Abstract
In plants, plant fructokinases (FRKs) are considered to be the main gateway of fructose metabolism as they can phosphorylate fructose to fructose-6-phosphate. Chinese white pears (Pyrus bretschneideri) are one of the popular fruits in the world market; sugar content is an important factor affecting the quality of the fruit. We identified 49 FRKs from four Rosaceae species; 20 of these sequences were from Chinese white pear. Subsequently, phylogenic relationship, gene structure and micro-collinearity were analysed. Phylogenetic and exon–intron analysis classified these FRKs into 10 subfamilies, and it was aimed to further reveal the variation of the gene structure and the evolutionary relationship of this gene family. Remarkably, gene expression patterns in different tissues or different development stages of the pear fruit suggested functional redundancy for PbFRKs derived from segmental duplication or genome-wide duplication and sub-functionalization for some of them. Additionally, PbFRK11, PbFRK13 and PbFRK16 were found to play important roles in regulating the sugar content in the fruit. Overall, this study provided important insights into the evolution of the FRK gene family in four Rosaceae species, and highlighted its roles in both pear tissue and fruits. Results presented here provide the appropriate candidate of PbFRKs that might contribute to fructose efflux in the pear fruit.
Highlights
Sucrose, fructose and glucose are the major soluble sugars in fruits [1]; sucrose is unstable and hydrolysed into glucose and fructose under the action of invertase
The FRK domain (PF00294) and A. thaliana FRK proteins were used as queries to search against the genomes, and 56 FRK genes were identified in four Rosaceae species
It is well known that the FRK genes play an important role in the development of various plant organs, in fructose metabolism and in response to abiotic stresses [16,17,31,32]
Summary
Fructose and glucose are the major soluble sugars in fruits [1]; sucrose is unstable and hydrolysed into glucose and fructose under the action of invertase. Hexose metabolism is a basis for photosynthetic products to enter another metabolism during fruit development stages. Though hexokinase (HXK) and fructokinase (FRK) could catalyse phosphorylation of fructose, the affinity of FRK to fructose is much higher than that of HXK [2], signifying that FRK plays an important role in fructose metabolism. Fructose could be subjected to glycolysis and oxidized pentose pathways under the catalysation of FRK via phosphorylation, which could be used for starch synthesis. Some previous studies reported that phosphorylated fructose can help to establish sink tissue [3,4], the study of fructose metabolism and FRK gene expression pattern in the fruit can help to expose the mechanism of sugar metabolism in the pear, and provides a scientific basis for improving fruit quality
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
