Characterization of Sucrose transporter alleles and their association with seed yield-related traits in Brassica napus L

Abstract

BackgroundSucrose is the primary photosynthesis product and the principal translocating form within higher plants. Sucrose transporters (SUC/SUT) play a critical role in phloem loading and unloading. Photoassimilate transport is a major limiting factor for seed yield. Our previous research demonstrated that SUT co-localizes with yield-related quantitative trait loci. This paper reports the isolation of BnA7.SUT1 alleles and their promoters and their association with yield-related traits.ResultsTwo novel BnA7.SUT1 genes were isolated from B. napus lines 'Eagle' and 'S-1300' and designated as BnA7.SUT1.a and BnA7.SUT1.b, respectively. The BnA7.SUT1 protein exhibited typical SUT features and showed high amino acid homology with related species. Promoters of BnA7.SUT1.a and BnA7.SUT1.b were also isolated and classified as pBnA7.SUT1.a and pBnA7.SUT1.b, respectively. Four dominant sequence-characterized amplified region markers were developed to distinguish BnA7.SUT1.a and BnA7.SUT1.b. The two genes were estimated as alleles with two segregating populations (F2 and BC1) obtained by crossing '3715'×'3769'. BnA7.SUT1 was mapped to the A7 linkage group of the TN doubled haploid population. In silico analysis of 55 segmental BnA7.SUT1 alleles resulted three BnA7.SUT1 clusters: pBnA7.SUT1.a- BnA7.SUT1.a (type I), pBnA7.SUT1.b- BnA7.SUT1.a (type II), and pBnA7.SUT1.b- BnA7.SUT1.b (type III). Association analysis with a diverse panel of 55 rapeseed lines identified single nucleotide polymorphisms (SNPs) in promoter and coding domain sequences of BnA7.SUT1 that were significantly associated with one of three yield-related traits: number of effective first branches (EFB), siliques per plant (SP), and seed weight (n = 1000) (TSW) across all four environments examined. SNPs at other BnA7.SUT1 sites were also significantly associated with at least one of six yield-related traits: EFB, SP, number of seeds per silique, seed yield per plant, block yield, and TSW. Expression levels varied over various tissue/organs at the seed-filling stage, and BnA7.SUT1 expression positively correlated with EFB and TSW.ConclusionsSequence, mapping, association, and expression analyses collectively showed significant diversity between the two BnA7.SUT1 alleles, which control some of the phenotypic variation for branch number and seed weight in B. napus consistent with expression levels. The associations between allelic variation and yield-related traits may facilitate selection of better genotypes in breeding.

A consensus map of rapeseed (Brassica napus L.) based on diversity array technology markers: applications in genetic dissection of qualitative and quantitative traits

“…The TN-DH population has been used to map 614 non-DArT markers based upon SSRs, SNP, STSs, single strand conformation polymorphisms (SSCPs), RFLPs, cleaved amplified polymorphic sequences (CAPSs), and AFLPs, as described previously [9,35,39] and with SNPs identified from the rapeseed transcriptome [49]. This population has resulted in the discovery and mapping of candidate genes for sucrose transporter, α-tocopherol, fatty acid elongase, indehiscent ( IND ) gene for pod shatter, and FLOWERING LOCUS C (FLC) , FLOWERING LOCUS T , APETALA2 for flowering time [15,34,40-42,65]. The TN-DH published map was further saturated with DArT markers in this study.…”

Comparison on the carbohydrate metabolic enzyme activities and their gene expression patterns in canola differing seed oil content

“…Because sucrose metabolism is distributed universally, wide association of sucrose transporter with other traits is predicted Gong et al 2015). For example, Li et al (2011) identified sucrose transporter alleles in Brassica napus that significantly correlated with seed yield traits, including number of effective branches, siliques per plant, and seed weight. In the present study, SUT4 had higher transcript amount than SUT1 and SUT2.…”

Structural Biology of the Major Facilitator Superfamily Transporters

“…Before the crystal structure of human GLUT1 was elucidated in early 2014 (14), homology models of GLUTs were generated based on the crystal structures of their bacterial homolog, XylE. GLUTs belong to the SP subfamily ( Table 2), the members of which are responsible for the cellular uptake of glucose and other monosaccharides or disaccharides in all kingdoms of life (7,39,66,81,109). Among the bacterial homologs, XylE from E. coli shares ∼30% sequence identity and ∼50% similarity with human GLUT1-GLUT4.…”