Abstract
BackgroundThe major fatty acids in seed oil of jatropha, a biofuel crop, are palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2). High oleic acid and total oil content are desirable for jatropha breeding. Until now, little was known about the genetic bases of these oil traits in jatropha. In this study, quantitative trait locus (QTL) and expression QTL analyses were applied to identify genetic factors that are relevant to seed oil traits in jatropha.ResultsComposite interval mapping identified 18 QTL underlying the oil traits. A highly significant QTL qC18:1-1 was detected at one end of linkage group (LG) 1 with logarithm of the odd (LOD) 18.4 and percentage of variance explained (PVE) 36.0%. Interestingly, the QTL qC18:1-1 overlapped with qC18:2-1, controlling oleic acid and linoleic acid compositions. Among the significant QTL controlling total oil content, qOilC-4 was mapped on LG4 a relatively high significant level with LOD 5.0 and PVE 11.1%. Meanwhile, oleosins are the major composition in oil body affecting oil traits; we therefore developed SNP markers in three oleosin genes OleI, OleII and OleIII, which were mapped onto the linkage map. OleI and OleIII were mapped on LG5, closing to QTLs controlling oleic acid and stearic acid. We further determined the expressions of OleI, OleII and OleIII in mature seeds from the QTL mapping population, and detected expression QTLs (eQTLs) of the three genes on LGs 5, 6 and 8 respectively. The eQTL of OleIII, qOleIII-5, was detected on LG5 with PVE 11.7% and overlapped with QTLs controlling stearic acid and oleic acid, implying a cis- or trans-element for the OleIII affecting fatty acid compositions.ConclusionWe identified 18 QTLs underlying the oil traits and 3 eQTLs of the oleosin acid genes. The QTLs and eQTLs, especially qC18:1-1, qOilC-4 and qOleIII-5 with contribution rates (R2) higher than 10%, controlling oleic acid, total oil content and oleosin gene expression respectively, will provide indispensable data for initiating molecular breeding to improve seed oil traits in jatropha, the key crop for biodiesel production.
Highlights
The major fatty acids in seed oil of jatropha, a biofuel crop, are palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2)
To conduct marker assisted selection (MAS) for genetic improvement of oil yield and quality in jatropha, the molecular bases of seed oil traits need to be understood by identifying genomic regions that contain favorite loci, i.e. quantitative trait locus (QTL) analysis
We describe the genetic bases of these seed fatty acid composition and content traits through QTL mapping with a backcrossing population consisting 286 individuals
Summary
The major fatty acids in seed oil of jatropha, a biofuel crop, are palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2). Molecular breeding in jatropha has not been started due to lack of molecular bases of economically important traits such as seed yield, seed oil traits, biotic or abiotic stress resistance. Traditional methods of genetic improvement of quantitative traits have relied mainly on phenotype and pedigree information [2], which are influenced by environmental factors. To conduct marker assisted selection (MAS) for genetic improvement of oil yield and quality in jatropha, the molecular bases of seed oil traits need to be understood by identifying genomic regions that contain favorite loci, i.e. QTL analysis. QTL analysis has been performed to detect the genetic bases of important agronomic or physiological traits, providing valuable information for trait improvement. MAS for oil traits improvement will be much advantageous compared to traditional breeding because seed oil traits cannot be measured at early stage or in field. By using MAS, decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, and which should be removed
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.
