Sucrose Phosphate Synthase Genes in Plants Belong to Three Different Families

Abstract

We present phylogenetic analyses to demonstrate that there are three families of sucrose phosphate synthase (SPS) genes present in higher plants. Two data sets were examined, one consisting of full-length proteins and a second larger set that covered a highly conserved region including the 14-3-3 binding region and the UDPGlu active site. Analysis of both datasets showed a well supported separation of known genes into three families, designated A, B, and C. The genomic sequences of Arabidopsis thaliana include a member in each family: two genes on chromosome 5 belong to Family A, one gene on chromosome 1 to Family B, and one gene on chromosome 4 to Family C. Each of three Citrus genes belong to one of the three families. Intron/exon organization of the four Arabidopsis genes differed according to phylogenetic analysis, with members of the same family from different species having similar genomic organization of their SPS genes. The two Family A genes on Arabidopsis chromosome 5 appear to be due to a recent duplication. Analysis of published literature and ESTs indicated that functional differentiation of the families was not obvious, although B family members appear not to be expressed in roots. B family genes were cloned from two Actinidia species and southern analysis indicated the presence of a single gene family, which contrasts to the multiple members of Family A in Actinidia. Only two family C genes have been reported to date.

Evolutionary Genomics of the HAD Superfamily: Understanding the Structural Adaptations and Catalytic Diversity in a Superfamily of Phosphoesterases and Allied Enzymes

“…The sucrose phosphate synthase C-terminal domain (SPSC) family is comprised of the C-terminal domains of a key enzyme in the sucrose synthesis pathway, which contains an N-terminal two domain glycosyltransferase module (related in structure to glycogen synthase) fused to a C-terminal HAD domain (SPS _ At in Figure 9). [182][183][184] It is likely to regulate the accumulation of sucrose by hydrolyzing the sucrose phosphate formed by the N-terminal domains. The sucrose phosphate phosphatase (SPP) family is closely related to the previous family and catalyzes the dephosphorylation of sucrose phosphate to form sucrose.…”

Metabolism of soluble sugars in developing melon fruit: a global transcriptional view of the metabolic transition to sucrose accumulation

“…Melon representatives of the three clades of NIN (Ji et al 2005;Murayama and Handa 2007;Nonis et al 2008;Vargas et al 2008), two clades of UGE (Barber et al 2006;Rösti et al 2007), two groups of FK , three groups of SUS Núñez et al 2008;Subbaiah et al 2006) and two groups of HK (Claeyssen and Rivoal 2007;Granot 2008;Olsson et al 2003) were all identified. The SPS gene family, which has been divided into three subfamilies, A, B and C (Komatsu et al 1999;Langenkämper et al 2002;Lutfiyya et al 2007) is the only exception. The two melon genes place in the A and B families and no representative from the C family was found.…”

Metabolism and Accumulation of Sugars Translocated to Fruit and Their Regulation

“…SPS activity in apple leaves was inhibited by sorbitol-6-P and the inhibition has a role in switching between the synthesis of sucrose and the synthesis of sorbitol as a translocation sugar (Zhou et al, 2002). Full-length cDNA was cloned from citrus fruit, including CitSPS1, CitSPS2, and CitSPS3 (Komatsu et al, 1996(Komatsu et al, , 1999, CmSPS1 from melon (Yu et al, 2007), from kiwifruit (Langenkämper et al, 2002), from Asian pear (Itai and Tanahashi, 2008) and from coffee (Privat et al, 2008). (3) Changes in expression of sucrose-metabolizing enzymes with fruit development Sucrose translocated in fruit is generally broken down to glucose, fructose, or UDPglucose by SuSy or invertase, then SPS functions actively to resynthesize sucrose in the fruit.…”