Wheat plants that contain the Lr34 / Yr18 combination of genes also experience slower rates of rust infection. This prevents widespread and rapid increase of rust spores reducing the potential for disease epidemics throughout the crop.
研究人员发现了二个重要的抗锈病基因Lr34 和Yr18的DNA标志，这项发现将有助于世界上的植物交配人员配种出更有效对抗黄锈病的小麦品种。小麦如果同时获得这二个基因，将可以帮助小麦对抗叶锈病。
澳大利亚科学与工业研究院(CSIRO)的植物产业科学家Evans Lagudah博士表示，虽然目前已经有许多抗锈病品种，但是只能对抗单一的锈病菌或有限的几种锈病菌。
研究人员辨认出可以出百分之99 有效标示Lr34 和Yr18存在与否的DNA标志，这意味着植物繁殖人员可以透过简单的DNA测试来追踪抗锈病基因。如果这个标志存在，几乎可以保证Lr34/Yr18也存在于植物中。
Lr34/Yr18 可以与其它抗锈病基因一起运作，促进植物自我保护的效果。含有Lr34/Yr18基因组合的小麦，感染黄锈病的速率也较为缓慢。但是直到目前为止，都很难追踪小麦里的Lr34/Yr18基因，因为会被其它抗锈病基因所掩盖。此外，Lr34/Yr18测试的步骤也很漫长，每季只能进行一次，而且只能检测成熟的植物。
如果利用DNA标志来辨认Lr34/Yr18基因，可以迅速地在幼苗进行测试。这个DNA标志也适用于世界各地的小麦品种，包括澳洲、印度、中国、北美洲等地。所以世界各地的小麦品种都能利用这个DNA标志来辨认Lr34/Yr18。
英文原文：
Elusive Rust Resistance Genes Located
The discovery of a DNA marker for two key rust resistance genes is enabling plant breeders around the world to breed more effective rust resistant wheat varieties. The genes, Lr34 and Yr18 are inherited together and provide wheat plants with improved protection against leaf rust and stripe rust - two major diseases of wheat in Australia and worldwide.
CSIRO Plant Industry scientist, Dr Evans Lagudah, says various types of rust resistance have been bred into Australian varieties but work against a specific rust species and in some cases are only effective against a limited range of rust strains.
"We have identified a 'DNA marker' that is 99 per cent effective in flagging the presence of Lr34 and Yr18, which provide resistance against different species and strains of rust," Dr Lagudah says.
"This means that breeders can track the presence of this rust resistance through a simple DNA test. If the marker is present then it's almost guaranteed Lr34 / Yr18 will be too."
Plant breeders have long recognised the usefulness of Lr34 / Yr18, which work together with other rust resistance genes to boost the plants' capacity to defend itself.
Wheat plants that contain the Lr34 / Yr18 combination of genes also experience slower rates of rust infection. This prevents widespread and rapid increase of rust spores reducing the potential for disease epidemics throughout the crop.
"Up until now it has been difficult to track Lr34 / Yr18 in wheat because of the masking effect of other resistance genes," Dr Lagudah says.
"In addition, tests for Lr34 / Yr18 were slow and could only be done once per season and on adult plants growing in the paddock.
"Using the marker technology breeders can now quickly and easily test seedlings for the presence of Lr34 / Yr18, to establish known and unknown genes, and ideally combine different sources of resistance to speed up the delivery of new rust resistant wheat varieties."
The marker has proven effective in a range of wheats from different backgrounds including from Australia, India, China, North America and the major wheat research centre, CIMMYT.
Breeders in Australia and across the world are now using the marker so that the durable rust resistance offered by Lr34 / Yr18 can be incorporated into locally adapted wheat varieties.
