Recognition of endogenous molecules acting as "damage-associated molecular patterns" (DAMPs) is a key feature of immunity in both animals and plants. Oligogalacturonides (OGs), i.e. fragments derived from the hydrolysis of homogalacturonan, a major component of pectin are a well-known class of DAMPs that activate immunity and protect plants against several microbes. However, hyper-accumulation of OGs severely affects growth, eventually leading to cell death and clearly pointing to OGs as players in the growth-defence trade-off. Here we report a mechanism that may control the homeostasis of OGs avoiding their deleterious hyper-accumulation. By combining affinity chromatography on acrylamide-trapped OGs and other procedures, an Arabidopsis thaliana enzyme that specifically oxidizes OGs was purified and identified. The enzyme was named OG OXIDASE 1 (OGOX1) and shown to be encoded by the gene At4g20830. As a typical flavo-protein, OGOX1 is a sulphite-sensitive H2O2-producing enzyme that displays maximal activity on OGs with a degree of polymerization >4. OGOX1 belongs to a large gene family of mainly apoplastic putative FAD-binding proteins [Berberine-Bridge Enzyme-like (BBE-like); 27 members], whose biochemical and biological function is largely unexplored. We have found that at least four BBE-like enzymes in Arabidopsis are OG oxidases (OGOX1-4). Oxidized OGs display a reduced capability of activating the immune responses and are less hydrolysable by fungal polygalacturonases. Plants overexpressing OGOX1 are more resistant to Botrytis cinerea, pointing to a crucial role of OGOX enzymes in plant immunity.
Four Arabidopsis berberine-bridge enzyme-like proteins are specific oxidases that inactivate the elicitor-active oligogalacturonides / Benedetti, Manuel; VERRASCINA, ILARIA; Pontiggia, Daniela; LOCCI, FEDERICA; Mattei, Benedetta; De Lorenzo, Giulia; Cervone, Felice. - In: PLANT JOURNAL. - ISSN 0960-7412. - STAMPA. - 94:2(2018), pp. 260-273. [10.1111/tpj.13852]
Four Arabidopsis berberine-bridge enzyme-like proteins are specific oxidases that inactivate the elicitor-active oligogalacturonides
Benedetti, Manuel;VERRASCINA, ILARIA;Pontiggia, Daniela;LOCCI, FEDERICA;Mattei, Benedetta;De Lorenzo, Giulia
;Cervone, Felice
2018
Abstract
Recognition of endogenous molecules acting as "damage-associated molecular patterns" (DAMPs) is a key feature of immunity in both animals and plants. Oligogalacturonides (OGs), i.e. fragments derived from the hydrolysis of homogalacturonan, a major component of pectin are a well-known class of DAMPs that activate immunity and protect plants against several microbes. However, hyper-accumulation of OGs severely affects growth, eventually leading to cell death and clearly pointing to OGs as players in the growth-defence trade-off. Here we report a mechanism that may control the homeostasis of OGs avoiding their deleterious hyper-accumulation. By combining affinity chromatography on acrylamide-trapped OGs and other procedures, an Arabidopsis thaliana enzyme that specifically oxidizes OGs was purified and identified. The enzyme was named OG OXIDASE 1 (OGOX1) and shown to be encoded by the gene At4g20830. As a typical flavo-protein, OGOX1 is a sulphite-sensitive H2O2-producing enzyme that displays maximal activity on OGs with a degree of polymerization >4. OGOX1 belongs to a large gene family of mainly apoplastic putative FAD-binding proteins [Berberine-Bridge Enzyme-like (BBE-like); 27 members], whose biochemical and biological function is largely unexplored. We have found that at least four BBE-like enzymes in Arabidopsis are OG oxidases (OGOX1-4). Oxidized OGs display a reduced capability of activating the immune responses and are less hydrolysable by fungal polygalacturonases. Plants overexpressing OGOX1 are more resistant to Botrytis cinerea, pointing to a crucial role of OGOX enzymes in plant immunity.File | Dimensione | Formato | |
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