Transcriptome Analysis Of Heterosis At Seedling Stage Of CCRI63

Heterosis usually refers to the phenomenon that hybrid progenies are genetically superior to their parents,that is an essential tool for breeding applications in traditional breeding.The strong hybrid cotton variety CCRI63 has excellent production characteristics compared to its maternal line Zhong9053 and its paternal line.In this study,CCRI63,its maternal line Zhong9053 and its paternal line sGK9708 at trileaf stage were used as materials.First,were performed on the data of a group of same-age seedlings of CCRI63 and their individual foot fresh weight and root dry weight.Secondly,high-throughput sequencing methods were utilized to detect the differences in transcriptional levels of the three materials,and the relationship between mRNA and lncRNA transcription levels and heterosis was further explored.We are then further GO and KEGG analysis of the expression of CCRI63 significantly higher than the parent or significantly lower than the parent gene based on heterosis upper hypothesis,in order to explain what genes trileaf stage involved in the formation of heterosis.Finally,we further validated 45 genes that were significantly changed during the development of heterosis by means of RealTime-PCR.Research indicates: The fresh and dry weight of the whole plant in the CCRI63 werebetter than that of the parents in comparison with the parents.At the same time,the fresh and dry weight of the CCRI63 roots were better than that of the parents.It can be seen that the development of the CCRI63 at the seedling stage and its root system is more developed than those of its parents.High-throughput sequencing data showed that there were 13117 differentially expressed transcripts(including lncRNAs and mRNAs),and 10674 differentially expressed transcripts that were significantly down-regulated between CCRI63 and the male parent.Compared with the female parent,there were 9081 differentially expressed transcripts markedly up-regulated in the CCRI63,and 6578 differentially expressed transcripts were significantly down-regulated.There was a total of 14918 differential transcripts unique to the hybrid between CCRI63 and its male parent,6866 of which were differential transcripts unique to the female parent,and 8873 differential transcripts shared between the two parents.The GO classification and KEGG functional annotations were performed for the chromosomal differentially expressed transcripts in the CCRI63 and its parents.The results showed that there were considerable differences in the metabolic process between CCRI63 and its parents,including glyceride metabolism,niacin and niacinamide metabolism,plant circadian rhythm,pyruvate metabolism,and photochemical fixation of medium carbon.Introduction of differential gene-expression in CCRI63: Gh_A05G0576,Gh_A11G1780,Gh_A06G0941,Gh_A06G1712,Gh_A08G0731,Gh_A11G2295,Gh_A01G0826 and Gh_A01G0775 genes significantly up regulated.These genes promote photosynthesis and energy metabolism in varying degrees,it is one factor CCRI63 formed heterosis;A total of 45 genes that were significantly altered in the pathway were selected for verification by real-time PCR.The consistency between the gene-expression differences of these genes and the sequencing results was 91.2%.Conclusion: The developmental status of CCRI63 in the whole plant and its roots in the trileaf stage was significantly better than that of the parents.By comprehensively analyzing the relationship between differentially expressed genes,we believe that high expression of key genes in the metabolic pathways of nicotine acid and nicotinamide,glyceride metabolism and plant circadian rhythms and carbon fixation in the hybrid species CCRI63.These highly expressed genes are affecting seedling plant photosynthesis and C,N fixation process while a direct impact on the metabolic accumulation of seedling stage,is one of the key representatives of the exhibit hybrid heterosis.