การวิเคราะห์พันธุกรรมของยีนที่เกี่ยวข้องกับแอนโทไซยานินในข้าวก่ำพื้นเมืองของไทย

Abstract

Khao Kum (purple rice) is a type of purple rice landrace widely cultivated in the northern and northeastern regions of Thailand. Purple rice landrace is popular among health food consumers due to its high nutritional value in the grain. Additionally, there is ongoing development and utilization of other parts of the purple rice landrace to add value and alleviate the burden of post-harvest management. However, However, there is a less of comprehensive studies on the anthocyanin content and the genes involved in anthocyanin synthesis in Thai purple rice landrace. This experiment aims to provide information for developing and improving purple rice landrace varieties with desired anthocyanin content. The study focuses on the OsDFR and OsANS1 genes involved in anthocyanin synthesis, analyzing their expression levels in leaves aged 45 days after transplanting and in grains. The experiment took place at the Agricultural Innovation Research, Integration, Demonstration, and Training Center, Faculty of Agriculture, Chiang Mai University, involving nine varieties of purple rice landrace categorized into two groups based on leaf and stem color appearance. The first group comprises purple rice landraces with purple leaves and stems: Kum Doi Saket, Kum Phayao, Kum Wiang Sa, and K4. The second group consists of purple rice landraces with green leaves and stems: Hom Nin, Kum Hom CMU, Kum Jao CMU 107, Luem Pua, and BL3.Two white rice varieties, Pathum Thani 1 and Khao Dawk Mali 105, were used as check varieties. The experiment employed a completely randomized design with samples divided into three replicates. The results indicate the expression of OsDFR and OsANS1 genes in leaves at 45 days in the purple rice landrace group with purple leaves and stems. Kum Doi Saket and Kum Wiang Sa exhibited the highest levels of OsDFR gene expression at 0.71 and 0.69, respectively. The highest levels of OsANS1 gene expression were found in Kum Doi Saket and K4, with relative gene expression levels of 0.57 and 0.56, respectively. Regarding anthocyanin content, K4 in the purple rice landrace group with purple leaves and stems showed the highest anthocyanin in leaves at 232.9 mg per 100 g of dry weight. In grains, K4, Kum Doi Saket, and Luem Pua had the highest anthocyanin content at 89.1, 78.1, and 62.21 mg per 100 g of dry weight, respectively. The study also investigated yield and yield components, revealing differences among the varieties studied. Most purple rice landrace varieties exhibited lower yield and yield components compared to the white rice check varieties with higher yields. Additionally, the relationship between OsDFR and OsANS1 gene expression levels and anthocyanin content in leaves and grains of purple rice landrace varieties was examined. A negative relationship was observed between OsDFR gene expression level and anthocyanin content in leaves, while no significant relationship was found between OsDFR gene expression and anthocyanin content in grains. Conversely, a positive relationship was found between OsANS1 gene expression level and anthocyanin content in leaves, but not in grains. Furthermore, the study examined the relationship between anthocyanin content in grains and yield, revealing a negative relationship between anthocyanin content and yield. Overall, the study provides valuable information about anthocyanin content in purple rice landrace and the relationship between anthocyanin biosynthesis genes and the synthesis process in purple rice landrace. This information can be utilized to develop molecular markers for selecting anthocyanin content in purple rice landrace, thereby streamlining breeding programs during variety selection and aiding decision-making. Utilizing parts other than the seeds of purple rice landrace can also help increase income for farmers.