Identification of QTLs for the accumulation of Dols, Prens,
chlorophylls, and carotenoids
The collected biochemical data for the EstC mapping population were
subsequently used to map QTL regions underlying the observed phenotypic
variation in isoprenoid accumulation. We were able to map QTLs for four
types of compounds (Prens, Dols, chlorophylls, and carotenoids). We
detected three QTLs on chromosome 5 for Pren accumulation (Figure S4A)
(127.3-133.4 cM, 166.5-170.8 cM, and 171.1-173.3 cM), explaining
approximately 33% of the phenotypic variance explained (PVE) by these
QTLs containing 948 loci (Table S1). For Dol, we detected a QTL region
on chromosome 2 (Figure S4B) (64.8-74.4 cM) containing 308 loci (Table
S1), which explains approximately 16.8% of the PVE.
Two QTLs were detected for chlorophyll accumulation on chromosome 2
(160.8-191.6 cM) and 3 (111.6-188.1 cM) (Figure S4C), which together
explain 16% of the PVE (Table S1). On chromosome 2, 3, and 5
(159.3-196.5 cM, 131.3-145.6 cM, and 151.3-187.2 cM, respectively)
(Figure S4D) we identified three QTLs underlying the variation in
carotenoid accumulation, as the whole model explains together almost
24% of the PVE (Table S1). It should be underlined that the QTL on
chromosome 3 (for chlorophylls) and the QTL on chromosome 5 (for
carotenoids) were included in this analysis even though their LOD scores
were below the threshold (below 3) (Figure S4C and Figure S4D,
respectively). Interestingly, two of the QTLs identified for
chlorophylls and carotenoids, localized on chromosomes 2 and 3, were
overlapping.
Our search also revealed two small QTL regions for phytosterols (data
not shown); however, they were not analyzed further due to their
statistical insignificance (LOD < 3.0). Despite the large set
of numerical data, no QTLs were identified for plastoquinone or
tocopherols. This might indicate that the mapping population used in
this study was not appropriate for investigating these metabolites.