Epidemiology of Phytoplasma-Associated Papaya Diseases in Queensland, Australia

Abstract

Three phytoplasma-related diseases of papaya (Carica papaya), dieback, yellow crinkle, and mosaic, are recognized within Australia. Immature leaf material was sampled every week for 8 months from a cohort of 60 female plants, located within a commercial papaya plantation, to determine the minimum time between infection and symptom expression. Phytoplasma DNA was detected using the polymerase chain reaction (PCR) with primers specific for phytoplasmas in general, and for the stolbur group of phytoplasmas. The dieback-associated phytoplasma was detected 1 week prior to (four cases) or the same week (nine cases) as symptom expression, while phytoplasma DNA was detected between 3 and 11 weeks prior to expression of mosaic symptom (six cases). Lateral shoot regrowth on the lower stem of plants which had suffered dieback disease failed to generate stolbur-specific PCR products in 15 cases. A dual infection with dieback and yellow crinkle or mosaic was diagnosed in a further two cases, using restriction fragment length polymorphism digests, and both cases were interpreted as secondary infections by the dieback-associated phytoplasma. Regrowth in three of seven cases of yellow crinkle- and three of nine cases of mosaic-affected plants tested positive for phytoplasma-specific DNA. Ratooning of dieback-affected plants and removal of yellow crinkle- or mosaic-affected plants is suggested for the management of these diseases.

Metabolomic analysis reveals the potential metabolites and pathogenesis involved in mulberry yellow dwarf disease

“…These findings confirm and extend earlier reports, which show phytoplasma infections lead to the accumulation of carbohydrates in source leaves (Lepka et al 1999;Bertamini et al 2002a;Maust et al 2003). It was reported that the sucrose contents in the sink organs of phytoplasma-infected plant, such as root, were lower than those in the healthy ones (Guthrie et al 1998). Therefore, there is an unresolved issue relating to the reason for which the infected plants cannot control the allocation of resources between source and sink organs at the whole-plant level.…”

“…It was reported that the sucrose contents in the sink organs of phytoplasma‐infected plant, such as root, were lower than those in the healthy ones (Guthrie et al . ). Therefore, there is an unresolved issue relating to the reason for which the infected plants cannot control the allocation of resources between source and sink organs at the whole‐plant level.…”

Comparative proteomic analysis provides new insights into mulberry dwarf responses in mulberry (Morus alba L.)

“…The model originally proposed by Guthrie et al . 46 could be modified based on our results (Fig. 9).…”

“…The mechanism by which symptoms arise might be complex and could involve a number of different virulence strategies. The model originally proposed by Guthrie et al [46] could be modified based on our results ( Fig. 9).…”

Polymerase Chain Reaction for Phytoplasmas Detection

“…Another pathway of phytoplasma survival and transmission is vegetative propagating plant material. As it mentioned phytoplasma invading phloem tissue and it is mostly find that in woody plants they disappear from aerial parts of trees during the winter and survive in the root system to recolonize the stem and branches in spring (149,150,58).…”