Map-based cloning of a novel rice cytochrome P450 gene CYP81A6 that confers resistance to two different classes of herbicides
Map-based cloning of a novel rice cytochrome P450 gene CYP81A6 that confers resistance to two different classes of herbicides
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DOI：
10.1007/s11103-006-0058-z
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发表时间：
2006-08-01
影响因子：
5.1
通讯作者：
Tu, Jumin
中科院分区：
文献类型：
--
作者：
Pan, Gang;Zhang, Xianyin;Tu, Jumin
在过去的三十年里，杂交水稻的发展极大地提高了产量。两个苯达松致死突变体8077 S和Norin 8 m正在开发新的杂交水稻系统。在此突变体背景下培育雄性不育系时，可通过苗期喷施苯达松，解决不育系自交种子污染F1代种子的问题。我们首先测定了突变体植株对苯达松的敏感性。这两种突变体从100 mg/l开始对苯达松表现出症状，这比其野生型对照的敏感性阈值低约60倍。此外，这两个突变体是敏感的磺酰脲类除草剂。突变表型的基因座是8077 S的bel和Norin 8 m的bsl。试验表明，这两个位点是等位的。通过图位克隆的方法克隆了这两个基因。有趣的是，这两个突变等位基因有一个单碱基缺失，这是由PCR-RFLP证实。这两个基因座被重新命名为bel（a）（表示bel）和bel（B）（表示bel）。野生型Bel基因编码一种新的细胞色素P450单加氧酶，命名为CYP 81 A6。对突变蛋白序列的分析也揭示了bel（a）比bel（B）稍微耐受的原因。野生型Bel基因的导入挽救了Bel（a）突变体的苯达松和磺酰脲敏感表型。另一方面，反义Bel在W 6154 S中的表达诱导突变表型。基于这些结果，我们得出结论，新的细胞色素P450单加氧酶CYP 81 A6编码的贝尔赋予两种不同类型的除草剂的抗性。
Development of hybrid rice has greatly contributed to increased yields during the past three decades. Two bentazon-lethal mutants 8077S and Norin8m are being utilized in developing new hybrid rice systems. When the male sterile lines are developed in such a mutant background, the problem of F1 seed contamination by self-seeds from the sterile lines can be solved by spraying bentazon at seedling stage. We first determined the sensitivity of the mutant plants to bentazon. Both mutants showed symptoms to bentazon starting from 100 mg/l, which was about 60-fold, lower than the sensitivity threshold of their wild-type controls. In addition, both mutants were sensitive to sulfonylurea-type herbicides. The locus for the mutant phenotype is bel for 8077S and bsl for Norin8m. Tests showed that the two loci are allelic to each other. The two genes were cloned by map-based cloning. Interestingly, both mutant alleles had a single-base deletion, which was confirmed by PCR-RFLP. The two loci are renamed bel(a) (for bel) and bel(b) (for bel). The wild-type Bel gene encodes a novel cytochrome P450 monooxgenase, named CYP81A6. Analysis of the mutant protein sequence also revealed the reason for bel(a) being slightly tolerant than bel(b). Introduction of the wild-type Bel gene rescued the bentazon- and sulfonylurea-sensitive phenotype of bel(a) mutant. On the other hand, expression of antisense Bel in W6154S induced a mutant phenotype. Based on these results we conclude that the novel cytochrome P450 monooxygenase CYP81A6 encoded by Bel confers resistance to two different classes of herbicides.