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ÃÞ »¨ ѧ ±¨ Cotton Science 2005£¬17(6)£º334-338
Transgenic Cotton£¨Gossypium hirsutum L.£©Expressing Wild Shepherd's purse Agglutinin Gene with High Quality Fiber Abstract£ºPlant Lectins are proteins that bind reversibly to specific monoor oligosaccharides. It has a prospective use in Agriculture/Medicine et al£¬especially in plant anti-insect gene engineering. Aphid damage is one of the reasons to decrease the yield and quality of cotton (Gossypium hirsutum L.). In order to improve the resistance to aphid£¬ the gene engineering was carried out in this study in cotton. The wild shepherd's purse agglutinin gene (WSA) driven under DE35s promoter was introduced into ten cotton varieties with high quality fiber by pollen tube-mediated transformation. Pollen tube pathway is one kind of direct genetic transformation technique£¬using the plant fertilized eggs as the transgenic receptor. The technique has the advantages of no genotype limitation£¬no tissue culture£¬ and easy operation for large scale of plant genetic transformation. For the convenience of screening transgenic plants and WSA gene expressing efficiently£¬the used transgenic expression vector also contains selected marker gene NPT¢ò (kanamycin-resistant gene) and sequence of ¦¸. In order to identify the transgenic engineering plants effectively and simply£¬it is beneficial for the identification of transgenic engineering plants to use kanamycin-resistance as an indirect marker. Smearing a drop of 2000 mg¡¤kg-1 kanamycin solution with writing brush on one pairs of cotyledons and first neonate expanded leaves. All of leaves of non-transgenic plants showed apparent yellow patches whereas the leaves of the transgenic engineering ones maintain green without any symptoms. The identification for resistance to kanamycin indicated that 4.88% plants have kanamycin-resistance (Kan+) in 3197 cotton seedlings of the contemporary transformation generation. One pair of specific primers complementary to the functional sequence of WSA gene was designed£¬ the fragment of expected DNA was about 290 bp in size. 45 trans-WSA gene plants were screened by PCR tests from 156 Kan+ plants. These results indicate that the wild shepherd's purse agglutinin gene is possibly integrated into the genome of these transgenic engineering plants. Fiber quality identification indicated that 9 trans-WSA gene cotton lines were up to the standard of high quality fiber (2.5% span length¡Ý31 mm£¬strength ¡Ý35 cN¡¤tex-1£¬Micronaire value£º3.7-4.2) in these 45 transgenic lines. These 9 trans-WSA gene cotton lines with high quality fiber can be used in conventional breeding program. The limitation of using NPT¢ò gene as selected marker gene in the plant gene engineering and the reasons for declination of fiber strength of transgenic cotton lines are also discussed.
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