Degradation of oxalic acid by transgenic oilseed rape plants expressing oxalate oxidase

Abstract

SummaryOxalic acid is thought to have a primary role in the pathogenicity of several plant pathogens, notably Sclerotinia sclerotiorum. A gene coding for the enzyme oxalate oxidase was isolated from barley roots and introduced into oilseed rape as a means of degrading oxalic acid in vivo. This report describes the production of several transgenic plants of oilseed rape and the characterisation of these plants by Southern, Western and enzyme activity assays. Plants were shown to contain an active oxalate oxidase enzyme and were tolerant of exogenously supplied oxalic acid.

Oxalate-Degrading Bacteria Can ProtectArabidopsis thalianaand Crop Plants AgainstBotrytis cinerea

“…Oxalate oxidase seems to be involved in resistance of wheat and barley to fungal pathogens (Steiner-Lange et al 2003;Zhang et al 1995) and its overexpression can make crop plants more resistant to Sclerotinia spp. (Cessna et al 2000;Donaldson et al 2001;Thompson et al 1995). The mechanism of resistance has not yet been elucidated; it could be the effect of reduction of oxalate concentrations to below phytotoxic levels, or the formation of H 2 O 2 with antimicrobial and resistance-inducing properties.…”

“…The partial protection by some carbonate salts against B. cinerea infection may be related to such a buffering mechanism (Fallik et al 1997;Gabler and Smilanick 2001). Some transgenic crop plants have been generated that degrade oxalic acid and are more resistant to S. sclerotiorum (Donaldson et al 2001;Livingstone et al 2005; Thompson et al 1995). Here, we have exploited the versatility of biological agents to degrade oxalic acid and act as plant protectors.…”

Genetic transformation of Brassica

“…The predominant gene in this category used for Brassica transformation is the bar gene (Thompson et al 1987) which confers resistance to the herbicides bialaphos and D + L-phosphinotricin . Good regeneration of transformed plants has been obtained with several transformation protocols and this marker offers the additional possibility of selection in the field.…”

“…In field trials increased resistance was reported against Alternaria brassicae, Cylindrosporium concentricum, Phoma lingam and Sclerotinia sclerotiorum in B. napus transformed with a chimeric 35S-chitinase gene (GrezesBesset et al 1995). Transforming the barley oxalate oxidase gene into oilseed rape increased resistance to Sclerotiana wilt (Thompson et al 1995).…”

The Roles of Germin Gene Products in Plants Under Salt Stress

“…Another peroxide generating enzyme, a fungal glucose oxidase, has been shown to enhance the resistance of transformed plants to fungal infection, when introduced as a transgene (Wu et al, 1995). In experiments designed to protect Brassica napus plants from the oxalate secreting fungus, Sclerotinia transgenic oilseed rape plants, transformed with barley oxalate oxidase, were found to express a 25 kDal protein reactive with anti-germin antiserum and to express oxalate oxidase activity which protected plants against potentially toxic applications of oxalic acid (Thompson et al, 1995). In a current study, 36 expressed sequence tags (ESTs) encoding GLPs from peanut (Arachis hypogaea L.) were identified.…”