Mastreviruses in chickpea (Cicer arietinum) and other dicotyledonous crops and weeds in Queensland and northern New South Wales, Australia

Abstract

Natural infection by mastreviruses was investigated in chickpea (Cicer arietinum) and other dicotyledonous crops and weeds in grain production areas of Queensland and northern New South Wales, Australia, from 2000 to 2005. Altogether, 33 639 plants comprising 31 species and 10 dicot families were screened for infection by a tissue-blot immunoassay that did not distinguish between mastrevirus strains or species. Nine plant species in three families were identified as natural hosts. Chickpea was infected throughout the region although infection incidence did not exceed 5%. Infection was rare in faba bean (Vicia faba), canola (Brassica napus), and mustard (B. juncea) and not detected in field pea (Pisum sativum). Infection of chickpea and turnip weed (Rapistrum rugosum) was confirmed by immunocapture polymerase chain reaction (IC-PCR) with primers generic for dicot-infecting mastreviruses, and also immunosorbent electron microscopy and graft transmission in the case of chickpea. Individual mastreviruses were identified by comparing their IC-PCR amplicons by a combination of methods. Among 42 isolates from 41 chickpea plants, one was typical Tobacco yellow dwarf virus (TYDV) and the others were three recently distinguished strains including two proposed novel species: 34 Chickpea chlorosis virus strain A, six Chickpea chlorosis virus strain B, and one Chickpea redleaf virus. All of 10 isolates from 10 turnip weed plants were TYDV-B, a strain distinct from typical TYDV. The symptoms associated with mastrevirus infection in chickpea included foliar chlorosis or reddening, stunting, and usually phloem browning. The potential for losses in winter and summer grown field crops is discussed.