Puccinia striiformis f. sp. tritici is the causal agent of wheat stripe rust that causes severe yield losses all over the world. As a macrocyclic heteroecious rust fungus, it is able to infect two unrelated host plants, wheat and barberry. Its urediniospores infect wheat and cause disease epidemic, while its basidiospores parasitize barberry to fulfill the sexual reproduction. This complex life cycle poses interesting questions on the different mechanisms of pathogenesis underlying the infection of the two different hosts. In the present study, transcriptomes of P. striiformis f. sp. tritici during the initial infection of wheat and barberry leaves were qualitatively and quantitatively compared. As a result, 142 wheat-specifically expressed genes (WEGs) were identified, which was far less than the 2,677 barberry-specifically expressed genes (BEGs). A larger proportion of evolutionarily conserved genes were observed in BEGs than that in WEGs, implying a longer history of the interaction between P. striiformis f. sp. tritici and barberry. Additionally, P. striiformis f. sp. tritici differentially expressed genes (DEGs) between wheat at 1 and 2 days postinoculation (dpi) and barberry at 3 and 4 dpi were identified by quantitative analysis. Gene Ontology analysis of these DEGs and expression patterns of P. striiformis f. sp. tritici pathogenic genes, including those encoding candidate secreted effectors, cell wall–degrading enzymes, and nutrient transporters, demonstrated that urediniospores and basidiospores exploited distinct strategies to overcome host defense systems. These results represent the first analysis of the P. striiformis f. sp. tritici transcriptome in barberry and contribute to a better understanding of the evolutionary processes and strategies of different types of rust spores during the infection process on different hosts.

Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

小麦条锈菌f。sp。小麦是小麦条锈病的病因，在世界范围内造成严重的产量损失。作为一种大环杂种锈病真菌，它能够感染两种不相关的寄主植物，小麦和伏牛花。它的梭子孢子感染小麦并引起疾病流行，而它的担子孢子寄生伏牛花以完成有性繁殖。这个复杂的生命周期对引起两个不同宿主感染的不同发病机理提出了有趣的问题。在本研究中，P。striiformis f。的转录组。sp。小麦定性和定量地比较了小麦和伏牛叶初次感染期间的品质。结果，鉴定出142个小麦特异性表达的基因（WEG），远小于2,677个伏牛花特异性表达的基因（BEG）。在BEGs中观察到的进化保守基因比例要比WEGs中更大，这意味着条纹假单胞菌f。之间有更长的相互作用历史。sp。小麦和伏牛花。此外，P。striiformis f.。sp。小麦在1次2天接种（dpi）的和在伏牛3和4 dpi的小麦之间差异表达的基因（DEGS）通过定量分析鉴定。这些DEGs的基因本体分析和cDNA的表达模式棒状线虫f。sp。小麦的致病基因，包括编码候选分泌效应子，细胞壁降解酶和营养转运蛋白的致病基因，证明了梭孢子和孢子孢子利用独特的策略来克服宿主防御系统。这些结果代表对P. striiformis f。的首次分析。sp。伏牛的小麦小麦转录组，有助于更好地了解不同寄主在感染过程中不同类型锈菌孢子的进化过程和策略。

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