| China is the largest apple cultivation country all over the world,but there are several virus diseases in domestic commercial apple orchards which greatly affected the development of apple industry of our country.The transmission of apple virus diseases in field is mostly through grafting or mechanical pruning.Once the tree was infected by viruses,the tree would carry the viruses for the lifetime.So far,there was limited information about non-human transmission way of apple virus disease,but there are studies shows that fungi can carry and transmit plant viruses.Virome Sequencing technology is a new emerging virus detection technology in recent years,which was established on the basis of Next Generation Sequencing technology(NGS),and could be used to detect of known or unknown viruses accurately.Our study takes apple viruses and fungi of apple roots as the main research objects,the isolation and identification of fungi,viruses detection of fungi by Virome Sequencing technology,fungi infecting indicator plants and other means were used to explore apple viruses can be carried by fungi and be transmitted between fungi and plants,and provide a new idea for the early detection and prevention of apple virus diseases.The research results are as follows:1.The leaves of infected apple trees were collected and the Virome Sequencing technology was used to detect the viruses of apple trees and to prove the feasibility of this detection method.The results showed that:a total of 5 kinds of apple viruses were detected from the leaves,including Apple stem grooving virus,Apple stem pitting virus,Apple chlorotic leaf spot virus,Apple necrotic Mosaic virus,and Apple green crinkle associated virus.Target bands were obtained after amplification of 5 kinds of apple viruses by RT-PCR method,which indicated that the detection results of Virome Sequencing technology were accurate and reliable,and could be used to detect apple virus in fungi.2.The roots of infected apple trees and the soil which the roots grew in were collected,and the fungi of the soil,rhizosphere and roots were isolated and identified.The results showed that:14 fungi were isolated from the environmental soil,7 fungi were isolated from the rhizosphere and 10 fungi were isolated from the roots.The total number was 31,which were classified into 14 different genera after identification.3.The results of apple viruses detection in fungi were as followings:ASGV was detected in 17 fungi and ASPV was detected in 15 fungi,among these there were 6 fungi simultaneously detected the existence of these 2 viruses,while ACLSV,APNMV and AGCAV were not detected in all the fungi.Cladosporium macrocarpum and Fusarium solani,which both carried ASGV and ASPV,were detected by Virome Sequencing technology,but only ASPV was detected.4.Using fungi which carried ASPV to infect ASPV indicator plant western tobacco 3 7B and virus-free Gala apple seedlings,and both materials were planted in the collected environmental soil.The results were:after growing for a period of time,the leaves of tobacco 37B infected with fungi showed the symptoms of yellow leaf and curled leaf edge,and similar symptoms occurred in tobacco which were planted in unsterilized soil;While the growth of virus free Gala apple seedlings decreased after a period of time,and ASPV was also detected by RT-PCR.5.The results of investigations on the phenomenon of apple viruses carried by fungi in multiple producing areas were:among the fungi isolated from 12 roots samples collected from different orchards in the main apple producing area of Henan Province,ASPV was detected in 7 of them,accounting for 58.3%,which proved that this phenomenon-fungi carries apple virus is common.The fungi isolated from the roots of infected apple trees can indeed carry apple viruses and transmit apple viruses disease,which is a new way of apple virus diseases transmission;it also proves that apple viruses can transmit between plants and fungi,and this phenomenon is commonly. |
