小麦puroindoline及其相关基因分子遗传基础研究进展

籽粒硬度是重要的小麦品质性状之一,对小麦的磨粉品质和加工品质有重要影响。控制籽粒硬度的主效基因puroindoline位于5D染色体的短臂上,可分为Pina和Pinb2种类型。Pina和Pinb紧密连锁,编码区均为447个碱基,没有内含子,共同形成小麦籽粒硬度的分子遗传基础。目前,普通小麦和山羊草中均已发现多种puroindoline变异类型,其中引起小麦籽粒硬度大幅度升高的Pina-D1b类型的分子机制为从编码区第23个碱基开始缺失15380个碱基。Puroindoline除了对小麦籽粒硬度有重要影响之外,对其它品质性状也有重要影响,不同puroindoline变异类型之间小麦品质具有一定差异。另外,与puroindoline紧密连锁的Gsp-1基因变异类型更为丰富,但对籽粒硬度没有明显的调节作用。最近发现的与puroindolineb高度同源的基因Pinb-2v具有4种类型,分别位于小麦7A、7B和7D染色体上,可能对籽粒硬度具有微效的调节作用。本文通过对puroindoline的分子特征和突变类型以及相关功能进行分析和总结,旨在为中国小麦品质的基因工程改良提供参考。

Advances in Research of Molecular Genetics of puroindoline and Its Related Genes in Wheat

Grain textIlre is one of the characteristics of bread wheat(Triticum aestivum L.)quality and has an important influence on wheat milling and processing quality.Puroindoline gene,mainly controlling grain texture of bread wheat,locates on the short arm of dismal 5D chromosome and is divided into Pina and Pinb genes tightly linking together.Pina and Pinb with the coding sequence of 447 bp have no any intron and form the basis ofmolecular genetics of grain texmre in bread wheat.Up to now,lots of haplotypes of Pina and Pinb genes have been identified in bread wheat and Aegilops tauschii.Of them.Pint-Dlb allele with hardest grain texture among the known haplotypeshas been found to possess a large 15 380 bp deletion beginning after nt 23 inside of Pina coding sequence in comparison with the wild type.Besides the obvious influence on grain texture,puroindoline gene plays a significant role on other aspects of wheat quality so that some Pina and Pinb alleles have significantly different quality characteristics,e.g.Pinb-Dlb have slightly superior quality of steamed bread,pan bread and Chinese noodles to Pina-Dlb.Gsp-1 gene tightly linking with Pina and Pinb posscsses more haplotypes than pumindoline genes while has no significant effect on grain texture according to lots of reports so far.Pinb-2v genes with approximate 70%identity to Pinb gene at the DNA level have been found to possess four variants very recently that locate on 7A,7B and 7D chromosome,respectively,which play a minor role in controlling grain texture.This stlldy has further provided useful information on understanding the molecular basis of grain texmre and Chinese wheat improvement.