Identification And Screening Of Brassica Napus With Resistance To Glyphosate

Rapeseed is one of widely grown oil crops, and plays an important role in the supply of edible oil and protein feed as well as raw industrial materials supply. The planting area of production of rapeseed in China rank first in the world. However, biotic and abiotic stresses induce much loss of the yield every year. Therefore, improving the rapeseed resistance to adversity will increase yield significantly. As one of the most serious biotic stress, weeds is also a main obstacle for rapeseed high yield, not only leading to declined yield abruptly, but also costing much labour to weeding. Given that, it is important to control and extirpate weeds effectively. Nonetheless, chemical weed control is often hard to obtain the ideal effect, for its strict demands on spray time and dose. Besides, specific crop narrows the applied scope and a great variety of weeds rises weeding difficulty. So it will be better to breed and spread herbicide-resistant rapeseed, which could make weed control more effectively, mitigate the labour time and increase the yield and profit.First, this research was about to obtain trangenic Arabidopsis and rapeseed with a artificially synthetic glyphoste-resistant gene cp4-epsp, and then identify their resistance to herbicide. Second, the glyphosate-resistant mutant from ethyl methanesulfonate-mutagenized rapeseed M2 seedlings under certain selected-stress was screened. Third, the epsp gene of rapeseed was cloned to gain a better understanding of the EPSP synthase which is the target enzyme of glyphosate. The major results are as follows:(1) cp4-epsp was successfully transferred into Arabidopsis and rapeseed through agribacterium-mediated transformation. Resistance identification indicates that transgenic plants could bear 100-time dilution of Roundup, while the wild type could not survive even at a 400-time dilution.(2) A M1 mutant population has been obtained by the treatment of seeds of B. napus Xiangyou15 with 0.45% aqueous EMS. Then glyphosate-resistance mutants were screened from the EMS-mutagenized M2 seedlings at the 4-5 leaf stage under 200x dilution of Roundup. Finally, all plants died after 10d, no resistant one existed.(3) Two copies of epsp has been cloned in Yellow Sarson(B.rapa). The homology between them is 92% in the nucleotide and 95% in the amino acid levels. Phylogenetic analysis suggested that epsp384 has a closest phylogenetic relationship with epsp in Brassica rapa subsp. Campestris and epsp319 with epsp in Brassica napus. Sequences Alignment showed that most amino acids are highly conserved among 23 EPSP synthases from different organisms.