Location Of Glyphosate-resistant Gene And Studies On Physiological And Biochemical Characteristics Of Glyphosate Inducing Infertile Pollen

Glyphosate is a world-widely-used herbicide which inhibits the enzyme5-enolpyruvylshikimata-3-phosphate(EPSP). Weed control mechanism by glyphosate is to inhibite the shikimic acid pathway of EPSPS synthase, block the synthesis of aromatic amino acids, eventually led to the death of plants. Glyphosate is one of the most commonly used herbicides in cotton fields which has the advantages of broad-spectrum weed control and rapid degradation in the soil. Meanwhile, herbicide glyphosate also has disadvantages that they kill the weeds will also bring harm to the crops. So, in order to better use of glyphosate, crops resistant to glyphosate produced. The cotton strains resistant to glyphosate were used in the paper, several meaning results have attained as following.1. Location of glyphosate resistance genes. Glyphosate-resistant cotton G-6and sea-island cotton Hai7124were used. All plants were resistant to glyphosate in hybrid F1groups. The number of resistant plants to non-resistant ones in F2population was consistent with3:1separation ratio, the resistant plants to non-resistant ones in recessive backcross population BC2consistent with1:1separation ratio. The above result showed that glyphosate-resistant trait was controlled by a pair of dominant gene. Using a pair of distinctive primer to detect the resistant plants displayed that the glyphosate-resistant gene was an artificial synthesis gene, CP4-EPSPS. Then,234pairs of core primer covered26pairs of chromosomes in cotton were used to screened differential marker by the method of BSA, a total of27polymorphic primers were obtained. Through detection of each plant’s genotype in F2population,5pairs of primers, NAU5417, NAU1339, BNL3992, BNL2448and NAU2140were found to link to target gene CP4-EPSPS. According to a known genetic map, these primers were located on chromosome5, so the target gene were located on fifth chromosome. Furthermore, screening all other primers on fifth chromosome,15pairs of primers linking to target gene CP4-EPSPS were gained, and the gene CP4-EPSPS located between primers BNL2448and NAU2140, their genetic distances were7.0cM and16.2cM, respectively.2. Research on physiological and biochemical characteristics of pollen sterility induced by glyphosate. The glyphosate resistance cotton N95were used as materials in this experiment. Spraying glyphosate solution since June25, no spraying glyphosate for comparison. The following results had been made.(1) Compared the pollen activity between treated and non-treated plants, the results showed that the pollen activity of plants treatment with0.2%glyphosate solution was just average3%compared to86%of non-treatment.(2) Assaying endogenous hormones contents in pollens during4development stages, the results showed that the content of IAA in sterile pollen was43.8%-64.3%of CK, content of ABA in sterile pollen was1.33-1.87times of CK, content of ZR in sterile pollen was39.6%-57.1%of CK, content of GA3in sterile pollen was50.5%-64.9%of CK. According to above result could deduce the reason led to pollen sterility was deficiency of IAA,ZR,GA3and overabundance of ABA.(3) Testing the Amino acids contents in pollens during4development stages, the results showed that the content of phenylalanine, tyrosine and proline in pollen from plants treated by glyphosate solution were significantly lower than control plants, while the content of glutamic acid is higher than the control plants. According to above result could concluse that deficiency of phenylalanine, tyrosine,proline and overabundance of glutamic closely associated with pollen sterility.