ظهور علایم زوال شدید در باغات مرکبات استان مازندران با آلودگی مخلوط ویروسی و شبه ویروسی کاککسیا

In recent years, Viral and Viroid symptoms Has increased In citrus orchards of Mazandaran province. Symptoms of cachexia on tangerines and their hybrids in other countries include yellowing, bark gumming, stem pitting, decline, dwarf and in some cases dwarf with decline, and in Iran include stem pitting, bark gumming and decline is also the separation basis for mild or severe isolates of the viroid. What happens in orchards and under natural conditions, especially on old trees that have been exposed to vectors of various infectious diseases, especially viruses, for years, increases the likelihood of mixed infections, making it difficult to identify cachexia-specific symptoms and, if inaccurate, identifying the infection with the viroid on the tree host and separation of the isolates in biological and molecular tests causes errors.In order to investigate the current situation and the possibility of mixing one or more viral pathogens with this pathogen in a host, during the years 1398 to 1400 local tangerine orchards, visited, sampled and transferred to the laboratory. Three grams of leaf tissue and three grams of skin tissue from each sample were powdered with liquid nitrogen. The nucleic acid extraction method was total RNA. RT-PCR with specific primers for tristeza , psorosis viruses, cachexia and exocortis viroids were used to amplify and identify these agents. In the sampling of orchards , out of a total of 150 samples collected, 63 samples were infected with tristeza virus, of which 30 samples were mixed with cachexia viroid. Of the 52 samples infected with citrus psorosis virus, 25 had mixed infection with cachexia viroid. 10 samples of trees were infected only with cachexia, six samples were infected with tristeza and psorosis, four samples were infected with all three pathogens and 17 samples were uninfected. Based on the obtained results, a mixture of viral and viroid pathogens has occurred in the local tangerine orchards of East Mazandaran. Mixed infections have a significant effect on the symptoms created in the host, causing variation in the type of symptoms and in some cases aggravating the symptoms, especially the decline of trees and impairing the ability to diagnose the type of disease based on the symptoms on the host. These differences may be related to the time of infection with each of these agents, the susceptibility of the host, and the severity of the pathogenicity of the each agent.