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Global warming, which was rhetorical in the previous century, is a preeminent issue in multiple scientific areas today. Global warming has increased the frequency of extreme high temperature events all around the globe and expanded heat zones from tropic areas through both poles and even changed frigid poles to temperate zones. In the terrestrial earth, plants are the major CO2 consumers. The emergence and evolution of plants on earth decreased the global temperatures dramatically from mid-Devonian to mid-Carboniferous Era; however, the human factors as industrialization were not in equation. Today, plants are still main actors of the nature-based solutions to global warming through afforestation and reforestation solutions. However, high temperature is a major deleterious abiotic stress for plant growth and productivity. Plant heat stress adaptation has been a focus of research for both environmental and agricultural purposes. Plant heat stress adaptation requires utilization of complex physiological traits and molecular networks combined. The present chapter summarizes recent progress in transgenic approach through five main targets as heat shock proteins, osmoprotectants, antioxidants, transcription factors, and miRNAs. Additionally, miscellaneous novel transgenic attempts from photosynthetic machinery to signal transduction cascades are included to cover different physiological, transcriptional, and post-transcriptional regulation of the plant heat responses.

All life forms, from the simplest to the most complicated, are inevitably exposed to altering environmental conditions in their natural habitats, gradually depending on their lifestyle. Unfavorable alterations drive these life forms either to avoidance or defense as a response. Most of the essential plant growth-promoting environmental factors can also turn out to be stress factors. Water as the most abundant molecule of all living cells can cause stress either in deficit as drought or in excess as waterlogging. Temperature is important for the maintenance of all biomolecules and metabolic reactions; hence, both low and high temperatures are deleterious stress factors. Even though the plants were exposed to various volcanic origin, heavy metals and pollutants and evolved molecular mechanisms during millions year of evolution, rapid urbanization, and industrial progress introduce brand new pollutants as micro- and nanoplastics as well as nanoparticles to plants like never before. This chapter defines and evaluates major environmental abiotic stress factors with an emphasis on the latest knowledge of molecular effects on plants. In addition, novel stress factors, such as nanoparticles and microplastics, are looked over as hot prospects for the future of plant abiotic stress areas.

In last decades, plants were increasingly subjected to multiple environmental abiotic stress factors as never before due to their stationary nature. Excess urbanization following the intense industrial applications introduced combinations of abiotic stresses as heat, drought, salinity, heavy metals etc. to plants in various intensities. Technological advancements brought novel biotechnological tools to the abiotic stress tolerance area as an alternative to time and money consuming traditional crop breeding activities as well as they brought vast majority of the problem themselves. Discoveries of single gene (as osmoprotectant, detoxyfying enzyme, transporter protein genes etc.) and multi gene (biomolecule synthesis, heat shock protein, regulatory transcription factor and signal transduction genes etc.) targets through functional genomic approaches identified abiotic stress responsive genes through EST based cDNA micro and macro arrays. In nowadays, genetic engineering and genome editing tools are present to transfer genes among different species and modify these target genes in site specific, even single nuclotide specific manner. This present chapter will evaluate genomic engineering approaches and applications targeting these abiotic stress tolerance responsive mechanisms as well as future prospects of genome editing applications in this field.

It is important for plants to survive when they are subjected to environmental stress factors under different combinations in nature. In such conditions, epigenetic modifications such as cytosine methylations have a regulatory role in adaptive responses to changing environment. WRKY transcription factor family is one of the largest families managing regulation of various processes in plants. Although, the WRKYs are known to play important regulatory role in stress tolerance, the exact mechanisms underlying for regulation of each member under different conditions are not clarrified yet. Among WRKY family members, WRKY50 and WRKY72 were reported to be differentially regulated under salt stress. In this study, we compared the level of cytosin methylation patterns of both WRKY transcription factors under different salt concentration treated Osmancik-97 rice variety (Oryza sativa L.) seedlings. DNA methylation status of both genes in leaf tissues of NaCl stressed (0, 30 mM, 90 mM, 150 mM and 210 mM) rice plants were assessed by bisulfite sequencing. The sequencing reads were mapped according to Oryza sativa genome (v.7). Principal Component Analysis and the Fisher’s exact test were performed to compare the levels of methylated cytosines in CpG in the samples. Differentially methylated cytosines were identified and comparatively analyzed by methylKit. A total of 155 MetCs positions in the CpG context were detected comparing all libraries. 72 methylated cytosines correspond to WRKY50 sequence and 83 methylated cytosines were detected in the WRKY72 region. The methylation levels of the WRKY genes were found in negative correlation with gene expression at 90 and 150 mM NaCl treatments, however at 210 mM concentration the data indicate more complex status of the relation.

Lycopersicon esculentum L., also known as tomato, is an important industrial plant due to its products which worth billions of dollars annually, besides its nutritional value and health benefits. In this study, we investigated the two-dimensional protein expression profiles in drought tolerant mutant plants derived from industrial 5MX12956 tomato variety by Cs-137 gamma radiation source induced mutations. Drought tolerance of mutants were evaluated and confirmed by in vivo and in vitro methods. Eleven drought responsive protein spots were identified by two-dimensional electrophoresis and MALDI-TOF-MS. Identified proteins which presented differential expression under drought conditions were clustered under six distinct groups based on their cellular functions. These clusters are ATP and carbohydrate metabolism, mRNA processing and protein phosphorylation, oxidation reduction and stress response, signaling and supporting cytoskeleton. Our results contributed proteomic data to drought tolerance of our tomato mutants which were originated from drought susceptible 5MX12956 variety. They may also facilitate basis for future investigations into the genetic and physiological aspects of this tolerance. © 2021 Elsevier B.V.

Heavy metal stress is a leading abiotic stress factor in the twenty-first century as a reflection of industrial developments and extensive urbanization. Plants adopt several adaptation mechanisms to cope with deleterious effects of heavy metal stress. Biosynthesis of amino acids/organic acids, phytochelatins (PCs), metallothioneins (MTs), heat-shock proteins (HSPs), metal chelators, chaperons, ABC-type transporters, and CDF family metal transporters are among the heavy metal binding or transporting mechanisms in plants. This chapter emphasizes phyto-miRNAs related to these tolerance mechanism pathways. Moreover, transcription factors which are targeted by heavy metal-related phyto-miRNAs are also summarized under the effect of various heavy metals due to their intertwined regulatory mechanisms.

Seeds belonging to fourth generation mutants (M4) of Ataem-7 cultivar (A7) variety and S04-05 (S) breeding line salt-tolerant soybeans were investigated by Raman spectroscopy, complemented by chemometrics methods, in order to evaluate changes induced by mutations in the relative lipid–protein contents, and to find fast, efficient strategies for discrimination of the mutants and the control groups based on their Raman spectra. It was concluded that gamma irradiation caused an increase in the lipid to protein ratio of the studied Ataem-7 variety mutants, while it led to a decrease of this ratio in the investigated S04-05 breeding line mutants. These results were found to be in agreement with data obtained by reflectance spectrum analysis of the seeds in the full ultraviolet to near-infrared spectral region and suggest the possibility of developing strategies where gamma irradiation can be used as a tool to improve mutant soybean plants targeted to different applications, either enriched in proteins or in lipids. Ward's clustering and principal component analysis showed a clear discrimination between mutants and controls and, in the case of the studied S-type species, discrimination between the different mutants. The grouping scheme is also found to be in agreement with the compositional information extracted from the analysis of the lipid–protein contents of the different samples.

With an increasing population around the world, the rapid loss of agricultural fields shows us the urgent importance of finding solutions to develop agricultural productivity. Besides industrialization, several effectors such as abiotic and biotic factors cause losses in crop productivity. Biotic factors threaten production and transportation of products worldwide. Bacteria, fungi, viruses, and oomycetes cause losses both pre- and postharvest. It is crucial to improve biotic stress-tolerant plants to overcome reduction in plant productivity. For many years, researchers focused on understanding plant defense mechanisms. Anatomical, physiological, and molecular adaptive mechanisms were investigated for several plant species. Besides the innate immunity mechanisms, including cross-talk, among the phytohormones to manage appropriate defense mechanisms against pathogens, new generation strategies in crop improvements are widely used in plant biotechnology. Although conventional breeding has importance in breeding new varieties, new technologies increase the possibility of success. Recently, new combinations of technologies have been proven effective to develop new cultivars. Small RNA technology is one of the developing crop improvement technologies relying on regulating specific genes together with their sequence identity. In this chapter, we focus on the small RNA technologies used in improvement of biotic stress-tolerant plants.

The effect of salinity on the conformation of proteins of four salt-tolerant M-2 generation mutants of soybean plants (S04-05/150-2, S04-05/150-8, S04-05/150-106, and S04-05/150-114) was investigated using Fourier transform infrared (FTIR) spectroscopy. Salinity is one of the important abiotic stress factors that limits growth and productivity of plants. The mutants belonging to the M-2 generation were determined as tolerant to 90 mM NaCl. The relative contents of alpha-helix, beta-sheet, turn, and irregular conformations for the soybean protein isolates were determined depending on the analysis of the amide I region. The comparison of the secondary structures of soybean proteins of the mutants with those of the control group indicated that the alpha-helix structure percentage was diminished while beta-turn and disordered structures were increased as a result of the salt stress.

Antioxidative mechanisms are important to protect cells from the hazardous effects of reactive oxygen species (ROS). Salt stress is one of the environmental stress factors that leads to accumulation of ROS at toxic levels. In this study, we analyzed the responses of two rice (Oryza sativa L.) cultivars against NaCl stress at enzymatic and transcriptional levels. In 14 day-old-seedlings, different antioxidant enzyme activities were observed. These findings were also supported by transcriptional analyses of the responsible genes. According to the results, Cyt-APX, CAT A, Cyt-GR1 and proline metabolism-related genes were differentially expressed between two rice varieties under different salt concentrations. Their regulational differences cause different salt sensitivities of the varieties. By this study, we provided an insight into understanding of the correlation between antioxidant defence genes and ROS enzymes under salt stress.

The aim of this study was to determine the ultrastructural changes and regulation of trichome-metabolism-related genes against salt stress in soybean (Glycine max L. Merr.) plants. The 14-day-old Ataem-7 and S04-05 soybean seedlings were subjected to 0, 50, 100, and 150 mM NaCl stress. While the chlorophyll quantities were reduced, the activities of guaiacol peroxidase were increased in both varieties due to increasing NaCl concentrations. In S04-05 soybean variety, trichome densities were increased on both surfaces of the leaves whereas decreases were recorded in Ataem-7 variety at 150 mM NaCl treatment. Stomatal densities were increased on both surfaces of the leaves of both soybean varieties after salinity stress. We also performed a qRT-PCR analysis to evaluate the relative transcription levels of the soybean orthologs of Arabidopsis trichome developmental genes. qRT-PCR analysis demonstrated an induction of the soybean orthologs of GL2 and GL3 genes in soybean plants after 50, 100, and 150 mM NaCl treatments in both varieties. While the expression level of TTG1 ortholog gene was negatively affected in both soybean varieties under different concentrations of salinity, GL1 ortholog gene expression profile differed as a result of changing salt concentrations in both varieties with respect to control plants. It is observed that the regulation of trichome formation differs between two soybean varieties.

Background The aim of this study is to compare the tolerance mechanisms of two industrial tomato varieties (X5671R and 5MX12956) under drought stress. 14 days-old tomato seedlings were subjected to 7 days-long drought stress by withholding irrigation. The effects of stress were determined by enzymatic and non-enzymatic parameters. The physiological damages were evaluated via lipid peroxidation ratio, total protein content, relative water content, chlorophyll content and proline accumulation. Enzymatic responses were determined by biochemical analysis and electrophoresis of SOD, APX, POX and CAT enzymes. Results Relative water contents of X5671R and 5MX12956 varieties at 7th day of drought were decreased to 8.4 and 12.2%, respectively. Applied drought decreased all photosynthetic pigments of X5671R and 5MX12956 varieties during the treatment period significantly comparing to the Day 0 as the control. Total protein content, lipid peroxidation and proline accumulation presented increased values in both varieties in accordance with the increasing stress intensity. According to lipid peroxidation analysis, 5MX12956 tomato variety was found more drought sensitive than X5671R variety. Antioxidative enzyme activities showed increases in both varieties as a response to drought stress, although CAT and APX activities presented decrease on the 7th day of applied stress. 7 days long drought stress differentially altered POX, APX and SOD isozyme patterns. Same POX bands were observed in both varieties with different band intensities. Conclusions However, main isozyme pattern differences were obtained for SOD and APX. APX1, Fe-SOD and Cu/Zn-SOD2 isozyme bands should be evaluated to define their main role in the tolerance mechanism of both tomato varieties.

Molecular structure and elemental composition of soybean (Glycine max L. Merr.) seeds of S04-05 (Ustun-1) variety together with its salt tolerant mutants were investigated by Fourier transform infrared (FTIR) and energy dispersive X-ray fluorescence (EDXRF) spectrometry. Salt tolerant soybean mutants were in vivo and in vitro selected from the M-2 generation of gamma irradiated S04-05 soybean variety. Examination of the secondary structure of proteins revealed the presence of some alterations in soybean mutants in comparison to those of the control groups. The difference IR spectra indicated that salt tolerant mutants (M-2) have less protein but more lipid contents. Chemometric treatment of the FTIR data was performed and principle component analysis (PCA) revealed clear difference between control group of seeds and mutants. EDXRF analysis showed that salt tolerant mutants considerably contained more chlorine, copper and zinc elements when compared to the control group, although most of the trace elements concentrations were not significantly altered. (C) 2013 Elsevier B.V. All rights reserved.

Micropropagation as an alternative method to conventional propagation, the culture of somatic cells, tissues and organs of plants under controlled conditions is a suitable way to produce a large number of progeny plants which are genetically identical to the stock plant in a short time. The important property of the plant cells is totipotency which is a capacity to produce the whole plant from different plant parts. Micropropagation has some features to be chosen in commercial production such as multiplicative capacity in a relatively short time, healthy and disease-free production capacity and ability to generate population during a year [1-5].

The aim of our study was to induce with radiation of atrazine resistant and tolerated mutants in Coles, Amsoy-71 and 1937 soybean varieties. Atrazine that is photosynthetic inhibitor is the most important herbicide of S-triazin group, and shows toxic effect on soybean plant. For the improvement of the atrazine resistant plants with mutation breeding, the seeds belonging to the three varieties were irradiated with 200 Gy of gamma radiation dose. The irradiated seeds were sown in the field and at the end of harvesting season, every pod at node situated on the main stem was picked up separately and M 2 generations were obtained. At the plants, which were obtained from M 2 generation, chlorophyll mutants were determined and atrazine selection was made. The percentage of chlorophyll mutants for Amsoy-71, Coles and 1937 soybean varieties were found as 1.07, 1.48 and 1.32, respectively. At the end of atrazine selection, the percentages of atrazine resistant plants for Amsoy-71, Coles and 1937 soybean varieties were 0.80, 0.60 and 0.53, respectively. The percentages of atrazine tolerated plants were 1.07, 1.18 and 1.05, respectively as well. In our research; the differences among the mutants replying to atrazine in various concentrations were examined by using RAPD procedure as the molecular marker techniques in comparison with polymorphism. In the study done by using 14 primers; according to the amplification results, the differences between atrazine resistant plants were shown.

The aim of this study is to investigate the enzymatic and non-enzymatic responses of two different industrial tomato varieties (X5671R and 5MX12956) against drought stress. Fourteen-day-old seedlings were subjected to drought stress by non-watering and the stress was continued for 7 days. The effects of drought stress on tomato varieties analysed due to the results of biochemical analysis (total protein content, lipid peroxidation, relative water content, chlorophyll contents) and enzymatic activity and isozyme analysis of SOD, CAT, APX and POX. The highest water loss was recorded in X5671R as 73.17%. 64% total chlorophyll decrease was observed in both varieties on 7th day. Total protein, proline, malondialdehyde concentrations and antioxidant enzymes presented increase with related to increasing drought stress for both varieties. Due to the results, we concluded that 5MX12956 variety is more drought tolerant then X5671R. Isozyme densities and band differences were recorded. The densities of POX isozymes were started to increase from 5th day of stress. Fe-SOD, Cu/Zn-SOD1-2 isozyme bands were identified in X5671R variety, while 5MX12956 showed only Cu/Zn-SOD isozyme band. Differences in APX isozymes were observed from the 4th day of drought stress in both varieties. The results indicated the differences in antioxidant metabolism of tomato plants.

▪ Yüksek lisans tezi. Bu tez kapsamında T.C. İstanbul Kültür Üniversitesi Bitki Biyoteknolojisi Labrotuvarı'nda ülkemizde yaygın ekime sahip olan Osmancık-97 çeşidi ve gama radyasyonu ile tuzluluğa toleranslı olarak elde edilmiş mutant 300-5 çeltik hattının, tuz stresi altında tuzlulukla ilişkisi belirlenen miRNA profilleri (miR156a, miR159a, miR169b, miR393a, miR398a ve miR820a) ve bu miRNA'ların etki ettiği genlerin (SPL16, MYB, HAPC2, AFB2, TIR1, CSD2 ve DRM2) tuz stresindeki ifadelerinin incelenmesi amaçlanmıştır. Tuza toleranslı mutant ile kontrol grubu olarak belirlenen Osmanık-97 çeşidi tuzlu (150 mM NaCl) ve tuzsuz ortamlarda T.C. İstanbul Kültür Üniversitesi Bitki Biyoteknolojisi Labrotuvarı'nda in-vivo ortamda geliştirilmiştir. Hasadı yapılan bitkilerin miRNA ifadelerindeki değişimleri karşılaştırmak amacı ile miRNA izolasyonu yapılmış ardından cDNA reaksiyonu gerçekleştirilmiş ve Probe tabanlı Real-Time PCR analizi yapılmıştır. Elde edilen veriler Osmancık-97 bitkisi ile M-300-5 hattı arasında karşılaştırılmıştır. miRNA'ların hedef gen bölgelerindeki ifadelerin değişimlerini incelemek için tasarımı yapılan primerler ile Real-Time PCR analizi yapılmıştır. Elde edilen bulgular Osmancık-97 çeltik çeşidine ait bitkiler ile M-300-5 hattı arasında karşılaştırılmıştır. Sonuç olarak yapılan bu çalışmada seçilen mutant bitkide tuz stresinde belirlediğimiz tüm miRNA'ların ifadelerinde artış gözlenmiştir. miRNA gruplarının hedef aldığı gen bölgelerinden metilasyon ile ilişkili gen bölgesi DRM2'de, transkripsiyon faktörü olan NF-YA (HAPC2), kök gelişimi ile ilişkili gen bölgesi AFB2 ve TIR1'de, çiçeklenme ile ilişkili gen bölgesi SPL16'da azalma meydana gelirken, MYB transkripsiyon faktöründe ve SOD ile ilişkili olan CSD2 gen bölgesinde artış olmuştur. Yapılan bu çalışma laboratuvarımızda mutasyon ıslahı metodu ile geliştirilmiş mutant hatlar ile gerçekleştirildiğinden elde edilen miRNA ifadelerindeki değişiklikler özgün değer taşımaktadır.