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Metallic nanoparticles are valuable materials and have a range of uses. Nanoparticles synthesized from plant wastes by environment-friendly methods have attracted the attention of researchers in recent years. Also, the advantages of biological resources and synthesis methods are attracting attention. In this study, silver nanoparticles were synthesized from Ananas comosus fruit peels using ecofriendly method steps. The characterization of the particles obtained was determined by using a UV-visible spectrophotometer (UV-Vis.), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction diffractometer (XRD), Fourier scanning electron microscope (FESEM), and transmission electron microscopy (TEM). The nanoparticles showed maximum absorbance at 463 nm, measuring 11.61 in crystal nanosize, and presented spherical in appearance. An antimicrobial activity test was determined with the minimum inhibition concentration (MIC) method. The nanoparticles showed promising inhibitory activity on the Gram-positive and Gram-negative pathogen microorganisms (Escherichia coli ATCC25922, Staphylococcus aureus ATCC29213, Bacillus subtilis ATCC11774, Pseudomonas aeruginosa ATCC27833 bacteria, and Candida albicans yeast) at low concentrations. The cytotoxic and growth inhibitory effects of silver nanoparticles on different cancer cell lines were examined via the MTT assay. © 2021 Ayşe Baran et al.

Objective: Grapevine (Vitis vinifera L.) is one of the major crops widely cultivated for the wine industry, as well as for the production of fresh and dried fruit in Azerbaijan. Grapevine leafroll disease (GLD) affects the vines throughout the world and is considered the most economically destructive among all virus and virus-like diseases. Vineyard surveys were conducted to determine the virus infection in the major grapevine growing region of Azerbaijan during 2019-2020. Methods/Statistical analysis: Forty-six samples were collected from grapevine fields and screened by rapid one-step assay AgriStrip and double-antibody sandwich Enzyme-linked immunosorbent assay (DASELISA). In our study, the levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), pigments, relative water content (RWC), alterations in the activities of peroxidase enzymes (the activities of ascorbate peroxidase (APO), benzidine peroxidase (BPO) and guaiacol peroxidase (GPO) were investigated. Findings: The results revealed that tested samples were infected with Grapevine leafrollassociated virus 3 (GLRaV-3), however, no sample was found infected with other Grapevine leafroll-associated viruses. Changes in the levels of MDA, H2O2, pigments, RWC, alterations in the activities of peroxidase enzymes were studied. Significant reduction in green pigments like chlorophylls (a, b and total) and a gradual reduction in carotenoids were observed in all infected species. Obtained results showed that the level of RWC and the amount of hydrogen peroxide had increased in all infected leaves. The activities of APO, BPO and GPO were observed to increase in virus-infected leaves compared to the healthy control. Based on the results, it can be concluded that the effect of GLRaV-3 was more destructive in the N2 sample. The antioxidant defense system works more effectively in the N5 sample and this plant is more resistant to viral infection. Novelty: These results indicate that GLRaV-3 was the only most prevalent endemic viral pathogen of grapevine in the dominantly warmhumid continental climate of our country. All variable physiological parameters are assessed as the plant’s response to the pathogen. Keywords: activity; chlorophyll; hydrogen peroxide; malondialdehyde; peroxidase; virus disease

The effects of the novel [CuL2]Br-2 complex (L = bis{4H-1,3,5-triazino [2,1-b]benzothiazole-2-amine,4-(2-imidazole)}copper(II) bromide complex) on the photosystem II (PSII) activity of PSII membranes isolated from spinach were studied. The absence of photosynthetic oxygen evolution by PSII membranes without artificial electron acceptors, but in the presence of [CuL2]Br-2, has shown that it is not able to act as a PSII electron acceptor. In the presence of artificial electron acceptors, [CuL2]Br-2 inhibits photosynthetic oxygen evolution. [CuL2]Br-2 also suppresses the photoinduced changes of the PSII chlorophyll fluorescence yield (F-V) related to the photoreduction of the primary quinone electron acceptor, Q(A). The inhibition of both characteristic PSII reactions depends on [CuL2]Br-2 concentration. At all studied concentrations of [CuL2]Br-2, the decrease in the F-M level occurs exclusively due to a decrease in Fv. [CuL2]Br-2 causes neither changes in the F-0 level nor the retardation of the photoinduced rise in F-M, which characterizes the efficiency of the electron supply from the donor-side components to Q(A) through the PSII reaction center (RC). Artificial electron donors (sodium ascorbate, DPC, Mn2+) do not cancel the inhibitory effect of [CuL2]Br-2. The dependences of the inhibitory efficiency of the studied reactions of PSII on [CuL2]Br-2 complex concentration practically coincide. The inhibition constant Ki is about 16 mu M, and logKi is 4.8. As [CuL2]Br-2 does not change the aromatic amino acids' intrinsic fluorescence of the PSII protein components, it can be proposed that [CuL2]Br-2 has no significant effect on the native state of PSII proteins. The results obtained in the present study are compared to the literature data concerning the inhibitory effects of PSII Cu(II) aqua ions and Cu(II)-organic complexes.

Coronavirus 2019 (COVID-19), as an emerging infectious disease, has caused significant mortality and morbidity along with socioeconomic impact. No effective treatment or vaccine has been approved yet for this pandemic disease. Cutting-edge tools, especially nanotechnology, should be strongly considered to tackle this virus. This review aims to propose several strategies to design and fabricate effective diagnostic and therapeutic agents against COVID-19 by the aid of nanotechnology. Polymeric, inorganic self-assembling materials and peptide-based nanoparticles are promising tools for battling COVID-19 as well as its rapid diagnosis. This review summarizes all of the exciting advances nanomaterials are making toward COVID-19 prevention, diagnosis and therapy., Lay abstract The emergence of the new coronavirus 2019 (COVID-19) has affected millions of people around the world and has become a serious threat to human life. To date, nanotechnology-based tools have been effective in preclinical studies against a variety of pathogens, including respiratory viruses, herpes virus, human papillomavirus and HIV. Nanoparticles, particles smaller than a micrometer, have drawn particular interest in the management of COVID-19 disease due to their unique properties (easy preparation, low cost, easy modification, appropriate size, etc). Nanotechnology-based strategies for COVID-19 disease management include the development of tools for rapid, accurate and sensitive diagnosis, production of effective disinfectants, delivery of mRNA vaccines into human cells and delivery of antiviral agents into the body.

The association between the angiotensin‑converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism and the risk of diabetes mellitus developing in the Azerbaijan population is not studied yet. Therefore, the aim of the present study was to investigate the association of ACE I/D gene polymorphism and the risk of developing diabetes in Azerbaijan population. A total of 200 individual consisting of 100 control subjects and 100 patients with diabetes mellitus (28 patients I type DM (11 male and 17 female); 72 patients II type DM (21 male and 51 female)) were recruited. DNA was extracted from the blood samples. Genotyping of ACE I/D gene polymorphism done by PCR and mistyping of the II and DD genotypes was conducted with an insertion/deletion‑specific primer. The genotyping frequency for the II, ID and DD polymorphism of the ACE gene ID=63, DD=36, II=1 in case subjects. The genotyping frequency for the II, ID and DD polymorphism of the ACE gene in control group: ID=49, DD=26, II=25. The frequency for the D allele is 67.5 and the frequency of I allele is 32.5 in case group. The frequency for the D allele is 50.5 and the frequency of I allele is 49.5 in control group. The dominant and recessive models revealed alleles on separate groups and at the population level: DD:DR=13.6; ID:IR=15; ID:DD=0.35; DD:ID= 2.97; DR: IR=3.26; IR:DR=0.3. Based on the results, D allele showed significant association with risk of disease. This finding revealed the association of I/D polymorphism with risk of diabetes. However, further studies with larger sample size are necessary to confirm the association of the I/D polymorphism of the ACE gene and diabetes mellitus in Azerbaijan population.

Cryphonectria parasitica, the causal agent of chestnut blight is controlled in Europe through natural spread of Cryphonectria hypovirus 1 (CHV1), a mycovirus able to induce hypovirulence to the host. In recent years C. parasitica was reported infecting Azerbaijani population of chestnut, but the presence of CHV1 still needs to be confirmed. Aim of this work was to investigate fifty-five C. parasitica isolates collected in Azerbaijan to describe the associated viruses. Our work found i) the first negative-sense ssRNA virus known to infect C. parasitica naturally for which we propose the name Cryphonectria parasitica sclerotimonavirus 1 (CpSV1) and ii) an RNA sequence showing peculiar features suggesting a viral nature for which we propose the name Cryphonectria parasitica ambivirus 1 (CpaV1). The discovery of CpaV1 expands our knowledge of the RNA virosphere suggesting the existence of a new lineage that cannot presently be reliably associated to the monophyletic Riboviria.

Land plants shorten their vegetation period during water deficiency. Under water stress, wheat plants undergo several changes at the morphophysiological level. We tried to elucidate the role of the morphophysiological parameters and the photosynthetic machinery in response to drought followed by rewatering. Therefore, some morphophysiological traits of two bread wheat genotypes (drought-tolerant Gobustan, drought-sensitive Tale 38) were studied. The H2O2 content increased under drought in both genotypes but recovered in the Gobustan genotype after rewatering. The isozymes of peroxidase manifested dynamic changes under drought. The electron transport rate and the maximum photochemical quantum efficiency of PSII showed similar responses to drought with subsequent rewatering in both genotypes. However, the amount of the photosynthetic pigments changed drastically resulting in structural changes of thylakoid membranes. In Gobustan, the thylakoid membrane structure almost completely recovered after rewatering. Thus, the drought-tolerant genotype shows a more dynamic response of photosynthetic machinery and antioxidant capacity.

Grapevine leafroll disease (GLD) is an economically important virus disease affecting grapes (Vitis spp.) in almost all grape-producing areas, but little is known about its effect on metabolic constitutes of affected grapes. Fifty-seven suspicious grapevine samples of various cultivars showing symptoms of leaf curl, vein greening, reduced leaf size, necrosis, mosaics or reddening and reduced fruit yield and quality were collected during the summer of 2016–2017 in two regions of Azerbaijan and tested serologically (rapid one-step assay AgriStrip, DAS-ELISA) and molecularly (RT-PCR) for the presence of the major viruses infecting these crop. According to the result of serological tests, two cultivars (Saperavi and Narchicheyi) were found to be infected by GLRaV-3. RT-PCR using specific primers (LR3-8504V and LR3-9445C) for a part of the GLRaV-3 viral coat protein gene confirmed the presence of the virus by amplification of expected 942 bp fragments. The levels of some metabolic constituents were studied comparatively in the leaves of GLRaV3-infected and non-infected grapes and an increase of tocopherols, soluble sugars, total phenols, soluble protein, proline and glycine betaine was detected in infected grapes. Thus, it can be considered as an adaptive ability of various grapevine varieties against pathogen infection.

Under natural environments, light quality and quantity are extremely varied. To respond and acclimate to such changes, plants have developed a multiplicity of molecular regulatory mechanisms. Non-photochemical quenching of chlorophyll fluorescence (NPQ) and thylakoid protein phosphorylation are two mechanisms that protect vascular plants. To clarify the role of thylakoid protein phosphorylation in energy-dependent quenching of chlorophyll fluorescence (qE) in rice plants, we used a direct Western blot assay after BN-PAGE to detect all phosphoproteins by P-Thr antibody as well as by P-Lhcb1 and P-Lhcb2 antibodies. Isolated thylakoids in either the dark- or the light-adapted state from wild type (WT) and PsbS-KO rice plants were used for this approach to detect light-dependent interactions between PsbS, PSII, and LHCII proteins. We observed that the bands corresponding to the phosphorylated Lhcb1 and Lhcb2 as well as the other phosphorylated proteins were enhanced in the PsbS-KO mutant after illumination. The qE relaxation became slower in WT plants after 10 min HL treatment, which correlated with Lhcb1 and Lhcb2 protein phosphorylation in the LHCII trimers under the same experimental conditions. Thus, we concluded that light-induced phosphorylation of PSII core and Lhcb1/Lhcb2 proteins is enhanced in rice PsbS-KO plants which might be due to more reactive-oxygen-species production in this mutant.

Azerbaijan is an Eurasian country in the Caucasian region, located in the Caspian Sea basin at the intersection of Europe and Central Asia in the South Caucasus, with an area of 86.600 km2; 11.5% being forests, 1.6% water basin, 50% cultivated lands, including 27% pastures, and 36.9% farms. Nearly 5.000 taxa (including cultivated flora) have been recorded in the “Flora of Azerbaijan” in 2016. The information on the state of rare species has been pooled up. Almost 20% of the flora needs protection, 140 being severely threatened; these include 5 categories: (1) belavers are endangered, 22 species; (2) rare species in smaller areas, 65 species; (3) gradually shrinking own area species, 45 species; (4) rarely species with little knowledge about them, 18. Rare species restored as a result of additional plantings kept in naturally (five species). Some species (16 species) can be assigned to several categories. Rare plants are more in Talysh and Nakhchivan: 35–40 species in the Greater and Lesser Caucasus regions, 16 species in Absheron and over 14 in the Kur-Araz lowland. Currently 800 taxa in the Flora of Azerbaijan need protection.

Tomato samples were collected from the field of Absheron peninsula in Azerbaijan in order to evaluate the incidence of main Tobamoviruses. According to results of serological and molecular tests, Tomato mosaic virus (ToMV), Tobacco mosaic virus (TMV), and Pepper mild mottle virus (PMMoV) were detected as single and mixed infections (TMV + PMMoV; ToMV + PMMoV) in various tomato samples. It was found that Tobamovirus infection caused an increase in the content of malondialdehyde, alterations in the activities of peroxidase enzymes and quantitative and qualitative changes in their molecular isoforms. A comparison of thylakoid membrane polypeptides from virus-infected leaves indicated a decrease in the content of the thylakoid membrane polypeptides with molecular masses of 123, 55, 47, 33, 28–24, 17, and 15 kD. PSII efficiency and the content of chlorophylls (a and b) were significantly lower in the virus-infected leaves.

Over the last two decades many reports have been published on diverse types of biohybrid electrodes utilizing components of the photosynthetic apparatus. Currently, the development of such devices does not extend beyond laboratory research. In the future, these electrodes could be used in biosensors, solar cells, and as a new technique to investigate photosynthetic pigment-protein complexes. Efficiency of light-to-current conversion is particularly important for solar cell applications. Selection of a suitable substrate for special pigment-protein complexes is a significant challenge for building an inexpensive and efficient device. Various combinations of pigment-protein complexes and substrates, as well as different measurement conditions make it difficult to directly compare performance of various solar cells. However, it has been shown, that one of the possible substrate materials, namely nanostructured TiO2, is the most preferred material for the immobilization of pigment-protein complexes in terms of both cost and efficiency. The photocurrent values reaching several mA, were reported for TiO2-based biohybrid electrodes. However, the efficiency of TiO2-based biohybrid is still far from its potential maximum value due to fundamental challenges related to designing an optimum interface between TiO2 nanostructure and pigment-protein complexes containing electron transferring cofactors. To date, counterproductive back reactions, also referred to as charge recombination, still dominate and lower internal quantum efficiency of these systems.

International audience; Bois noir (BN) is an important grapevine yellows endemic to the Euro-Mediterranean basin caused by ‘Candidatus Phytoplasma solani’ (‘Ca. P. solani’), a non culturable plant pathogenic Mollicute. Bois noir symptoms could be associated with ‘Ca. P. solani’ in two Azerbaijanian vineyards where disease incidence and severity were recorded for five local Vitis vinifera cultivars. In order to gain insight into the epidemiology of Bois noir in Azerbaijan, ‘Ca. P. solani’ isolates infecting plants were characterized by multi-locus sequence analysis and their secY and stamp gene sequences compared to that of the strains detected in other plants and in local Cixiidae planthoppers. Genotypes were determined for two non-ribosomal house-keeping genes, namely tuf and secY, as well as two variable markers namely Stamp and mleP1 genes, that respectively encode the antigenic membrane protein AMP and a 2-Hydroxycarboxylate transporter. The Azerbaijanian BN phytoplasma isolates corresponded to three tufB and secY genotypes. A finer differentiation of Azerbaijanian ‘Ca. P. solani’ isolates was obtained with mleP1 as five different mleP1 genetic variants were found. Finally, Stamp gene allowed differentiating four new genotypes in grapevine among the 10 new Stamp genotypes detected in various plants in Azerbaijan. The preliminary survey for infected insects conducted in northern Azerbaijan, led to the identification of Hyalesthes obsoletus and Reptalus noahi as potential vectors for two ‘Ca. P. solani’ new genotypes phylogenetically distant from the known genetic clusters. Altogether these results indicate an important genetic diversity of BN phytoplasmas in Azerbaijan that certainly result from spread through local insect vectors.

We aimed to (i) assess the extant genetic diversity of the riparian relict tree Pterocarya fraxinifolia across its current distribution range in the South Caucasus, including the past refugial areas Colchis and Hyrcan, and (ii) test if a separation of these areas is reflected in its phylogeographic history. Genetic diversity of natural populations was examined using nuclear microsatellite and plastid DNA markers. Spatial genetic structure was evaluated using Bayesian clustering methods and the reconstruction of plastid DNA networks. Divergence times of Colchic and Hyrcanian populations were estimated via divergence dating using a relaxed molecular clock. Allelic richness, private allelic richness, and expected heterozygosity were significantly higher in Hyrcan than in Colchis and the Greater Caucasus, and significant genetic differentiation was revealed between the two groups. Whereas only two plastid haplotypes were detected for the Colchic and Caucasian populations, the Hyrcanian populations displayed 1...

The ascorbate-glutathione (AsA-GSH) cycle is a major pathway of H2O2 scavenging in plants. The effect of diurnal variations in hydrogen peroxide (H2O2) content, the intensity of lipid peroxidation (malondialdehyde, MDA), photosynthesis, antioxidants and antioxidative enzyme activities involved in AsA-GSH metabolism has been studied comparatively in leaves of durum (Triticum durum Desf.) and bread (Triticum aestivum L.) wheat genotypes exposed to soil drought. Drought stress caused an increase in the content of H2O2, MDA, alterations in the activities of AsA-GSH cycle enzymes and quantitative changes in AsA and GSH content during the day. PSII efficiency was significantly lower in the control and drought exposed leaves at the highest temperature in the afternoon. The ascorbate peroxidase activity was found to increase and ascorbic acid amount decreased with increasing temperature during the day. Further, the glutathione amount and glutathione reductase activity increased at the expense of the regeneration of the oxidised form of glutathione. Our results revealed that wheat can tolerate drought stress by enhancing the antioxidant enzyme activities and alteration of the concentration of ascorbate and glutathione.

Global climate change, which is rising steeply in the world today, has caused further increases in the influence of abiotic stress factors. Abiotic stresses such as drought, high salinity, and high temperatures are common detrimental environmental circumstances that extremely influence growth, cultivation, and productivity worldwide. Traditionally, the varietal selection is based on morphological feature; hence, polygenic characters were very difficult to analyze, and thus such constraints can be overcome by using molecular marker-assisted selection (MAS). As markers are currently available for relatively few traits, MAS must be integrated with the ongoing conventional breeding to maximize its impact. Molecular markers are useful tools to determine the variation in the DNA sequence and eventually the regions of DNA or the genes controlling the qualitative and/or quantitative traits of agronomic significance. The aim of the presented research was to detect the genes and gene loci responsible for the tolerance to salt stress, drought, and high temperatures in wheat using various molecular markers. Wheat genotypes with contrasting stress tolerance, architectonics, productivity, and other physiological traits kept in the gene fund of the Research Institute of Crop Husbandry were used as research objects. Plants were cultivated in the Absheron experimental base under natural conditions (Baku, Azerbaijan). Salt tolerance potential of wheat genotypes was examined genetically based on PCR analysis using various molecular markers associated with salt tolerance. According to the results of the molecular analysis performed with RAPD (OPZ 09) markers linked with salt tolerance, expected 590 bp DNA fragments were amplified in 39% of bread wheat and 27% of durum wheat genotypes. At the same time, salt tolerance gene Nax1 was examined with gwm312 primer in durum wheat genotypes. An expected 200 bp amplicon indicating the existence of this gene in the Barakatli 95, Garabag, Shiraslan 23, Sharg, and Gyrmyzy bugda genotypes was successfully amplified. This amplicon was also synthesized in Barakatli 95, Garabag, Shiraslan 23, and Gyrmyzy bugda genotypes using wmc170 primer linked to salt tolerance locus in durum wheat genotypes. The study of physiological senescence of the flag leaf playing the pivotal role in the uptake of solar energy and stipulating plant productivity in wheat is very important for providing high productivity under stress. Therefore, using RAPD OPH13 marker, the existence of a gene locus linked to the physiological life-span of flag leaf was examined in wheat genotypes under drought stress. Based on the analysis of electrophoretic profiles of PCR results, expected 450 bp fragments were synthesized in 30 wheat genotypes. This result confirms the existence of a gene locus providing the physiological youth of flag leaf, which is considered as the drought tolerance indicator in these genotypes. The existence of the studied locus was not confirmed in 19% of the genotypes. Tolerance to heat stress is a complex phenomenon and controlled by multiple genes imparting a number of physiological and biochemical changes. To differentiate the heat-tolerant and heat-susceptible genotypes of wheat, a heat shock protein (HSP16.9) was taken as a target gene, and domestic genotypes were examined using allele-specific PCR primers. The obtained results can be used in wheat breeding programs for developing wheat varieties tolerant to stresses.

International audience; Two surveys were conducted in September 2014 and July 2015 in important vegetable-growing areas in Azerbaijan. Cucurbit and solanaceous plants exhibiting symptoms of mosaic, yellowing, leaf curl or necrosis were collected and tested serologically and molecularly for the presence of the major viruses infecting these crops. For cucurbits, the most common viruses in both sampling sets were aphid-transmitted ones, including potyviruses (watermelon mosaic virus, WMV, zucchini yellow mosaic virus, ZYMV), cucumoviruses (cucumber mosaic virus, CMV) and poleroviruses (cucurbit aphid-borne yellows virus, CABYV). Eggplant mottled dwarf (EMDV) was also detected for the first time in Azerbaijan on cucumber at a low prevalence. In solanaceous crops, CMV was the most common virus detected, followed by potato virus Y (PVY). Tomato spotted wilt virus (TSWV), alfalfa mosaic virus (AMV) and tobamoviruses (tomato mosaic virus (TMV), pepper mild mottle virus (PMMoV)) were also detected in 2015. The begomovirus tomato yellow leaf curl virus (TYLCV) was present on tomato only in the Absheron area, where it had a high prevalence and induced important losses. TYLCV-like symptoms on tomato in other areas of Azerbaijan were due to phytoplasma diseases.

Water deficit is a key factor influencing the yield and quality of crops. In the present study, the photosynthetic responses by means of chlorophyll fluorescence of chloroplasts, thylakoid membrane proteins, and antioxidant components were analyzed in wheat (Triticum durum Desf.) plants differing in their tolerance to drought. Two durum winter wheat varieties, Barakatli 95 (drought tolerant) and Garagylchyg 2 (drought sensitive) were grown under field well-watered and drought conditions. It was found that contents of the PS I core (CPI) with Mr of 123 kD and apoprotein P700 with Mr of 63 kD were relatively higher in Barakatli 95 variety under drought stress compared with the control plants. Synthesis of α- and β-subunits of CF1 ATP-synthase complex with Mr of 55 and 53.5 kD also slightly increased in the tolerant Barakatli 95 and decreased in the drought sensitive variety Garagylchyg 2. A decrease in the intensity of 30 kD band and a significant increase were found in the content of the 25-16 kD region in Garagylchyg 2 variety. The synthesis of 60 kD and content of low molecular mass polypeptides (21.5 and 12 kD) were increased in the tolerant genotype Barakatli 95. The intensity of peaks at 687, 695, and 742 nm considerably increases in the fluorescence spectra (77 K) of chloroplasts isolated from the sensitive variety Garagylchyg 2, and there is a stimulation of the ratio of fluorescence band intensity F687/F740. At the same time, higher level of glycine betaine was found in the drought tolerant variety compared with the control one throughout the different periods of growth.

The dynamics of the activity of catalase, ascorbate peroxidase, guaiacol peroxidase, and benzidine peroxidase, as well as the level of hydrogen peroxide in the vegetative organs of durum wheat (Triticum durum Desf.) cultivars was studied under long-term soil drought conditions. It was established that hydrogen peroxide generation occurred at early stages of stress in the tolerant variety Barakatli-95, whereas in the susceptible variety Garagylchyg-2 its significant amounts were accumulated only at later stages. Garagylchyg-2 shows a larger reduction of photochemical activity of PS II in both genotypes at all stages of ontogenesis under drought stress than Barakatli-95. The highest activity of catalase which plays a leading role in the neutralization of hydrogen peroxide was observed in the leaves and roots of the drought-tolerant variety Barakatli-95. Despite the fact that the protection system also includes peroxidases, the activity of these enzymes even after synthesis of their new portions is substantially lower compared with catalase. Native PAGE electrophoresis revealed the presence of one isoform of CAT, seven isoforms of APX, three isoforms of GPO, and three isoforms of BPO in the leaves, and also three isoforms of CAT, four isoforms of APX, two isoforms of GPO, and six isoforms of BPO in the roots of wheat. One isoform of CAT was found in the roots when water supply was normal and three isoforms were observed under drought conditions. Stress associated with long-term soil drought in the roots of wheat has led to an increase in the heterogeneity due to the formation of two new sedentary forms of catalase: CAT2 and CAT3.

A characteristic feature of C4 plants is the differentiation of the photosynthetic leaf tissues into two distinct cell types: mesophyll (M) and bundle sheath (BS) cells. We have investigated several biochemical parameters, including pigment composition, polypeptide patterns, fluorescence at 77K, the activity of photosystems and ultrastructure of mesophyll and bundle sheath chloroplasts of maize (Zea mays L.) plants. It is shown that the BS chloroplasts have ~2-fold higher chlorophyll a/b ratio than M chloroplasts, 6.15 and 3.12 respectively. The PSI apoprotein (68 kDa) was more abundant in BS than in M thylakoids. Polypeptides belonging to PSII core antenna, are in similar amounts in both types of membranes, but the 45kDa band is more intensive in M thylakoids. Polypeptides in the region of 28–24 kDa of the light-harvesting complex of PSII (LHCII) are also present in both types of chloroplasts, though their amounts are reduced in BS thylakoids. The chlorophyll fluorescence emission spectra in M cells showed the presence of three bands at 686, 695 and 735 nm characteristics of LHCII, PSII core and PSI complexes, respectively. However, in the fluorescence spectrum of agranal plastids, there are almost traces of the band at 695 nm, which belongs to the PSII core complex. The research results revealed that the photochemical activity of PSII in BS chloroplasts is ~5 times less than in the chloroplasts of M cells. The highest PSI activity was found in maize BS chloroplasts.

Extremes of environmental conditions, such as biotic stresses, strongly affect plant growth and development and may adversely affect photosynthetic process. Virus infection is especially problematic in crops, because unlike other diseases, its impact cannot be reduced by phytosanitary treatments. The vegetable crops ( Solanum lycopеrsicum L, Cucurbita melo L., Cucumis sativus L., Piper longum L., Solanum melongena L., Vicia faba L.) showing virus-like symptoms were collected from fields located in the main crop production provinces of Azerbaijan. Infection of the plants were confirmed by Enzyme-linked immunosorbent assay using commercial kits for the following viruses: Tomato yellow leaf curl virus , Tomato mosaic virus , Tomato chlorosis virus , Melon necrotic spot virus and Cucumber mosaic virus , Bean common mosaic virus and Bean yellow mosaic virus . Generation sites of superoxide and hydrogen peroxide radicals and activities of enzymes involved in the detoxification of reactive oxygen species (catalase, glutathione reductase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase) were examined in uninfected leaves and in leaves infected with viruses. High accumulation of superoxide and hydrogen peroxide radicals was visualized in infected leaves as a purple discoloration of nitro blue tetrazolium and 3,3′-diaminobenzidine tetrahydrochloride. It was found that the activities of APX and CAT significantly increased in all infected samples compared with non-infected ones. Dynamics of GR and Cu/Zn-SOD activities differed from those of CAT and APX, and slightly increased in stressed samples. Electrophoretic mobility profiling of APX, GPX and CAT isoenzymes was also studied.

Water is a key factor influencing the yield and quality of crops. One of the parameters of plant biological tolerance to constantly changing environmental conditions is the change of activities and numerous molecular forms of antioxidant enzymes. Two durum (Triticum durum Desf.) wheat varieties contrasting for drought tolerance, such as Barakatli-95 (drought tolerant) and Garagylchyg-2 (drought sensitive) were grown over a wide area in the field. Experiments were carried out to study the effect of soil drought on changes in activities and subcellular localization of superoxide dismutase isoforms. The levels of malondialdehyde, glycine betaine and total proteins were also analyzed. The level of the enzyme activity appeared to depend on the wheat varieties, duration of drought and stages of leaf development. Native polyacrylamide gel electrophoresis (PAGE) revealed the presence of 9 isoenzymes of superoxide dismutase in wheat leaves during drought. Mn-SOD was found in the mitochondrial fractions, Fe-SOD in the chloroplast fraction and Cu/Zn-SOD is localized in all subcellular fractions. Wheat leaves contain three different isoforms of SOD (Mn-, Fe-, Cu/Zn-SOD). Three isoforms of Mn-SOD, one isoform of Fe-SOD and five of Cu/Zn-SOD were observed in wheat leaves using 3 mM KCN and 5 mM H2O2 as selective inhibitors. The expression of Mn-SOD was preferentially enhanced by drought stress. It seems that Mn-SOD isoforms more than SOD ones play a major role in the scavenging of superoxide radicals. The observed data showed that status of antioxidant enzymes such as SOD could provide a meaningful tool for depicting drought tolerance of wheat genotype.

The recent identification of a new nanovirus, pea necrotic yellow dwarf virus, from pea in Germany prompted us to survey wild and cultivated legumes for nanovirus infections in several European countries. This led to the identification of two new nanoviruses: black medic leaf roll virus (BMLRV) and pea yellow stunt virus (PYSV), each considered a putative new species. The complete genomes of a PYSV isolate from Austria and three BMLRV isolates from Austria, Azerbaijan and Sweden were sequenced. In addition, the genomes of five isolates of faba bean necrotic yellows virus (FBNYV) from Azerbaijan and Spain and those of four faba bean necrotic stunt virus (FBNSV) isolates from Azerbaijan were completely sequenced, leading to the first identification of FBNSV occurring in Europe. Sequence analyses uncovered evolutionary relationships, extensive reassortment and potential remnants of mixed nanovirus infections, as well as intra- and intercomponent recombination events within the nanovirus genomes. In some virus isolates, diverse types of the same genome component (paralogues) were observed, a type of genome complexity not described previously for any member of the family Nanoviridae. Moreover, infectious and aphid-transmissible nanoviruses from cloned genomic DNAs of FBNYV and BMLRV were reconstituted that, for the first time, allow experimental reassortments for studying the genome functions and evolution of these nanoviruses.

Drought is one of the major factors limiting the yield and quality of crops in the world. The activity of antioxidative system to tolerate the drought stress is significant in plants. In the present study, the activities and isoform profiles of catalase (CАТ), ascorbate peroxidase (APX), glutathione reductase (GR), and superoxide dismutase (SOD) were analyzed in four barley genotypes grown under soil water restriction. Drought stress caused increase in the activities of CАТ and SOD in all studied genotypes, while APX activity decreased. The total GR activity increased substantially in genotypes K 2778 and St.Garabag 7 and decreased in No. 77 local and St.Pallidum 596 genotypes under conditions of severe water stress. No detectable differences were observed in the isoenzyme pattern (the appearance of a new isoenzymes and disappearance of another one) between control plants and those subjected to soil drought. However, intensification of corresponding isoforms in electrophoretic spectra was observed in stressed barley leaves relative to watered ones. The obtained results possibly suggest that antioxidant protection in barley plants under drought conditions could be attributed mainly to SOD and CAT.

In this brief report, we provide a pictorial essay on an international conference “Photosynthesis Research for Sustainability-2013 in honor of Jalal A. Aliyev” that was held in Baku, Azerbaijan, during June 5–9, 2013 ( http://photosynthesis2013.cellreg.org/ ). We begin this report with a brief note on Jalal Aliyev, the honored scientist, and on John Walker (1997 Nobel laureate in Chemistry) who was a distinguished guest and lecturer at the Conference. We briefly describe the Conference, and the program. In addition to the excellent scientific program, a special feature of the Conference was the presentation of awards to nine outstanding young investigators; they are recognized in this report. We have also included several photographs to show the pleasant ambience at this conference. (See http://photosynthesis2013.cellreg.org/Photo-Gallery.php ; https://www.dropbox.com/sh/qcr124dajwffwh6/TlcHBvFu4H?m ; and https://www.copy.com/s/UDlxb9fgFXG9/Baku for more photographs taken by the authors as well as by others.) We invite the readers to the next conferences on “Photosynthesis Research for Sustainability—2014: in honor of Vladimir A. Shuvalov” to be held during June 2–7, 2014, in Pushchino, Russia. Detailed information for this will be posted at the Website: http://photosynthesis2014.cellreg.org/ , and for the subsequent conference on “Photosynthesis Research for Sustainability—2015” to be held in May or June 2015, in Baku, Azerbaijan, at http://photosynthesis2015.cellreg.org/ .

61 varieties of wheat collected in the gene fund of the Research Institute of Crop Husbandry were screened using SCAR-markers associated with the gene of resistance to brown leaf rust, Lr19. As a result of PCR analysis using SCS123 marker the 737 bp locus was detected in 48 genotypes. The expected fragment of the 688 bp was detected in 53 genotypes using the SCS253 marker. The results obtained using both markers indicate that the Lr19 gene is present on 7D chromosomes of 45 genotypes. The existence of the Lr19 gene has not been proven only for 5 from the 61 analyzed wheat genotypes.

In this brief report, we provide a perspective on an international conference “Photosynthesis Research for Sustainability-2011”, held in Baku, Azerbaijan, during July 24–30, 2011 ( http://www.photosynthesis2011.cellreg.org/ ). At this conference, awards were given to nine young investigators; they are recognized in this Report. We have also included here some photographs to show the pleasant ambiance at this conference. (See http://www.photosynthesis2011.cellreg.org/Photos.php and http://www.life.illinois.edu/govindjee/g/Photo/Baku.html for more photographs taken by the authors as well as by others.) We invite the readers to the next conference on “Photosynthesis Research for Sustainability-2013” to be held in May or June 2013, in Baku, Azerbaijan. Information will be posted at: http://www.photosynthesis2013.cellreg.org/ .

International audience

Two wheat (Triticum aestivum L.) cultivars contrasting in architectonics and differing in drought resistance, Azamatli-95 (short stature, vertically oriented small leaves, drought-tolerant) and Giymatli-2/17 (short stature, broad and drooping leaves, drought-sensitive), were studied. It was found that the content of CP I (115 kDa) and 63-kDa apoprotein P700 and also LHC II polypeptides increases slightly in the drought-resistant cv. Azamatli-95 under extreme water supply limitation, while their content decreases in drought-sensitive cv. Giymatli-2/17. The intensity of synthesis of alpha- and beta-subunits of CF(1) (55 and 53.5 kDa) and 33-30.5 kDa proteins also decreases in the sensitive genotype. The intensity of short wavelength peaks at 687 and 695 nm sharply increases in the fluorescence spectra (77K) of chloroplasts from Giymatli-2/17 under water deficiency, and there is a stimulation of the ratio of fluorescence band intensity F687/F740. After exposure to drought, cv. Giymatli-2/17 shows a larger reduction in the actual PS II photochemical efficiency of chloroplasts than cv. Azamatli-95.

Equipe Mollicutes; First Report of Grapevine ‘Bois noir’ in Azerbaijan

Many natural disasters, including drought, result in crop production and quality losses worldwide and global climate change makes the situation worse. A wide range of strategies used to enhance the drought tolerance depend on the genetically determined plant capacity and sensitivity, as well as the intensity and duration of the stress. Understanding the physiological, biochemical, and molecular mechanisms of drought tolerance is very important in development of selection and breeding strategies. Among crop plants, wheat is the staple food for more than 35 % of world population and is often grown in water-limited conditions. Wheat anti-drought study is of importance to worldwide wheat production and biological breeding. For this purpose, a rich gene fund was created, comprising thousands of wheat genotypes with contrasting photosynthetic traits, productivity, and tolerance to drought stress, and both selected from the ancient, aboriginal varieties of national selection and introduced from the world gene pool, particularly from Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), International Centre for Agricultural Research in Dry Areas (ICARDA), and other international centers. All these genotypes are grown in the field conditions on a wide area at the Absheron Experimental Station of the Research Institute of Crop Husbandry (Baku, Azerbaijan) under normal irrigation and drought. Numerous winter durum (Triticum durum Desf.) and bread (Triticum aestivum L.) wheat genotypes were the main target of the research. The main parameters for selection of these genotypes were grain yield, plant phenotypic features (stem height, area and architectonics of the leaf surface, etc.), duration of the vegetation, and other morphophysiological traits, as well as drought resistance. Random amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) spectra were analyzed in 220 bread (T. aestivum L.) and 46 durum (T. durum Desf.) wheat genotypes. Using primer P6 (TCGGCGGTTC), 920-bp fragment was revealed in 234 genotypes. Primer P7 (TCGGCGGTTC) produced a 750-bp band only in 203 genotypes. Results obtained by using both P6 and P7 primers match in 74 % of the analyzed genotypes: In 184 genotypes, specific loci were amplified by both markers. The obtained results show that these genotypes possess loci associated with drought tolerance. In 13 genotypes (total 5 %), none of the primers amplified specific fragments. So, the presented data could be used for monitoring the environmental stresses in field-grown plants and help in selection of stress-resistant varieties.

Biotic stress is one of the major environmental factors affecting plants. Viruses, fungi, bacteria, weeds, insects, and other pests and pathogens represent a major constraint to agricultural productivity and a serious threat to vegetable and grain crops. Plant protection against pathogens and pests is a commercially important issue and one of the main directions of researches. Almost half of new infectious diseases identified in plants during the past 10 years have a viral nature. The number and distribution areas of some plant viruses in Europe have been increasing rapidly during the past 35 years that caused big problems from an economic point of view. Viral diseases have also become a real threat for different cultivars of vegetables, grains, and other agricultural crops in our country. It causes extensive leaf yellowing, stem and leaf deformation, reducing the fruit quality, substantial yield loss, and shortening the lifecycle of crops. The probable cause of decay of virus-infected plants is not only the virus activity itself but also reduced tolerance to unfavorable environmental conditions. The identification of the viruses affecting plants and the study of the plant responses are very important for the better understanding of the plant–virus interactions and for developing the tendency to reduce the plant virus-associated risks in Azerbaijan. Therefore, the main goal of the present study is to identify the most widespread plant viruses in Azerbaijan using different molecular techniques and to evaluate some characteristics of plant response to viral stress.

Present research is aimed to identify a Dreb1 gene in different wheat Triticum L. genotypes using functional markers. A total of 12 wheat genotypes: 3 tetraploid (Triticum durum L., AABB, 2n = 4x = 28) and 9 hexaploid cultivars (Triticum aestivum L., AABBDD, 2n = 6x = 42) including tolerant, semi-tolerant and nontolerant to drought were used. Five pairs of genome-specific primers designed for the wheat Dreb 1 genes using the Primer Premier 5.0 software was used for DNA amplification. P21F/P21R and P25F/PR were designed to amplify downstream regions of the Dreb-A1 in A genome. The P18F/P18R primers were designed as a B genomespecific primer pair. Similarly, P22F/PR and P20F/P20R was selected to amplify sequences from D genome. PCR products excised from agarose gels found out that Dreb 1 gene was located on chromosome 3A in all genotypes, including drought-resistant and drought-sensitive ones, excepting one semi-tolerant genotype Tale-38. In comparison with other genotypes, a 717 bp PCR product of Dreb-B1 gene was located on B genome in drought-tolerant sample Barakatli-95. Primers P22F/PR and P20F/P20R amplified 596- and 1193-bp fragments, respectively, from D genome, which is characteristic for hexaploid Triticum aestivum L. genotypes, did not revealed positive results.

Activities of catalase, ascorbate peroxidase, superoxide dismutase and glutathione reductase, as well as carotenoid content and photochemical activity of photosystem I and photosystem II were studied in leaves of durum and bread wheat genotypes. It was found out that dynamics of catalase and ascorbate peroxidase functioning in well-watered plants through ontogenesis practically did not change both among durum and among bread wheat cultivars. Functioning of these enzymes during ontogenesis under water deficit differed. Catalase activity increased in all stressed genotypes: in durum wheat cultivars maximal activity was observed in the milk ripeness and in bread wheat cultivars — in the end of flowering. Ascorbate peroxidase activity also increased under water deficit: in tolerant wheat genotypes maximal activity occurred in the end of flowering, in sensitive ones—in the end of ear formation. The maximum activity of glutathione reductase both as in the control, as well as in drought-subjected plants was observed in the anthesis stage. Superoxide dismutase activity was lower than the control during ontogenesis, excepting the last stages. It should be noted that PS I and PS II photochemical activity were also high in genotypes subjected to drought both in the end of ear formation and flowering stages.

This work is devoted to study the antioxidant enzymes and functional state of photosystem (PS) II under the different concentrations of the radium in barley (Hordeum vulgare L.) and clover (Trifolium pratense L.) plants. It was determined that CAT activity increased in barley grown in the soil contaminated with low radium concentrations (29.45 ± 3.00 and 124 ± 15.00 Bq kg−1) as compared with control, but decreased dramatically upon the effect of high radium concentration (242.25 ± 28 Bq kg−1). CAT activity was 0.078 mmol/g min in control plants, and 0.18, 0.23 and 0.03 mmol/g min in 29.45 ± 3.00, 124 ± 15.00, 242.25 ± 28.00 Bq kg−1, respectively. It was observed that in clover seedlings as the radium activity increased, CAT activity also rised, but at high concentrations, as well as in barley, enzyme activity decreased. The APX activity in barley as compared to the control decreased as a result of radium effect. APX activity in clover increased in soil with higher radium concentrations. SOD activity in barley increased at high levels of radium concentration (i.e. 0.5 unit/mg in the control, 0.6, 2.7 and 3 units/mg in 29.45 ± 3.00, 124 ± 15.00 and 242.25 ± 28.00 Bq kg−1, respectively). In clover, changes in PS II activity decreased significantly at high 226Ra concentrations.

Wheat (Triticum aestivum L.) cultivars contrasting in genetic makeup and differing in drought-resistance were grown in field conditions in a wide area under normal water supply and severe water deficit. One of the genotypes (Azamatli-95) was short-stemmed, with vertically oriented small leaves and drought-tolerant while the other genotype (Giymatli-2/17) was short-stemmed, with broad and drooping leaves and drought-sensitive. It was found out that the content of CP I (Mr 115 kD) and apoprotein of P700 with Mr 63 kD, also LHC II polypeptides insignificantly increased in the drought-resistant cv. Azamatli-95 under extreme water supply condition while their content decreased in drought-sensitive cv. Giymatli-2/17. The intensity of synthesis of α- and β-subunits of CF1 (55 and 53.5 kD) and 33–30.5 kD proteins also decreased in the sensitive genotype. The intensity of short wavelength peaks at 687 and 695 nm sharply increased in the fluorescence spectra (77 K) of chloroplasts from Giymatli-2/17 under water deficiency and there was a stimulation of the ratio of fluorescence band intensity F687/F740. After exposure to drought, cv Giymatli-2/17 showed a larger reduction in the actual PS II photochemical efficiency of chloroplasts than cv. Azamatli-95. Activities of catalase, ascorbate peroxidase, superoxide dismutase and glutathione reductase, as well as photochemical activity of photosystem I and photosystem II were studied in leaves of durum and bread wheat genotypes in ontogenesis. It was found out that dynamics of catalase and ascorbate peroxidase functioning in well-watered plants through ontogenesis practically did not change both among durum and among bread wheat cultivars. Functioning of these enzymes during ontogenesis under water deficit differed. Catalase activity increased in all stressed genotypes: in durum wheat cultivars maximal activity was observed in the milk ripeness and in bread wheat cultivars at the end of flowering. Ascorbate peroxidase activity also increased under water deficit: in tolerant wheat genotypes maximal activity occurred at the end of flowering, and in the sensitive ones at the end of ear formation. The maximum activity of glutathione reductase both as in the control, as well as in drought-subjected plants was observed in the anthesis stage. Superoxide dismutase activity was lower than the control during ontogenesis, except in the last stages. It should be noted that PS I and PS II photochemical activities were also high in genotypes subjected to drought both at the end of ear formation and flowering stages. Drought resistance was checked by RAPD-PCR as a quick and easy method for durum (Triticum durum L.) and bread (Triticum aestivum L.) wheat genotypes contrasting in tolerance. P6 primer (5′ TCGGCGGTTC 3′) produced 920 bp band mainly in drought tolerant genotypes. It was found that P7 (5′ TCGGCGGTTC 3′) primer produced 750 bp band was not absolutely universal for Triticum L. genotypes. In order to identify DREB1 genes in these genotypes PCR-analysis was carried out using functional markers specific for A, B, and D genomes. It was found that DREB 1 gene was located on chromosome 3A in all genotypes, excepting one semi-tolerant genotype Tale-38. In comparison with other genotypes, a 717 bp PCR product of DREB -B1 gene was located on B genome in drought-tolerant Barakatli-95. The results reported here provide an entry point and a reference to future analysis of gene expression during drought. In addition, these results can suggest possible targets for the enhancement of stress tolerance in crops by genetic engineering. The data presented here might be used for monitoring environmental stresses in field-grown plants and selecting stress-resistant varieties for growth under unfavorable conditions.

Chlorophyll fluorescence induction kinetics of cyanobacteria is known to reflect various cellular metabolisms. A simple mathematical method was developed to quantify the kinetic similarity of the chlorophyll fluorescence, and applied to cyanobacterial mutants involved in the regulation of photosystem stoichiometry. We showed that simple sum of the squared deviation between two fluorescence kinetics could be used as a measure of similarity. Appropriate weighting function enabled us to characterize the kinetics further. When the mutant having similar fluorescence kinetics to that of a certain photosystem stoichiometry mutant was listed according to the similarity distance, other photosystem stoichiometry mutants ranked high in the list. Apparently, the mutants with similar fluorescence induction kinetics share the common phenotype among them, thus opening the way to reveal the function of genes by chlorophyll fluorescence induction kinetics.

Plants were grown in field conditions in the wide area under normal water supply and severe water deficit. Two wheat (Triticum aestivum L.) genotypes contrasting by architectonics and differing in drought-resistance were used: Giymatli-2/17, short stature, with broad and drooping leaves, drought-sensitive, and Azamatli-95, short stature, with vertically oriented small leaves, drought-tolerant). It was found out that Giymatli-2/17 was characterized by relatively low content of Chl a-protein of PS I (CP I) and beta-subunit of ATP-synthase complex, the high content of proteins in the 33-30.5 kDa region and LHC polypeptides (28-24.5 kDa), the intensive fluorescence at 740 nm and more high photochemical activity of PS II under normal irrigation compared with Azamatli-95. However, the content of CP I (M(r) 115 kDa) and apoprotein of P700 with M(r) 63 kDa insignificantly increases in the drought-resistant genotype Azamatli-95 under extreme water supply condition while their content decreases in drought-sensitive cv Giymatli-2/17. Intensity of synthesis alpha- and beta-subunits of CF(1) (55 and 53.5 kDa) also decreases in Giymatli-2/17. The levels of the core antenna polypeptides of FS II with M(r) 46 and 44.5 kDa (CP47 and CP43) remains stable both in normal, and stressful conditions. At the same time the significant reduction is observed in the content of polypeptides in the 33-30.5 kDa region in the more sensitive genotype Giymatli-2/17. There is an increase in the LHC II polypeptides level in tolerant genotype Azamatli-95 in contrast to Giymatli-2/17 (where the content of these subunits is observed decreasing). The intensity of short wavelength peaks at 687 and 695 nm sharply increases in the fluorescence spectra (77 K) of chloroplasts from sensitive genotype Giymatli-2/17 under water deficiency and there is a stimulation of the ratio of fluorescence band intensity F687/F740. After exposure to drought, cv Giymatli-2/17 shows a larger reduction in the actual PS II photochemical efficiency of chloroplasts than cv Azamatli-95.

Two durum (Triticum durum L.), Barakatli-95 and Garagylchyg-2; and two bread (Triticum aestivum L.) wheat cultivars, Azamatli-95 and Giymatli-2/17 with different sensitivities to drought were grown in the field on a wide area under normal irrigation and severe water deficit. Drought caused a more pronounced inhibition in photosynthetic parameters in the more sensitive cvs Garagylchyg-2 and Giymatli-2/17 compared with the tolerant cvs Barakatli-95 and Azamatli-95. Upon dehydration, a decline in total chlorophyll and relative water content was evident in all cultivars, especially in later periods of ontogenesis. Potential quantum yield of PS II (Fv/Fm ratio) in cv Azamatli-95 was maximal during stalk emergency stage at the beginning of drought. This parameter increased in cv Garagylchyg-2, while in tolerant cultivar Barakatli-95 significant changes were not observed. Contrary to other wheat genotypes in Giymatli-2/17 drought caused a decrease in PS II quantum yield. Drought-tolerant cultivars showed a significant increase in CAT activity as compared to control plants. In durum wheat cultivars maximal activity of CAT was observed at the milk ripeness and in bread wheat cultivars at the end of flowering. APX activity also increased in drought-treated leaves: in tolerant wheat genotypes maximal activity occurred at the end of flowering, in sensitive ones at the end of ear formation. GR activity increased in the tolerant cultivars under drought stress at all stages of ontogenesis. SOD activity significantly decreased in sensitive cultivars and remained at the control level or increased in resistant ones. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.