Seçilmiş Yerel Buğday Çeşitlerinin Karşılaştırmalı Transkriptomik Analizi ve Çinko Uygulamasının Bazı Enzim Genlerinin İfade Düzeyine Olan Etkisi

Abstract

Wheat is an easy-to-cultivate, high-yielding cereal product and is grown in many places in the world due to its adaptability to different climatic and soil conditions. In order to meet the increasing population demand, wheat production has to increase as in other plant products. However, it is important to understand the molecular basis of antioxidant and flavonoid biosynthesis in wheat varieties due to the "healthy food" trend in recent years. The research approach is supported by using omics technologies such as genomics and transcriptomics to understand the relevant biosynthesis mechanism.

More than two billion people worldwide suffer from "hidden hunger". Micronutrient components which are important for hidden hunger are essential mineral elements necessary for both plant and human development. Fortification and/or biofortification applications are made during the production of basic foods such as rice, wheat and corn, which are easily accessible and make up the majority of the daily diet, in order to combat the hidden hunger seen especially in developing countries today. Zinc (Zn) deficiency is a well-known problem that causes reduced yield and nutritional quality in plants. When faced with a shortage of Zn supply, plants adapt to the climate by increasing their Zn uptake. In recent years, although there has been a better understanding of plant resistance to Zn deficiency, genotypic variations in plants' Zn utilization efficiency and its effect on antioxidant and flavonoid biosynthesis seem important.

In this study, it was aimed to investigate the expression levels of the antioxidant enzyme genes Superoxide Dismutase (SOD) and Catalase (CAT) and the flavonoid biosynthesis enzyme genes Phenylalanine Ammonium Lyase (PAL) and Chalcone Synthase (CHS) in the local wheat genotypes selected. In addition, it was aimed to investigate the changes in the expression levels of these key enzyme genes in the same samples by foliar zinc biofortification. For this purpose, first of all, local wheat genotypes were determined and the antioxidant capacities of these genotypes were analyzed by ABTS test, which is one of the rapid antioxidant tests of QUENCER (Quick, Easy, New, CHEap and Reproducible). Then, local wheat genotypes were germinated and two different pot trials were established, and foliar zinc biofortification was applied in one pot trial. Wheat leaves were harvested 20 days after planting, and RNA isolation and cDNA synthesis were performed immediately. Obtained cDNA samples were used in further gene expression analysis. For this, first of all, cDNA samples obtained from commercial wheat varieties (Demir 2000 and Eminbey) and antioxidant enzyme genes (SOD and CAT) and flavonoid biosynthesis enzyme genes (PAL and CHS) were used for optimization for RT-PCR analyzes and standard curves were obtained. After this step, gene expression levels were analyzed by RT-PCR analyzes in all selected wheat genotypes. After that, statistical analyzes and comparative evaluations are given.

As a result, in this study, activity changes in antioxidant enzyme and flavonoid biosynthesis enzyme genes in local wheat genotypes were revealed for the first time with the transcriptomic analysis approach, depending on the genotype difference. In addition, the distribution of the change in the expression profile of these genes with foliar Zn application was revealed. The study is important because it includes the local Triticum monococcum, Triticum dicoccum, Triticum durum and Triticum spelta genotypes, as well as the Triticum aestivum genotypes, which have been frequently studied on the antioxidant capacity and expression levels of the related genes, and constitutes a source for further studies to be made in the specified genotypes.