Validation Of QTL Related To Fatty Acid Content In Rice

Rice（Oryza sativa L.）is one of the widely cultivated cereals around the world,and China has achieved fruitful achievements in high-yield breeding of rice.With the continuous improvement of people’s living standards,rice with excellent cooking and eating quality and high nutritional value is increasingly adopted by people.The nutritional quality traits of rice are generally regulated by multiple genes,and research on fatty acids in rice has great significance for the improvement of rice quality and breeding.Fatty acid is the third largest nutritional component of rice,determines the cooking quality,eating quality and storage quality of rice.In this study,QTL（quantitative trait loci）related to fatty acid content in rice were studied using three populations through high-throughput sequencing technology to verify the genetic effects.The main results are as follows:1.In the early stage,fifty seven QTL were mapped using the recombinant inbred line（RIL）population of HD9802S/88B-2.In order to verify the genetic effects of these rice fatty acid QTL,we used molecular marker assisted selection（MAS）screened fourteen QTL of residual heterozygous line in F₆ and F₈ populations of this RIL to construct isolated populations as near isogenic line（NIL）,which were distributed on chromosomes1,4,5,6,and 11,respectively,and passed F_6:2 and F_8:2 populations verification showed that six QTL related to fatty acid components were repeatedly detected,and the range of phenotypic variation rates was 0.01%to 40.24%.2.Fifty one QTL were mapped using the RIL population of Hua6S/B805D-MR-16-8-3 in the early stage.In order to verify the genetic effect of these rice fatty acid QTL,we screened the F₆ and F₈ populations of this RIL using MAS.Residual heterozygous line of eleven QTL target segments were constructed as NIL to form isolated populations,which were distributed on chromosomes 5,6,and 12,respectively.The F_6:2 and F_8:2 populations were verified QTL and related to six fatty acid components were repeatedly detected.Explaining the range of phenotypic variation is 0.02%-22.24%.3.The DH population constructed by Zhenshan 97B/Wuyujing 2 and the three populations constructed by backcrossing with their parents were co-localized to a crude fat QTL q CFC5.To further verify the genetic effect of q CFC5,we screened BC₄F₃ segregating population with Zhenshan 97B as the recurrent parent by MAS to test the QTL and revealed two effect intervals.We also used the BC₆F₂ independent populations to verify q CFC5 significantly affected total fatty acid and various fatty acid components in rice.The range of phenotypic variation rates was 0.57%-23.54%.Combining the above results,qa OLE5.2&qa LA5,qa STE6,qb OLE6&qb LA6 and qb PLA12,which have been repeatedly verified in two years in the HD9802S/88B-2 and Hua 6S/B805D-MR-16-8-3 populations and regulate the content of various unsaturated fatty acids,and q CFC5,which regulates the content of total fatty acids and multiple component fatty acids in the Zhenshan 97B/Wuyujing 2 population,are used as candidate QTL for the next fine mapping and cloning.It has laid an important material foundation for further analyzing the genetic mechanism of these fatty acid genes and improving rice quality.