Plant Cell and Environ:华中农业大学徐芳森研究组发表甘蓝型油菜硼
近日，国际期刊《plant Cell and Environment》 在线发表了华中农业大学油菜营养遗传课题组在甘蓝型油菜硼高效研究方面取得的新进展。该研究借助QTL精细定位与转录组分析克隆了油菜中一个硼高效基因BnaA3.NIP5;1。论文标题为Transcriptomics-assisted QTL fine mapping for the rapid identification of a NODULIN 26-LIKE INTRINSIC PROTEIN gene regulat。2014级博士研究生华营鹏为论文第一作者，徐芳森教授为论文通讯作者。
硼是植物生长发育必需的微量营养元素。甘蓝型油菜是我国主要的油料作物，需硼多，对缺硼敏感，而我国油菜主产区正是土壤有效硼缺乏的地区，施用硼肥是我国油菜生产的重要保障。由徐芳森教授领导的油菜营养遗传课题组长期致力于油菜养分高效利用的研究，最近在油菜硼高效基因克隆的研究中取得新进展。
课题组在甘蓝型油菜A3染色体检测到一个硼高效主效QTLqBEC-A3a的基础上，利用发展构建的油菜qBEC-A3a近等基因系，通过苗期营养液和悬浮细胞系的培养试验，发现在缺硼条件下qBEC-A3a显著提高了油菜耐低硼胁迫的能力;在土壤盆栽缺硼条件下，该QTL显著提高了油菜成熟期的籽粒产量。研究进一步采用全基因组重测序技术开发SNP及InDel分子标记，利用BC4F3/BC4F3:4与BC4F4/BC4F4:5群体开展基因型分析和硼效率表型测验，将目标QTL精细定位到119 kb包含21个基因的染色体区段内。随后，利用全基因组数字基因表达谱分析低硼胁迫下近等基因系间的差异表达基因，发现二者在根部差异表达的仅有一个NODULIN 26-LIKE INTRINSIC PROTEIN (NIP)基因，其与拟南芥硼酸通道基因AtNIP5;1同源并命名为BnaA3.NIP5;1。生物信息学分析表明甘蓝型油菜的BnaA3.NIP5;1蛋白属于MIP蛋白超家族中NIP II亚家族成员，该基因起源于其二倍体祖先白菜的BraA3.NIP5;1基因，在油菜硼吸收转运基因的共表达网络中发挥核心作用。BnaA3.NIP5;1基因在硼高效与低效亲本间氨基酸序列并无差异，但5'UTR区存在11个SNP及1个InDel变异。序列保守性及顺式作用元件分析表明，5'UTR区可能是调控不同基因型硼效率差异的关键因子。研究结果为进一步揭示甘蓝型油菜硼高效的分子调控机制及油菜硼营养的遗传改良提供了新的基础。该研究也证明了QTL-seq技术在具有复杂基因组的异源四倍体油菜中进行QTL分析的可行性。
原文链接：
Transcriptomics-assisted QTL Fine Mapping for the Rapid Identification of a NODULIN 26-LIKE INTRINSIC PROTEIN GENE Regulating Boron Efficiency in Allotetraploid Rapeseed
原文摘要：
Allotetraploid rapeseed (Brassica napus L., AnAnCnCn, 2n=38) is extraordinarily susceptible to boron (B) deficiency, a ubiquitous problem causing severe losses in seed yield. The breeding of B-efficient rapeseed germplasm is a cost-effective and environmentally friendly strategy for the agricultural industry; however, genes regulating B efficiency in allotetraploid rapeseed have not yet been isolated. In this research, QTL fine mapping and digital gene expression (DGE) profiling were combined to identify the candidate genes underlying the major-effect quantitative trait locus (QTL) qBEC-A3a, which regulates B efficiency. Comparative phenotype analyses of the near-isogenic lines (NILs) indicated that qBEC-A3a plays a significant role in improving B efficiency under B deficiency. Exploiting QTL fine mapping and DGE analyses revealed a NODULIN 26-LIKE INTRINSIC PROTEIN (NIP) gene, which encodes a likely boric acid channel. The gene co-expression network for putative B transporters also highlighted its central role in the efficiency of B uptake. An integration of whole-genome re-sequencing (WGS) with bulked segregant analysis (BSA) authenticated the emerging availability of QTL-seq for the QTL analyses in allotetraploid rapeseed. Transcriptomics-assisted QTL mapping and comparative genomics provided novel insights into the rapid identification of quantitative trait genes (QTGs) in plant species with complex genomes.
作者：徐芳森
