Calmodulin-binding transcription activators(CAMTA)are a family of transcription factors that widely exist in plants and can be combined with calmodulin(CaM),they are also called SRs because they are respond to a variety of signals. They play an important role in growth and development as well as in response to stress. In this paper,we summarized the discovery process,structure,and roles of CAMTA/SR in growth and under stress,in order to provide reference for future research on CAMTA/SR.
Belonging to bHLH(Basic Helix-Loop-Helix)transcriptional factor family,phytochrome- interaction factors(PIFs) are involved in many biological processes of plants. As the“hub”of intracellular signal regulation,PIFs not only participate in the regulation of plant growth and development,but also plays an important role in the process of plant resistance to stress. The main points of this paper are:PIFs integrate complex networks to regulate plant responses to abiotic stresses such as temperature,shading stress and drought,meanwhile,they mediate the defense of plants against biotic stresses such as pests and diseases through plant hormone signaling pathway. Our research could provide reference for further study of PIFs.
Glutathione(GSH)is an important antioxidant substance that widely exists in plants. It can eliminate the excess reactive oxygen radicals produced in cell metabolism,thus reducing the damage of membrane lipid peroxidation to cells. Glutathione disulfide(GSSG)is the oxidation form of GSH. In recent years,it has been found that the glutathione/glutathione disul?de redox couple(GSH/GSSG)also plays an important role as a signal molecule in plant stress response. This paper reviews the role of GSH/GSSG in plant response to stress,which provides theoretical basis for the regulation of plant resistance by regulating GSH/GSSG.
Callose is a β-1,3-glucan polymer,which is deposited during plant growth and development,biotic and abiotic stresses. Callose synthase,also known as β-1,3-glucan synthase like,usually controls the synthesis of callose in the form of multi-subunit complexes. The isolation and identification process of callose synthase,the subunits of the callose synthase complex and their roles are described in the review. The processes of callose synthase gene regulated by transcription factors,plant growth regulator and others are highlighted. In addition,the function of callose synthase under abiotic stresses(wound,phosphate,metal ions,etc.)and biotic stresses(pests,bacteria,fungi,etc.) are summarized. Finally,the research direction of callose synthase in future is discussed. The related content would be helpful for illuminating regulating mechanism of callose synthase and searching for resistance genes in plant(especially horticultural plants).
Sugar transporters play important roles in the growth and development,fruits sugar accumulation and response to stress in horticultural crops,and their expression is regulated by many factors. Monosaccharide transporters,sucrose transporters and SWEETs are three kinds of transporters in plants. In this study,the transport activity and substrate specificity,tissue and cell localization of the three types of transporters were discussed and compared,with emphasis on the latest progress in the function and regulation of sugar transporters in horticultural crops. What’s more,the regulation of sugar transporter expression by sugar signal,biotic stress and abiotic stress was analyzed.
Chloroplast protein is an indispensable substance for plant photosynthesis. Most of proteins involved in photosynthesis are first synthesised in the cytoplasm and subsequently transported into chloroplast by TOC-TIC complexes,then a series of life activities can be carried out. In this review,the characteristics and roles of TOC-TIC complexes,transport peptide and chaperone protein as well as protein transport pathways were summarized,and some new findings on chloroplast protein transport in recent years were introduced and discussed.
Trichome is a specialized structure appendage developed from plant epidermal cells,and is widely present in plants in different forms. It plays an important role in plant defense against biotic and abiotic stress. In the meantime,its secretions,containing various secondary metabolites,have been exerting a considerable socio economic impact. The genes regulating the development of trichome have been cloned and functionally verified in various plants. Particular in Arabidopsis thaliana,regulatory genes which code mostly transcription factors related to development of trichome have been extensively studied. In the present paper,we attempt to intergrate the recent progress in the studies on developmental characteristics and biological function of trichome in various plants,and reviewed the factors and regulatory genes related to trichome development.
The base editing is a new technology developed on the basis of the CRISPR/Cas system that can precisely edit the genome. It includes cytosine base editor(CBE),adenine base editor(ABE)and the latest prime editing(PE). The cytosine base editor can convert C/G to T/A at the target site of the genome,the adenine base editor can convert the A/T to G/C,while the prime editing can realize all 12 types nucleotides replacing(C-T,G-A,A-G,T-C,C-A,C-G,G-C,G-T,A-C,A-T,T-A,T-G),and the bases insertion and deletion. This article makes a systematic introduction of the principles,development processes,respective advantages and disadvantages of the three base editors,and their applications and developments in crop genetic improvement. Meanwhile,It looks forward to the application prospects of base editing technology in crop breeding.
Whole genome sequencing can obtain genome sequence information of species,which is very important for exploring the origin and evolution of the species,and fundamental for the development and utilization of genes. This article reviewed the progress of genome sequencing of seven important fruit trees(apple,citrus,grape,pear,strawberry,banana and peach),discussed the currently existing problems of whole genome sequencing of fruit trees,and elaborated selection of DNA sequencing technology,openness of sequencing data,and research after sequencing and other issues in the future research.
Benefited from the utilization of excellent fruit germplasm,breeding of new varieties,and introduction of foreign superior varieties,the fruit industry in China has developed rapidly with the world’s the largest cultivation area and total production. This article reviewed the main achievements in the investigation and collection,the identification and evaluation,the safety conservation,the sharing and utilization of fruit germplasm,the innovation of breeding technology as well as the breeding of new varieties in the past seventy years. The main problems in the enhancement of germplasm and genetic improvement of fruit crops in China were pointed out,and suggestions for future development were also addressed.
Self-incompatibility is a genetic mechanism which inhibits self-crossing and promotes out-crossing in flowering plants. Apple,pear,and other fruit trees exhibit the typical gametophytic self-incompatibility that is determined by the multiple alleles(S-allele)at a single locus(S-locus)containing at least two genes. One is the stylar-S determinant that is determined by the S-RNase gene,while the other is the pollen-S determinant that may be controlled by one or multiple F-box genes. The research progress of gametophytic self-incompatibility in Rosaceae and Rutaceae fruit trees is introduced as follows:the discovery of the male and female determinants,the mechanism of self-incompatibility mutation,S-RNase-mediated pollen tube signal transduction,and the application of self-incompatibility mutation in new variety breeding. These information is available for the studies of gametophytic self-incompatibility in future.
The allelopathy caused by root exudates and decompositions of strawberry(Fragaria ananassa Duch.),always leading to the strawberry unhealthy growth and development,the decrease of yield and quality,the imbalance of soil micro-ecology and the aggravation of root diseases,and is one of the important reasons for the occurrence of continuous cropping obstacles. In order to provide theoretical reference for the creation of comprehensive control technology system of continuous cropping obstacles of strawberry, the research progress of allelochemicals in strawberry root exudates and decomposed substances, extraction and detection methods, allelopathy mechanism and its mitigation measures were reviewed, and the shortcomings and future directions in the current research were discussed.
There have been some advanced progresses in ploidy manipulation of citrus. Firstly,numerous triploid and tetraploid have been reported,and some triploid and tetraploid varieties have been released. Secondly,Some tetraploid perform well in controlling tree shape,and being resistant to dieseases and stresses when used as rootstocks. Thirdly,haploid and dihaploid were used in genome researches of Citrus,and great achievements had been harvested. Nevertheless,there are still some difficulties in ploidy manipulation of citrus. Firstly,long juvenile phase and nucellar embryo affect the efficiency of new polyploid varieties breeding. Secondly,it is still difficult to obtain haploid and dihaploid,which limits the promotion of citrus genome researches and breeding. Thirdly,some polyploids with high qualities are lowly fertile,blocking the efficiency of breeding by using these materials. Regarding the problem of long juvenile phase in citrus polyploidy breeding,it is nessary to use new technologies of shortening it or to take advantage of germplasm resources with short juvenile phase. For overcoming the interference of nucellar embryo,it is nessary to develop more monoembryonic tetraploids. When using polyembryonic tetraploids as parents to produce triploids,embryo rescue,and molecular marker can be used to improve the breeding efficiency. At last,the authors suggested that ploidy manipulation in citrus could be extending in the following aspects:firstly,improving the frequency of 2n gamete production in order to develop more polyploid,especially monoembryonic types;secondly,the advantages of polyploid being used as rootstock and polyploid rootstock should be brought into play to promote the development of rootstock breeding;thirdly,continuing to induce haploid and dihaploid in order to accelerate genome research,functional gene research and breeding of citrus;fourthly,on the basis of allopolyploids and their creation technology,new materials with only small amount of alien genomic components and target traits could be bred by combining with chromosome manipulation techniques.
Parthenocarpy is an important reason for citrus to produce seedless fruit. The parthenocarpy ability of citrus germplasm resources,mechanism of hormones regulating development of parthenocarpy fruit,the progress of seedless genes and genetic engineering seedless breeding are reviewed. Meanwhile,the latest research techniques on parthenocarpy of other horticultural plants are summarized,which may provide reference for parthenocarpy research.
From the bioactive compounds in citrus peel and peel-related important horticultural traits,this article reviewed the recent study advances and proposed the future perspective. Various bioactive compounds are abundant in citrus peel,including pectin,essential oil,flavonoids,limonoids,carotenoids and coumarins,which confer the characteristic nutrient trait of citrus. Due to pleiotropic functions of these bioactive compounds in the health maintenance and disease prevention/treatment,citrus peel is the promising material ideally for the production and development of functional food,natural health products and drugs. The peel-related horticultural traits are critical to the commercial value of citrus fruits. As some key genes such as CCD4b and Ruby were recently unraveled in the regulation of peel colour,great knowledge has been achieved about the molecular mechanism of the development of the red and purplish-red citrus peel. Peel roughness,thickness,firmness and peelability are also important traits,which directly affect the external quality,tolerance to storage/transportation and convenience of raw eating,and closely related to some physiological disorders such as rough fruits and puffing. However,only modest progress has so far been made in the physiological and molecular mechanism underlying these traits. With the higher demand for the overall nutrient and quality of citrus fruit,more efforts should be invested in the genetic regulation for the metabolism of the bioactive compounds in citrus peel and peel-related horticultural traits.
‘Qiushi’is a new pollinated apple cultivar selected from the offsprings ofMalus prunifolia Brokh‘Fupingqiuzi’. It has large amount of flowers with 20 anthers and 152 800 pollen in single flower,and the germination rate of pollen is 91.6%. Because of the long flowering period,it has high degree of coincidence with Fuji. The fruit-setting rate of‘Fuji’pollinated by‘Qiushi’is 92.37%,and the fruit quality is improved.‘Qiushi’has wide adaptability and strong resistance to early leaf disease,powdery mildew and rot.
‘Zhongnong Zaozhenzhu’is a new nectarine cultivar selected from a seedling of‘Qiuhongzhu’. The flower is showy with more than five pink petals for ornamental and early flowering. The fruit is small,round with average weight of 72.9 g. Its flesh and pericap are light green. The fruit skin color is bright,and the attractive red blush covers over 3/4 of the skin surface. The soluble soilds content is 14.1%;titratable acid content is 0.54%;vitamin C content is 56 μg·g-1. It has a good charateristic for storage and transportation,which ripens in late-June in Ju County,Rizhao City,Shandong Province. The yield is up to 275 00 kg·hm-2.
‘Lüsun 70’is a new heading Chinese cabbage F1 hybrid cultivar which was crossed by cytoplasmic male sterile line and inbred line. It takes about 70 d from sowing to harvesting. The plant head is erect and folding by screwing with 39 cm in height and 12.4 cm in diameter. The average head weight is about 1.3 kg. The yield is about 60 000 kg·hm-2. It has high quality with resistance to TuMV and downy mildew. It is suitable to be planted in Hebei,Tianjin,Gansu,Ningxia,Yunnan and Guangxi provinces of China.
‘Liangyuanla 2’,a new pepper cultivar,was developed from the inbred lines of F1(‘Neihuang Xinyidai’ בSanying Lajiaowang’). The string-shaped fruit are deep green. The longitudinal and transverse diameter of fruit are 7.2 and 1.3 cm,respectively. The fresh weight of single fruit is 3.6 g with 1.55 mg·g-1vitamin C,0.31% capsaicin,and 22.6% dry matter. The cultivar has high resistance to CMV and TMV,anthracnose and blight,and moderate resistance to sunburn. It is suitable for open field cultivation in Henan Province,with the yield of dried pepper more than 5 398.5 kg·hm-2.
‘Cuiluo 2’is a new pepper cultivar with early maturity. The fruit is linear with wrinkles in the fruit shoulder and spiral in the other part,with 26-30 cm in length,1.8-2.0 cm in diameter,0.2 cm in pulp thickness and 35 g in average weight. The fruit is crispy and spicy in taste. The average yield is about 38 565 kg·hm-2.‘Cuiluo 2’is suitable for protected and open field cultivation in Zhejiang and Anhui provinces.
A new pepper cultivar‘Shifeng 801’is developed by crossing two inbred lines PE12-206 and PE13-27. The shape of fruit is long linear with good consistency of fruit type;the fruit is dark green in immature and red in mature. The fruit has strong spicy taste. The whole growth period is 140 d,and it is a mid-maturing cultivar. The yield of fresh fruit is up to 60 185 kg·hm-2. This cultivar is resistant to anthracnose,TMV,CMV and Phytophthora capsici in field investigation. It is tolerant to low temperature in spring and has resistance to high temperature and high humidity in summer. It is suitable for harvesting fresh pepper. It is suitable for cultivation in the open field in Southern China and protected cultivation in spring in Shandong Province.