Disease relevance of CALS1

• This biochemical evidence is supported by immunolocalization studies on papillae forming at bacterial infection sites that show the peroxidase isoform present at sites of H(2)O(2) production revealed by cerium chloride staining together with the cross-linked wall proteins and callose and callose synthase [1].

High impact information on CALS1

• We cloned an Arabidopsis cDNA encoding a callose synthase (CalS1) catalytic subunit [2].
• Protein gel blot results revealed that UGT1 is associated with the membrane fraction and copurified with the product-entrapped callose synthase complex [3].
• A novel UDP-glucose transferase is part of the callose synthase complex and interacts with phragmoplastin at the forming cell plate [3].
• We demonstrate that one of these genes, CalS5, encodes a callose synthase which is responsible for the synthesis of callose deposited at the primary cell wall of meiocytes, tetrads and microspores, and the expression of this gene is essential for exine formation in pollen wall [4].
• CalS1 shares high sequence homology with the well-characterized yeast beta-1,3-glucan synthase and transgenic plant cells over-expressing CalS1 display higher callose synthase activity and accumulate more callose [5].

Biological context of CALS1

• Enzyme kinetics suggested the existence of positive homotropic cooperativity of (1-->3)-beta-D-glucan synthase for the substrate UDP-glucose, in agreement with the hypothesis that callose synthase consists of a multimeric complex containing several catalytic subunits [6].
• Loss of a callose synthase results in salicylic acid-dependent disease resistance [7].

Associations of CALS1 with chemical compounds

• Different CesA isoforms may also play distinct roles within the rosette, and there is some circumstantial evidence that CesA genes may encode the catalytic subunit of the mixed linkage glucan synthase or callose synthase [8].

References