Grain color is a key agronomic trait that greatly determines food quality. The molecular and evolutionary mechanisms that underlie grain-color regulation are also important questions in evolutionary biology and crop breeding. Here, we confirm that both bHLH and MYB genes have played a critical role in the evolution of grain color in Triticeae. Blue grain is the ancestral trait in Triticeae, whereas white grain caused by bHLH or MYB dysfunctions is the derived trait. HvbHLH1 and HvMYB1 have been the targets of selection in barley, and dysfunctions caused by deletion(s), insertion(s), and/or point mutation(s) in the vast majority of Triticeae species are accompanied by a change from blue grain to white grain. Wheat with white grains exhibits high seed vigor under stress. Artificial co-expression of ThbHLH1 and ThMYB1 in the wheat endosperm or aleurone layer can generate purple grains with health benefits and blue grains for use in a new hybrid breeding technology, respectively. Our study thus reveals that white grain may be a favorable derived trait retained through natural or artificial selection in Triticeae and that the ancient blue-grain trait could be regained and reused in molecular breeding of modern wheat.

粮食作物是人类主要的能量来源,大部分作物品种的种子是白色或黄色,而小麦、玉米、水稻等物种中有些品种的种子因黄酮类物质花青素的积累表现出红、蓝、黑等颜色.不同于其他作物中天然存在有色种子的品种,蓝粒小麦则是普通小麦与其他物

Common wheat (Triticum aestivum L.) is one of the three major food crops in the world; thus, wheat breeding programs are important for world food security. Characterizing the genes that control important agronomic traits and finding new ways to alter them are necessary to improve wheat breeding. Functional genomics and breeding in polyploid wheat has been greatly accelerated by the advent of several powerful tools, especially CRISPR/Cas9 genome editing technology, which allows multiplex genome engineering. Here, we describe the development of CRISPR/Cas9, which has revolutionized the field of genome editing. In addition, we emphasize technological breakthroughs (e.g., base editing and prime editing) based on CRISPR/Cas9. We also summarize recent applications and advances in the functional annotation and breeding of wheat, and we introduce the production of CRISPR-edited DNA-free wheat. Combined with other achievements, CRISPR and CRISPR-based genome editing will speed progress in wheat biology and promote sustainable agriculture. © 2021, The Author(s).

The breeding of herbicide-resistant wheat varieties has helped control weeds in wheat fields economically and effectively. Imidazolinone (IMI) herbicides are popular as they have low toxicity in mammals, are effective at small doses, and exhibit broad-spectrum herbicidal action in the field. Therefore, the isolation and genetic and molecular characterization of IMI-resistant wheat mutants will enhance weed management in wheat fields. In the present study, 352 IMI-resistant plants were isolated by genetic screening from a mutant pool prepared by EMS-based random mutagenesis. Cloning of the mutated genes from the IMI-resistant plants indicated that ten taals alleles had been isolated, and mutation in one of three TaALS homolog genes conferred IMI resistance, and such a mutation is a dominant trait. Further analysis showed that taals-d exhibited the greatest IMI resistance, whereas taals-b exhibited the weakest resistance to IMI among three homologous taals mutants. In terms of IMI resistance, the taals triple mutant was stronger than the taals double mutants, and the taals double mutants were stronger than the single mutants, indicating a dose-dependent effect of the TaALS mutation on IMI resistance in wheat. Biochemical analysis indicated that the mutation in TaALS increased the tolerance of TaALS to inhibition by NI. Our work details the genetic and molecular characterization of als wheat mutants, provides a foundation for understanding IMI resistance and breeding wheat varieties with herbicide resistance, and indicates that genetic screening using a mutagenized pool is an effective and important means of breeding crops with additional desired agricultural traits. (C) 2020 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

北部冬麦区是我国重要的小麦产区之一。优质强筋小麦有较大的市场需求。随着生产条件的不断改善，对小麦品种产量、抗病性、抗倒伏性有更高的要求，同时，新品种要适应生产管理方式的变化，比如化学除草剂的广泛利用，要求品种对除草剂有一定的抗性。本研究围绕主要育种目标，创制新种质，培育优质高产抗病新品种。建立了快速批量制备和培育抗除草剂小麦新种质资源和抗除草剂小麦新品种的新技术。育成小麦新品种63个，其中，优质强筋品种津强11在品质性状上有较大提高，拉伸曲线参数的拉伸面积达到215平方厘米，最大拉伸阻力达到1017EU。节水高产品种京花12在北京市节水组区试和国家北部冬麦区区试中，分别比节水对照品种京冬8号和高产对照品种中麦175增产8.3%和6.6%。轮选266于2018年通过京、津、冀3省(市)品种审定，该品种的创新性主要体现在3个方面。一是产量水平有较大突破。该品种两年区域试验平均亩产557.2公斤，比对照中麦175增产5.2%;生产试验平均亩产561.5公斤，比对照中麦175增产7.5%。二是抗倒伏性强。轮选266区域试验和生产试验平均株高70.5厘米，比北部冬麦区主栽品种中麦175株高矮10厘米左右，抗倒伏性明显提高。三是综合抗病性好。中抗条锈病，中抗白粉病。轮选266的育成标志着北部冬麦区小麦品种株型和产量结构的重要变化，即株高进一步降低，抗倒伏性增强，穗粒数和千粒重都有所提高，为进一步提高产量打下了基础。Northern Winter Wheat Zone is one of the major wheat growing areas in China.Good quality wheat with strong and elastic strength of dough has a big market.Requirement of varieties for higher yield,better disease resistance and lodging tolerance has been increased as the condition of wheat production,such as input of fertilizer and irrigation system,has been continuously improved.At the same time the new varieties should adapt to the changed production management,such as the wide application of herbicide.This project focus on development of new germplasm and new varieties based on the main breeding objectives.The method to develop herbicide resistant germplasm and new varieties has been established.Sixty-three new varieties has been released.Jinqiang11,one of the new varieties with improved quality,has the extensibility area of 215 squire centimeter and max dough resistance of 1017EU in Extensiongraph test.Jinghua12,one of the new varieties,with both improved water use efficiency and high yield,has 8.3%and 6.6%higher yield respectively than the check varieties in Beijing Reduced Irrigation List Trial and National Irrigation List Trial.Lunxuan266,one of the new varieties developed by CAAS was released in Beijing,Tianjin and Hebei Province in 2018.It has three major advantages over the other present varieties.First,also the most important,it has the significant improved yield potentials.It had average yield of 8.35 ton per hectare,5.2%higher than Zhongmai175,the check variety,in list trial,and 8.42 tons in demonstration trial,7.5%higher yield than Zhongmai175.Secondly,it has better lodging resistance than the check variety.Lunxuan266 is 10 centimeter shorter in plant height than the Zhongmai175.Thirdly,Lunxuan266 has better powdery mildew resistance than the Zhongmai175.The release of Lunxuan266 indicates the future trend in the development of wheat breeding for high yield in this area,i.e.further reduction in plant height,continuously improved lodging resistance,increase in both number of kernels per spike and thousand kernel weight.

The characterization of agronomically important genes has great potential for the improvement of wheat. However, progress in wheat genetics and functional genomics has been impeded by the high complexity and enormous size of the wheat genome. Recent advances in genome sequencing and sequence assembly have produced a high-quality genome sequence for wheat. Here, we suggest that the strategies used to characterize biological mechanisms in model species, including mutant preparation and characterization, gene cloning methods, and improved transgenic technology, can be applied to wheat biology. These strategies will accelerate progress in wheat biology and promote wheat breeding program development. We also outline recent advances in wheat functional genomics. Finally, we discuss the future of wheat functional genomics and the rational design-based molecular breeding of new wheat varieties to contribute to world food security. (C) 2020 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

The characterization of agronomically important genes has great potential for the improvement of wheat. However, progress in wheat genetics and functional genomics has been impeded by the high complexity and enormous size of the wheat genome. Recent advances in genome sequencing and sequence assembly have produced a high-quality genome sequence for wheat. Here, we suggest that the strategies used to characterize biological mechanisms in model species, including mutant preparation and characterization, gene cloning methods, and improved transgenic technology, can be applied to wheat biology. These strategies will accelerate progress in wheat biology and promote wheat breeding program development. We also outline recent advances in wheat functional genomics. Finally, we discuss the future of wheat functional genomics and the rational design-based molecular breeding of new wheat varieties to contribute to world food security. (C) 2020 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

小麦赤霉病是世界性的真菌病害，严重影响小麦的产量和品质。随着全球气候变暖和耕作栽培制度的改变，我国赤霉病发生开始北移,“重灾区”逐渐由长江中下游麦区扩展到北方冬麦区。目前，赤霉病已经成为威胁冬小麦生产的主要病害之一。加强培育抗赤霉病品种是解决该问题的重要途经之一。在前期研究中，已经证实导入不同供体的Fhb1抗病等位基因能够显著提高冬小麦品种的赤霉病抗性，但是关于Fhb1基因在不同遗传背景下对赤霉病抗性的影响，以及该基因是否对农艺性状有不利影响，有待研究。 本研究利用含有Fhb1抗病等位基因且高抗或中抗赤霉病的5个品种(系)与周麦16及其衍生品种(系)轮选136和轮选13回交构建10个BC2群体。利用田间病圃和人工单花滴注接种方法，对来自10个BC2F2群体和4个BC2F2:3群体进行赤霉病抗性鉴定，同时对10个BC2F1和BC2F2群体进行农艺性状考察，主要进展如下:(1)在轮选136和轮选13两个遗传背景下，含有纯合Fhb1抗病基因型(Fhb1-R)的单株赤霉病抗性显著优于含有纯合Fhb1感病基因型(Fhb1-S)的单株;(2)不同供体后代中，含有Fhb1-R单株平均病小穗数和严重度均低于其轮回亲本;(3)同一供体后代中，含有Fhb1-R单株在不同的遗传背景下抗性表现不同，且该基因具有较强的遗传背景效应;(4)生选6号为供体的回交后代抗性最好、最稳定;(5)该基因对农艺性状无明 Fusarium head blight(FHB)is a fungal disease of global importance in wheat(Triticum aestivum).It causes significant decrease in production and end-used quality.With the global warming and the changes of cropping systems,the occurrence of FHB in China has expanded from the Middle and Low Yangtze Winter Wheat Zone to Northern Winter Wheat Zone.As present,FHB has become one of the main diseases.The development of resistant cultivars is one of important approaches to solve this problem.We have previously confirmed that Fhb1 resistance alleles from different donors can significantly increase the FHB resistance;however,the effects of genetic backgrounds on Fhb1 and whether Fhb1 has negative influence on agronomic traits remain unclear. In this study,FHB resistance was evaluated to 10 BC2F2 populations in the field and single-floret inoculation assessments to 4 BC2F2:3 populations.Eight agronomic traits were investigated for the 10 BC2F1 and BC2F2 populations,respectively.The main results showed that:(1)In the plants carrying the homozygous Fhb1 resistance genotype(Fhb1-R)had higher FHB resistance than those with the homozygous Fhb1 susceptibility genotype(Fhb1-S)in both backgrounds;(2)The Fhb1-R plants from different donors had fewer infected spikelets and lower disease severity than their recurrent parents;(3)The Fhb1-R plants from the same donors had different resistance under different genetic backgrounds.The genetic backgrounds of Fhb1 impact the expression of FHB resistance;(4)The plants containing the Fhb1-R from Shengxuan 6 had the best FHB resistance;(5)The Fhb1 does not have significantly negative impact on the main agronomic characters. Results of this study provide important information in the improvement of the FHB resistance by introgressing Fhb1 resistance allele into winter wheat cultivars.

The ability to modify complex genomes precisely to create specific mutants is the holy grail of basic research and applied genetics in the postgenomic era. Programmable sequence-specific nucleases (e.g., zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems (e.g., CRISPR/Cas9)), which induce targeted DNA breaks that are then repaired by endogenous repair machinery to generate mutants in a variety of organisms, are being developed at an unprecedented rate. Herein, this paper reviews the history, structure, and biological function of CRISPR/Cas systems, describing how it has been adapted for genome editing (especially CRISPR/Cas9, which has prompted a genome engineering revolution), and emphasizes recent applications and advances in the functional annotation of plant genomes and crop genetic improvement. In addition, the challenges of using the CRISPR/Cas9 system and strategies for improving its specificity are discussed. This review also introduces the creation of CRISPR-edited DNA-free plants, which may be more publicly acceptable than other genetically modified organisms. Finally, the future directions and applications of the CRISPR/Cas9 system are speculated on. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The ability to modify complex genomes precisely to create specific mutants is the holy grail of basic research and applied genetics in the postgenomic era. Programmable sequence-specific nucleases (e.g., zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems (e.g., CRISPR/Cas9)), which induce targeted DNA breaks that are then repaired by endogenous repair machinery to generate mutants in a variety of organisms, are being developed at an unprecedented rate. Herein, this paper reviews the history, structure, and biological function of CRISPR/Cas systems, describing how it has been adapted for genome editing (especially CRISPR/Cas9, which has prompted a genome engineering revolution), and emphasizes recent applications and advances in the functional annotation of plant genomes and crop genetic improvement. In addition, the challenges of using the CRISPR/Cas9 system and strategies for improving its specificity are discussed. This review also introduces the creation of CRISPR-edited DNA-free plants, which may be more publicly acceptable than other genetically modified organisms. Finally, the future directions and applications of the CRISPR/Cas9 system are speculated on.