Authors: Maolong Hu Huiming Pu Lingna Kong Jianqin Gao Weihua Long Song Chen Jiefu Zhang Cunkou Qi
Publish Date: 2015/01/24
Volume: 35, Issue: 1, Pages: 46-
Abstract
Imidazolinone herbicide IMIresistant varieties of many crops induced by mutations to acetohydroxyacid synthase AHAS genes are planted worldwide However in the case of rapeseed which is a common source of edible oil for nearly onehalf of China’s population no IMI resistance has been reported for any of the varieties currently cultivated We have developed an imazethapyrresistant rapeseed M9 derived from a naturally occurring mutant plant The goals of this study were to determine the biochemical and molecular bases of herbicide resistance in M9 to develop molecular markers for the detection of herbicideresistant genes and to utilize herbicideresistant traits to enhance seed purity in hybrid rapeseed production An in vitro AHAS activity assay indicated that the AHAS enzyme from M9 conferred a specific resistance to IMIs Molecular analysis identified a singlepoint mutation leading to an amino acid substitution from serine 653 AGT to asparagine AAT at the herbicidebinding site of the rapeseed BnAHAS1 gene This substitution mutation Ser653Asp did not change the transcription levels of BnAHAS1 in M9 compared with the wild type An allelespecific PCR marker for the BnAHAS1 mutant sequence was developed and cosegregated with IMI resistance in the F2 BC1 and BC2 populations Finally the CMS restorer line 10M169 was developed to show the resistance of M9 and F1 seeds of different purity were generated from 10M169 and Ning A7 under different pollination conditions The increases in seed purity under natural hybridization and hybridization in tents reached 1341 and 1641 respectively after IMI treatment suggesting that the herbicideresistant trait can be utilized for the efficient elimination of false hybrids in hybrid rapeseed production leading to increases in yield of up to 322 and 394 kg ha−1 respectively The molecular mechanism and molecular marker of herbicide resistance described here provide the basis for the release of IMIresistant rapeseed cultivarsThis research was funded by the National Natural Science Foundation of China Grant No 31101174 863 National HighTech RD Program of China Grant No 2011AA10A10403 Jiangsu Provincial Natural Science Foundation of China Grant No BK2011679 Jiangsu Provincial Independent Innovation of Agriculture Sciences Grant No CX125018 and Opening Research Project of State Key Laboratory of Crop Genetics and Germplasm Enhancement NAU Grant No ZW2011006
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