Australian Centre for Plant Functional Genomics, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
Plant Cell Environ. 2010 Feb;33(2):188-98. doi: 10.1111/j.1365-3040.2009.02069.x. Epub 2009 Nov 11.
Boron tolerance is a quantitative trait controlled by multiple genes. Suppression subtractive hybridization was carried out on root cDNA from bulked boron tolerant and intolerant doubled haploid barley lines grown under moderate boron stress to identify genes associated with boron tolerance. One hundred and eleven clones representing known proteins were found to be up-regulated in the tolerant bulk upon boron stress. Nine clones were genetically mapped to previously reported boron tolerance QTL. These include a clone identical to the boron transporter gene Bot1 and a clone coding for a bromo-adjacent homology domain-containing protein, mapping to the 6H boron tolerance locus and co-segregating with reduced boron intake in a Clipper x Sahara-3771 mapping population. A third clone mapping to the 2H QTL region encoding an S-adenosylmethionine decarboxylase precursor was found to provide tolerance to high boron by heterologous expression. Yeast cells expressing Sahara SAMDC were able to grow on 15 mm boron solid media and maintained cellular boron concentrations at 13% lower than control cells expressing empty vector. The data suggest that an antioxidative response mechanism involving polyamines and the ascorbate-glutathione pathway in Sahara barley may provide an advantage in tolerating high soil concentrations of boron.
硼耐性是由多个基因控制的数量性状。在中度硼胁迫下，对来自大量硼耐性和不耐性双单倍体大麦品系的根 cDNA 进行抑制性消减杂交，以鉴定与硼耐性相关的基因。在硼胁迫下，在耐性品系中发现 111 个代表已知蛋白的克隆上调。其中 9 个克隆被遗传图谱定位到先前报道的硼耐性 QTL 上。这些克隆包括与硼转运蛋白基因 Bot1 相同的克隆和编码溴相邻同源结构域蛋白的克隆，该基因位于 6H 硼耐性位点，与 Clipper x Sahara-3771 作图群体中硼吸收减少共分离。第三个克隆位于 2H QTL 区域，编码 S-腺苷甲硫氨酸脱羧酶前体，通过异源表达提供对高硼的耐受性。表达 Sahara SAMDC 的酵母细胞能够在 15mm 硼固体培养基上生长，并将细胞硼浓度维持在比表达空载体的对照细胞低 13%。数据表明，撒哈拉大麦中的多胺和抗坏血酸-谷胱甘肽途径的抗氧化反应机制可能为耐受高土壤硼浓度提供优势。
