Aberrant mRNA processing of the maize Rp1-D rust resistance gene in wheat and barley
Aberrant mRNA processing of the maize Rp1-D rust resistance gene in wheat and barley
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DOI：
10.1094/mpmi.2004.17.8.853
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发表时间：
2004-08-01
影响因子：
3.5
通讯作者：
Pryor, AJ
中科院分区：
文献类型：
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作者：
Ayliffe, MA;Steinau, M;Pryor, AJ
玉米Rp1-D基因对含有相应avrp1 - d无毒基因的高粱叶锈病（普通叶锈病）分离株具有种族特异性抗性。一个Rp1-D基因组克隆和一个由玉米泛素启动子调控的类似Rp1-D转基因被独立转化到易感玉米品系中，并被证明具有Rp1-D抗性，这表明这种抗性可以作为单个基因转移。当小麦和大麦受到小麦茎锈病（P. graminis）、小麦叶锈病（P. triticina）或大麦叶锈病（P. hordei）分离株的攻击时，将这些功能性转基因转移到小麦和大麦中并没有产生新的抗性。无论使用何种启动子，都观察到低水平的基因表达。当构建启动子用于转基因表达时，大部分Rp1-D转录本在核苷酸结合位点编码区被过早聚腺苷化截断。这种异常的mRNA加工与基因功能无关，因为基因的非活性版本也产生了这样的转录本。这些数据表明，物种之间的抗性基因转移可能不仅受到信号效应分子和病原体无毒配体的差异的限制，而且可能受到更基本的基因表达和转录加工的限制。
The maize Rp1-D gene confers race-specific resistance against Puccinia sorghi (common leaf rust) isolates containing a corresponding avrRp1-D avirulence gene. An Rp1-D genomic clone and a similar Rp1-D transgene regulated by the maize ubiquitin promoter were transformed independently into susceptible maize lines and shown to confer Rp1-D resistance, demonstrating that this resistance can be transferred as a single gene. Transfer of these functional transgenes into wheat and barley did not result in novel resistances when these plants were challenged with isolates of wheat stem rust (P. graminis), wheat leaf rust (P. triticina), or barley leaf rust (P. hordei). Regardless of the promoter employed, low levels of gene expression were observed. When constitutive promoters were used for transgene expression, a majority of Rp1-D transcripts were truncated in the nucleotide binding site-encoding region by premature polyadenylation. This aberrant mRNA processing was unrelated to gene function because an inactive version of the gene also generated such transcripts. These data demonstrate that resistance gene transfer between species may not be limited only by divergence of signaling effector molecules and pathogen avirulence ligands, but potentially also by more fundamental gene expression and transcript processing limitations.