A Novel Mutation of OsPPDKB, Encoding Pyruvate Orthophosphate Dikinase, Affects Metabolism and Structure of Starch in the Rice Endosperm

Abstract

Starch, as a main energy storage substance, plays an important role in plant growth and human life. Despite the fact that several enzymes and regulators involved in starch biosynthesis have been identified, the regulating mechanism of starch synthesis is still unclear. In this study, we isolated a rice floury endosperm mutant M14 from a mutant pool induced by 60Co. Both total starch content and amylose content in M14 seeds significantly decreased, and starch thermal and pasting properties changed. Compound starch granules were defected in the floury endosperm of M14 seeds. Map-based cloning and a complementation test showed that the floury endosperm phenotype was determined by a gene of OsPPDKB, which encodes pyruvate orthophosphate dikinase (PPDK, EC 2.7.9.1). Subcellular localization analysis demonstrated that PPDK was localized in chloroplast and cytoplasm, the chOsPPDKB highly expressed in leaf and leaf sheath, and the cyOsPPDKB constitutively expressed with a high expression in developing endosperm. Moreover, the expression of starch synthesis-related genes was also obviously altered in M14 developing endosperm. The above results indicated that PPDK played an important role in starch metabolism and structure in rice endosperm.

Over-Expressing TaSPA-B Reduces Prolamin and Starch Accumulation in Wheat (Triticum aestivum L.) Grains

“…Our RNA-seq analysis identified a wide range of metabolic pathways regulated by TaSPA-B ( Figure 6), especially starch and amino acid metabolism, which might explain the content changes of starch and protein in TaSPA-B OE-3 lines (Figure 4B,C). PPDK play an important role in the balance of starch and protein as the central substance by regulating the ratio of phosphoenolpyruvate and pyrophosphoric acid in maize and rice [51][52][53]. PDH catalyzes a rate-limiting step of pyruvate entering the tricarboxylic acid cycle (TCA).…”

Genetic Control and High Temperature Effects on Starch Biosynthesis and Grain Quality in Rice

“…Moreover, FLO2 was predicted to encode a tetratricopeptide repeat (TPR) domain-containing protein (She et al, 2010). The candidate gene responsible for FLO4 encodes a pyruvate orthophosphate dikinase (Kang et al, 2005;Zhang et al, 2018b). OsHsp70 is the gene responsible for the FLO11 phenotype, and FLO15 encodes glyoxalase I (Zhu et al, 2018;You et al, 2019).…”

Identification of Selection Signatures in Commercial Asian Rice Subspecies Deciphered Selection Footprints for Four Overrepresented Biological Processes

“…These windows contain 145 genes related to 40 biological processes (Supplementary data 2 and Supplementary information, Table S1); however, these biological processes were not signi cantly enriched. Additionally, we detected three important candidate genes including: Os05g0405000, Os05g0402700 and Os03g0318500 related to different economical traits, such as temperature response [30], response to stresses [31], starch metabolism, structure [32], root growth, and development. The Glucose-6-phosphate1-dehydrogenase gene is the ortholog of Os03g0318500; the important role of this gene was shown in response to stresses, such as metal toxicity [33], osmotic stress [34] and pathogenesis [35].…”

“…The Glucose-6-phosphate1-dehydrogenase gene is the ortholog of Os03g0318500; the important role of this gene was shown in response to stresses, such as metal toxicity [33], osmotic stress [34] and pathogenesis [35]. The ortholog of Os05g0405000 is PPDK1, which in rice endosperm can play a key role in starch metabolism and structure by regulating starch synthesis-related enzymes expression [32]. The temperature tolerance has been one of the important traits in rice breeding strategies [36,37].…”