Life Sciences Centre, Institute of Biosciences, Vilnius University, Saulėtekis Ave. 7, 10257, Vilnius, Lithuania.
Botanical Garden of Vilnius University, Kairėnai Str. 43, 10239, Vilnius, Lithuania.
Planta. 2018 Feb;247(2):483-498. doi: 10.1007/s00425-017-2802-9. Epub 2017 Oct 27.
The triggers of genetic instability in barley homeotic double mutants are tweaky spike -type mutations associated with an auxin imbalance in separate spike phytomeres. Barley homeotic tweaky spike;Hooded (tw;Hd) double mutants are characterized by an inherited instability of spike and flower development, which is absent in the single parental constituents. The aim of the present study was to show that the trigger of genetic instability in the double mutants is the tw mutations, which are associated with an auxin imbalance in the developing spikes. Their pleiotropic effects on genes related to spike/flower development may cause the genetic instability of double mutants. The study of four double-mutant groups composed of different mutant alleles showed that the instability arose only if the mutant allele tw was a constituent of the double mutants. Application of auxin inhibitors and 2,4-dichlorophenoxyacetic acid (2,4-D) demonstrated the relationship of the instability of the double mutants and the phenotype of the tw mutants to auxin imbalance. 2,4-D induced phenocopies of the tw mutation in wild-type plants and rescued the phenotypes of three allelic tw mutants. The differential display (dd-PCR) method allowed the identification of several putative candidate genes in tw that may be responsible for the initiation of instability in the double mutants by pleiotropic variations of their expression in the tw mutant associated with auxin imbalance in the developing spikes. The results of the present study linked the genetic instability of homeotic double mutants with an auxin imbalance caused by one of the constituents (tw). The genetic instability of the double mutants in relation to auxin imbalance was studied for the first time. A matrocliny on instability expression was also observed.
大麦同源异型双突变体中遗传不稳定性的触发因素是与单独小穗分生组织中生长素失衡相关的扭曲穗型突变。大麦同源异型扭曲穗；罩状（tw；Hd）双突变体的特征是穗和花发育的遗传性不稳定，而在单个亲本成分中则不存在。本研究的目的是表明双突变体中遗传不稳定性的触发因素是与发育中的穗中生长素失衡相关的 tw 突变。它们对与穗/花发育相关基因的多效性影响可能导致双突变体的遗传不稳定性。对由不同突变等位基因组成的四个双突变体组的研究表明，只有当突变等位基因 tw 是双突变体的组成部分时，不稳定性才会出现。生长素抑制剂和 2,4-二氯苯氧乙酸（2,4-D）的应用表明，双突变体的不稳定性及其 tw 突变体的表型与生长素失衡有关。2,4-D 在野生型植物中诱导出 tw 突变的表型，并挽救了三个等位基因 tw 突变体的表型。差异显示（dd-PCR）方法允许鉴定出 tw 中的几个假定候选基因，这些基因可能通过其在与发育中的穗中生长素失衡相关的 tw 突变体中的表达的多效性变化而导致双突变体中不稳定性的起始。本研究将同源异型双突变体的遗传不稳定性与由一个成分（tw）引起的生长素失衡联系起来。首次研究了双突变体与生长素失衡有关的遗传不稳定性。还观察到不稳定性表达的母系遗传。
