Incidence of mud crab reovirus (MCRV) outbreak in polyculture ponds of Andhra Pradesh, south east coast of India.

Reovirus designated as Mud crab reovirus (MCRV) is associated with the mass mortalities of mud crabs resulting in significant economic loss to crab and shrimp-mud crab polyculture farmers in the Nagayalanka, Krishna district, Andhra Pradesh. The 100 % chronic mass mortalities have been attributed to the outbreak of Mud crab reovirus (MCRV) in the polyculture farms. The moribund crabs showed autotomy, discoloration of carapace, loss of appetite, slow movement and loose gills. Histopathological observations of the infected mud crabs showed an atrophied hepatopancreas, complete degeneration of tissues along with viral inclusions in hepatopancreas, gills and muscles. Further analysis using Transmission electron microscopy (TEM), showed that the viral particles had a diameter of 70 nm and exhibited a non-enveloped, icosahedral shape arranged in a crystalline manner. The virus mainly infects the connective tissue of hepatopancreas, gills, muscle and develops in the cytoplasm. RT-PCR reconfirmed the presence of reovirus in the hepatopancreas of spontaneously infected mud crab Scylla serrata. The current study shows the importance of monitoring the MCRV prevalence in polyculture farms to minimize its spread and precautionary measures can be taken by screening the brooders from the crab hatchery and stocking of wild crabs without screening should be avoided in order to prevent MCRV outbreak.

A reference-grade genome identifies salt-tolerance genes from the salt-secreting mangrove species Avicennia marina.

Water scarcity and salinity are major challenges facing agriculture today, which can be addressed by engineering plants to grow in the boundless seawater. Understanding the mangrove plants at the molecular level will be necessary for developing such highly salt-tolerant agricultural crops. With this objective, we sequenced the genome of a salt-secreting and extraordinarily salt-tolerant mangrove species, Avicennia marina, that grows optimally in 75% seawater and tolerates >250% seawater. Our reference-grade ~457 Mb genome contains 31 scaffolds corresponding to its chromosomes. We identified 31,477 protein-coding genes and a salinome consisting of 3246 salinity-responsive genes and homologs of 614 experimentally validated salinity tolerance genes. The salinome provides a strong foundation to understand the molecular mechanisms of salinity tolerance in plants and breeding crops suitable for seawater farming.

The genus Lernaeenicus Lesueur (Copepoda, Siphonostomatoida, Pennellidae) in India: a checklist with notes on its taxonomy and ecology.

Members of the pennellid genus Lernaeenicus Lesueur, 1824 (Copepoda, Siphonostomatoida) have frequently been recorded from commercially important fishes collected along the coasts of India. Marine fish hosts from landing centres at Nagapattinam and Parangipettai Tamil Nadu, southeast coast of India, were examined for parasitic copepods between January 2011 and December 2013. A total of nine species including three unidentified species of Lernaeenicus were recorded: (1) L. alatus Rangnekar, 1962 from the Indo-Pacific king mackerel Scomberomorus guttatus (Bloch & Schneider, 1801), (2) L. anchoviellae Sebastian & George, 1964 from the golden trevally Gnathanodon speciosus (Forsskål, 1775), (3) L. hemirhamphi Kirtisinghe, 1932 from the blue-barred halfbeak Hemiramphus far (Forsskål, 1775), Lutke's halfbeak H. lutkei Valenciennes in Cuvier & Valenciennes, 1847a and the ribbon halfbeak Euleptorhamphus viridis (van Hasselt, 1823b), (4) L. polynemi Bassett-Smith, 1898 from the fourfinger threadfin Eleutheronema tetradactylum (Shaw, 1804), (5) L. seeri Kirtisinghe, 1934 from the wahoo Acanthocybium solandri (Cuvier in Cuvier & Valenciennes, 1832), (6) L. stromatei Gnanamuthu, 1953 from the black pomfret Parastromateus niger (Bloch, 1795), (7) Lernaeenicus sp. 1 from the Indian anchovy Stolephorus indicus (van Hasselt, 1823a) and the rainbow sardine Dussumieria acuta Valenciennes in Cuvier & Valenciennes, 1847b, (8) Lernaeenicus sp. 2 from the goldspot mullet Chelon parsia (Hamilton, 1822), and (9) Lernaeenicus sp. 3 from the flathead grey mullet Mugil cephalus Linnaeus, 1758. Four pennellid species (L. hemirhamphi, L. polynemi, L. seeri and L. stromatei) were studied for their seasonal occurrence including prevalence and mean intensity, both of which were high in postmonsoon (2011) and low in premonsoon (2013) seasons. A checklist is provided for the Indian species of Lernaeenicus.

A new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) from the marine fish Terapon jarbua (Forsskål) (Terapontidae) off the eastern coast of India.

A new nematode species, Philometra terapontis n. sp. (Philometridae), is described from male and female specimens found in the ovary of the jarbua terapon Terapon jarbua (Forsskål) (Terapontidae, Perciformes) from the Bay of Bengal off the eastern coast of India. Based on light and scanning electron microscopical examination, the new species differs from most other gonad-infecting Philometra spp. in the length of the spicules (105-114 µm), a gubernaculum with dorsal, lamella-like structures and a distinct protuberance on its distal end, and a U-shaped, dorsally uninterrupted caudal mound in the male. From a few congeneric, gonad-infecting species with unknown males, it can be distinguished by morphological and biometrical features found in gravid females (i.e. length of body, length of first-stage larvae or oesophagus, and caudal structure), by the host type (fish family) and by the geographical distribution. Philometra terapontis is the first philometrid species reported from a fish belonging to the family Terapontidae. Philometra sawara Quiazon, Yoshinaga & Ogawa, 2008 is considered a junior synonym of P. scomberomori (Yamaguti, 1935). A key to gonad-infecting species of Philometra parasitising marine and brackish-water fishes is provided.