The New Zealand Institute for Plant and Food Research Limited, Lincoln 7608, New Zealand.
The New Zealand Institute for Plant and Food Research Limited, Te Puke 3182, New Zealand.
Plant Dis. 2020 Jun;104(6):1771-1780. doi: 10.1094/PDIS-11-19-2302-RE. Epub 2020 Apr 9.
Resistance to the pandemic strain of was identified in New Zealand provenance , , and plants. Only 1 -resistant plant was found (of the 570 tested) and no resistant plants of either or were found. Three types of resistance were identified in . The first two, a putative immune response and a hypersensitive response, are leaf resistance mechanisms found in other myrtaceous species while on the lateral and main stems a putative immune stem resistance was also observed. Both leaf and stem infection were found on and plants as well as branch tip dieback that developed on almost 50% of the plants. , and are the first myrtaceous species where consistent infection of stems has been observed in artificial inoculation trials. This new finding and the first observation of significant branch tip dieback of plants of the two spp. resulted in the development of two new myrtle rust disease severity assessment scales. Significant seed family and provenance effects were found in , and : some families produced significantly more plants with leaf, stem, and (in spp.) branch tip dieback resistance, and provenances provided different percentages of resistant families and plants. The distribution of the disease symptoms on plants from the same seed family, and between plants from different seed families, suggested that the leaf, stem, and branch tip dieback resistances were the result of independent disease resistance mechanisms.
在新西兰起源的 、 和 植物中发现了对该疾病流行株的抗性。仅发现了 1 株抗性植物（在测试的 570 株中），未发现任何 或 抗性植物。在 中鉴定出了 3 种抗性类型。前两种，一种假定的免疫反应和一种过敏反应，是在其他桃金娘科物种中发现的叶片抗性机制，而在侧枝和主茎上也观察到了一种假定的免疫茎抗性。在 、 和 植物上发现了叶片和茎部感染，以及在近 50%的植物上发生的枝条顶端枯死。 、 和 是首次在人工接种试验中观察到茎部持续感染的桃金娘科物种。这一新发现以及首次观察到这两个 种的植物显著的枝条顶端枯死，导致开发了两种新的桃金娘锈病严重程度评估量表。在 、 和 中发现了显著的种子家族和起源效应：一些家族产生了具有叶片、茎和（在 种中）枝条顶端枯死抗性的植物显著更多，而起源提供了不同比例的抗性家族和植物。来自同一种子家族的植物之间以及来自不同种子家族的植物之间的疾病症状分布表明，叶片、茎和枝条顶端枯死抗性是独立的疾病抗性机制的结果。
