Apple chlorotic leaf spot virus

Introduction:-
Apple chlorotic leaf spot virus (ACLSV) is the type member of family Flexiviridae of the genus Trichovirus.This virus with flexuous filamentous particles 680-780 nm long and 12 nm in width containing linear positive-sense, ssRNA. Occurs in woody plants of the family Rosaceae including apple, peach, pear, and plum, cherry, apricot and prune. Its natural mode of spread is unknown. Transmissible by mechanical inoculation to herbaceous plants. Apple chlorotic leaf spot virus is a common latent virus. Latent viruses are those viruses which survive without causing symptoms in most cultivars, but may cause symptoms in other varieties or rootstock combinations.

Virion Properties:-
Morphology:
Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous; is cross-banded, is obliquely striated with a crisscrossed appearance, and has rope-like features.
Nucleic Acid:
The Mr of the genome constitutes 5% of the virion by weight. The genome is monopartite; only one particle size of linear, single-stranded RNA is recovered. The complete genome is 7555 nucleotides long, is fully sequenced, complete sequence is 7555 nucleotides long
Proteins:
The viral genome encodes structural proteins and non-structural proteins. Virions consist of 1 structural protein(s) (Lister and Bar-Joseph, 1981; Bar-Joseph et al., 1979).
Non-Structural Proteins: Virus-coded non-structural proteins have been isolated (Chairez and Lister (1973, Lister and Bar-Joseph (1981)) and 2 non-structural protein(s) are found.
Transmission and Vector Relationships:
Virus is transmitted by a vector, or not transmitted by a vector. Virus can be transmitted by mechanical inoculation and also by grafting.
Symptoms:
As the designation "latent" implies, these viruses are symptomless in most commercial cultivars, but may cause symptoms in certain cultivars, rootstock combinations, and ornamental varieties. Symptoms of Apple chlorotic leaf spot virus may include chlorotic leaf spots, leaf distortion, chlorotic rings and line patterns, reduced leaf size, and stunting.

Genome Properties:
The complete nucleotide sequences of the single genomic RNA of ACLSV isolates have been determined. They are isolates P863 from Prunus domestica.The ACLSV genome consists of a single strand polyadenylated RNA molecule of 7555 kb nucleotides excluding the poly-A tail, with the open reading frames (ORFs 1, 2 and 3) encoding protein with molecular masses of 216.5, 50.4 and 21.4 kDa, respectively (German et al., 1990). The 216.5 kDa ORF encodes a protein suspected to be involved in viral replication and the 50.4 kDa protein is suggested to be the movement protein, while the 21.4 kDa product is the viral coat protein (German et al., 1992).

Apple chlorotic leaf spot virus genome information: