Liao Hong, Yan Xiaolong, Rubio Gerardo, Beebe Steve E, Blair Matthew W, Lynch Jonathan P
Department of Horticulture, The Pennsylvania State University, University Park, PA 16802, USA.
Laboratory of Plant Nutritional Genetics and Root Biology Center, South China Agricultural University, Guangzhou 510642, China.
Funct Plant Biol. 2006 Mar;33(2):207. doi: 10.1071/FP03255_CO.
Root gravitropism determines the relative distribution of plant roots in different soil layers, and therefore, may influence the acquisition of shallow soil resources such as phosphorus (P). Growth pouch and field studies were conducted to evaluate root gravitropism of common bean (Phaseolus vulgaris L.) in response to P deficiency and to detect quantitative trait loci (QTL) associated with this trait. A deep-rooted genotype, DOR364, was crossed with a shallow-rooted genotype, G19833, to obtain 86 F recombinant inbred lines (RILs). Root gravitropic traits were measured as basal root growth angle (BRGA), shallow basal root length (SBRL, basal root length in the top 0-3 cm of soil) and relative shallow basal root length (RSBRL, percentage of basal root length in the top 0-3 cm of soil relative to total basal root length). Large genetic variability for these traits was found in the parents and RILs, with BRGA ranging from -18.73 to 56.69º and SBRL ranging from 0.42 to 2.63 m per plant. The parents and six RILs with contrasting root gravitropism were further evaluated in the field, where root shallowness was significantly correlated with plant growth and P uptake. QTL were detected by single point analysis (SPA), interval mapping (IM) and composite interval mapping (CIM) techniques with a genetic map for the DOR364 × G19833 population consisting of 236 molecular markers. The IM/CIM QTL were detected among the 11 linkage groups of common bean, with 16 QTL controlling the above root traits and six QTL controlling P acquisition efficiency (PAE) in the field study. At least three of the root trait QTL were associated with QTL for PAE, suggesting that root gravitropic traits are associated with PAE and that QTL for these traits can be used to facilitate selection and breeding for higher P efficiency in common bean and other crops.
根向地性决定了植物根系在不同土壤层中的相对分布，因此，可能会影响对浅层土壤资源（如磷）的获取。进行了生长袋试验和田间研究，以评估普通菜豆（Phaseolus vulgaris L.）对缺磷的根向地性，并检测与该性状相关的数量性状位点（QTL）。将一个深根基因型DOR364与一个浅根基因型G19833杂交，获得86个F重组自交系（RIL）。根向地性性状通过基部根生长角度（BRGA）、浅层基部根长度（SBRL，土壤表层0 - 3厘米处的基部根长度）和相对浅层基部根长度（RSBRL，土壤表层0 - 3厘米处的基部根长度占基部根总长度的百分比）来衡量。在亲本和RIL中发现了这些性状的较大遗传变异，BRGA范围为-18.73至56.69°，SBRL范围为每株0.42至2.63米。对亲本和六个具有不同根向地性的RIL在田间进行了进一步评估，在田间，根的浅生性与植物生长和磷吸收显著相关。利用由236个分子标记组成的DOR364×G19833群体的遗传图谱，通过单点分析（SPA）、区间作图（IM）和复合区间作图（CIM）技术检测QTL。在普通菜豆的11个连锁群中检测到IM/CIM QTL，在田间研究中有16个QTL控制上述根性状，6个QTL控制磷获取效率（PAE）。至少三个根性状QTL与PAE的QTL相关，这表明根向地性性状与PAE相关，并且这些性状的QTL可用于促进普通菜豆和其他作物中更高磷效率的选择和育种。
