Abiotic Stress Tolerance in Crops, INRES, University of Bonn, Bonn, Germany.
J Exp Bot. 2017 Jan 1;68(3):687-700. doi: 10.1093/jxb/erw423.
Boron (B) toxicity is a nutritional disorder affecting crop production in many parts of the world. This study explored genetic factors associated with B tolerance in rice (Oryza sativa L.) through an integrated genome mapping and transcriptomic approach. Variation in B tolerance was first evaluated by screening a panel of 137 indica genotypes in B toxic conditions (+2 mM B), followed by genome-wide association study (GWAS). Leaf bronzing and greenness were significantly correlated with shoot and root dry weight, but B uptake was not correlated with any stress phenotype. Single nucleotide polymorphism (SNP) markers exceeding a significance value of –log10P>4.0 were obtained for four traits, namely leaf bronzing, shoot dry weight, root dry weight, and root length. Linkage disequilibrium block analysis of the corresponding chromosomal regions revealed candidate loci containing 75 gene models. Two contrasting genotypes from the panel were selected for transcriptomic analysis, which included gene ontology enrichment analysis of differentially regulated genes and investigating transcriptional responses of GWAS candidate genes. Characteristic expression patterns associated with tolerance or sensitivity were seen in genes related to biochemical binding, transport, transcriptional regulation, and redox homeostasis. These results advance the understanding of genetic and physiological factors associated with B tolerance in rice.
硼（B）中毒是一种影响世界许多地区作物生产的营养失调症。本研究通过整合基因组图谱和转录组学方法，探讨了与水稻（Oryza sativa L.）B 耐受性相关的遗传因素。首先通过在 B 毒性条件（+2mM B）下筛选 137 个籼稻基因型来评估 B 耐受性的变异，然后进行全基因组关联研究（GWAS）。叶片青铜色和绿色与地上部和根干重显著相关，但 B 吸收与任何胁迫表型均不相关。对于叶片青铜色、地上部干重、根干重和根长这四个性状，获得了超过显著值-Log10P>4.0 的单核苷酸多态性（SNP）标记。对相应染色体区域的连锁不平衡块分析揭示了包含 75 个基因模型的候选基因座。从该组中选择了两个具有代表性的基因型进行转录组分析，包括差异调节基因的基因本体富集分析和调查 GWAS 候选基因的转录响应。与耐/敏感相关的特征表达模式出现在与生化结合、运输、转录调控和氧化还原稳态相关的基因中。这些结果提高了对与水稻 B 耐受性相关的遗传和生理因素的理解。
