State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, People's Republic of China.
Plant Physiol Biochem. 2013 Jan;62:11-8. doi: 10.1016/j.plaphy.2012.10.014. Epub 2012 Nov 6.
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat worldwide. We report the use of the non-host plant Arabidopsis thaliana to identify the basis of resistance to Pst at the cytological and molecular levels. No visible symptoms were observed on Arabidopsis leaves inoculated with Pst. Microscopic observations showed that significantly reduced numbers of Pst urediospores had successfully achieved penetration in Arabidopsis compared with those in wheat. There were significant differences in the frequency of stomatal penetration but not in fungal growth among different Pst races in Arabidopsis. The fungus failed to successfully form haustoria in Arabidopsis and attempted infection induced an active response including accumulation of phenolic compounds and callose deposition in plant cells. A set of defence-related genes were also up regulated during the Pst infection. Compared with wild type plants, increased fungal growth was observed in an npr1-1 mutant and in NahG transformed plants, which both are insensitive to salicylic acid. However, treatment of Arabidopsis plants with cytochalasin B, an inhibitor of actin microfilament polymerization, did not increase susceptibility to Pst. Our results demonstrate that Arabidopsis can be used to study mechanisms of non-host resistance to wheat stripe rust, and highlight the significance of participation of salicylic acid in non-host resistance to rust fungi.
小麦条锈病由条形柄锈菌小麦专化型（Pst）引起，是全球范围内对小麦危害最大的病害之一。我们利用非寄主植物拟南芥，从细胞学和分子水平上研究了对 Pst 抗性的基础。用 Pst 接种拟南芥叶片后，叶片上没有观察到可见的症状。显微镜观察表明，与在小麦上相比，成功穿透拟南芥的 Pst 夏孢子数量明显减少。在拟南芥中，不同 Pst 小种之间在气孔穿透频率上存在显著差异，但在真菌生长方面没有差异。真菌未能在拟南芥中成功形成吸器，尝试侵染诱导了包括酚类化合物积累和植物细胞中胼胝质沉积在内的活跃反应。在 Pst 侵染过程中，还上调了一组与防御相关的基因。与野生型植物相比，在水杨酸不敏感的 NPR1-1 突变体和 NahG 转化植物中观察到真菌生长增加。然而，用细胞松弛素 B（一种肌动蛋白微丝聚合抑制剂）处理拟南芥植物并没有增加其对 Pst 的易感性。我们的研究结果表明，拟南芥可用于研究小麦条锈病非寄主抗性的机制，并强调了水杨酸参与锈菌非寄主抗性的重要性。
