Department of Horticulture, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
Horticulture and Crop Research Department, Kermanshah Agricultural and Natural Resources Research and Education Center (AREEO), Kermanshah, Iran.
BMC Plant Biol. 2021 Mar 22;21(1):148. doi: 10.1186/s12870-021-02919-5.
The main objectives of this study were to find the possible structural association between the activity of enzymatic antioxidants and the grain yield of triticale plants as well as identifying the genotypic variability which might be effective on this association. Accordingly, expression levels of superoxide dismutase (SOD) isozymes (Mn-SOD, Cu/Zn-SOD, and Fe-SOD) were appraised to distinguish any possible relationship between SOD expression and drought resistance of triticale. A novel analytical method for distinguishing elite genotypes based on measured features was proposed. Additionally, a new programing based on SAS-language (IML) was introduced to estimate the genetic parameters rooted from combined ANOVA model (linear mixed model), which is capable of being used in any field study other than the current one.
Thirty genotypes of triticale were studied under normal and drought stress conditions during 6 years (three different locations). Accordingly, based on the results of genetic variability, heatmap analysis, biplot graph, and clustering technique, two genotypes with the highest genetic distance were selected to appraise the differential expression profiling of three SOD isozyme in shoot and root organs.
Field experiments and bioinformatics results showed that superoxide dismutase (SOD) was the most influential antioxidant in resistance of triticale to drought stress; therefore, it could be used as an indirect selection index in early stages to distinguish resistant genotypes to drought stress. Additionally, Mn-SOD and Fe-SOD showed roughly similar expression levels for both genotypes under drought stress. However, Cu/Zn-SOD expression level was higher in root and shoot of the tolerant genotype than the susceptible genotype.
Heatmap analysis that is applied for the first time to screen suitable genotypes, showed to be highly capable of distinguishing elite genotypes and pointing out the proper features for selection criteria. Bioinformatics results indicated that SOD is more important than other enzymatic antioxidant for being considered as selection criteria or candidate gene for transgenic purposes. Based on expressional results, Mn-SOD announced as a general isozyme that is probably highly expressed in most of the species, while, Cu/Zn-SOD was introduced as a genotype specific isozyme that is likely more expressed in tolerant genotypes.
本研究的主要目的是寻找酶抗氧化剂活性与黑小麦籽粒产量之间可能存在的结构关联，并确定可能对这种关联产生影响的基因型变异。因此，评估了超氧化物歧化酶（SOD）同工酶（Mn-SOD、Cu/Zn-SOD 和 Fe-SOD）的表达水平，以区分 SOD 表达与黑小麦抗旱性之间的可能关系。提出了一种基于测定特征来区分优良基因型的新分析方法。此外，还介绍了一种基于 SAS 语言（IML）的新程序，用于估计基于组合 ANOVA 模型（线性混合模型）的遗传参数，该模型可用于当前研究以外的任何领域研究。
在 6 年期间（三个不同地点），对 30 个黑小麦基因型进行了正常和干旱胁迫条件下的研究。因此，基于遗传变异、热图分析、双标图和聚类技术的结果，选择两个遗传距离最大的基因型来评价三种 SOD 同工酶在根和茎器官中的差异表达谱。
田间试验和生物信息学结果表明，超氧化物歧化酶（SOD）是黑小麦对干旱胁迫抗性中最具影响力的抗氧化剂；因此，它可以作为早期间接选择指数，以区分对干旱胁迫有抗性的基因型。此外，在干旱胁迫下，两种基因型的 Mn-SOD 和 Fe-SOD 表达水平大致相似。然而，在耐干旱基因型的根和茎中，Cu/Zn-SOD 的表达水平高于敏感基因型。
首次应用热图分析来筛选合适的基因型，结果表明该方法具有高度区分优良基因型的能力，并指出了选择标准的适当特征。生物信息学结果表明，SOD 比其他酶抗氧化剂更重要，可作为选择标准或转基因目的的候选基因。基于表达结果，Mn-SOD 被宣布为一种普遍同工酶，可能在大多数物种中高度表达，而 Cu/Zn-SOD 被介绍为一种可能在耐干旱基因型中更表达的基因型特异性同工酶。
