Genetic Analysis And Primary Mapping Of A Aroma Gene In Guizhou HE AC39

Aromatic rice is popular in domestic and foreign markets.Its fragrance is usually caused by the accumulation of flavor substance 2-AP caused by the mutation of OsBadh2 gene.AC39 is a characteristic japonica glutinous rice in Guizhou Province.In order to explore the cause of flavor generation of AC39,the full-length sequencing of the OsBadh2 gene of AC39 was carried out.The result showed that the exon of the OsBadh2 gene did not mutate,but the mutation occurred in the second,fourth and thirteenth introns.The expression level of OsBadh2 gene was tested.The results showed that there was no significant difference between the expression level of OsBadh2 gene of AC39 and non-fragrant rice QR35 and Ningjing 7,but there was a very significant difference between the expression level of OsBadh2 gene of AC39 and fragrant rice YFB and Dalixiang.The expression of the mutant OsBadh2 of the OsBadh2 gene was further detected.The results showed that the expression of OsBadh2 in AC39 had no significant difference between QR35 and Ningjing 7,but was significantly lower than that of the fragrant rice YFB and the fragrant rice Dalixiang.The 2-AP content in the rice of AC39,QR35,YFB,Ningjing 7 and Dalixiang was detected.The results showed that there was no significant difference in the 2-AP content in the rice of AC39,QR35 and Ningjing 7,but the 2-AP content in the rice of AC39 was significantly lower than that of fragrant rice YFB and Dalixiang.The above studies have confirmed that the reason for flavor production of AC39 is different from that of traditional fragrant rice.It is not caused by the mutation of OsBadh2 gene.There may be unknown genes regulating flavor substances.In this study,the F1 hybrid of AC39 and QR35 was used as the material.Through molecular detection,F1 was all true hybrids.The flavor of the parent and the hybrid material F1 was identified by KOH immersion method.The results showed that the F1 hybrid material did not contain flavor.Therefore,the gene controlling the flavor production of AC39 was a recessive gene.KOH immersion method was used to further identify the fragrance of parents and F2 generation population.Chi-square test showed that the proportion of non-fragrance individuals in F2 generation population phenotype was 9:7,indicating that the flavor characteristics of AC39 were affected by 2 pairs of genes.In order to clone and control the flavor gene in AC39,the F2 population genetic linkage map of AC39/QR35 was constructed first,and then based on the population phenotype,the QTL of rice flavor gene was preliminarily located by using Windows QTL Cartographer."Finally,the flavor gene of AC39 was initially located between chromosome 2 0c2b215-0c2b216 and chromosome 6 0c6b097-0c6b098".The LOD values were 3.79 and 2.67,and the reliability was 6.67%and 4.77%respectively..Goudang 3 is a special cultivated rice in Guizhou Province,with strong fragrance and good quality.However,there are few reports on the fragrance of Goudang 3 at present.On the one hand,the genotype of Goudang No.3 OsBadh2 was analyzed by sequencing,On the other hand,1.7%KOH immersion method,headspace solid phase microextraction(HS-SPME),gas chromatography-mass spectrometry(GC-MS)and soil element identification method were used to analyze the fragrance concentration,volatile components and soil components of Goudang No.3.The results showed that the genotype of OsBadh2 gene of Goudang 3 was OsBadh2.1,that is,3 bp mutation and 8 bp deletion occurred in exon 7.The aroma of rice will be more intense with the increase of planting point,and the content of 2-AP and nonanal in rice will increase with the increase of planting point.In addition,the total nitrogen content in the soil will also increase with the increase of planting sites.The correlation analysis of soil components and volatile matter content shows that the total nitrogen in the soil has a significant positive correlation with 2-AP and nonanal,which contributes the most to the aroma of rice.This paper will provide reference for exploring the development of rice flavor genes and the effect of soil properties on rice flavor.