Irada M. Huseynova

Photosynthetic characteristics and enzymatic antioxidant capacity of leaves from wheat cultivars exposed to drought.

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 (F(v)/F(m) 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.

Genome diversity and evidence of recombination and reassortment in nanoviruses from Europe

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.

International Conference on “Photosynthesis Research for Sustainability-2011”, July 24–30, 2011, Baku, Azerbaijan

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 conference on “Photosynthesis research for sustainability-2013: in honor of Jalal A. Aliyev”, held during June 5–9, 2013, Baku, Azerbaijan

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/.

Important genetic diversity of ‘Candidatus Phytoplasma solani’ related strains associated with bois noir grapevine yellows and planthoppers in Azerbaijan

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.

Hydrogen peroxide generation and antioxidant enzyme activities in the leaves and roots of wheat cultivars subjected to long-term soil drought stress

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.

Phylogeography and population genetics of the riparian relict tree Pterocarya fraxinifolia (Juglandaceae) in the South Caucasus

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 11 different haplotypes. Significant isolation by distance was detected in Hyrcan. The most recent common ancestor of all P. fraxinifolia haplotypes was dated to a time well before a suggested glaciation period in the Caucasus during the late Pliocene (5.98 Ma [11.3–2.48 Ma HPD]). The widespread Colchic haplotype that also occurs along the southern slope of the Greater Caucasus and reaches south-eastern Azerbaijan has appeared more recently (0.24 Ma [1.41–0 Ma HPD]). This diversification pattern of Colchic haplotypes from ancient Hyrcanian haplotypes suggests a colonization of the region from south-east to north-west that predates the last glacial maximum (LGM). Natural populations of P. fraxinifolia show low-to-intermediate levels of genetic diversity and a significant decrease of diversity from Hyrcan to Colchis. However, the genetic differentiation between Colchic-Caucasian and Hyrcanian populations for nuclear markers suggests that independent gene pools existed in both areas at least since the LGM. Particular attention to conservation seems justified for the more diverse Hyrcanian populations.

Virus-induced changes in photosynthetic parameters and peroxidase isoenzyme contents in tomato (Solanum lycopersicum L.) plants

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.

Antioxidant Defence System and Chloroplasts Photochemical Characteristics of Wheat Genotypes Subjected to Water Stress

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.

Biochemical and Molecular Aspects of Drought Tolerance in Wheat Triticum L. Genotypes

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.