高粱遗传转化研究进展

Progress on Genetic Transformation of Sorghum

高粱是世界第五大粮食作物,可作为食用、饲用、酿造用和生物能源用。高粱遗传转化技术是高粱功能基因组学研究中必不可少的重要工具,同时,也可作为传统育种方法的重要补充。本文对近年来高粱遗传转化的研究进展进行总结,分析高粱遗传转化中存在的难题,并提出进一步的解决策略,以期为高粱遗传转化技术的进一步改良提供参考。通过对近年来50余篇高粱组织培养和遗传转化文献进行归纳总结。介绍用于遗传转化的高粱基因型、外植体来源、再生体系构建等方面的研究现状,对比电穿孔法、花粉管通道法、基因枪法和农杆菌介导法4种高粱遗传转化常用方法的优劣,总结遗传转化载体主要组成部分启动子、目的基因、选择标记基因和报告基因对转化效率的影响,阐述高粱遗传转化的应用现状,分析高粱遗传转化技术存在的主要瓶颈问题,研究对策措施。高粱基因型对组织培养有很大影响,以P898012和Tx430最为常用。基因枪法和农杆菌介导法是最常用的高粱遗传转化方法,且农杆菌介导法的优势逐渐显现。在载体构建中,CaMV35S启动子和ubi1启动子最为常用,抗生素抗性基因(nptII、hpt)、除草剂抗性基因(bar)和养分同化基因为常用的三大类选择标记基因。随着高粱遗传转化技术及CRISPR/Cas9介导的基因编辑技术的不断发展,一些重要农艺性状基因被成功转入高粱。但基因型依赖性强、组织培养周期长、遗传转化稳定性差是限制高粱遗传转化的主要瓶颈,通过引入形态发生调节因子,直接进行体细胞发生,缩短了组织培养周期,提高了转化效率,扩大了外植体来源,高粱遗传转化技术取得重大突破。通过引入形态发生调节因子,采用切-浸-芽(CDB)递送系统等方式可进一步改良高粱遗传转化技术,结合CRISPR/Cas9基因编辑技术的应用,必将为高粱分子育种及相关基因功能鉴定提供重要的技术支撑。

Sorghum is the fifth largest grain crop in the world and can be used for food,feed,brewing and bioenergy.Sorghum genetic transformation technology is an essential and important tool in the research of sorghum functional genomics and can also serve as an important complement to traditional breeding methods.In this review,we summarize the research progress of sorghum transformation in recent years,analyze the problems in sorghum genetic transformation and propose strategic solutions to them in order to provide a reference for further improvement of sorghum genetic transformation technology.By summarizing more than 50 literatures on sorghum tissue culture and genetic transformation in recent years,we introduced the current research status of sorghum genotypes,explant sources,and regeneration system construction for genetic transformation,and compared the advantages and disadvantages of four commonly used methods for sorghum genetic transformation:electroporation,pollen-mediated transformation,particle bombardment and Agrobacterium-mediated transformation,summarized the effects of the main components of genetic transformation vectors,including promoters,target genes,selective marker genes and reporter genes,on transformation efficiency,explained the current application status of sorghum genetic transformation,analyzed the main bottleneck problemns in sorghum genetic transformation technology,and studied countermeasures.Sorghum genotypes have a significant influence on tissue culture and P898012 and Tx430 are the most widely used.Gene bombardment and Agrobacterium-mediated transformation are the most commonly used methods for sorghum genetic transformation,and the advantages of Agrobacterium-mediated transformation are gradually emerging.In vector construction,CaMV35S and ubi1 are the most commonly used promoters,and antibiotic resistance genes(nptII,hpt),herbicide resistance genes(bar),and nutrient assimilation genes are the three commonly used selection markers.With the development of sorghum genetic transformation technology and CRISPR/Cas9-mediated gene editing technology,some genes with important agronomic traits have been successfully transferred into sorghum.However,strong genotype dependence,long tissue culture cycle,and poor genetic transformation stability are the main bottlenecks that limit the genetic transformation of sorghum.By introducing morphogenesis regulatory factors,somatic cell generation can be directly performed,which shortens the tissue culture cycle,improves the transformation efficiency,and expands the source of explants.This has become a major breakthrough in sorghum genetic transformation technology.The use of morphogenesis regulatory factors and adoption of cut-dip-budding(CDB)delivery system can further improve the sorghum genetic transformation technology.Combined with the application of CRISPR/Cas9 gene editing technology,they will surely provide an important technical basis for the sorghum molecular breeding and gene function identification.