The maize brevis plant1 is a type II inositol polyphosphate 5-phosphatase
The genes associated with the dwarf phenotype have been utilized in crop breeding to prevent lodging and stem breakage. Brevis plant1 (Bv1), encoding a putative inositol polyphosphate 5-phosphatase (5PTase), has been associated with stem elongation in maize (Zea mays L.); however, the enzymatic activity of BV1 has not been experimentally characterized. In this study, the phosphatase activity of BV1 was verified with biochemical assays. BV1 demonstrated type II 5PTase activity capable of hydrolyzing both inositol polyphosphates and phosphoinositides. Similar to other type II 5PTases that share similar sequences and common domain architecture with BV1, the enzymatic activity of BV1 is sensitive to changes in Mg2+ and pH. 367G-R and 565S-L are two mutations in Bv1 that have been associated with the dwarfing phenotype in maize. To characterize the dwarfing mechanism, mutant BV1 proteins were expressed in vitro and assayed for phosphatase activity. The results showed that both mutations significantly reduced the enzymatic activity of BV1, but neither altered its substrate specificity and dependence on Mg2+ and pH. This biochemical verification of BV1 as a type II 5PTase is important as it sheds light on the molecular basis of deficient BV1-mediated dwarfing phenotype.
KeywordsBrevis plant1 Inositol polyphosphate 5-phosphatase Stem elongation
Inositol polyphosphate 5-phosphatase
Protein-A immunoglobulin G (IgG) binding domains
Tobacco etch virus
Polymerase chain reaction
Quantitative polymerase chain reaction
Basic Local Alignment Search Tool
Compliance with ethical standards
Conflict of interest
The authors declare that there is no conflict of interest regarding the publication of this paper.
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