| Carrying out QTL mapping research on leaf pigment content traits of rice is of great significance to promote the reasonable dynamic change of leaf pigment content traits and the breeding of high-yield rice varieties.There are differences in leaf pigment content and dynamic changes between the parent of super hybrid rice Liangyoupeijiu Peiai 64 s and 9311,so this study chose this parent combination to construct a recombinant inbred line population.The recombinant inbred line was used as the materials to test the data of pigment content traits at different periods for QTL mapping analysis.In addition,the positions of most QTL cannot be directly compared with each other.Therefore,using the whole genome meta-analysis method to locate consistent QTL regions of rice pigment content,which provides a powerful strategy for longitudinal comparison of QTL and a reference for molecular marker-assisted breeding and aggregation,and identifies candidate genes that regulate leaf pigment content.The main results are as follows:(1)Leaf pigment content was significant decrease in the later filling stage,and 20 related QTL were detected.Among them,7 QTL belonged to the major QTL;for the positive alleles,7 QTL were derived from the female parent PA64 s,and 13 QTL were derived from the male parent 9311.In addition,there were 3 QTL were co-located in the mks4-242-mks4-243 marker interval on chromosome 4.Only one candidate gene GLTP encoding an important component of the chloroplast thylakoid membrane was found in the interval,and there were differences both in parental sequences and in gene expression levels which facilitates the later development of molecular markers and their application in molecular marker-assisted selection breeding.(2)Through meta-analysis,64 consistent QTL related to rice pigment content were obtained.Among them,the QTL density of chromosomes was positively correlated with the number of MQTL.58 MQTL genetic intervals were smaller than the minimum confidence interval in the original QTL,indicating that the genetic interval of the initial QTL can be reduced by meta-analysis.In addition,it was found that 3 of the MQTL covered 6 of the 20 QTL detected in this study,verifying the effectiveness of the MQTL in detecting consistent QTL.(3)Six overlapping MQTL controlling Chla,Chlb and Chla+b were identified.Overlapping MQTL may contain pleiotropic candidate genes.And there are only 6 MQTL with a physical interval greater than 5 Mb,and the other 11 with a physical interval less than 0.5 Mb.These MQTL with narrow genetic and physical ranges can be further studied in MAS,fine mapping,candidate gene identification and functional analysis.(4)Among the 64 MQTL,a total of 34 candidate genes related to pigment content were found.Among them,the genes involved in the chlorophyll synthesis pathway,Os HCAR and Os V5 B,were candidate genes in MQTL4.3 and MQTL8.3 were respectively covered in the QTL q FS＿Chlb4 and q MFS＿Chla/b8 detected in this study.The study found that the genes Os HCAR and Os V5 B have polymorphisms between the parental sequences,and all the gene expression level of PA64 s were higher than 9311,indicating that these MQTL can be used as important regions of MAS and applied to functional analysis of candidate genes related to pigment content.In summary,through the analysis of QTL related to pigment content in RIL population,provided a reference for understanding the dynamic changes of pigment content in different growth periods and enriched the genetic regulation mechanism of pigment content traits.At the same time,combined with meta-analysis,it lays a foundation for further fine mapping of QTL related to rice pigment content and the discovery of related genes,and provides a relatively reliable reference for the development of similar work on genetic and functional analysis of related genes in the future and the promotion of MAS selection of high-light-efficiency rice varieties. |
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