The team of nature biotechnol | Li Jiayang / Yu Hong used the tile deletion strategy to break the linkage of traits and break through the bottleneck of rice yield

There is often a trade-off between different agronomic traits Trade off effects （trait trade-off）, For example, plant high yield and disease resistance 、 High yield and high quality 、 Negative correlation among yield factors, etc , Making it difficult for these excellent traits to have both , It also makes it difficult for crop breeding to break through the bottleneck . This trade-off effect may be caused by Chain hindrance （linkage drag） Or genetic pleiotropy （gene pleiotropy） cause . Linkage burden can be solved by fine mapping, exchange and recombination of genes , However , There is still no effective way to remove the trade-off effect caused by gene pleiotropy . Besides , At present, the study of gene function mainly focuses on its excellent phenotype , While ignoring the negative effects it brings , This makes it difficult to get rid of this negative effect in breeding practice , As a result, only a few genes can be well used . How to solve the trade-off effect between phenotypes caused by gene pleiotropy , It is of great scientific significance to break through the existing breeding bottleneck .

2022 year 4 month 21 Japan , Institute of genetics and developmental biology, Chinese Academy of Sciences Li Jiayang / Yu Hong Team in Nature Biotechnology Published on Targeting a gene regulatory element enhances rice grain yield by decoupling panicle number and size Research paper of , Use tiles to delete (tiling deletion) By editing the cis regulatory region of key genes in rice, the strategy successfully removed the negative correlation among the key elements of rice yield , It provides an effective strategy for creating new genetic resources to break the bottleneck of rice yield .

Rice is one of the most important staple crops , Feeding more than half of the world's population . Rice yield is mainly determined by three core factors ： Number of ears 、 Number of grains per panicle 、 Grain weight . However , These three traits are usually negatively correlated in rice .IPA1（Ideal Plant Architecture 1） It is a major gene for rice plant type regulation identified by Li Jiayang's team （Jiao et al., 2010）, Encode a containing SBP-box Domain specific plant transcription factors , Regulating various growth and development processes of rice , Disease resistance and environmental adaptability also play an important regulatory role （Lu et al., 2013; Wang et al., 2017; Song et al., 2017; Zhang et al., 2017; Wang et al., 2018）. Its functional acquisition genotype ipa1-1D and ipa1-2D It can enlarge the ear 、 Ineffective tillers decreased 、 The stem is strong 、 Developed root system , Finally, the output will be significantly increased , It has been widely used in the cultivation of excellent rice varieties . but IPA1 Is a typical pleiotropic gene , The number of tillers decreased with the increase of panicle , It limits its potential to increase rice yield .

For breakthrough IPA1 The restrictive relationship between panicle and tiller caused by pleiotropy , In this latest study , The research team proposed to transform IPA1 Cis regulatory region of , They were regulated in young panicles 、 Expression level in stem base and other tissues , To achieve specific regulation of different phenotypes , So as to break the negative effect between yield factors . However, due to the restriction of previous technical methods , The research on the function of cis regulatory region in crops is very scarce , And yes IPA1 Little is known about the function of cis regulatory region . The team uses Tile delete (tiling deletion) Methods , Through multiple targets CRISPR/Cas9 Yes IPA1 The cis regulatory region of C , Create a large number of IPA1 The cis regulatory region is tiled with deleted gene editing materials , An editing material which can increase the number of tillers and grains per panicle at the same time IPA1-Pro10 And the corresponding 54bp Key cis acting elements .IPA1-Pro10 With the increase of ear weight and ear number 、 Plant height becomes higher 、 The phenotype of stout stems and roots . Through the yield measurement and identification of field plot ,IPA1-Pro10 Compared with the control variety Zhonghua 11 Can increase production compared to 15.9%, The rice yield has been greatly increased . And then , The study further clarified IPA1 Molecular mechanism of cis regulatory region regulating spike phenotype , Discovery of key transcription factors for domestication An-1 By combining 54bp One of the key cis acting elements GCGCGTGT Motif specific regulation IPA1 At the expression level of young panicles , And then specifically regulate the spike phenotype .

chart ： Molecular mechanism of breaking trait linkage and breaking through rice yield bottleneck

Sum up , This study provides a feasible method to break the restriction between phenotypes , It provides new genetic resources and research ideas for breaking through the bottleneck of rice yield , It is an important progress in this field . In the future, the systematic function of cis regulatory regions of crop core genes will be excavated , It is expected to provide new molecular mechanisms and genetic resources to break through the bottleneck of existing crop breeding .

Lijiayang research group, Institute of genetic development, Chinese Academy of Sciences Songxiaoguang The associate researcher is the first author of this paper , Yu Hong The researcher is the corresponding author . The thesis has won the National Natural Science Foundation of China , Chinese Academy of Sciences pilot project , Support from Hainan excellent talents team .

Coordinating editor | Yifan （BioArt plant ）