Association of Citrus Virus A to Citrus Impietratura Disease Symptoms

Abstract

Citrus impietratura disease (CID) is a graft transmissible, virus-like disease observed in old-line citrus trees; its characteristic symptom is the appearance of gum in the albedo of the affected fruits. To identify the causal agent of the disease, high throughput sequencing (HTS) was performed on symptomatic orange fruits. The analysis of the obtained data revealed in all samples, mixed infections of viroids commonly found in citrus trees together with the recently described citrus virus A (CiVA). Examination of additional symptomatic fruits with conventional RT-PCRs led to the identification of a single CiVA infection in one tree, which was verified by HTS. Indexing of the single CiVA-infected tree on indicator plants resulted in the appearance of characteristic symptoms in the leaves that were correlated with virus accumulation. Moreover, a comparative analysis among symptomatic and asymptomatic fruits derived from the same trees was performed and included the single CiVA-infected orange tree. The analysis revealed a positive correlation between the appearance of symptoms and the accumulation of CiVA RNAs. To facilitate CiVA detection during certification programs of propagation material a quantitative RT-qPCR targeting the movement protein of the virus, was developed and evaluated for reliable and sensitive detection of the virus. To the best of our knowledge this is the first study that associates CiVA with the appearance of impietratura disease symptoms.

Molecular Characteristics and Incidence of Apple Rubbery Wood Virus 2 and Citrus Virus A Infecting Pear Trees in China

“…Except for sample LYXS, we did not detect the Mb and Sb segments of ARWV-2 from other pear samples, indicating a low occurrence frequency of the ARWV-2 Mb and Sb segments in pear grown in China. The complete genomic sequences of three CiVA isolates from citrus [ 8 , 12 ], two CiVA isolates from apple [ 14 ], and a near-completed genomic sequence of two CiVA isolates from pear have been reported recently [ 11 , 13 ]. Here, we reported the complete genomic sequence of a CiVA-P isolate from a pear tree grown in China.…”

“…Now, CiVA has been identified in pear in France [11], and is also found to infect pear and citrus in South Africa [12,13]. A recent study showed that the virus was related to the impietratura symptoms of citrus by using high-throughput sequencing (HTS)for identification of the impietratura infectious agent along with a comparative analysis among symptomatic and asymptomatic orange fruits in Greece [14].…”

Identification and Characterization of Citrus Concave Gum-Associated Virus Infecting Citrus and Apple Trees by Serological, Molecular and High-Throughput Sequencing Approaches

“…CiVA was not associated with trunk (CG or cristacortis, CR) and leaf symptoms in citrus [8]. However, it has been recently associated with symptoms of impietratura, a disease inducing spotting and gumming in rind and albedo of fruits, on naturally infected grapefruit (Citrus x paradisi MacFad) trees grown in Greece [9] and with symptoms of oak leaf in indicator plants in both Greece and South Africa [9,10]. Akin to CCGaV, the host range of CiVA has been extended to a pome fruit tree species (Pyrus communis L.), although the virus pathogenicity in this host has not been assessed yet [11,12].…”

“…Molecular methods based on RT-PCR to specifically detect CCGaV and CiVA have been developed since early reports of these viruses [1,8]. Moreover, a multiplex RT-PCR protocol to identify and discriminate in a single reaction the two viruses in citrus has also been fixed recently [13], and an RT-qPCR has been applied for quantitative assays of CiVA in citrus fruits [9] and for the detection of CCGaV, CiVA and other negative-stranded RNA viruses [14]. Although these molecular methods allow detection of coguviruses, the availability of serological assays would strongly reduce the detection costs and provide new opportunity for large-scale surveys and for extensive tests requested by certification programs of vegetative propagation materials.…”

HTS-Based Diagnostics of Sugarcane Viruses: Seasonal Variation and Its Implications for Accurate Detection

“…On the other hand, the advent of high-throughput sequencing technologies (HTS) have revolutionized the identification and characterization of plant pathogens over the last decade [ 18 , 19 ]. Since its debut in identifying novel viruses infecting grapevine and several other plant species, an increasing number of plant viruses and viroids have been fully or partially characterized using HTS-based techniques, greatly improving virus detection, disease diagnosis, and the study of diseases with unknown etiology [ 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. There are several advantages of HTS when compared with conventional detection methods, including its capability to identify both anticipated and unknown pathogens without acquiring prior knowledge of their presence in the specimen [ 19 , 27 ], its reduced timeframe, and enhanced comprehensiveness in virus detection by a direct comparison with biological indexing [ 28 ].…”