SUN Zhenyuan
• Acta Horticulturae Sinica. 2023, 50(6): 1343-1354. DOI:10.16420/j.issn.0513-353x.2022-0349
• Abstract ( 284 ) HTML ( 72 ) PDF (3287KB) ( 72 ) 　　　

• Cut rose（Rosa hybrida‘Legends’）was used as the experimental material in this study. The photosynthetic characteristic of the branch cortex chlorenchyma and its contribution to the cortex water uptake of isolated branch segment were investigated. On the basis，the branches of cut rose immersed in water were treated with dark and light（200 μmol · m^-2 · s^-1）to study the effects of branch illumination on vase life prolonging of cut rose. Results showed that the total chlorophyll concentration in the cortex of the branch was about 24.30% of that in the leaves. And the maximum photochemical efficiency of cortex was significantly higher than that of xylem and pith in the cross section of branch. When exposed to the photosynthetically active radiation of 200 μmol · m^-2 · s^-1，the net corticular photosynthesis rate of cut rose branch peaked at 0.15 μmol · m^-2 · s^-1. In relative to dark treatment，cortex water uptake content was significantly increased by 50% in the isolated branch segments illuminated with the 200 μmol · m^-2 · s^-1 light condition. Compared with the dark treatment，light treatment significantly increased the content of soluble sugar in the cortex of water-soaked branch，improved the water balance value，slowed down the decrease of water potential and inhibited the decrease of photosynthetic rate of leaves. These effects maintained the supply of water and soluble sugar required for cut rose flowering，increasing the flowers diameter significantly，slowing down the decrease of fresh weight，and prolonging the vase life by four days.

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Plant Protection

• Cloning and Expression Analysis of CsAOS1-2 in Responding to Citrus Canker Disease
• ZHANG Lehuan, ZOU Changyu, WANG Zhaohao, YANG Wen, ZOU Xiuping, HE Yongrui, CHEN Shanchun, LONG Qin
• Acta Horticulturae Sinica. 2023, 50(6): 1355-1367. DOI:10.16420/j.issn.0513-353x.2022-0296
• Abstract ( 304 ) HTML ( 106 ) PDF (5085KB) ( 106 ) 　　　

• The AOS genes，encoding the key rate limiting enzyme in the jasmonic acid（JA）biosynthetic pathway in citrus，are annotated，and their expression patterns in response to Xanthomonas citri subsp. citri（Xcc）were determined by qRT-PCR. Based on the reference genome databases of sweet orange（Citrus sinensis），three AOS genes（CsAOS1-1，CsAOS1-2 and CsAOS1-3）were detected in citrus. Gene expression analysis showed that CsAOS1-2 is the most responsive to Xcc，compared with the other two AOS genes. The expression of CsAOS1-2 was increased by Xcc in both‘Wanjincheng’orange（Citrus sinensis Osbeck，canker-susceptible cultivar）and‘Jindan’（Fortunella crassifolia Swingle，canker-resistant cultivar）. But its expression level induced by Xcc in‘Wanjincheng’orange was significantly higher than that in‘Jindan’. A 2 656 bp long sequence of CsAOS1-2 was amplified from Wanjincheng orange. Bioinformatics analysis showed that CsAOS1-2 had a 1 599 bp open reading frame which encodes a 59 499.81 protein with 532 amino acids. CsAOS1-2 is a non-secretory protein and the 349-510 aa is a typical P450 domain. The similar expression levels of CsAOS1-2 were found in leaf，stem，rind and seed tissues. The AOS1-2 promoters of‘Wanjincheng’orange and‘Jindan’contained multiple cis-acting elements involved in plant adversity and hormone responses，but there were differences in their number and type. Subcellular localization analysis showed CsAOS1-2 located in tobacco chloroplasts. The study suggested that CsAOS1-2 strongly respond to Xcc infection and is closely related to susceptibility to citrus canker in citrus.

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New Technology & New Method

• Establishment of a Method for Quantitative Detection of Latent Infection of Powdery Mildew in Wine Grape by Real-time PCR
• WANG Wenwen, ZHANG Qiangqiang, LI Ling, JIN Jing, WANG Ruotong, GU Peiwen
• Acta Horticulturae Sinica. 2023, 50(6): 1368-1376. DOI:10.16420/j.issn.0513-353x.2022-0333
• Abstract ( 177 ) HTML ( 85 ) PDF (2145KB) ( 85 ) 　　　

• In order to caculate molecular-detected disease index（MDI）of grape powdery mildew，according to the P450 sequence of Uncinula necator and EF1-α sequence of Vitis vinifera L.，pairs of primers，F-P450-Un/R-Un and F-g-6/R-g-6，were designed to establish the real-time PCR reaction system. The sensitivity of real-time PCR of V. vinifera and U. necator was 1.0 × 10^-2 ng · µL^-1 and 1.0 × 10^-5 ng · µL^-1 genomic DNA respectively，which was 100 and 1 000 times greater than that of the conventional PCR. At the same time，the standard curves of V. vinifera and U. necator were established respectively. There were good linear relationship between the cycling threshold（Ct）and template DNA concentration with the correlation coefficient of 0.99637 and 0.99564 respectively. Application of this technology to detect 30 samples in the field. A total of 22 samples were detected to contain grape powdery mildew, and the MDI was significantly correlated with the field DI after 18 days (correlation coefficient was 0.916). The established real time PCR system of U. necator could provide theoretical basis for early detection and monitoring of powdery mildew.

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New Cultivars

• A New Kiwifruit Cultivar‘Jinli’
• LIU Nanxiang, ZHANG Huiqin, XIE Ming, XU Xianghua, FAN Fangjuan
• Acta Horticulturae Sinica. 2023, 50(6): 1377-1378. DOI:10.16420/j.issn.0513-353x.2021-0264
• Abstract ( 211 ) HTML ( 61 ) PDF (995KB) ( 61 ) 　　　

• ‘Jinli’is a newly released cultivar which was selected from a seedling of Actinidia chinensis germplasm resource survey. It is a mid-late maturity tetraploid with yellow flesh. The fruit are large，mean weight 110 g with a maximum of 200 g and cylindrical. The fruit skin is yellow-green with a small amount of light brown dot-like protrusions. The flesh is purely yellow to golden with good flavor and aroma. The soluble solids content（SSC）is 17%，and vitamin C 1 440 mg · kg^-1. The fruit can be kept for three months at 4 ℃ low temperature. The yield can reach to 25 900 kg · hm^-2.

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• A New Cherry Tomato Cultivar‘Huying 9’
• ZHANG Hui, ZHU Weimin, ZHU Longying, YANG Xuedong, ZHANG Yingying, TIAN Shoubo, WAN Yanhui, LIU Yahui, YANG Zhijie
• Acta Horticulturae Sinica. 2023, 50(6): 1379-1380. DOI:10.16420/j.issn.0513-353x.2021-0127
• Abstract ( 224 ) HTML ( 83 ) PDF (1328KB) ( 83 ) 　　　

• ‘Huying 9’is a new cherry tomato F₁ hybrid with resistance to tomato yellow leaf curl virus disease，which is developed by crossing inbred line B14-23 as female parent and inbred line B14-102 as male parent. The cultivar is indeterminate growth type，with strong growth vigour. There are 7-8 leaf nodes below the first infloescence. The fruit is oval and the mature fruit is pink with green shoulder. It is more than 14.3 g in weight per fruit and 64 294.5 kg · hm^-2 in yield. The fruit is resistant to cracking. It shows resistant to tomato yellow leaf curl virus，and suitable for protected cultivation in Shanghai，Shandong，Inner Mongolia and Yunnan.

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• A New Pepper Cultivar‘Jinjiao 2’
• CAO Chunxin, YAN Jiqiong, LIU Xinhua
• Acta Horticulturae Sinica. 2023, 50(6): 1381-1382. DOI:10.16420/j.issn.0513-353x.2021-1295
• Abstract ( 315 ) HTML ( 63 ) PDF (1319KB) ( 63 ) 　　　

• ‘Jinjiao 2’is a new mid-ripe hybrid chili pepper cultivar with inbred lines Jinjiao 1A as its female parent and F912 as its male parent. The plant of‘Jinjiao 2’has a strong growth vigor and 180 days growing period. The fruit is sheep-horn shaped and its single weight is 4.5-5.0 g. The unmatured fruit is green in color and matured one is red. Besides，the capsaicin content is 0.18%，vitamin C content is 767.2 mg · kg^-1. This cultivar is medium resistance to viral disease，epidemic disease and anthracnose disease. ‘Jinjiao 2’can achieved a yield of about 28 380 kg · hm^-2 and is suitable for spring cultivation in protected and open fields in Zhejiang and other similar areas.

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• An Elite Bambusa variostriata Cultivar of‘Diaosidanzhu’
• XIA Haitao, WANG Yueying, JIN Chuan, LI Xiaowen, XU Jianxin, CHEN Shengzhuan
• Acta Horticulturae Sinica. 2023, 50(6): 1383-1384. DOI:10.16420/j.issn.0513-353x.2021-0273
• Abstract ( 341 ) HTML ( 38 ) PDF (1693KB) ( 38 ) 　　　

• Bambusa variostriata‘Diaosidanzhu’was introduced from Guangdong Province，and bred through years of domestication and cultivation in southern Zhejiang Province. It is 9-11 m in height，7-8 cm in diameter，apically long pendulous，showing a hanging filament shape，internodes initially with longitudinal stripes，aerial roots around each bamboo joint near the base of the stem. The shoot is 25-30 cm long and 10-12 cm wide. The shoot yield of four-year-old bamboo was 5 700-9 255 kg · hm^-2，which was 25.4%-46.5% higher than that of Bambusa oldhamii，and the shoot weight was 0.4-1.0 kg. Fresh bamboo shoots are delicious，and suitable for fresh edible and processed products.

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• A New Melon Cultivar‘Tianmi 20’
• DIAO Qiannan, CAO Yanyan, CHEN Youyuan, ZHANG Yongping
• Acta Horticulturae Sinica. 2023, 50(6): 1385-1386. DOI:10.16420/j.issn.0513-353x.2021-0250
• Abstract ( 203 ) HTML ( 72 ) PDF (2941KB) ( 72 ) 　　　

• Hami melon type‘Tianmi 20’is a new melon hybrid cultivar by crossing‘14-6I’as female parent and‘16-7A’as male parent. The fruit is oval shaped with milky-white peel，evenly and netty streaks，the single fruit weight is above 1.8 kg. The flesh is orange，crisp and juicy，not easy to ferment，and has a strong fragrance，the central soluble solids content is above 16%. The plant is resistant to low temperature and low light，resistant to storage. The yield is 37 800-40 650 kg · hm^-2.

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• A New Salvia miltiorrhiza Cultivar‘Chuandan 2’
• YU Yan, JIANG Yuanyuan, WANG Long, WU Yichao, YANG Ruiwu, ZHOU Yonghong, XU Zhigang, ZHANG Li
• Acta Horticulturae Sinica. 2023, 50(6): 1387-1388. DOI:10.16420/j.issn.0513-353x.2021-0245
• Abstract ( 333 ) HTML ( 39 ) PDF (1277KB) ( 39 ) 　　　

• ‘Chuandan 2’is a new Salvia miltiorrhiza cultivar，which is derived from the S. miltiorrhiza cultivated mixed population in Sichuan by system selection. The seeding stage is 60 to 70 d and the growth period is 270 to 290 d. The average production of fresh roots is 13 544.55 kg · hm^-2 and the proportion of first grade products is 40.49%. The total content of tanshinone ⅡA, tanshinone Ⅰ and cryptanshinone is 0.262% and the content of salvianolic acid B is 7.24%. Superiorities of cultivar are early emergence，long growing period，high yield and high superior product rate，good quality and so on. Its regional adaptability and resistance are strong，and it is suitable for cultivation in Longquan Mountain of Northwestern Sichuan Province.

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