Mechanism Of Maize DNA Induced Rice Mutation

Rice is one of the important food crops,and it has been a hot spot in the field of breeding about genetic improvement of rice and creation of new materials.Although zhou guangyu proposed the distant DNA fragment hybridization hypothesis as the theoretical support,and researchers have been discussing the theoretical basis of this hypothesis,but so far there has been no complete theoretical system to prove this hypothesis.In this study,Oryza sativa l.Nipponbare?Oryza sativa l.Nipponbare,Japan?was randomly introduced into the genome of rice?Oryza sativa l.Nipponbare?using modified"pollen tube mediated technology"to obtain a batch of mutant materials.The mutant RMIM92?hereinafter referred to as R92?with significant differences in genetic traits was selected for genome and transcriptome sequencing analysis,in order to explore the mechanism of maize DNA on rice genome and provide theoretical data for the hybridization hypothesis of distant DNA fragments.In this study,specific maize sequence and SNP,InDel and other mutations of R92 T₄ generation isolates were analyzed,so as to analyze the heritability of R92mutant and provide theoretical basis for pollen tube mediated rice breeding.In this study,high-throughput sequencing and bioinformatics technology were used to sequence and analyze the whole genome?second-generation sequencing?and transcriptome of mutant R92.The results showed that:1.It was found that 3 maize DNA sequences were imported into the receptor genome,among which 2 maize DNA sequences were detected in the V₈ strain of T₄ generation mutation,indicating that the maize DNA sequences could be imported into the rice genome and could be inherited.2.According to the resequencing results of R92 genome,there were 231,352 SNP mutation sites and 190,847 InDel mutation sites,indicating that the introduction of maize DNA mixed fragments into rice can cause a large number of SNP and InDel mutations.In other words,the introduction of maize DNA mixed fragments into rice has the mutagenesis function.3.Chr12 had the most SNPS,accounting for 11.2%of the total number of mutations,higher than other chromosomes.4.Chr 3 had the most InDel mutations,accounting for 11.90%of the total mutations,higher than other chromosomes.5.The mutation probability of single base is from high to low:C?31.81%?,>G?31.72%?,>A?18.31%?,>T?18.15%?.The mutation rate of base C and G is significantly higher than that of A and T,indicating that the base C and G are prone to mutation.6.The frequency of base conversion and transmutation in SNP mutations was 60.84%and 39.16%respectively,indicating that base conversion was the main mutation type in SNP mutations.7.The analysis of the adjacent base of SNP showed that GNC&CNG?13.53%?was the adjacent base with relatively high frequency,indicating that in R92,when the adjacent base of the mutation site was C and G,the base was prone to mutation.8.The InDel mutation with the most mutations is the frame-shift mutation,which has1,703,accounting for 84.56%of the total InDel mutation,indicating that the InDel mutation is more destructive to the gene.9.InDel mutation occurs most frequently with-2² bases,among which single base insertion or deletion occurs most frequently.10.The expression levels of some SNP mutant genes were significantly different in the flowering stage,among which the expression levels of OS12G0133050 in the stem node of CK1 and R92 were 35.22 and 2.61,respectively,which were significantly down-regulated.The expression levels of OS07G0261200 in CK1 and R92 were 2.63 and 9.71 respectively.The expression levels of dwarf gene OS01G0718300 in the stem node of CK1 and R92 were 45.44 and 33.21,respectively,and the expression was down-regulated,indicating that the introduction of maize DNA sequence into rice genome had a great influence on the gene expression during flowering.As can be seen from the above research results,the pollen tube mediated corn DNA technology,not only can make some corn DNA fragments randomly inserted into the rice genome,but also cause the SNP and InDel mutation rice genome,and influence the expression of receptor gene,and some can genetic mutations,shows that this technology is an effective method of biological mutagenesis.