Differential Evolution of α-Glucan Water Dikinase (GWD) in Plants

Abstract

The alpha-glucan water dikinase (GWD) enzyme catalyzes starch phosphorylation, an integral step in transitory starch degradation. The high phosphate content in stored starch has great industrial value, due to its physio–chemical properties making it more versatile, although the phosphate content of stored starch varies depending on the botanical source. In this study, we used various computational approaches to gain insights into the evolution of the GWD protein in 48 plant species with possible roles in enzyme function and alteration of phosphate content in their stored starch. Our analyses identified deleterious mutations, particularly in the highly conserved 5 aromatic amino acid residues in the dual tandem carbohydrate binding modules (CBM-45) of GWD protein in C. zofingiensis, G. hirsutum, A. protothecoides, P. miliaceum, and C. reinhardtii. These findings will inform experimental designs for simultaneous repression of genes coding for GWD and the predicted interacting proteins to elucidate the role this enzyme plays in starch degradation. Our results reveal significant diversity in the evolution of GWD enzyme across plant species, which may be evolutionarily advantageous according to the varying needs for phosphorylated stored starch between plants and environments.

Glucan, Water‐Dikinase 1 (GWD1), an ideal biotechnological target for potential improving yield and quality in rice

“…The starch phosphorylation reaction catalysed by GWD is the beginning of the degradation of transitory starch produced by photosynthesis. GWD, a key enzyme with essential roles in the first step of transitory starch degradation, plays important roles in both spore‐forming plants and angiosperms (Mahlow et al ., 2016 ; Muyiwa et al ., 2020 ). GWD has been studied in a number of plant species, including Arabidopsis, potato, rice, maize and wheat (Betti et al ., 2016 ; Bowerman et al ., 2016 ; Hirose et al ., 2013 ; Malinova et al ., 2018 ; Xu et al ., 2017 ).…”

“…The protein encoded by the R1 gene was then found to be an α‐glucan hydration dikinase (GWD), which can catalyse the reaction of α‐glucan and adenosine triphosphate (ATP) with water to generate α‐glucan phosphate monoester, adenosine monophosphate (AMP) and orthophosphate (Ritte et al ., 2002 ). The GWD gene is present in many plants, but the evolutionary history and enzyme functions are not identical (Muyiwa et al ., 2020 ). In Arabidopsis, GWD1 phosphorylates glucosyl residues of amylopectin at the C6 position (Ritte et al ., 2002 ); then, GWD3/PWD further phosphorylates a different glucosyl residue at the C3 position (Baunsgaard et al ., 2005 ; Kötting et al ., 2005 ).…”

Strategies for Efficient Gene Editing in Protoplasts of Solanum tuberosum Theme: Determining gRNA Efficiency Design by Utilizing Protoplast (Research)

“…Exon one of GWD1 and exons one and two of DMR6-1 as well as active sites encoded by exons 24 and 25 in GWD1 and exon three in DMR6-1, i.e., situated at the start or latter third of the genes on the chromosomes, here designated 5′ and 3′ end of the genes, respectively, were chosen as target regions for the editing’s ( Figures 1 and 2 ). The target region of the GWD1 gene includes the ‘CFATC’ region, containing cysteines hypothesized to be involved in inter or intra-di-sulfide bond formation and thus in putative redox-state modulation activity of GWD, and the residue histidine in the active site ( Adegbaju et al, 2020 ; Ritte et al, 2006 ; Mikkelsen et al, 2005 ) ( Figure 1 ). Catalytic site residues of DMR6-1 are histidine H212, and H269 as well as aspartic acid D214 ( Zeilmaker et al, 2015 ) ( Figure 2 ).…”

A banana transcriptional repressor MaAP2a participates in fruit starch degradation during postharvest ripening

“…Studies on leaf starch degradation in Arabidopsis thaliana show that temporary starch degradation is accomplished by the co-participation of multiple enzymes (Zeeman et al, 2010). In this complex project, firstly, temporary starch is phosphorylated by combined actions of GWD (glucan, water dikinase) and PWD (phosphoglucan, water dikinase), which breaks the semicrystalline granule surface for starch degradation initiation (Kötting et al, 2005;Hejazi et al, 2010;Adegbaju et al, 2020). Then, glucans are dephosphorylated by phosphoglucan phosphatases starch excess 4 (SEX4) and like SEX four 1/2 (LSF1/2) (Silver et al, 2014;Wilkens et al, 2016).…”