Bacteria and Yeast Associated with Sugar Beet Root Rot at Harvest in the Intermountain West

Abstract

An undescribed wet rot of roots was observed in surveys of recently harvested sugar beet roots in Idaho and eastern Oregon in 2004 and 2005. Microorganisms isolated from 287 roots fell into the following groups: A (41% of strains), B (29%), C (17%), D (11%), E (2%), and F (1%). Groups A, B, C, and F were composed of bacteria while groups D and E were yeasts. Subgroup A1 (80% of group A strains) included Leuconostoc mesenteroides subsp. dextranicum strains and subgroup A2 (20%) contained Lactobacillus strains. Group B was dominated by subgroup B1 (92% of strains), which included Gluconobacter strains. When only one organism was isolated from rotted roots, strains from subgroup A1 were isolated most frequently. Group C was composed of enteric bacteria. Strain B322 of L. mesenteroides subsp. dextranicum caused the most severe rot on root slices and produced symptoms similar to those in harvested roots. Results suggest that L. mesenteroides subsp. dextranicum is among the first bacterial species to enter sugar beet roots, closely following fungal infections or entering directly through openings such as growth cracks. The bacterial rot leads to yield loss in the field but likely also leads to storage and factory-processing problems.

Sugar beet root rot at harvest in the US Intermountain West

“…The Fusarium isolates were grouped and identified based on techniques and descriptions by Nelson et al (1983) (Altschul et al 1997) to search the GenBank database via the National Center for Biotechnology Information website (www.ncbi.nlm.nih.gov/blast). The methods and results for the identification of the bacterial and yeast isolates were reported previously (Strausbaugh and Gillen 2008). This paper relates the results from fungal isolations to the previously reported bacterial isolations.…”

“…(71% of isolates), Phoma betae (85%), and oomycetes (55%) were predominantly found in the Magic Valley. Bacteria and yeast associated with wet rot symptoms had been reported previously (Strausbaugh and Gillen 2008).…”

“…Recently, lactic acid bacteria have been shown to be the primary bacteria associated with bacterial root rot in sugar beet grown in the IMW (Strausbaugh and Gillen 2008). Leuconostoc mesenteroides subsp.…”

“…betavasculorum Thomson et al), but recently, Leuconostoc mesenteroides subsp. dextranicum (Beijerinck) Garvie has also been found to cause root rot in sugar beet (Ruppel et al 1975;Strausbaugh and Gillen 2008;Tallgren et al 1999; Thomson et al 1977;Whitney 1986;Whitney and Mackey 1989).…”

“…Rhizoctonia solani anastomosis group (AG) 2-2IIIB, considered the leading cause of sugar beet root rot in the IMW, was shown to cause crown and brace root rot in corn (Brantner and Windels 2008;Führer Ithurrart et al 2004). Recently, a bacterial root rot caused by L. mesenteroides was demonstrated to be widespread in the IMW (Strausbaugh and Gillen 2008) and potentially interacts with fungal root rots. With the changes in rotations, cultural practices, and occurrence of bacterial root rot in the IMW, an investigation was conducted to establish the fungal pathogens important in root rot and their association with bacterial root rot in sugar beet.…”