Fen Edebiyat Fakültesi / Faculty of Letters and Science
Permanent URI for this collectionhttps://hdl.handle.net/11727/1396
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Item Role Of Sulfur Metabolism In Acquiring Of Boron Tolerance In Arabidopsis Thaliana(TURKISH JOURNAL OF BOTANY, 2024) Yirmibes, Seda; Kayihan, Ceyhun; Cicek, Nuran; Ekmekci, YaseminThe purpose of this study was to assess whether sulfate treatment (pre- and combined) caused changes in the tolerance against boron (B) toxicity in Arabidopsis thaliana at the physiological, biochemical, and molecular levels. Germinated plants were grown in a controlled climate chamber (22 +/- 1 degrees C temperature, 16/8 s photoperiod, 200 mu mol m -2 s -1 light intensity and 50%-60% humidity) for 12 days. The sulfate pretreatment groups (PS-3B and PS-5B) were then transferred to nutrient medium containing Mg2SO4- type sulfate for 3 days. Afterward, they were transferred to petri dishes containing different boron concentrations (3 and 5 mM H3BO3), along with the nonpretreatment and combined (S+3B and S+5B) treatment groups, and exposed to boron toxicity for 10 days. The leaf area, plant biomass, and total chlorophyll content decreased significantly depending on the accumulation of B. Toxic levels of B adversely affected the structure and functionality of the photosynthetic apparatus. Changes were seen in the specific and phenomenological energy fluxes, quantum yields, and efficiency of the photosystem II (PSII) donor and acceptor sides. These changes led to decreases in the photosynthetic performance of the plants. Although B toxicity adversely affected the integrity of the membrane and the amount of photosynthetic pigment in the antenna and reaction centers (RCs), this effect was not at a level that completely blocked the functionality of the photosystems, and this negative effect was alleviated with the sulfate treatment. The increases in the antioxidant enzyme activities (especially peroxidase) and phenolic compounds with the sulfate treatment may have provided tolerance against toxicity and oxidative damage by regulating the defense systems. Moreover, B toxicity affected the relative expression of genes related to sulfate uptake, transport, and sulfur metabolism. In fact, the genes of sulfate transporters ( SULTR ); SULTR3;1, SULTR3;3, and SULTR3;5 were more expressed in PS-B group. The glutamate cysteine ligase (GSH1) and glutathione synthetase 1 (GSH2) relative gene expressions were increased in the treatment groups, indicating induced glutathione metabolism. In conclusion, plants may have acquired tolerance against B toxicity by assimilating sulfate, especially that provided by sulfate pretreatment.Item Advancements in QTL Mapping and GWAS Application in Plant Improvement(TURKISH JOURNAL OF BOTANY, 2024) Altaf, Muhammad Tanveer; Tatar, Muhammed; Ali, Amjad; Liaqat, Waqas; Mortazvi, Parnaz; Kayihan, Ceyhun; Olmez, Fatih; Nadeem, Muhammad Azhar; Javed, Jazib; Gou, Jin-Ying; Wang, Meng-Lu; Umar, Ummad Ud Din; Dasgan, Hayriye Yildiz; Kurt, Cemal; Yildiz, Mehtap; Mansoor, Sheikh; Dababat, Abdelfattah A.; Celiktas, Nafiz; Baloch, Faheem ShehzadIn modern plant breeding, molecular markers have become indispensable tools, allowing the precise identification of genetic loci linked to key agronomic traits. These markers provide critical insight into the genetic architecture of crops, accelerating the selection of desirable traits for sustainable agriculture. This review focuses on the advancements in quantitative trait locus (QTL) mapping and genome-wide association studies (GWASs), highlighting their effective roles in identifying complex traits such as stress tolerance, yield, disease resistance, and nutrient efficiency. QTL mapping identifies the significant genetic regions linked to desired traits, while GWASs enhance precision using larger populations. The integration of high-throughput phenotyping has further improved the efficiency and accuracyof QTL research and GWASs, enabling precise trait analysis across diverse conditions. Additionally, next-generation sequencing, clustered regularly interspaced short palindromic repeats (CRISPR) technology, and transcriptomics have transformed these methods, offering profound insights into gene function and regulation. Single-cell RNA sequencing further enhances our understanding of plant responses at the cellular level, especially under environmental stress. Despite this progress, however, challenges persist in optimizing methods, refining training populations, and integrating these tools into breeding programs. Future studies must aim to enhance genetic prediction models, incorporate advanced molecular technologies, and refine functional markers to tackle the challenges of sustainable agriculture.Item The involvement of the induction of anthocyanin biosynthesis and transport in toxic boron responsive regulation in Arabidopsis thaliana(2021) Kayihan, Ceyhun; 0000-0003-1684-4147; AAW-8352-2021Recently, boron (B) has been found to form a complex with anthocyanin, which could be evidence for the B tolerance mechanisms that reduce free B in the leaf tissues of plants. However, the molecular mechanism of anthocyanin biosynthesis and transport has not been satisfactorily elucidated in plants exposed to toxic B. Therefore, the changes in expression levels of some of the phenylpropanoid pathway genes, early and late flavonoid biosynthetic genes, and transcription factors related to anthocyanin biosynthesis and transport were determined in Arabidopsis thaliana under B toxicity. Accordingly, 1 mM boric acid treatment did not cause any significant change in the expression levels of anthocyanin biosynthesis genes such as PAL1, PAL2, C4H, 4CL3, CHS, ANS and transcription factors such as MYBD and TT8 in Arabidopsis thaliana. However, 3 mM boric acid treatment induced the expression levels of anthocyanin biosynthesis genes such as C4H, 4CL3 and transcription factors including MYB75, MYB114 and anthocyanin transporter genes such as TT13 and TT19. In addition to B-anthocyanin, B-anthocyanins conjugated with glutathione (GSH) complexes can also participate in the internal B tolerance mechanism in plants. Therefore, the direct role of the B-anthocyanin complex without GSH conjugation needs to be determined. For this purpose, anthocyanin accumulation was determined in slim1 mutant Arabidopsis thaliana exposed to excess B because SLIM1 transcription factor activates sulfate acquisition for S assimilation, which generates cysteine, the substrate for GSH. Accordingly, it was gradually increased through increasing toxic B levels in both wild type (WT) and slim1 mutant plants. slim1 mutant had more anthocyanin accumulation than WT under control and all toxic B conditions. In conclusion, increases in expression levels of MYB75, MYB114, TT13, TT19 and in anthocyanin level in slim1 mutant in response to increased toxic B levels showed that anthocyanins may play a primary role in B tolerance in plants.Item Higher nisin yield is reached with glutathione and pyruvate compared with heme in Lactococcus lactis N8(2020) Ersoy, Zeynep Girgin; Kayihan, Ceyhun; Tunca, Sedef; 0000-0003-1684-4147; 31898248; Q-4515-2016There are different studies that aim to enhance the production of nisin by Lactococcus lactis since its chemical synthesis is not possible. In this study, glutathione (GSH) and pyruvate, which are known to reduce the oxidative stress of cells, have been shown to trigger the production of nisin at both transcriptional and translational levels in L. lactis cells grown under aerobic condition. Presence of GSH and pyruvate caused more nisin yield than the heme-supplemented medium. Moreover, the expression of genes that encode stress-related enzymes were apparently upregulated in the presence of GSH and pyruvate. It can be concluded that GSH and pyruvate contribute to the defense system of L. lactis cells and so that higher biomass was obtained which in turn enhance nisin production. Antioxidant effect of GSH and pyruvate was known; however, their stimulating effect on nisin production was shown for the first time in this study.Item Moderate level of toxic boron causes differential regulation of microRNAs related to jasmonate and ethylene metabolisms in Arabidopsis thaliana(2019) Kayihan, Doga Selin; Kayihan, Ceyhun; Ciftci, Yelda Ozden; 0000-0003-1684-4147; Q-4515-2016Earlier our colleagues detected that the genes related to jasmonate (JA), ethylene, and cell wall modification were significantly regulated under boron (B) toxicity in wheat. Determination of regulation mechanisms of these novel genes under B toxicity is very important in Arabidopsis thaliana as a model plant. As key regulators, the microRNAs (miRNAs) regulate gene expression at the posttranscriptional level and respond to numerous abiotic stresses in plants. In this study, expression levels of miRNAs such as miR159, miR172, miR319, and miR394 targeting JA and ethylene-related transcription factors and also miR397 targeting laccase were determined in Arabidopsis thaliana under toxic B conditions. Stem-loop quantitative reverse transcription polymerase chain reaction was used to amplify mature miRNAs for expression analyses. Expression levels of miRNAs targeting transcription factors related to JA and ethylene metabolisms were induced remarkably in moderate B toxicity (condition 1B) but not in severe B toxicity (condition 3B). Most remarkable regulations were obtained in miR172 and miR319 in Arabidopsis thaliana. Expression level of miR397 did not remarkably change under B toxicity, indicating a lack of posttranscriptional regulation of laccase related to cell wall modification. Moreover, miRNAs targeting transcription factors related to JA and ethylene metabolisms might be oxidative stress-adaptive responses of Arabidopsis to B toxicity.Item Regulation of boron toxicity responses via glutathione-dependent detoxification pathways at biochemical and molecular levels in Arabidopsis thaliana(2019) Kayihan, Doga Selin; Kayihan, Ceyhun; Ciftci, Yelda Ozden; 0000-0002-9799-3648; Y-6244-2018The fine-tuned regulation of the Halliwell-Asada cycle (ascorbate-glutathione pathway) in Arabidopsis thaliana under boron (B) toxicity was shown in our previous report. In this study, we investigated the expression levels of some members of the glutathione S-transferase (GST) superfamily, such as phi (GSTF2, GSTF6, GSTF7, and GSTF8), tau (GSTU19), and zeta (GSTZ1) classes in Arabidopsis thaliana that were exposed to 1 mM boric acid (1B) and 3 mM boric acid (3B). Additionally, the expression levels of genes for glutathione (GSH) and phytochelatin biosynthesis as well as miR169 and miR156 were evaluated in Arabidopsis thaliana exposed to 1B and 3B. Moreover, changes in the levels of total GST activity; GSH; and total, protein-bound, and nonprotein thiols were spectrophotometrically determined. GSH levels and nonprotein thiol content did not change significantly following both B-toxicity conditions. Expression levels of GSH1 and GSH2 stayed stable under 1B toxicity; however, GSH1 expression increased significantly under 3B conditions in Arabidopsis thaliana. The expression levels of four genes from phi class members of GST were not dramatically changed under B-toxicity conditions. However, the transcript levels of miR169, ATGSTU19, and ATGSTZ1 were significantly increased after 1B and 3B exposure. These GST genes may have a role in the dramatic increase of total GST activity under toxic B. To the best of our knowledge, this is the first report displaying an integrative view of high-B-induced regulation of GSH-dependent enzymatic machinery at different biological organization levels in Arabidopsis thaliana.