Citrus genetic improvement has achieved a great progress during the last six decades in China. A repository harboring more than 1 700 accessions of Rutaceae in Chongqing and an embryogenic callus collection including more than 100 varieties in Wuhan have been established,respectively. Continuing exploration of citrus germplasm resulted in the identification of wild Daoxian tangerine,Honghe papeda and the mini-citrus,a mono-embryonic Hongkong kumquat for functional genmics research. A new type of rootstock,Ziyang Xiangcheng(Citrus junos)has been utilized in Chinese citrus industry. A total of 122 citrus varieties including 121 for scion and one for rootstock have been registered or protected by PVP. Out of the scion varieties,88.5% is from the natural mutation including the bud-sport and chance seedling variation,and the rest from artifically created mutants,such as the irradiation,hybridization and protoplast fusion etc. These varieties covered nearly all types of citrus,including loose-skin mandarin,sweet orange and pummelo etc,with improved seedlessness,mature season and fruit color etc. The omics technologies have been widely used in citrus genetic improvement in China. Genomes including sweet orange and other main citrus species have been sequenced and assembled during the recent decade,as has accelerated cloning of the key genes controlling import agronomic traits,such as the polyembryonic related gene CitRWP etc. Genetic transformation and gene editing are also setup in Citrus. These achievments have laid a solid base for citrus genome-design breeding for the future.
In the past 60 years,remarkable achievements have been made in cabbage genetics and breeding in China:Heterosis utilization technology has been broken through. Breeding technology systems of self-incompatible line and male sterile line have been established successively. A number of excellent germplasm resources have been introduced and innovated. A batch of new varieties adapted to market consumption demand were developed and applied in cabbage production. Great progress have been made in the research and application of biotechnology. This paper summarized the important research progress made in the past 60 years and analyzed the main problems in cabbage breeding and the development trend in the future.
This paper introduces the important achievements of pepper breeding over the past 60 years in China. It includes the collection,identification,evaluation,utilization and exploration of germplasm resources. The paper also discusses the important advancement in breeding technologies which includes heterosis utilization,anther culture,marker-assisted selection(MAS),multiple resistance breeding and shuttle breeding. In addition,the history of pepper breeding is reviewed,including the traditional breeding before 1980s and the modern breeding guided with National scientific and technological research after 1980s. Then,driven by the industrial demands,China's pepper breeding has been undergoing several major optimizations:increasing yield,adjusting growth period,enhancing disease resistance,breeding for easy storage and transportation,breeding processed-food-specific varieties,improving product quality,and breeding for mechanized harvesting. After more than four decades of development,a modern and world-leading commercial pepper breeding system has been completely established. Domestic varieties with independent intellectual property rights are taking over 95% of market share across the country. Meanwhile,there are several unique advantages of in China's pepper breeding industry,such as low barrier to entry,low risk,high efficiency,large team,rich varieties,and high effectiveness. However,there are also several problems that strongly restrict the development of the pepper seed industry in China,including homogenization of pepper varieties,difficulty in expanding pepper seed business enterprises and slow research progress of pepper molecular breeding technology. Long-season varieties cultivated in green house and ornamental pepper varieties are mainly imported because the pepper breeding in China is still lagging behind developed countries. Therefore,the future directions for pepper breeding in China will be improving product quality,producing varieties suitable for mechanized production,breeding varieties with medicinal or other functional ingredients,exploring and advertising local varieties with excellent properties,and innovating novel breeding technologies.
In this article,the development history of protected horticulture in China during the last 60 years has been reviewed briefly including,the accomplishments of protected horticulture in China in industrial growth,scientific and technical innovation,talents training,and team platform construction. Moreover,the potential for future development and the main tasks of protected horticulture in China are prospected.
This article focuses on the development and industrial application of vegetable cultivation technologies in China over the past 60 years. The main scientific and technological achievements made in the past 60 years are summarized in terms of facility vegetable production and environmental control technology,soilless cultivation and plant factory technology,seedling nursing and grafting technology,vegetable growth,development and stress tolerance regulation technology,soil maintenance and resource efficient utilization technology,pest and continuous cropping soil sickness prevention and improvement technology,vegetable quality and safety control technology,vegetable mechanized and intelligent production technology. On the basis of the prominent problems analysis of vegetable cultivation in China,the countermeasures and prospect for the future development of vegetable cultivation industry and scientific research in China are also discussed.
This review briefly summaries the processes for chrysanthemum development,and recalls the progress and main achievements that have been made in the germplasm resources,inheritance and molecular mechanisms underlying important traits formation,traditional breeding as well as modern biotechnology breeding programs during the last six decades in China. We also summarize the application status of modern biological technologies such as transgenic,genome editing,molecular marker-assisted selection,and multi-omics in the area of chrysanthemum genetics and breeding,and propose suggestions for the development of chrysanthemum genetics and breeding accordingly.
High-resolution single-cell RNA sequencing(scRNA-seq)technology based on high- throughput sequencing technology has been developed recently to resolve the heterogeneity of plant tissues at the single-cell level,identify distinct cell types in single tissue,and construct continuous cell differentiation trajectories and the transcriptional regulatory networks,in addition,it can search for rare cell types in tissues,thus deeply analyze molecular mechanisms of tissue development. To explore the application of scRNA-seq technology in plants,this paper reviews the progress of scRNA-seq technology and its application in plants. Firstly,the development course of scRNA-seq technology was overviewed; subsequently,we analyzed the progress of scRNA-seq technology in the identification of different plant tissue cell types,screening of specific expression marker genes for different cell types,and analyzing the continuous differentiation trajectories and transcriptional regulatory networks during the development of different plant tissues;finally,we summarized the challenges and future research directions of the
scRNA-seq technology applicating in plants,and aims to provide reference for the application of scRNA-seq technology in more plant species in the future.
The cold stress during the greenhouse production in winter and spring has seriously affected the photosynthesis of thermophilic crops such as tomato. Importantly,the inappropriate light intensity,photoperiod,light quality and other light environments have intensified the cold-induced photoinhibition in crop,resulting in the decline of yield and quality. Therefore,it is necessary to analyze the physiological and molecular mechanism of plant response to light and temperature stresses for the regulation of crop stress tolerance during winter and spring. Recently,the molecular mechanism of plant response to light and temperature stresses has been gradually clarified. However,the integration factors of light and temperature signaling pathways and their functions still need to be further explored. Here,we review some recent advances in our understanding of the physiological and molecular mechanisms of tomato response to light and temperature stresses,with an emphasis on the effects of light and its signals on plant cold tolerance. In addition,the main problems in current researches were pointed out and the key points in future studies were also proposed. It is expected to provide a reference for alleviating the stress effects of tomatoes,improving yield and quality,and laying a foundation for in-depth exploration of new light-temperature integration factors and their functions.
Fruit shape is the one of the most important appearance qualities of fruit vegetables,which is also the main factor affecting the preference of consumers. The trait of fruit shape is affected greatly by environmental factors,and the genetic basis and molecular regulation mechanism are complex. The advancement of genetic mechanism about fruit shape of fruity vegetable including QTL mapping,gene fine mapping,GWAS analysis and candidate gene cloning were reviewed;The progresses about gene family members of IQD,OFP,TRM,WUSHEL and CLAVATA participating in the regulation of fruit shape were also reviewed,and the suggestions were given on the genetic basis and regulation mechanism about the fruit shape,which will put some solid basis for the improvement and precise regulation of the fruit shape.
Autophagy is a highly conservative degradation process in the evolution of eukaryotes. It plays an important role in pathogen infection and the process of plants resisting pathogen infection. Pathogens invading plants mainly use hyphae to penetrate through natural orifices or micro-wounds to invade host cells,establish pathogen-host plant interactions,and trigger plant autophagy response. Host plants use autophagy to directly resist pathogens and enhance plant disease resistance. On the other hand,host plants can also participate in other signal transduction events and indirectly defend against pathogen infection. At present,there are few reports on the interaction between plant autophagy and pathogens. Therefore,studies on the interaction between plant autophagy and pathogens,including the interaction between plant and pathogens,how host plants use autophagy to directly defend against pathogen invasion and indirectly defend against pathogen invasion through the crosstalk between autophagy and other signaling pathways,have been summarized in this paper. Herein,the plant signaling molecular networks involved in regulating autophagy were analyzed from the perspective of plant disease resistance.
To elucidate the biological function of the apple(Malus × domestica Borkh.)phospho- fructokinase gene MdPFPβ(Pyrophosphate-fructose 6-phosphate 1-phosphotransferase subunit beta,gene sequence number MD09G1112800),its sequence and promoter information were analyzed. The results showed that its open reading frame was 483 bp in length,encoding 161 amino acids. Cis-acting element analysis of its promoter using the PlantCare database revealed that regulatory elements related to abscisic acid(ABA),low temperature,and drought signaling were present in the promoter sequence of MdPFPβ. Quantitative real-time PCR analysis revealed that MdPFPβ was highly expressed in apple leaves and mature fruits. It was also induced by external application of ABA in apple leaves. Overexpressing MdPFPβ significantly increased soluble sugar content in apple calli compared to that in wild-type under ABA treatment. Moreover,ectopic expression of MdPFPβ promoted photosynthetic performance in tomato leaves,as well as the content of soluble sugar in tomato fruits,indicating MdPFPβ plays a key role in regulating soluble sugar content in fruits.
The purpose of this study was to explore the effects of brassinolides(EBR)and methyl jasmonate(MeJA)on apple fruit quality during storage. The'Yuehua'apple fruit was used as a test material at different concentrations of EBR(0,0.02,0.05 mg · L-1)with MeJA(0,20,50 mg · L-1) mixed in pairs,and sprayed once on the fruit 30 days before harvest,and distilled water was sprayed as the control. The results showed that the mixed treatment of 20 mg · L-1 MeJA + 0.05 mg · L-1 EBR could delay the fruit firmness,titratable acid content,ascorbic acid content and soluble solids content increase of 'Yuehua'fruit during storage at room temperature,and prolong the fruit storage period. At the same time,the production of ethylene was 17.4% lower than that of the control,and the expression of ethylene synthesis genes MdACO1,MdACS1 and ethylene response factor MdERF3 were inhibited. 20 mg · L-1 MeJA + 0.05 mg · L-1 EBR treatment increased the color difference and anthocyanin content of the fruit by 7.3 and 1.4 times compared with the control,respectively,and increased the expression of MdMYB1,MdCHS,MdDFR and MdF3H in the peel. Moreover,50 mg · L-1 MeJA + 0.05 mg · L-1 EBR treatment group significantly increased the color difference and anthocyanin content of the fruit;however,the effect on other indicators was not significant. In summary,the treatment of 20 mg · L-1 MeJA + 0.05 mg · L-1 during apple fruit development had a significant promoting effect on the maintenance of internal quality and the improvement of appearance quality during fruit storage.
In order to clarify the specific regulation mode of DAM gene in dormancy,'Dangshan Suli'pear floral buds were used as the material to explore the upstream transcriptional factors of a DAM gene PpyMADS71 identified in previous studies. The results are as follows:(1) PpyERF060(Ethylene responsive factor 060)and PpyMADS71 were co-expressed during bud dormancy cycle. The yeast binding site mutation assays and the dual-luciferase assays were used to confirm that PpyERF060 could bind to the DRE1 element of the PpyMADS71 promoter and activates PpyMADS71's expression,which was further proved by the upregulation of PpyMADS71 expression in PpyERF060 transgenic pear calli. (2) To explore the upstream genes of PpyERF060,we found that the transcription factor PpyABF3(ABRE BINDING FACTOR 3)could activate the expression of PpyERF060 and the binding site of PpyABF3 on the promoter of PpyERF060 was primarily determined. (3) Furthermore,ethylene treatment on'Dangshan Suli'buds caused up-regulation of PpyERF060 and down-regulation of PpyABF3. In addition,overexpression of PpyERF060 in pear calli caused inhibition of the transcription of PpyABF3. Based on the above results,we found that there is a regulatory network among PpyERF060,PpyABF3,and PpyMADS71,which could combine ethylene and ABA signaling pathway,and ultimately regulates the dormancy process.
In this study,the genome of Solanum pimpinellifolium PI365967 was sequenced by HiFi long sequencing technology and de novo assembled. A total of 924 contigs were constructed,and the length of N50 was up to 12.8 MB. A 834 M high-quality genome at the chromosome-level of PI365967 was obtained. Compared with the reference genome of cultivated tomato Heinz1706,a large number of structural variations are existed in PI365967,including inversion,deletion and so on. GO enrichment analysis revealed the possible biological functions of the genes with structural variation.
Based on the 13 morphological traits of 950 accessions of spray cut chrysanthemum (Chrysanthemum morifolium)including eight ligulate flower color groups preserved by China Chrysanthemum Germplasm Resources Conservation Center,cluster analysis was performed by systematic cluster method. Based on two genetic distances,four clustering methods and five overall sampling scales,40 candidate core collections were constructed,and thereafter four evaluation indexes were used to compare the quality of the candidate core collections and an optimal scheme was selected to construct primary core collection. Six characteristic values and five evaluation parameters were used to comprehensively evaluate the effectiveness and representativeness of core collections,and finally an optimum core collection constructed by standardized Euclidean distance,Ward's method and 10% overall sampling ratio was observed showing superior comprehensive performance. The derived primary core collection containing 95 spray cut chrysanthemums could fully represent the genetic diversity of the original collection under the condition of less redundancy,and thus should be effective and of high quality.
'Zhonggan 26' is an early-maturing spring cabbage hybrid derived from the dominant genic male sterile line DGMS01-20 and the inbred line 93-719. The head is round in shape and green in color,with the weight of 0.9 kg. The head tastes crisp,tender and fresh,with high quality. It has broad adaptability and high tolerance to premature bolting. It takes about 50 days from transplantation to harvest when planted in the open field in North China as the spring cabbage. The yield is 67 670 kg · hm-2. It is suitable for protected and open field cultivation in spring in Beijing,Hebei,Henan,Gansu,Shaanxi,Shandong,Zhejiang,etc.
'Ganjiao 20'is a new hot pepper hybrid for both dry and fresh fruit production,developed by crossing CMS line B351A7 as female parent and restorer line WY113 as male parent. The fruit is linear and pungent with green skin and bright red skin in maturity,23.20 cm in length,1.2 cm in width,0.15 cm in flesh thickness and 14.70 g in weight. It has mid-early maturity. The yield of fresh fruit is about 38 000-48 000 kg · hm-2,while the yield of dry hot pepper is up to 5 000 kg · hm-2.'Ganjiao 20'is suitable for early spring cultivation in the Yangtze River Valley and other areas with similar climate.
'Xinfeng 2'is a new F1 hybrid eggplant cultivar developed by crossing two inbred lines,one was'Zonglian 1'(♀)with resistance to bacterial wilt and strong tolerance to heat,the other was 'Fengchuang'(♂)with moderate heat tolerance and moderate resistance to bacterial wilt. It produces long cylindrical fruits with shining purple skin,white flesh and good quality. It is 248.5-262.3 g in weight,27.6-29.1 cm in length and 4.92-5.29 cm in diameter per fruit. It is moderately resistant to bacterial wilt. It is suitable for open field cultivation in spring and autumn in South China. The yield of commercial fruit was from 39 500 kg ∙ hm-2 to 46 900 kg ∙ hm-2 in one cultivating season.
A new large-flowered marigold cultivar'Xueyu 3'was selected from progenies which were obtained from sterile plant of male sterile two-type line AKC3-2 and fertile plant of marigold male sterile two-type line C40-1(2). The plant height of this cultivar is 35.45 cm ± 5.60 cm. The crown diameter is 36.98 cm ± 6.00 cm. The flower diameter is 8.55 cm ± 2.00 cm. Its flower is orange yellow with super double petals. The single flowering period is 30 d ± 3 d,and the whole flowering period is 80 d ± 10 d. It presents strong disease resistance during propagation. The cultivar is suitable for growing in Qinghai as a garden plant or pot flower.