Crampton Bridget G, Hein Ingo, Berger Dave K
CSIR Biosciences, PO Box 395, Pretoria 0001, South Africa.
Mol Plant Pathol. 2009 Mar;10(2):291-304. doi: 10.1111/j.1364-3703.2008.00532.x.
Studies were undertaken to assess the induction of defence response pathways in pearl millet (Pennisetum glaucum) in response to infection with the leaf rust fungus Puccinia substriata. Pretreatment of pearl millet with salicylic acid (SA) conferred resistance to a virulent isolate of the rust fungus, whereas methyl jasmonate (MeJA) did not significantly reduce infection levels. These results suggest that the SA defence pathway is involved in rust resistance. In order to identify pearl millet genes that are specifically regulated in response to SA and not MeJA, and thus could play a role in resistance to P. substriata, gene expression profiling was performed. Substantial overlap in gene expression responses between the treatments was observed, with MeJA and SA treatments exhibiting 17% co-regulated transcripts. However, 34% of transcripts were differentially expressed in response to SA treatment, but not in response to MeJA treatment. SA-responsive transcripts represented genes involved in SA metabolism, defence response, signal transduction, protection from oxidative stress and photosynthesis. The expression profiles of pearl millet plants after treatment with SA or MeJA were more similar to one another than to the response during a compatible infection with P. substriata. However, some SA-responsive genes were repressed during P. substriata infection, indicating possible manipulation of host responses by the pathogen.
开展了多项研究，以评估珍珠粟（Pennisetum glaucum）在受到叶锈病菌柄锈菌（Puccinia substriata）感染时防御反应途径的诱导情况。用水杨酸（SA）预处理珍珠粟可使其对锈病菌的一个强毒株产生抗性，而茉莉酸甲酯（MeJA）并未显著降低感染水平。这些结果表明，SA防御途径参与了对锈病的抗性。为了鉴定珍珠粟中那些受SA而非MeJA特异性调控、因而可能在抗柄锈菌中发挥作用的基因，进行了基因表达谱分析。观察到各处理之间基因表达反应存在大量重叠，MeJA处理和SA处理有17%的转录本是共同调控的。然而，34%的转录本对SA处理有差异表达，但对MeJA处理无差异表达。对SA有反应的转录本代表了参与SA代谢、防御反应、信号转导、抗氧化应激保护和光合作用的基因。用SA或MeJA处理后珍珠粟植株的表达谱彼此之间比与在与柄锈菌亲和性感染期间的反应更相似。然而，一些对SA有反应的基因在柄锈菌感染期间受到抑制，这表明病原体可能对宿主反应进行了操控。
