Effect of virulence and serial transfers of Xanthomonas campestris on xanthan gum production

Abstract

The virulence of six Xanthomonas campestris isolates was evaluated using the percentage of lesion area of leaves in Brassica oleraceae host plant, compared to diameter of colonies, xanthan production and gum viscosity. In terms of virulence, the isolates belonged to two statistically different groups: isolates B, UPF and C 7 showed values between 52 and 69%, while isolates CF, C and strain B-1459 gave 0-30% of lesion area. Final xanthan concentration, gum viscosity and colony diameter did not correlate with virulence calculated by percentage of lesion area, showing that this parameter is not a good criterium for selection of potential xanthan producer isolates. Serial transfers of X. campestris isolates in host plant did not show a significant effect on in vitro production of xanthan or on viscosity levels, suggesting that the increasing interaction between plant and bacteria did not stimulate the increase in xanthan production and viscosity.

Produção de goma xantana por cepas nativas de Xanthomonas campestris a partir de casca de cacau ou soro de leite

“…Pode-se observar que o ponto ótimo da fase log ocorre entre 40-70 horas de inoculação [20] Estudando a mesma cepa com condições de agitação diferente e um meio fermentativo mais complexo obteve um rendimento de 7,97 g.L -1 de goma xantana. Nitschke & Rodrigues (2000) [22] no Existem alguns estudos que testaram a utilização do soro de leite para a produção de goma xantana. [3] Produziram goma a partir de soro de leite com Xanthomonas campestris C 7 L atingindo uma produção media de [26] utilizou o soro de queijo mussarela para a produção de goma xantana e obteve um rendimento de 13,70 g.L -1 e com soro de queijo prato obteve 7,81 g.L -1 .…”

Xanthomonas campestris, a novel stress tolerant, phosphate-solubilizing bacterial strain from saline–alkali soils

“…Virulence test against different plants of citrus and crucifer varieties for the pathogenicity was evaluated by the percentage of lesion area of leaves, through comparison with a standard visual scale (Nitschke and Rodrigues 2000). The isolated strain did not show any sign of infection during the period tested.…”

The citrus plant pathogen Xanthomonas citri has a dual polyamine-binding protein

“…Xanthomonas citri ( X. citri ) is a gram-negative phytopathogenic bacterium responsible for the citrus canker, a disease that causes significant losses of citrus fruits affecting the economy in Brazil and the World [ 1 ]. Production of xanthan gum polysaccharide [ 2 , 3 ] induction of adhesins [ 4 , 5 ] and type III and IV effector proteins are some of the many mechanisms involved in the infection and pathogenesis [ 6 , 7 ]. The relationship between ATP-Binding Cassette systems (ABC transporters) and physiological processes has been largely demonstrated in bacteria and also in Xanthomonas genus [ [8] , [9] , [10] , [11] , [12] ].…”