Fine Mapping Of Anti-nicosulfuron Gene In Wax Maize And Bioinformatic Analysis Of Candidated Sequences Between Flanking Markers Linked With Anti-nicosulfuron Gene

Nicosulfuron is a kind of sulfonvlurea herbicide.It often has advantages such as high effect,low toxicity and high selectivity.It has been widely and rapidly used for weed control because of the characteristic auch as low application rates,broad,stability and so on. Using nicosulfuron-resisted and nicosulfuron-sensitive near-isogenic lines of wax maize shennuo R-509,-509as materials to identify nicosulfuron resistance,research mechanism of resistance,analyze the genetic basis of resistance, locate the gene and analyze candicate sequence with bioinformatics.In order to lay the foundation for resistance marker-assisted selective breeding and transgenic breeding.The main results are as follows:1.Base on the investigation of seed germination,seeding growth and yield formation on nicosulfuron-sensitive near-isogenic lines of wax maize shennuo R-509,S-509,the experiments show that all indentification indexes of near-isogenic lines has been inhibited in different concentration nicosulfuron.When the concentration of nicosulfuron below80ppm,the indexes of resistance inbred lines are normal.Phytotoxicity of shennuo R-509is being more serious with increasing concentration of nicosulfuron. When the concentration of nicosulfuron ablove160ppm, resistance inbred lines are all dead. Shennuo S-509is more sensitive with nicosulfuron. Non-resistance inbred lines are all dead in low concentration of nicosulfuron(≤8ppm).2.Physiolocial measures of nicosulfuron-sensitive near-isogenic lines change dramatically after spaying nicosulfuron.It shows that Pro content,soluble sugar content,MDA content,SOD activity and POD activity increase. ALS activity,chlorophyll content,net photosynthetic rate and Fv/Fm decrease dramatically.The physiolocial measures of resistance inbred lines is more stable than non-resistance’s.This maybe one key reason of increasing tolerance to nicosulfuron for resistance inbred lines,compare with non-resistance inbred lines.3.There are no difference between reciprocal F1generations,so the gene is not a nuclear gene.Segregation of F2families derived from a cross between resistance inbred lines and non-resistance inbred lines for response to nicosulfuron is3:1(resistance:non-resistance) which is not significantly different from an expected3:1ratio(χ2=0.041＜ 3.84=x20.05),indicating that resictance gene to nicosulfuron is conditioned by a single dominant gene.The gene affecting resistance in shennuo R-509is maped to the5.04region,located between S129and IDP6476,and the genetic distance between the two markers is2.0cM.4.In order to get resistance gene candidate sequences,analyze sequences between two flanking markers S129and IDP6476linked with resistance gene by using bioinformaties method.Among the candidate sequences, G473697has both high identity and close relation ship with Gox resisitance to glyphosate,and is predieted to be related with resistance gene.G473697contains a lot of random coils in secondary structure of protein,and a particular biological activity function in tertiary structure of protein.In a word, G473697is predieted to be composed of the most important parties in resistance tiongene functional domains to nicosulfuron.