| A.arenaria has increased serious harmly in paddy fields and control efficiency of bensulfuron-methyl(BSM) is becoming worse. Research on cross-resistance level of this weed to ALS inhibitor herbicide is not reported in the world. In this paper, it is determined the cross-resistance of different biotypes of A. arenaria to the four ALS inhibitors, and fluorescence quantitative PCR technique was used to study the molecular mechanism of A. arenaria, the results are as follows:1、The results of potted experiments showed that the ED50 value of BSM to five A. arenaria biotypes HZ001(Zhejiang), NB0143-05(Zhejiang), JX110(Zhejiang), JS039(Jiangsu) and AH014(Anhui) are respectively 0.18, 3.16, 12.20, 8.02 and 1.50gai/ha, the resistance index(RI) are respectively 44.63, 67.90, 17.59 and 8.37. The ED50 value of penoxsulam, bispyribac-sodium and imazethapyr to sensitive biotype HZ001 are respectively 0.16, 0.19 and 0.24, RI of the biotypes NB0143-05, JX110, JS039 and AH014 to penoxsulam are respectively 5.43, 4.96、3.73 and 4.55, RI to bispyribac-sodium are respectively 4.60, 5.05, 2.17 and 3.63, RI to imazethapyr are respectively 6.45, 2.60, 4.16 and 1.96. This suggests that NB0143-05, JX110, JS039 and AH014 develop high levels of resistance to BSM, and develop low resistance of interaction to penoxsulam( triazole pyrimidine herbicide). Three biotypes except JS039 develop low resistance of interaction to bispyribac-sodium( pyrimidine glucosinolates benzoic acid esters). NB0143-05 and JX110 develop low resistance of interaction to that. This is the first report that for cross-resistance level to other ALS inhibitor in the world.2、This study obtained the full length gene sequence of ALS of four Ammannia arenaria biotypes: HZ001, NB0143-05, JS039 and JX110 in paddy fields in Zhejiang and Jiangsu province. The results showed that the full DNA sequence length were 2235 bp, encoding 667 amino acids. The ALS gene 93 th leucine(CTCS) are replaced by the proline(CCC) in three Ammannia arenaria resistant biotypes. But the mutations are not binding site to amino acid and herbicide. Conservative region is not mutated.3、In this paper, it used real-time fluorescent quantitative PCR technology, β-actin as reference genes, to analyze expression difference of ALS gene by comparing resistant biotype (NB0143-05) to BSM and sensitive biotype(HZ001)at the m RNA level. The results show that Ammannia arenaria was sprayed the BSM at the dosage of 0.1 gai/ha in 3-4 leaf stage. At 2、4、6 after treatment(DAT), the expression of ALS gene of HZ001 were respectively 1.23、2.74 and 2.41 times higher than that of control, the expression of ALS gene of NB0143-05 were respectively 1.83、4.45 and 2.72 times higher. The results indicated that the expression of ALS gene increase gradually after spraying BSM, and reached maximum peak at 4 DAT, then steped down. At 4 DAT, resistant biotype was 1.86 times higher than that of sensitive biotype. The increasing expression of ALS gene may be key reason that NB0143-05 develop resistance and cross-resistance to BSM and other herbicides in paddy field of Zhejiang province. It reported for the first time that the expression of ALS gene increased after BSM treatment. |
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