Review of transgenic crop breeding in China / 生物工程学报

The development history and fundamental experience of transgenic crops (Genetically modified crops) breeding in China for near 30 years were reviewed. It was illustrated that a scientific research, development and industrialization system of transgenic crops including gene discovery, transformation, variety breeding, commercialization, application and biosafety assessment has been initially established which was few in number in the world. The research innovative capacity of transgenic cotton, rice and corn has been lifted. The research features as well as relative advantages have been initially formed. The problems and challenges of transgenic crop development were discussed. In addition, three suggestions of promoting commercialization, speeding up implementation of the Major National Project of GM Crops, and enhancing science communication were made.

Optimized condition for protoplast isolation from maize, wheat and rice leaves / 生物工程学报

Maize (Zea mays L.), wheat (Triticum aestivum L.) and rice (Oryza sativa L.) are three staple crops and accordingly it is very meaningful to optimize the condition of their protoplasts isolation. The concentration of the enzyme, the time of isolation and centrifugal force in protoplast isolation were investigated to find their effects on protoplast yield and viability using leaves of maize (Zong 3), wheat (Chinese Spring) and rice (Nipponbare). The results show that the concentration of the enzyme and the time of isolation affected the protoplast yield significantly. Although the yield of protoplast was increased with high concentration of enzyme and long incubated time, it led to too much cells breakdown. The orthogonal experimental design results show that the best condition of maize protoplast isolation was Cellulase R-10 1.5%, Macerozyme R-10 0.5%, 50 r/min 7 h, 100 x g 2 min and the protoplasts yield was 7x106 cells/g fresh weight (FW); the best condition of wheat protoplast isolation was Cellulase R-10 1.5%, Macerozyme R-10 0.5%, 50 r/min 5 h, 100 x g 2 min and the protoplasts yield was 6 x 10(6) cells/g FW; the best condition of rice protoplast isolation was Cellulase R-10 2.0%, Macerozyme R-10 0.7%, 50 r/min 7 h, 1 000 x g 2 min and the protoplasts yield was 6x10(6) cells/g FW. The vitalities were more than 90% using fluorescein diacetate staining method. 50%-80% transformation efficiency was obtained when protoplasts were transformed by green fluorescent protein using PEG-Ca2+ method.

Relationship between structure and function of loops from Bacillus thuringiensis insecticidal crystal protein Cry1Ba / 生物工程学报

To indicate the relationship between structure and function of loops from Bacillus thuringiensis insecticidal crystal protein Cry1Ba, and the influence of amino acids mutation on toxicity against diamond back moth Plutella xylostella, five mutations at the loops of Cry1Ba were constructed by overlapping primer PCR, and expressed in E. coli BL21 (DE3). Bioassay results showed that the toxicity of mutation M1 (loop1: 340WSNTR344-deletion), compared with that of Cry1Ba (LC50 0.96 microg/mL), decreased significantly with LC50 35.51 microg/mL. And the toxicity of mutation M2 (402Y-G), M3 (400GIYLEP405-PSAV), M4 (400GIYLEPIH407-ILGS) was also reduced to some extent respectively. Only M5 (mutation at loop3: 472LQSRV476 - AGAVYTL) showed slightly increased activity against P. xylostella, but not significantly (LC50 0.81 microg/mL). Referring to the structures of Cry1Ba which was predicted using Swiss-Model software, and bioassay data, we can conclude that loop1 and loop2 play a important role on determining the activity of Cry1Ba against P. xylostella.