Molecular detection of phytoplasmas associated with root wilt disease in coconut seedlings

Abstract

Root (wilt) disease is a major production constraint in coconut, causing an estimated loss of 968 million nuts. The most prominent symptom of the disease includes a characteristic bending of leaflets (flaccidity), foliar yellowing and marginal necrosis. (Solomon et al, 1999). The symptoms are only obvious in palms that are more than 30 months old (Butler, 1908). The microscopic and serological evidence reveals phytoplasma as a pathogen associated with root (wilt) disease (Sasikala et al, 1998). Phytoplasmas, formerly known as mycoplasma like organisms, are a group of plant pathogenic organism, without a cell wall, and are unculturable prokaryotes. They are associated with diseases in more than 300 plant species worldwide. The inability to culture them has greatly hampered research efforts to understand various aspects of phytoplasmal biology such as pathogenicity, vector relationship, and pathogen-host interactions (Guo et al, 2000).