RESUMEN
The citrus yellow mosaic badnavirus (CMBV) is one of the most important viruses causing yellowing and declining in different Citrus species. The Coorg mandarin, pomelo and grapefruit showing the yellow mosaic disease symptoms were collected from different famers field during the survey. Further viral pathogenicity was confirmed through grafting on Rangpur lime as root stock. To confirm the identity of the pathogen, total genomic DNA was extracted from Coorg mandarin, Pomelo and grapefruit were subjected to PCR amplification using ORF III specific primers. Further the complete genome of CMBV amplified using different sets of specific primers were cloned and sequenced. The sequence analysis showed that CMBV from the Coorg mandarin showed maximum nt identity of 94.5% with CMBV-AL infecting acid lime. Recombination and GC plot analysis showed that the recombination occurred at in low GC content regions of genome of the CMBV and are derived from the previously reported Badnaviruses infecting different Citrus species. Supplementary Information: The online version contains supplementary material available at 10.1007/s13337-024-00864-z.
RESUMEN
Besides apple mosaic virus (ApMV), apple necrotic mosaic virus (ApNMV) has also been found to be associated with apple mosaic disease. Both viruses are unevenly distributed throughout the plant and their titer decreases variably with high temperatures, hence requiring proper tissue and time for early and real-time detection within plants. The present study was carried out to understand the distribution and titer of ApMV and ApNMV in apple trees from different plant parts (spatial) during different seasons (temporal) for the optimization of tissue and time for their timely detection. The Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR) was carried out to detect and quantify both viruses in the various plant parts of apple trees during different seasons. Depending on the availability of tissue, both ApMV and ApNMV were detected in all the plant parts during the spring season using RT-PCR. During the summer, both viruses were detected only in seeds and fruits, whereas they were detected in leaves and pedicel during the autumn season. The RT-qPCR results showed that during the spring, the ApMV and ApNMV expression was higher in leaves, whereas in the summer and autumn, the titer was mostly detected in seeds and leaves, respectively. The leaves in the spring and autumn seasons and the seeds in the summer season can be used as detection tissues through RT-PCR for early and rapid detection of ApMV and ApNMV. This study was validated on 7 cultivars of apples infected with both viruses. This will help to accurately sample and index the planting material well ahead of time, which will aid in the production of virus-free, quality planting material.
Asunto(s)
Ilarvirus , Malus , Virus del Mosaico , Virus de Plantas , Enfermedades de las Plantas , PlantasRESUMEN
Symptoms of leaf roll, swollen nodes, flat branch and witches' broom were observed in five cultivars of sweet cherry from Srinagar, Jammu and Kashmir province, India, during 2019-2021. Phytoplasmas association were confirmed by amplifying 16S rRNA, secA, rp, tuf and secY genes with phytoplasma-specific primers in all symptomatic sweet cherry cultivars in nested PCR assays. Pairwise sequence comparison, phylogeny and virtual RFLP (16S rRNA gene) analyses confirmed the presence of 'Candidatus Phytoplasma asteris' and 'Ca. P. trifolii' strains in the sweet cherry samples. The incidence of flat branch and witches' broom symptoms associated with 'Ca. P. trifolii' varied from 5.8 to 25% in cultivars Bigarreau Nepoleon (Double), Bigarreau Noir Grossa and CITH-Cherry-9. However, incidence of leaf rolling, swollen nodes and bud proliferation associated with 'Ca. P. asteris' was recorded 7.5% in cultivar Stella and 10% in Sunburst, respectively, in the surveyed area. The multigene characterization of sweet cherry phytoplasma strains confirmed the validity of these molecular markers for identification of phytoplasmas enclosed in 16SrI and 16SrVI groups. The presence of phytoplasmas in sweet cherry is the first report from India.
RESUMEN
The major viruses infecting apple cultivars throughout the world including India are apple mosaic virus (ApMV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple chlorotic leaf spot virus (ACLSV), and recently, a new virus, apple necrotic mosaic virus (ApNMV), was reported from mosaic-infected apple cultivars in India. The aim of this study was to detect the ApNMV virus along with the other three viruses (ApMV, ASPV and ASGV) simultaneously by multiplex RT-PCR. Four primer-pair-produced amplicons of 670, 550, 350 and 210 bp corresponding to ApNMV, ApMV, ASPV and ASGV, respectively, were found to be specific for these viruses when tested individually. The annealing temperature (55°C), primer concentration (0·8 µl) and other components of the master mix were standardized for the development of one-step m-RT-PCR assay. The m-RT-PCR protocol developed was further validated with 30 samples from seven symptomatic or asymptomatic apple cultivars, which revealed the presence of more than one virus in these cultivars. Most of the viruses were found to be present either alone or in mixed infection; however, ASPV was more common in tested cultivars. An easy, cost-effective and rapid multiplex RT-RCR protocol was developed to detect the four viruses, which infect apple plants either in individually or together in the field. This assay will help in the surveying and indexing of apple germplasm and the distribution of all four viruses in the apple growing regions of India.
