Enhancing wheat field performance and response to abiotic stress with novel growth-regulatory alleles

20世纪60年代以来提高全球谷物产量的“绿色革命”归功于小麦和水稻新品种的结合以及氮肥和杀虫剂的增加使用。新品种的一个重要特征是降低了高度/虽然最初引入是为了让植物耐受高水平的肥料，而不会过度生长和坍塌，但人们发现，这些新的半矮秆品种提高了产量，因为植物的能量更少地浪费在生产秸秆上，更多的能量浪费在收获的谷物上。我们现在知道，这些矮秆小麦品种携带了一种基因(称为“降低高度”或Rht)，这种基因使它们对植物自身的生长激素赤霉素(GA)没有反应，赤霉素通常会增加茎高。同样，新的半矮秆水稻品种含有一种缺陷基因，导致激素水平降低。只有两种类型的Rht基因被广泛用于小麦，其中一种主要用于英国品种。气候变化、农业实践以及对生长调节剂使用的可能限制，可能意味着含有这种基因的小麦品种不再能够生产最高产量。该计划的一部分是为了识别新的小麦基因，这些基因可以改变GA信号，因此对身高有不同的影响。然后，这些基因可以单独或与现有的Rht基因结合，用于培育新的矮秆品种。我们还发现，矮化基因通过GA信号的变化来降低身高，也保护植物免受干旱、高温或盐等胁迫。随着气候变化减少小麦产区的降雨量，这一点可能变得更加重要。有证据表明，现有的Rht基因并不是保护小麦免受胁迫的理想基因。因此，该项目的第二个目标将是测试一系列影响GA信号的基因，以确定它们在保护植物免受干旱和其他胁迫方面的有效性。最后，这个项目的一个重要目标是，我们发现的新的矮秆基因应该被植物育种者利用来开发新的商业品种。因此，我们与国家农业植物学研究所共同制定了一项‘预育种’战略，将这些新基因引入现代高产品种中，这些品种可以传递给育种者，并用于他们的小麦育种计划。

The 'Green Revolution' that improved worldwide cereal yields from the 1960s was due to a combination of new varieties of wheat and rice and the increased use of nitrogen fertilisers and pesticides. An important feature of the new varieties was reduced height / although originally introduced to allow the plants to tolerate high levels of fertiliser without overgrowing and collapsing, it was discovered that these new semi-dwarf varieties increased yield, as less of the plants' energy was wasted on producing straw and more went into the harvested grain. We now know that these dwarf varieties of wheat carried a gene (called 'Reduced Height' or Rht) that made them unresponsive to the plant's own growth hormone, gibberellin (GA), which normally increases stem height. Similarly, the new semi-dwarf rice varieties contained a defective gene that resulted in reduced levels of the hormone. There are only two types of Rht gene that have been widely used in wheat, and predominantly one in UK varieties. Changes in climate, agricultural practise and possible restrictions in the use of growth-regulating chemicals may mean that wheat varieties containing this gene are no longer capable of producing the highest yield. Part of this programme is aimed at identifying new wheat genes that alter GA signalling and therefore have different effects on height. These genes could then be used to produce new dwarf varieties, either alone or in combination with the existing Rht genes. We have also discovered that dwarfing genes, that confer reduced height through changes in GA signalling, also protect plants against stresses such as drought, heat, or salt. This may become even more important as climate change reduces the amount of rainfall in wheat-producing areas. There is evidence that the existing Rht gene is not ideal for protecting wheat plants from stress. A second aim of this project will therefore be to test a range of genes affected GA signalling for their effectiveness in protecting plants from drought and other stresses. Finally, an important aim of this project is that the new dwarfing genes that we discover should be taken up by plant breeders to develop new commercial varieties. Therefore, we have developed a 'pre-breeding' strategy with the National Institute of Agricultural Botany to bring these new genes into modern, high-yielding varieties that can be passed on to breeders and used in their wheat breeding programmes.