Genetic Identification Of QTL For Contents Of 8 Mineral Elements In Rice Grain

Mineral elements in rice not only play an important role in its growth and development, but also the contents of mineral elements including toxic heavy metal are closely related to human health. Thus, it is very important to study the genetic mechanism of the formation of mineral contents. In present research, RIL were constructed using a population derived from Zhenshan97B and Miyang46, detection of the QTL of mineral elements for the whole genome was carried out. The majority of QTL was detected in the region RM190-RM225 on the short arm of chromosome 6. Based on the results, five NIL were selected, which had a segregate region RM190-RM225 and were homozygous in genetic background. These series of individuals were selected for QTL dissection and fine mapping. The results were summarized as follows:1. The contents of eight mineral elements of 233 RIL lines were detected by ICP-AES. With a linkage map containing 256 DNA markers and covering 1814.17cM of 12 chromosomes, 20 QTL controlling mineral elements were detected on chromosome 1,3,5,6,10and 11 by Windows QTL Cartographer 2.5. They can explain 4.2%~11.8% of phenotypic variance, respectively. The additive effects of qCa5, qMn1.2, qMn11 and qZn11 were from Zhenshan97 B, others'were from Miyang46.2. Five individuals were selected from the population crossed by Zhenshan97B and Miyang46, which carrying small heterozygous segments on targeted region. The heterozygous segments of five individuals were RM4923-RM19410, RM510-RM19407, RM19407-RM3414, RM19410-Si2950 and Si2944-RM204, respectively.20 non-recombinant lines selected from each selfing individual, including 10 maternal homozygous and 10 paternal homozygous, formed five NIL called TF6-2, TF6-10, TF6-12, TF6-15 and TF6-17. The mineral contents of five populations were measured, and the significant difference among different genotypes was analyzed by SAS. The qFe was delimited to a 466.6kb region on chromosome 6; The QTL of other mineral elements was delimited to 30.4~50.0kb region on chromosome 6.3. Based on the fine mapping of qMg6, qMn6, qK6, qP6, 9 candidate genes were searched, including 3 genes encoding unknown proteins and 6 genes encoding known proteins. The function of known proteins were as follows: LOC_Os06g06300 and LOC_Os06g06320 were two genes encoding phosphatidylethanolamine binding protein; LOC_Os06g06340 was a gene encoding lipid transporters; LOC_Os06g06350 was a gene encoding adenosine monophosphate desmoenzyme; LOC_Os06g06360 was a gene encoding WRKY DNA binding protein; LOC_Os06g06380 was a gene encoding NBS-LRR resistance protein.