Institute of Experimental Botany of the Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 78371, Olomouc, Czech Republic.
Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 19086, Tallinn, Estonia.
Theor Appl Genet. 2019 Apr;132(4):1061-1072. doi: 10.1007/s00122-018-3259-3. Epub 2018 Dec 7.
A segment of Triticum militinae chromosome 7G harbors a gene(s) conferring powdery mildew resistance which is effective at both the seedling and the adult plant stages when transferred into bread wheat (T. aestivum). The introgressed segment replaces a piece of wheat chromosome arm 4AL. An analysis of segregating materials generated to positionally clone the gene highlighted that in a plant heterozygous for the introgression segment, only limited recombination occurs between the introgressed region and bread wheat 4A. Nevertheless, 75 genetic markers were successfully placed within the region, thereby confining the gene to a 0.012 cM window along the 4AL arm. In a background lacking the Ph1 locus, the localized rate of recombination was raised 33-fold, enabling the reduction in the length of the region containing the resistance gene to a 480 kbp stretch harboring 12 predicted genes. The substituted segment in the reference sequence of bread wheat cv. Chinese Spring is longer (640 kbp) and harbors 16 genes. A comparison of the segments' sequences revealed a high degree of divergence with respect to both their gene content and nucleotide sequence. Of the 12 T. militinae genes, only four have a homolog in cv. Chinese Spring. Possible candidate genes for the resistance have been identified based on function predicted from their sequence.
一段来自节节麦染色体 7G 的片段携带有一个能够赋予抗白粉病的基因，当该基因被转移到普通小麦（T. aestivum）中时，无论是在幼苗期还是成株期都非常有效。该导入片段取代了小麦 4AL 染色体臂的一部分。对用于定位克隆该基因的分离材料进行分析，突出表明在导入片段杂合的植物中，导入区域与普通小麦 4A 之间仅发生有限的重组。尽管如此，仍有 75 个遗传标记成功地定位在该区域内，从而将该基因限制在 4AL 臂上 0.012 cM 的窗口内。在缺乏 Ph1 基因座的背景下，局部重组率提高了 33 倍，使包含抗病基因的区域长度缩短至 480 kbp，其中包含 12 个预测基因。普通小麦 cv. Chinese Spring 参考序列中的替换片段更长（640 kbp），并包含 16 个基因。对两个片段序列的比较表明，它们在基因组成和核苷酸序列方面都存在高度的差异。在 12 个节节麦基因中，只有 4 个在 cv. Chinese Spring 中具有同源基因。根据它们的序列预测的功能，已经确定了可能的抗病候选基因。
