Association of a phytoplasma with a yellow leaf syndrome of sugarcane in Africa

Abstract

Evidence is presented for the association of a phytoplasma, provisionally named sugarcane yellows phytoplasma (ScYP), in sugarcane affected by a yellow leaf syndrome. The phytoplasma was consistently detected in leaves of more than 40 varieties from eight African countries. It was present in all symptomatic as well as some asymptomatic field grown cane samples but not in plants grown from true seed, and it was also observed in phloem sieve tubes by transmission electron microscopy. Phytoplasma 16s rDNA was confirmed by PCR, and restriction fragment analysis using RsaI and HaeIII confirmed that PCR-amplified products were of phytoplasma rather than of plant or of other pathogen origin. Sequences obtained from the intergenic spacer region, between the 16s and 23s rDNA genes, confirmed the identity of the phytoplasma as belonging to the western X group of phytoplasmas.

‘Candidatus Phytoplasma graminis' and ‘Candidatus Phytoplasma caricae’, two novel phytoplasmas associated with diseases of sugarcane, weeds and papaya in Cuba

“…Symptomless phytoplasma infections in sugarcane occur widely (Bailey et al, 1996;Cronjé et al, 1998;Arocha et al, 2000;Tran-Nguyen et al, 2000;Aljanabi et al, 2001), and the relatively long growth period of this crop allows infections to be carried through seasonal barriers and crop cycles. In this study, 14?2 % of sugarcane plants without symptoms were infected with phytoplasmas.…”

Analyses of Genotypic Diversity among North, South, and Central American Isolates ofSugarcane Yellow Leaf Virus: Evidence for Colombian Origins and for Intraspecific Spatial Phylogenetic Variation

“…Two of the SPV forms identified correspond to the extremes in a continuum of sequence evolution displayed in a SCYLV superpopulation structure, and the third form was diagnostic of a C-population structure. The application of these types of models has value in terms of predicting the types of SCYLV intraspecies diversity that may exist worldwide, and in general, may be useful in application for more informed design of transgenes for use in the elicitation of homology-dependent virus resistance mechanisms in transgenic plants.In the Americas, Sugarcane yellow leaf virus (SCYLV) is associated with a disease referred to as yellow leaf syndrome (YLS [3,5,6,47,55]), although a similar disease via phytoplasma infection may produce otherwise identical symptomology and is also currently referred to as YLS disease in certain areas of the world (6, 45). In sugarcane, losses of as high as 50% have been estimated to have occurred in field sites as the result of virus-induced YLS (55).…”

“…In the Americas, Sugarcane yellow leaf virus (SCYLV) is associated with a disease referred to as yellow leaf syndrome (YLS [3,5,6,47,55]), although a similar disease via phytoplasma infection may produce otherwise identical symptomology and is also currently referred to as YLS disease in certain areas of the world (6,45). In sugarcane, losses of as high as 50% have been estimated to have occurred in field sites as the result of virus-induced YLS (55).…”

Detection of Sugarcane Yellow Leaf Luteovirus of India

“…Subsequently, growers in Queensland (Australia) also reported having seen symptoms serious enough to warrant attention. Yellow leaf syndrome symptoms have now been observed and reported from sugarcane growing areas in Louisiana (Grisham et al 1997), Florida and Texas (Comstock et al 1994), in the USA, Australia (Borg et al 1997), Mauritius (Saumtally and Moutia, 1997), Brazil (Anon, 1995, 1996a, South Africa, Zimbabwe and Malawi (Anon, 1996b, Bailey et al 1997Cronje et al 1997), and India (Rao et al 2000).Yellow leaf syndrome (YLS) has recently been recognized as new disease of sugarcane (Comstock et al 1994; Ulian and Sangunio, 1994). Symptoms consist of yellowing leaves with a bright yellow midrib, often when the rest of the lamina is still green.…”

“…Louisiana (Grisham et al 1997), Florida and Texas (Comstock et al 1994), in the USA, Australia (Borg et al 1997), Mauritius (Saumtally and Moutia, 1997), Brazil (Anon, , 1996a, South Africa, Zimbabwe and Malawi (Anon, 1996b, Bailey et al 1997; Cronje et al 1997), and India (Rao et al 2000).…”