Mapping QTLs for oil traits and eQTLs for oleosin genes in jatrophaReport as inadecuate

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BMC Plant Biology

, 11:132

Genetics and crop biotechnology


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 R 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.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2229-11-132 contains supplementary material, which is available to authorized users.

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Author: Peng Liu - Chun Ming Wang - Lei Li - Fei Sun - Peng Liu - Gen Hua Yue



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