Response of Waxy Gene Expression in Glutinous Rice Grain to the Variation of Upstream DNA Sequence

• Main Authors: Jian, Jen-You, 簡禎佑
• Other Authors: Lin, Shun-Fu
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/41238954826128644598

碩士 === 國立臺灣大學 === 農藝學研究所 === 90 === To study waxy gene expression under glutinous background, to detect Wxa allele in glutinous or japonica rice (Oryza sativa L.) varieties, to identify sequences related waxy gene expression, and to evaluate genetic similarity among glutinous rices, the 5'' upstream sequences of waxy alleles among 144 rice germplasm, (including 118 waxy and 26 non-waxy), were analyzed. Because ten germplasm classified as waxy-type by their appearance had higher amylose amount (>12%), there was a little difference in judging waxy-type varieties between by checking grain appearance and amylose content. The diverse nucleotides “G” and “T” respectively representing Wxa and Wxb were found in glutinous germplasm. The single nucleotide substitution could explain 42.6 % of amylose content. Besides, we have found eight alleles of (CT) repeat in our study, and six of the eight alleles have significant effects on amylose contents. The alleles (CT)11, (CT)17 and (CT)10 contributed 34.5 %, 19.5 % and 18.7 % of total amylose variation, respectively. The finding of three glutinous (C102, C105, and C124) and four (C010, C050, C093, and C100) japonica germplasm carrying a Wxa allele has refreshed the previous understanding that glutinous or japonica rice carry Wxb allele only. According to the sequence of waxy alleles, the gene tree of 144 germplasm was established. The investigated varieties were separated predominantly by repeat numbers of (CT), amylose content, and origins of germplasm. Similar results have been found in clustering based on ISSR markers previously. A method using the principal components regression analysis (PCRA) to determine sequence correlated with gene expression was proposed and displayed with our example. From the PCRA results, 144th(G/T) and (CT) repeated alleles were detected and other newly discovered factors including (AATT)5/6, 390-C/T, 363-T/G, and 229-G/A. We have proved that these newly markers have a significant attributions for amylose accumulation by GLM method. (AATT)5/6, 390-C/T, and 363-T/G could explain 40.2 % of amylose variantion, and 229-G/A could contribute 54.9 %. Therefore, this method (RCPA) is powerful in identifying sequences correlated with gene expression.