Albugo candida (pers.) O. Kuntze (white blister rust) is a biotrophic fungus which infects cruciferous plants including Arabidopsis thaliana (L) Heynh. We report the effect of this pathogen on the photosynthetic and carbohydrate metabolism of A. thaliana. As infection progressed A. Candida caused a reduction in the rate of photosynthesis when measured at either ambient or saturating concentrations of CO2. These data suggested that both chlorophyll and Rubisco were lost from regions of infected leaves, and measurements of chlorophyll, Rubisco content and activity supported these observations. The reduction in the rate of photosynthesis was not caused by closure of stomata as transpiration was unaffected by the disease. Infected leaves accumulated both soluble carbohydrates and starch. The activities of sucrose‐phosphate synthase, sucrose synthase and ADP glucose pyrophosphorylase did not change in response to infection. However, the activities of both the wall‐bound and soluble acid invertases were higher in infected leaves than in controls; a new soluble invertase isoform with a pl of 5‐1 appeared in infected leaves. The possible origin of the increase in wall‐bound and soluble invertase activities and its effect on the carbohydrate and photosynthetic metabolism of the leaf are discussed.
Multiple isoforms of beta-fructofuranosidase (invertase, EC 3.2.1.26) were identified in mature green leaves of the cruciferous plant Arabidopsis thaliana (L.) Heynh. There were four major and one minor isoforms of soluble acid invertase and an additional activity which could be released from the cell wall by buffers of high ionic strength. This study reports the separation and characterisation of three soluble isoforms following ammonium sulphate and polyethylene glycol 6000 precipitations, Concanavalin A, MonoQ ion exchange, Superose 12 size-exclusion chromatography and chromatofocusing. These isoforms, designated INV1, INV2 and INV3, had isoelectric points of 4.75, 4.70 and 4.65 and a Km for sucrose of 5, 12 and 5 mM, respectively. Each had a pH optimum of 5.5, exhibited optimal activity at 45 degrees C and used sucrose as the preferred substrate. All fractions containing these isoforms contained a 52-kDa polypeptide which was specifically detected by immunoblotting with an antibody raised against deglycosylated wheat invertase. The N-terminal amino-acid sequence of this polypeptide was homologous to acid invertases isolated from other plant species. The possible origin of isoforms of soluble acid invertase is discussed.
Metal-Organic Frameworks (MOFs) are constructed from metal ions/cluster nodes and functional organic ligands through coordination bonds. Owing to the advantages of diverse synthetic methods, easy modification after synthesis, large adsorption...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.