Laser Capture Microdissection of Uredinia Formed by Melampsora larici-populina Revealed a Transcriptional Switch Between Biotrophy and Sporulation
Laser Capture Microdissection of Uredinia Formed by Melampsora larici-populina Revealed a Transcriptional Switch Between Biotrophy and Sporulation
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DOI：
10.1094/mpmi-05-10-0111
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发表时间：
2010-10-01
影响因子：
3.5
通讯作者：
Duplessis, Sebastien
中科院分区：
文献类型：
--
作者：
Hacquard, Stephane;Delaruelle, Christine;Duplessis, Sebastien
由落叶松-populina担子菌引起的叶锈病是影响欧洲杨树人工林的主要病害。在宿主感染过程中，锈菌的生物营养状况是研究细胞或组织类型基因表达的主要限制。在尿毒期，被感染的杨叶含有明显的锈病组织，如吸器、感染菌丝和尿毒症，其中有孢子生菌丝和新形成的无性尿毒症孢子。利用激光捕获显微解剖技术（LCM）分离出叶肉中与尿嘧啶区和下邻区相对应的3个区域，并应用全基因组外显子寡阵列进行表达分析。优化LCM前的组织制备，可以分离出具有良好完整性的RNA进行全基因组表达谱分析。研究结果表明，杨树锈病尿尿期具有与寄主栅栏叶肉生物营养和尿尿中产孢有关的独特遗传程序。在叶肉中观察到编码小分泌蛋白的转录本的强烈诱导，可能含有锈病效应物，这表明在含有吸器和感染菌丝的组织中，宿主防御抑制的后期维持。另一方面，细胞周期和细胞防御救援转录本在产孢区大量积累。这种结合lcm -转录组学方法为铁锈真菌中脲孢子形成的分子机制带来了新的见解。
The foliar rust caused by the basidiomycete Melampsora larici-populina is the main disease affecting poplar plantations in Europe. The biotrophic status of rust fungi is a major limitation to study gene expression of cell or tissue types during host infection. At the uredinial stage, infected poplar leaves contain distinct rust tissues such as haustoria, infection hyphae, and uredinia with sporogenous hyphae and newly formed asexual urediniospores. Laser capture microdissection (LCM) was used to isolate three areas corresponding to uredinia and subjacent zones in the host mesophyll for expression analysis with M. laricipopulina whole-genome exon oligoarrays. Optimization of tissue preparation prior to LCM allowed isolation of RNA of good integrity for genome-wide expression profiling. Our results indicate that the poplar rust uredinial stage is marked by distinct genetic programs related to biotrophy in the host palisade mesophyll and to sporulation in the uredinium. A strong induction of transcripts encoding small secreted proteins, likely containing rust effectors, is observed in the mesophyll, suggesting a late maintenance of suppression of host defense in the tissue containing haustoria and infection hyphae. On the other hand, cell cycle and cell defense rescue transcripts are strongly accumulated in the sporulation area. This combined LCM-transcriptomic approach brings new insights on the molecular mechanisms underlying urediniospore formation in rust fungi.