Impact of Stolbur Phytoplasmas on Potato Tuber Texture and Sugar Content of Selected Potato Cultivars

Abstract

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg −1 fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg −1 FW in 2007 and 19,560 mg kg −1 FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. 'Courage' and 'Lady Rosetta' showed high numbers of diseased tubers and high sucrose concentrations, 'Lady Claire' had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones.

Pentastiridius leporinus (Linnaeus, 1761) as a Vector of Phloem-Restricted Pathogens on Potatoes: ‘Candidatus Arsenophonus Phytopathogenicus’ and ‘Candidatus Phytoplasma Solani’

“…In Southeastern Europe, Reptalus quinquecostatus transmits CPs to sugar beets [ 13 ], and Reptalus panzeri and H. obsoletus have been confirmed to transmit CPs to grapevines [ 27 , 28 , 29 ]. Hyalesthes obsoletus was further reported to be a vector for the Stolbur disease in lavender [ 30 ] but also in vegetables like tomato, eggplant, tobacco [ 31 ] and annual crops like maize [ 32 ], sugar beet [ 33 ] and potato [ 34 , 35 , 36 , 37 , 38 , 39 ], where it can cause serious effects in yield and tuber quality [ 40 ]. Whereas nymphs of P. leporinus have been reported to transmit CAp to potatoes [ 17 ], this is, to our knowledge, the first report that adults of this species transmit CPs as well as CAp to potatoes.…”

Scientific Opinion on the pest categorisation of Candidatus Phytoplasma solani

“…Symptoms of CPs on potato plants include upward rolling and purplish or red discoloration of the top leaves, shortened internodes, aerial tubers, early senescence and, finally, plant wilt and death. Severe CPs outbreaks have been reported in potato fields in several countries, including the Czech Republic, Hungary, Romania and Russia, causing significant (30 %-80 %) yield loss and a reduction in seed potato quality (Paltrinieri and Bertaccini 2007;Mozhaeva et al, 2008;Girsova et al, 2008;Lindner et al, 2008Lindner et al, , 2011Fialová et al, 2009). In addition, CPs infection increases the sucrose content of tubers by three-to six-fold; this severely affects the suitability of tubers for fried potato processing, as sucrose serves as a substrate in Maillard reactions to produce brown discoloration (Lindner et al, 2011).…”

“…Severe CPs outbreaks have been reported in potato fields in several countries, including the Czech Republic, Hungary, Romania and Russia, causing significant (30 %-80 %) yield loss and a reduction in seed potato quality (Paltrinieri and Bertaccini 2007;Mozhaeva et al, 2008;Girsova et al, 2008;Lindner et al, 2008Lindner et al, , 2011Fialová et al, 2009). In addition, CPs infection increases the sucrose content of tubers by three-to six-fold; this severely affects the suitability of tubers for fried potato processing, as sucrose serves as a substrate in Maillard reactions to produce brown discoloration (Lindner et al, 2011). In severe epidemics, yield losses as high as 60 % in tomato, 93 % in pepper, and 100 % in celery have been reported (Navratil et al, 2009).…”

Molecular detection and multilocus sequence analysis of Candidatus Phytoplasma solani-related strains infecting potato and sugar beet plants in Southern Germany

“…Symptoms of stolbur in potato plants include aerial tubers, shortened internodes, upward rolling and purplish or red discoloration of the top leaves, early senescence and nally, plant wilt and death. In addition, the suitability of tubers for fried potato processing is affected by the increased sucrose content in infected tubers (Lindner et al, 2011).…”