Genetic variation at bx1 controls DIMBOA content in maize
Genetic variation at bx1 controls DIMBOA content in maize
复制标题
DOI：
10.1007/s00122-009-1192-1
复制
发表时间：
2010-02-01
影响因子：
5.4
通讯作者：
McMullen, M. D.
中科院分区：
文献类型：
--
作者：
Butron, Ana;Chen, Y. C.;McMullen, M. D.
玉米 (Zea mays L.) 中的主要异羟肟酸是 2-4-二羟基-7-甲氧基-1,4-苯并恶嗪-3-酮 (DIMBOA)。丁波亚 (DIMBOA) 可以抵抗多种玉米螟取食叶子的能力。大多数参与 DIMBOA 代谢途径的基因位于 4 号染色体的短臂上，与玉米对玉米螟取食叶子的抗性有关的数量性状基因座 (QTL) 已定位于该区域。然而，QTL 连锁图谱的低分辨率无法令人信服地证明 bx 位点的遗传变异是造成抗性变异的原因。本研究实现了以下目标：使用嵌套关联作图群体中的 8 个 RIL 家族确定遗传差异玉米自交系中参与 DIMBOA 合成的 QTL，通过在 2 年内评估其中两个 RIL 家族来检查多年来 DIMBOA 含量 QTL 的稳定性，并通过对 281 个不同自交系进行关联作图来测试 bx1 的参与。 QTL 在不同环境中保持稳定。包含八个标记的遗传模型解释了八个 RIL 家族约 34% 的表型变异，并且最大 QTL 的位置与 DIMBOA 途径的大多数结构基因共定位。候选关联分析确定，bx1 的序列多态性极大地影响了不同玉米自交系中 DIMBOA 含量的变化，但尚未确定负责区域 4.01 中检测到的 QTL 的特定因果多态性或多态性。这个结果可能是因为因果多态性没有被测序、同一性被连锁不平衡掩盖、群体结构的调整降低了因果多态性的显着性或影响bx1自交系之间分离的多重因果多态性。
The main hydroxamic acid in maize (Zea mays L.) is 2-4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA confers resistance to leaf-feeding by several corn borers. Most genes involved in the DIMBOA metabolic pathway are located on the short arm of chromosome 4, and quantitative trait loci (QTLs) involved in maize resistance to leaf-feeding by corn borers have been localized to that region. However, the low resolution of QTL linkage mapping does not allow convincing proof that genetic variation at bx loci was responsible for the variability for resistance. This study addressed the following objectives: to determine the QTLs involved in DIMBOA synthesis across genetically divergent maize inbreds using eight RIL families from the nested association mapping population, to check the stability of QTLs for DIMBOA content across years by evaluating two of those RIL families in 2 years, and to test the involvement of bx1 by performing association mapping with a panel of 281 diverse inbred lines. QTLs were stable across different environments. A genetic model including eight markers explained approximately 34% of phenotypic variability across eight RIL families and the position of the largest QTL co-localizes with the majority of structural genes of the DIMBOA pathway. Candidate association analysis determined that sequence polymorphisms at bx1 greatly affects variation of DIMBOA content in a diverse panel of maize inbreds, but the specific causal polymorphism or polymorphisms responsible for the QTL detected in the region 4.01 were not identified. This result may be because the causal polymorphism(s) were not sequenced, identity is masked by linkage disequilibrium, adjustments for population structure reduce significance of causal polymorphisms or multiple causal polymorphisms affecting bx1 segregate among inbred lines.