International advances of the research on the phytoplasma diseases in cherry

Abstract: Phytoplasmas, which was originally called mycoplasma, are a class of A prokaryote resembling a bacterium that have no cell walls, the mycelium is only surrounded by a unit membrane composed of adipose membrane, it cannot be cultured, and exist in plant screens. Its morphological structure is easily affected by external environmental conditions, and it is still difficult to conduct in vitro artificial culture. It has been reported that phytoplasma can cause more than 1 000 kinds of plant systemic diseases in various parts of the world. The extent of the disease includes crops, horticulture, flowers,fruit trees and forest trees, etc., the disease is highly transmitted, obvious symptoms, and great harm, the phytoplasma infection can cause plant hormone or growth regulator disorders, which can lead to abnormal growth or variation of plants, and if seriously it can even cause plant death. Our country has announced more than 100 original body related diseases, and this number continues to rise, the current domestic for the naming of the original body has more than 60 kinds of graft, and constantly have new candidate reports and named reported from the plant in the original body has 16 S rDNA group members across the world in addition to classify according to symptoms and features on the body, the early name are caused in the diseases of plants with the characteristics of the disease, such as paulownia witches' original body since the late 1980 s, has designed many PCR primers combination to amplify the operon part is used for the diagnosis and the system development, due to the availability of general primers,rooted in the history of the original diagnosis and system development has been based on 16 S rRNA genes and 16 S-23 S rRNA spacer to detect plant disease is the most difficult to solve and prevention and control of the original body is difficult to control the spread of the original body, under natural conditions, plant not only can the original body by leafhoppers aphids Insects such as psyllid can be spread and diffused as mediators. In addition, phytoplasma can be spread by grafting Cherry phytoplasma disease is one of them. In recent years, this disease has become one of the most important diseases threatening the development of cherry industry, mainly causing cherry phyllody(virescence) disease and abnormal growth and variation of the flower organs, leaves and fruits. Eventually, the plant will die rapidly within 2-5 years, causing a very significant loss to the cherry industry in China and the world. The extent of the disease varies from region to region. With the increasing area, scale and damage degree of cherry phytoplasma in different regions in recent years, especially cherry phytoplasma breaks out in large area of Chongqing city, which has brought us severe threat. The yield and quality of cherry planting area in this area have been greatly affected, which has caused serious losses to the cherry planting industry around Chongqing. So the systematic research on its pathogenic mechanism, plant growth and development characteristics and control methods is particularly important. Only a systematic study of all relevant information can cure the disease. In view of the research needs of cherry phytoplasma disease research, this paper reviews the research progress at home and abroad, mainly from the classification,detection and transmission of phytoplasma and cherry phytoplasma diseases, etc., it provides an important basis for further research and prevention of cherry plant diseases, and analyses the future research prospect and application value.