ABSTRACT
Background: Rice seed proteins are lacking essential amino acids [EAAs]. Genetic engineering offers a fast and sustainable method to solve this problem as it allows the specific expression of heterologous EAA-rich proteins. The use of selectable marker gene is essential for generation of transgenic crops, but might also lead to potential environmental and food safety problems. Therefore, the production of marker-free transgenic crops is becoming an extremely attractive alternative and could contribute to the public acceptance of transgenic crops
Objectives: The present study was conducted to examine whether AmA1 can be expressed specifically in rice seeds, and generate marker-free transgenic rice with improved nutritive value
Materials and Methods: AmA1 was transferred into rice using Agrobacterium-mediated co-transformation system with a twin T-DNA binary vector and its integration in rice genome was confirmed by southern blot. Transcription of AmA1 was analyzed by Real-Time PCR and its expression was verified by western analysis. Protein and amino acid content were measured by the Kjeldahl method and the high-speed amino acid analyzer, respectively
Results: Five selectable marker-free homozygous transgenic lines were obtained from the progeny. The expression of recombinant AmA1 was confirmed by the observation of a 35 kDa band in SDS-PAGE and western blot. Compared to the wild-type control, the total protein contents in the seeds of five homozygous lines were increased by 1.06 tilde 12.87%. In addition, the content of several EAAs, including lysine, threonine, and valine was increased significantly in the best expressing line
Conclusions: The results indicated that the amino acid composition of rice grain could be improved by seed-specific expression of AmA1
Subject(s)
Amaranthus , Agrobacterium , Amino Acids, Essential , Genes, PlantABSTRACT
Objective: To investigate six mineral element contents of rice bran and milled rice from three color rice cultivars (white rice, red rice, black rice). Methods: Select 36 typical cultivars and determine Se, Zn, Fe, Ca, Mn, Cu contents in their rice bran and milled rice with AFS-2201 atomic fluorescent spectrometer and AA-680 atomic absorption spectrometer. Results: 1. The six mineral element contents of rice bran were 2.58, 3.35, 10.04, 4.58, 12.79 and 6.59 times as those of milled rice respectively. 2. The Ca content of black milled rice was significantly higher than that of white and red milled rice. The Mn content in rice bran of white rice was significantly higher than those of black and red rice. Other mineral element contents were not significantly different. 3. For rice bran and milled rice of different cultivars, the contents of each mineral element in three color rices varied greatly. Conclusions: 1. The content of six minerals in rice bran was 5.66 times on average as that in milled rice in all cultivars of three color rice. 2. Eight cultivars of the highest content of each mineral in rice bran and milled rice were recommended for commercial use and human consumption.