A Second Mechanism for Aluminum Resistance in Wheat Relies on the Constitutive Efflux of Citrate from Roots
A Second Mechanism for Aluminum Resistance in Wheat Relies on the Constitutive Efflux of Citrate from Roots
复制标题
DOI：
10.1104/pp.108.129155
复制
发表时间：
2009-01-01
期刊：
影响因子：
7.4
通讯作者：
Delhaize, Emmanuel
中科院分区：
文献类型：
--
作者：
Ryan, Peter R.;Raman, Harsh;Delhaize, Emmanuel
第一个被证实的植物抗铝机制是由小麦（Triticum aestivum）染色体4DL上的基因TaALMT 1编码的。TaALMT 1控制铝激活的苹果酸从根流出，这种机制是广泛存在于不同遗传来源的抗铝基因型。本研究描述了小麦抗铝的第二种机制，依赖于柠檬酸外流。柠檬酸流出发生组成巴西品种Carazinho，马林加，Toropi，和Trintecinco的根。两个群体分离的这一性状的检查表明，柠檬酸流出由一个单一的基因座控制。利用来自Carazinho（柠檬酸外排）和栽培品种EGA-Burke（无柠檬酸外排）之间杂交的F2群体进行全基因组连锁作图，确定了染色体4 BL上的主要位点Xce（c），其占柠檬酸外排表型变异的50%以上。将柠檬酸盐流出的定量变化转化为定性数据，将Xce（c）位点定位在微卫星标记Xgwm 495位点的6.3cM范围内。这种连锁在第二个群体的F-2：3家庭来自Carazinho和品种白鹭（无柠檬酸外流）之间的交叉验证。我们表明，表达的序列标签，属于多药和毒素外排（MATE）基因家族的表达，与柠檬酸盐外排表型。本研究为柠檬酸外流是小麦抗铝的第二机制提供了遗传和生理证据。
The first confirmed mechanism for aluminum (Al) resistance in plants is encoded by the wheat (Triticum aestivum) gene, TaALMT1, on chromosome 4DL. TaALMT1 controls the Al-activated efflux of malate from roots, and this mechanism is widespread among Al-resistant genotypes of diverse genetic origins. This study describes a second mechanism for Al resistance in wheat that relies on citrate efflux. Citrate efflux occurred constitutively from the roots of Brazilian cultivars Carazinho, Maringa, Toropi, and Trintecinco. Examination of two populations segregating for this trait showed that citrate efflux was controlled by a single locus. Whole-genome linkage mapping using an F 2 population derived from a cross between Carazinho (citrate efflux) and the cultivar EGA-Burke (no citrate efflux) identified a major locus on chromosome 4BL, Xce(c), which accounts for more than 50% of the phenotypic variation in citrate efflux. Mendelizing the quantitative variation in citrate efflux into qualitative data, the Xce(c) locus was mapped within 6.3 cM of the microsatellite marker Xgwm495 locus. This linkage was validated in a second population of F-2:3 families derived from a cross between Carazinho and the cultivar Egret (no citrate efflux). We show that expression of an expressed sequence tag, belonging to the multidrug and toxin efflux (MATE) gene family, correlates with the citrate efflux phenotype. This study provides genetic and physiological evidence that citrate efflux is a second mechanism for Al resistance in wheat.