• The Plant Pathology Journal
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• v.34 no.6
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• pp.532-543
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• 2018

Complete genome sequences of 22 isolates of Cucurbit aphid-borne yellows virus (CABYV), collected from melon plants showing yellowing symptom in Korea during the years 2013-2014, were determined and compared with previously reported CABYV genome sequences. The complete genomes were found to be 5,680-5,684 nucleotides in length and to encode six open reading frames (ORFs) that are separated into two regions by a non-coding internal region (IR) of 199 nucleotides. Their genomic organization is typical of the genus Polerovirus. Based on phylogenetic analyses of complete nucleotide (nt) sequences, CABYV isolates were divided into four groups: Asian, Mediterranean, Taiwanese, and R groups. The Korean CABYV isolates clustered with the Asian group with > 94% nt sequence identity. In contrast, the Korean CABYV isolates shared 87-89% sequence identities with the Mediterranean group, 88% with the Taiwanese group, 81-84% with the CABYV-R group, and 72% with another polerovirus, M.. Recombination analyses identified 24 recombination events (12 different recombination types) in the analyzed CABYV population. In the Korean CABYV isolates, four recombination types were detected from eight isolates. Two recombination types were detected in the IR and P3-P5 regions, respectively, which have been reported as hotspots for recombination of CABYV. This result suggests that recombination is an important evolutionary force in the genetic diversification of CABYV populations.

• The Plant Pathology Journal
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• v.32 no.6
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• pp.580-583
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• 2016

The cotton leafroll dwarf virus (CLRDV) is one of the most devastating pathogens of cotton. This malady, known as cotton blue disease, is widespread in South America where it causes huge crop losses. Recently the disease has been reported from India. We noticed occurrence of cotton blue disease and chickpea stunt disease in adjoining cotton and chickpea fields and got interested in knowing if these two viral diseases have some association. By genetic studies, we have shown here that CLRDV is very close to chickpea stunt disease associated virus (CpSDaV). We were successful in transmitting the CLRDV from cotton to chickpea. Our studies indicate that CpSDaV and CLRDV in India are possibly two different strains of the same virus. These findings would be helpful in managing these serious diseases by altering the cropping patterns.

• Research in Plant Disease
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• v.23 no.3
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• pp.262-267
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• 2017

Throughout year 2015 to 2016, 101 proso millet and 200 sorghum samples were collected from five provinces in South Korea. The samples were subjected to paired-end RNA sequencing and further analyzed by RT-PCR. The results indicated that Rice black-streaked dwarf virus (RBSDV) was detected from sorghum collected in Gyeongsang province. The other four viruses, including RBSDV, Rice stripe virus (RSV), Barley virus G (BVG), and Cereal yellow dwarf virus (CYDV), were detected from proso millet. Among four viruses, both RSV and RBSDV were identified high frequency from proso millet collected from Gyeongsang province. Otherwise, BVG was nearly equally identified from five provinces, suggesting that the virus was supposedly widespread nationwide. RBSDV was first identified from both proso millet and sorghum in South Korea. The other virus annotated CYDV identified proso millet was shown to have relatively low identities compared to CYDV previously reported, suggesting that the virus might be new member of Polerovirus.

• Research in Plant Disease
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• v.23 no.1
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• pp.69-74
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• 2017

In 2015, a nationwide survey was carried out to investigate about occurrence pattern of virus infecting foxtail millet. A total 100 foxtail millet leaf samples showing virus-like and abnormal symptoms were collected in the seven main cultivated regions of Korea. Four viruses were identified using reverse transcription polymerase chain reaction and RNA sequencing. Of the collected 100 foxtail millet samples, 10 were Barley virus G (BVG), 4 were Rice stripe virus (RSV), 1 was Northern cereal mosaic virus (NCMV), and 1 was Sugarcane yellow leaf virus (ScYLV) infection. To our best knowledge, this is the first report of BVG and NCMV infecting foxtail millet in Korea and ScYLV is expected as new Polerovirus species. This research will be useful in breeding for improved disease-resistant foxtail millet cultivars.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.536-557
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• 2020

Sugarcane yellow leaf virus (SCYLV) is a distinct member of the Polerovirus genus of the Luteoviridae family. SCYLV is the major limitation to sugarcane production worldwide and presently occurring in most of the sugarcane growing countries. SCYLV having high genetic diversity within the species and presently ten genotypes are known to occur based on the complete genome sequence information. SCYLV is present in almost all the states of India where sugarcane is grown. Virion comprises of 180 coat protein units and are 24-29 nm in diameter. The genome of SCYLV is a monopartite and comprised of single-stranded (ss) positive-sense (+) linear RNA of about 6 kb in size. Virus genome consists of six open reading frames (ORFs) that are expressed by sub-genomic RNAs. The SCYLV is phloem-limited and transmitted by sugarcane aphid Melanaphis sacchari in a circulative and non-propagative manner. The other aphid species namely, Ceratovacuna lanigera, Rhopalosiphum rufiabdominalis, and R. maidis also been reported to transmit the virus. The virus is not transmitted mechanically, therefore, its transmission by M. sacchari has been studied in different countries. SCYLV has a limited natural host range and mainly infect sugarcane (Sachharum hybrid), grain sorghum (Sorghum bicolor), and Columbus grass (Sorghum almum). Recent insights in the protein-protein interactions of Polerovirus through protein interaction reporter (PIR) technology enable us to understand viral encoded proteins during virus replication, assembly, plant defence mechanism, short and long-distance travel of the virus. This review presents the recent understandings on virus biology, diagnosis, genetic diversity, virus-vector and host-virus interactions and conventional and next generation management approaches.