mlo-based powdery mildew resistance in hexaploid bread wheat generated by a non-transgenic TILLING approach.
mlo-based powdery mildew resistance in hexaploid bread wheat generated by a non-transgenic TILLING approach.
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DOI：
10.1111/pbi.12631
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发表时间：
2017-03
影响因子：
13.8
通讯作者：
Panstruga R
中科院分区：
文献类型：
--
作者：
Acevedo-Garcia J;Spencer D;Thieron H;Reinstädler A;Hammond-Kosack K;Phillips AL;Panstruga R
小麦是世界上种植最广泛的谷类作物之一，是人类重要的粮食来源。然而，许多非生物和生物胁迫因素可降低小麦产量，包括由小麦白粉病菌引起的白粉病。因此，产生抗性品种是植物育种中的主要努力。在这里，我们利用非转基因组靶向诱导损伤（TILLING）技术来选择TaMlo的部分功能缺失等位基因，TaMlo是大麦Mlo（抗霉基因座o）基因的直向同源物。已知大麦Mlo的天然和诱导的功能丧失等位基因（mlo）赋予持久的广谱白粉病抗性，通常以多效性表型如过早叶片衰老为代价。我们在三种小麦TaMlo同源物TaMlo-A1、TaMlo-B1和TaMlo-D1中鉴定了16个错义突变，每个错义突变都导致单个氨基酸交换。利用大麦单细胞瞬时基因表达分析，我们功能分析了不同的错义突变体，并确定了最有前途的候选人影响白粉病的易感性。通过堆叠选定的突变等位基因，我们产生了在三个TaMlo同源物中的每一个中具有非保守突变的四个独立系。纯合的三重突变体系和令人惊讶的是，一些纯合的双突变体系显示出增强的但不完全的Bgt抗性，而没有出现可辨别的多效性表型。因此，这些品系代表了生产商业非转基因抗白粉病面包小麦品种的重要一步。
Wheat is one of the most widely grown cereal crops in the world and is an important food grain source for humans. However, wheat yields can be reduced by many abiotic and biotic stress factors, including powdery mildew disease caused by Blumeria graminis f.sp. tritici (Bgt). Generating resistant varieties is thus a major effort in plant breeding. Here, we took advantage of the non‐transgenic Targeting Induced Lesions IN Genomes (TILLING) technology to select partial loss‐of‐function alleles of TaMlo, the orthologue of the barley Mlo (Mildew resistance locus o) gene. Natural and induced loss‐of‐function alleles (mlo) of barley Mlo are known to confer durable broad‐spectrum powdery mildew resistance, typically at the expense of pleiotropic phenotypes such as premature leaf senescence. We identified 16 missense mutations in the three wheat TaMlo homoeologues, TaMlo‐A1, TaMlo‐B1 and TaMlo‐D1 that each lead to single amino acid exchanges. Using transient gene expression assays in barley single cells, we functionally analysed the different missense mutants and identified the most promising candidates affecting powdery mildew susceptibility. By stacking of selected mutant alleles we generated four independent lines with non‐conservative mutations in each of the three TaMlo homoeologues. Homozygous triple mutant lines and surprisingly also some of the homozygous double mutant lines showed enhanced, yet incomplete, Bgt resistance without the occurrence of discernible pleiotropic phenotypes. These lines thus represent an important step towards the production of commercial non‐transgenic, powdery mildew‐resistant bread wheat varieties.