Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
BMC Plant Biol. 2014 Jan 8;14:10. doi: 10.1186/1471-2229-14-10.
Rust diseases are of major importance in wheat production worldwide. With the constant evolution of new rust strains and their adaptation to higher temperatures, consistent and durable disease resistance is a key challenge. Environmental conditions affect resistance gene performance, but the basis for this is poorly understood.
Here we show that a change in day temperature affects wheat resistance to Puccinia striiformis f. sp tritici (Pst), the causal agent of yellow (or stripe) rust. Using adult plants of near-isogenic lines UC1041 +/- Yr36, there was no significant difference between Pst percentage uredia coverage in plants grown at day temperatures of 18°C or 25°C in adult UC1041 + Yr36 plants. However, when plants were transferred to the lower day temperature at the time of Pst inoculation, infection increased up to two fold. Interestingly, this response was independent of Yr36, which has previously been reported as a temperature-responsive resistance gene as Pst development in adult UC1041 -Yr36 plants was similarly affected by the plants experiencing a temperature reduction. In addition, UC1041 -Yr36 plants grown at the lower temperature then transferred to the higher temperature were effectively resistant and a temperature change in either direction was shown to affect Pst development up to 8 days prior to inoculation. Results for seedlings were similar, but more variable compared to adult plants. Enhanced resistance to Pst was observed in seedlings of UC1041 and the cultivar Shamrock when transferred to the higher temperature. Resistance was not affected in seedlings of cultivar Solstice by a temperature change in either direction.
Yr36 is effective at 18°C, refining the lower range of temperature at which resistance against Pst is conferred compared to previous studies. Results reveal previously uncharacterised defence temperature sensitivity in the UC1041 background which is caused by a change in temperature and independently of Yr36. This novel phenotype is present in some cultivars but absent in others, suggesting that Pst defence may be more stable in some cultivars than others when plants are exposed to varying temperatures.
锈病在世界范围内的小麦生产中具有重要意义。随着新锈菌株的不断进化及其对更高温度的适应，持续和持久的抗病性是一个关键挑战。环境条件会影响抗性基因的表现，但这方面的基础知之甚少。
在这里，我们表明日温的变化会影响小麦对条锈病（Puccinia striiformis f. sp tritici，Pst）的抗性。使用近等基因系 UC1041 +/- Yr36 的成年植株，在 18°C 或 25°C 下生长的 UC1041 + Yr36 植株中，Pst 百分率的锈菌覆盖率没有显著差异。然而，当植株在接种 Pst 时被转移到较低的日温下时，感染增加了两倍。有趣的是，这种反应与 Yr36 无关，Yr36 以前被报道为一种温度响应性抗性基因，因为在成年 UC1041 -Yr36 植株中，Pst 的发育也受到植物经历温度降低的类似影响。此外，在较低温度下生长然后转移到较高温度的 UC1041 -Yr36 植株有效抵抗，并且在接种前 8 天内，无论方向如何改变温度都会影响 Pst 的发育。与成年植株相比，幼苗的结果相似，但更具变异性。当转移到较高温度时，UC1041 和 Shamrock 幼苗对 Pst 的抗性增强。在 UC1041 和 Solstice 品种的幼苗中，无论温度如何变化，抗性都不受影响。
Yr36 在 18°C 时有效，与之前的研究相比，细化了赋予 Pst 抗性的温度下限。结果揭示了 UC1041 背景下以前未被描述的防御温度敏感性，这种敏感性是由温度变化引起的，与 Yr36 无关。这种新表型存在于一些品种中，但在其他品种中不存在，这表明当植物暴露在不同温度下时，某些品种的 Pst 防御可能比其他品种更稳定。
