Authors:Songwei Wu; Siqi Wei; Chengxiao Hu; Qiling Tan; Tianwu Huang; Xuecheng Sun Abstract: Abstract The fact that molybdenum (Mo) applications can alleviate low temperature stress (LTS) in plants has been widely reported, but the underlying mechanisms are not fully understood. The effects of Mo (0 and 0.15 mg kg−1) on photosynthetic pigments, fatty acids and the chlorophyll–protein complex of wheat seedlings in pot culture were investigated at 0, 2, 4 and 6 days of LTS. Chlorophyll a and b, total chlorophyll and carotenoid contents were significantly enhanced by Mo application. The palmitic acid (C16:0) content and total saturated fatty acids (TSFA) were drastically decreased in wheat cultivar 97003 at 2 and 4 days of LTS and in wheat cultivar 97014 at 2 days of LTS. The linolenic acid (C18:3) content and total unsaturated fatty acids (TUSFA) were significantly increased in both cultivars at 2 and 4 days of LTS. The palmitoleic acid (C16:1) content was also drastically increased in cultivar 97003 at 2 days of LTS, suggesting that Mo induced a greater production of unsaturated fatty acids or the conversion of TSFA to TUSFA. The ratio of unsaturated to saturated fatty acids and the index of unsaturated fatty acids in the thylakoid membranes were enhanced with supplemental Mo, suggesting that Mo might improve the degree of unsaturation. However, no significant differences were observed in the chlorophyll–protein complexes between the +Mo and −Mo treatments. These results indicated that the alteration of fatty acids induced by Mo application in the thylakoid membranes of wheat contributed to LTS tolerance. PubDate: 2017-09-18 DOI: 10.1007/s11738-017-2534-2 Issue No:Vol. 39, No. 10 (2017)
Authors:Leonardo Faria-Silva; Camilla Zanotti Gallon; Eduardo Purgatto; Diolina Moura Silva Abstract: Abstract Several experiments have highlighted the complexity of stress interactions, in field conditions, involved in plant response. However, these impacts on the mechanisms involved in plant photosynthetic response remains understudied. The aim of this work was to compare the photosynthetic efficiencies and fruit quality of mango tree (Mangifera indica L.) cv. Ubá harvested from plants cultivated on the east and west sides of a commercial orchard, according to the position of plants in relation to sunrise. Chlorophyll a fluorescence, was analyzed in leaves in four different periods: fruit growth phase, fruit ripening phase, post-harvest period and after plant pruning. Photoinhibitory damage was detected by the trapped energy flux and transported electron flux per reaction center during the fruit ripening phase, and by specific energy fluxes and yield quantum efficiency after plant pruning. Although high radiation caused photoinhibition on leaves from plants cultivated on the west side of the orchard, it provided sweeter fruits. In contrast to our initial hypothesis, it was verified that plants cultivated on the west side of the orchard presented better photochemical performance in periods with the greatest requirements of photoassimilates. In addition, plants demonstrated different abilities to deal with changes on photosynthetic active radiation and high temperature. This information suggests that the phenotypic plasticity of the Ubá mango cultivar is considerable, which can be exploited to be used in regions with great relief variations and the combination of increased irradiance and high temperature. PubDate: 2017-09-18 DOI: 10.1007/s11738-017-2533-3 Issue No:Vol. 39, No. 10 (2017)
Authors:Maria Luce Bartucca; Silvia Celletti; Tanja Mimmo; Stefano Cesco; Stefania Astolfi; Daniele Del Buono Abstract: Abstract Many chemicals, including herbicides, are routinely applied to crops for weed management and food production improvement. However, the intensive use of herbicides could lead eventually to a great environmental threat due to their persistence and accumulation in the ecosystems and contamination of soils. Furthermore, the possible effect of these chemicals on nutrient uptake and assimilation in crops has only recently been discussed. The present study aimed at understanding the effect of the herbicide terbuthylazine (TBA), a herbicide commonly applied to control weeds in leguminous species and triazine tolerant crops, on the capability of maize plants to cope with iron (Fe) shortage. The application of 2 and 5 mg L−1 TBA caused a significant reduction of root Fe concentration. This reduction might be attributed to a decreased release of phytosiderophores, which in turn could be ascribed to a reduced sulfur assimilation. Results provide evidence that TBA impairs Fe uptake and accumulation in non-target plants most likely interacting with sulfur-assimilating enzymes [ATP sulfurylase and O-acetylserine(thiol)lyase]. PubDate: 2017-09-16 DOI: 10.1007/s11738-017-2537-z Issue No:Vol. 39, No. 10 (2017)
Authors:Maria Stolarz; Halina Dziubińska Abstract: Abstract Action potentials (APs) in plants are involved in fast leaf or trap closure as well as elongation, respiration, photosynthesis, and fertilization regulation. Here, spontaneous APs (SAPs) in relation to endogenous stem movement named circumnutation (CN) have been investigated in Helianthus annuus in different light conditions in freely circumnutating and immobilized plants. Extracellular electrical measurements and time-lapse photography were carried out simultaneously. The parameters of CN (trajectory length, period, and direction) and the number and transmission direction of SAPs were analysed. In continuous light (25–40 μmol m−2 s−1), all plants circumnutating vigorously in a regular elliptical manner and no SAPs were observed. In light/dark conditions, the plants circumnutated in a daily pattern, most SAPs were observed in the dark and freely circumnutated sunflowers had two times more SAPs (10 SAPs/24 h/plant) than the immobilized plants (5 SAPs/24 h/plant). In continuous very low light (5 μmol m−2 s−1), the plants circumnutated weakly and irregularly and SAPs appeared without the circadian pattern. 3–5 SAPs/24/plant occurred in the freely circumnutating and immobilized plants. In light/dark and continuous very low light conditions, an ultradian rhythm of SAPs was observed and the mean spacing between SAPs was approx. 121–271 min in the freely circumnutating and immobilized plants. Under all light conditions, more SAPs were transmitted basipetally than acropetally. One-hour lasting series of 3–4 min spaced SAPs locally propagated were observed as well in very low light. Basipetal and acropetal SAPs passing along the stem motor region accompany irregularity, changes in the CN trajectory direction, and stem torsion. These results demonstrate that APs and CN changes play a role in plant adaptation to light conditions and that there is an ultradian rhythm of SAPs beside ultradian CN rhythm. PubDate: 2017-09-16 DOI: 10.1007/s11738-017-2528-0 Issue No:Vol. 39, No. 10 (2017)
Authors:Sebastian Gasparis; Yuliya Yanushevska; Anna Nadolska-Orczyk Abstract: Abstract As an essential regulatory component in plants, microRNAs (miRNAs) have been intensively studied over the past decade. Although hundreds of miRNAs have been identified and analyzed in many important crops and model plants, very little is known about the function of common wheat (Triticum aestivum L.) miRNAs. In this study, we performed computational prediction of novel wheat miRNAs based on BLAST searches of the expressed sequence tag database. The expression profiles of all miRNAs were performed for both vegetative and reproductive tissues to identify developmentally regulated miRNAs. A total of 19 new miRNAs belonging to 12 MIR families were identified using stringent criteria for miRNA annotation. For all of the miRNAs, the secondary structures of their precursor sequences were predicted. Two pairs of distinct miRNAs were found to be located on the same precursor. The predicted miRNAs were experimentally verified by a stem-loop qRT-PCR-based assay. The expression profiles were performed in both vegetative and reproductive tissues to find the potential correlations between the developmental phase and miRNA activity. Thirteen out of 19 miRNAs were upregulated at certain phases of plant development, and three of them (miR319, miR395, and miR171) showed the greatest expression in young spikes during microsporogenesis. Our results provide useful information for future studies of miRNA-mediated regulation of flower and grain development in wheat. PubDate: 2017-09-16 DOI: 10.1007/s11738-017-2530-6 Issue No:Vol. 39, No. 10 (2017)
Authors:Zhilan Ye; Jianbin Zeng; Xing Li; Fanrong Zeng; Guoping Zhang Abstract: Abstract Plants adopt several strategies for fighting against low potassium (LK) stress. Our previous study identified some Tibetan wild barley accessions which show the higher LK tolerance than cultivated barley. However, the physiological mechanisms underlying the wild barley are not well understood. In this study, growth performance, elements content, SPAD value, photosynthetic parameters, and ATPase activities were measured to investigate the effect of LK stress on the two wild barley genotypes (XZ153 and XZ141) and one barley cultivar (ZD9) differing in LK tolerance. The results revealed that LK stress inhibited barley growth and induced reduction in dry weight, with XZ153 being least inhibited. Moreover, XZ153 had less reduction in photosynthetic rate, SPAD value, and K concentrations in the younger leaves under LK stress compared to the other two genotypes. Although the activities of H+/K+-ATPase and Ca2+/Mg2+-ATPase were increased significantly in all three genotypes in response to LK, the highest H+/K+-ATPase activity was observed in XZ153. The current results indicate that higher LK tolerance of XZ153 is partly attributed to its high capacity of transferring K from the old leaves to younger ones. PubDate: 2017-09-15 DOI: 10.1007/s11738-017-2516-4 Issue No:Vol. 39, No. 10 (2017)
Authors:Jasper B. Alpuerto; Ananya Mukherjee; Ai Kitazumi; Andrei Alyokhin; David De Koeyer; Benildo G. de los Reyes Abstract: Abstract While the functions of vacuolar processing enzymes (VPE) in plant responses to pathogens are now better established, their possible roles against insect herbivores need validation. Inspired by an observation that βVPE and δVPE represent the most highly upregulated transcripts in leaves of Solanum bulbocastanum and its backcross progenies that were highly resistant to the phloem-feeding green peach aphids (Myzus persicae), we used a reverse genetic approach in Arabidopsis to investigate whether T-DNA insertion mutants for specific βVPE and δVPE loci would exhibit compromised defenses at the whole-plant, physiological, and molecular levels. We hypothesized that impaired expression of VPE genes would lead to hyper-susceptibility if VPE-mediated processes were essential for basal defenses, given that Arabidopsis is naturally susceptible. Compared to the wild-type, βvpe and δvpe mutants exhibited an early onset of leaf curling and necrosis, rapid aphid population build-up, and significant physiological tissue injuries as a result of herbivory. This indicates that basal defenses were compromised by the loss-of-functions of either VPE-encoding gene. VPE co-expression networks were comprised of genes involved in sucrose metabolism and transport (AtSUC5, AtSUS3, and invertases), efflux and oxidative detoxification proteins, and modulators of gene-for-gene-type disease response linked to sucrose metabolism (AtSWEET13 and AtSWEET15). These results suggest that VPEs play a role in basal defenses by mediating mechanisms of detoxification and metabolite availability in host tissues to counteract the rapid depletion caused by the phloem sucker. These processes might be important as first line of defense to delay the progression of perturbations caused by herbivory. PubDate: 2017-09-15 DOI: 10.1007/s11738-017-2529-z Issue No:Vol. 39, No. 10 (2017)
Authors:Zohreh Emami Bistgani; Seyed Ataollah Siadat; Abdolmehdi Bakhshandeh; Abdollah Ghasemi Pirbalouti; Masoud Hashemi Abstract: Abstract Thymus daenensis Celak. is an aromatic herb used as a popular medicine and its natural products in the form of extracts and essential oil have significant economic values in Iran. We hypothesized that spraying plants grown under deficit irrigation system with chitosan can be considered as an applicable method to enhance essential oil and antioxidant activity in thyme. Response of thyme to three irrigation regimes including well-watered, moderate stress, and severe stress along with three levels of chitosan application rates 0, 200, and 400 μL L−1 was evaluated in a 2-year study in 2014 and 2015. Drought stress condition significantly shortened phenologic stages, more specifically in the first (establishment) year. All growth parameters were reduced dramatically as drought stress intensified. Imposing even moderate stress reduced leaf area as much as 59 and 44% in the first year and the second year, respectively. Biomass yield of plants grown under severe drought stress decreased substantially, whereas essential oil content and the share of thymol in thyme oil which possesses the greatest degree of biological activity improved. Maximum oil yield (1.50 g plant−1) was obtained from plants under mild drought stress when sprayed with 400 μL L−1 chitosan in the second year when plants were well-established. Foliar applications of chitosan reduced the adverse effect of water deficit on oil yield and improved thymol content of the essential oil. Chitosan also increased secondary metabolites including α-terpinene, p-cymene, γ-terpinene, thymol, carvacrol and β-caryophyllene. Leaf flavonoid reduced under deficit irrigation while more phenol was found in plants grown under deficit irrigation. The essential oil of thyme exhibited antioxidant property when the plants were sprayed with 400 μL L−1 chitosan. The results of this study indicated that thyme can be grown successfully under moderate stress and that application of chitosan elicitor can to some degree compensate the negative impact of deficit irrigation on its biomass and essential oil yield. PubDate: 2017-09-15 DOI: 10.1007/s11738-017-2526-2 Issue No:Vol. 39, No. 10 (2017)
Authors:Daniela Soares dos Santos; Poliana Cardoso-Gustavson; Catarina Carvalho Nievola Abstract: Abstract Acanthostachys strobilacea Link, Klotzsch, & Otto is an ornamental bromeliad native to Brazilian Atlantic Forest that naturally exhibits a rosette growth pattern. According to the temperature conditions of the in vitro culture, this species can exhibit stem elongation, facilitating the isolation of the nodal segments to be applied in its micropropagation. The rosette morphology is reestablished when this species is maintained under low temperature, thus allowing the maintenance of a germplasm collection (slow growth storage). Gibberellins (GA) are usually applied to stimulate stem elongation in micropropagated plants. Thus, our aim here was to verify the influence of temperature over the stem elongation of A. strobilacea when GA3 is applied to the medium, thus estimating the use of this phytoregulator in slow growth cultures at low temperatures. Physiological and anatomical studies were performed on plants obtained from nodal segments maintained at 10, 15, 20, and 25 °C. Regardless of the applied treatment, no segments developed at 10 °C. Stem elongation occurred at 25 and 30 °C, and was not seen for plants grown under 15 and 20 °C. The application of 50 µM of GA3 restored stem elongation in plants at 20 but not at 15 °C. The influence of gibberellins on stem elongation of this tropical bromeliad depends on the cultivation temperature, in which low temperature preponderates over the stem elongation effects of GA3. In addition, the optimum temperature for the slow growth of this species depends on the starting temperature of the explant used in the micropropagation. PubDate: 2017-09-14 DOI: 10.1007/s11738-017-2536-0 Issue No:Vol. 39, No. 10 (2017)
Authors:Cristian Silvestri; Silvia Celletti; Valerio Cristofori; Stefania Astolfi; Bruno Ruggiero; Eddo Rugini Abstract: Abstract Olive is one of the most important tree crops in the Mediterranean region, because of its ability to grow and produce acceptable yields under limited water availability. In this study, the drought tolerance of an olive cultivar Canino was compared to the performance of its derived transgenic line expressing osmotin gene from tobacco, obtained by Agrobacterium-mediated transformation of Canino cultivar. Shoot cultures of both wild-type (wt) and transgenic lines were exposed to drought stress over a 28-day period, and their differential responses to in vitro-drought stress were investigated. After exposure to PEG, most of the shoots from wt plants resulted in damage and exhibited decreased levels of chlorophyll, while those of transgenic line did not show injuries and showed a normal growth even when exposed to the highest PEG concentration (4%). After preliminary evaluation we characterized Canino AT17-1, by measuring several physiological parameters, including the activities of the antioxidant enzymes (POD and CAT), and the content of malondialdehyde (MDA). Both the activity of catalase and the proline content were higher in the leaves of the transgenic shoots compared to wt plants. Consequently, it was observed that the transgenic line accumulated less MDA indicating that the presence of the osmotin gene protected the cell membrane from damage by lipid peroxidation. Together, these results could suggest that the transgenic line Canino AT17-1 was more efficient in the activation of defense responses against oxidative stress with respect to the Canino wt. The further finding that the transgenic shoots also showed higher proline accumulation supported the hypothesis that the osmotin gene conferred to transgenic shoots increased tolerance to drought stress compared with the wt. PubDate: 2017-09-13 DOI: 10.1007/s11738-017-2535-1 Issue No:Vol. 39, No. 10 (2017)
Authors:Geetika Sirhindi; Harpreet Kaur; Renu Bhardwaj; Poonam Sharma; Ruquia Mushtaq Abstract: Abstract Exploration of scavenging potential of 28-homobrassinolide (28-homoBL) in mitigating the oxidative stress caused by free radicals (·O2 −, H2O2, ·NO, OH−) produced due to temperature stress (4, 44 °C) in Brassica juncea L. was made in the present research. Brassica juncea var. RLC-1 seeds were given pre-sowing soaking of different concentrations of 10−9 M 28-homoBL for 8 h. Seeds were sown in bedded petri plates lined with 10 No. What’s man filter paper under controlled laboratory conditions. Temperature of 4 and 44 °C, taken as low- and high-temperature stress, suppressed membrane stability and overall growth of the seedlings, while cell death was triggered. Accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), and nitric oxide (NO) was boosted which resulted in enhanced oxidative stress on the 10th day after sowing. Activity level of antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPOX), and ascorbate peroxidase (APOX) was enhanced which was ensued for up-regulation of total antioxidant potential in 10-day-old plants exposed to negative effect of temperature stress. Priming treatment of 28-homoBL at seed level helped in maintaining the growth of seedlings to higher level as compared to only stressed as well as from control double distilled water-raised seedlings. 10−9 M 28-HBL found to be the best in enhancing the enzymatic activities of SOD, CAT, GPOX, and APOX and thus maintained antioxidant potential at higher level which accounted for alleviating oxidative stress caused due to extreme temperature stress. Dead cell formation reduced significantly in 28-homoBL-treated plants, membrane stability was upturned, while production of MDA, H2O2, and NO was under control. These results suggested and try to establish 28-homoBL as effective stress protector for B. juncea particularly from the oxidative damage induced by extreme temperatures. PubDate: 2017-09-12 DOI: 10.1007/s11738-017-2524-4 Issue No:Vol. 39, No. 10 (2017)
Authors:Adel Kadri; Bernadette Julier; Meriem Laouar; Cécile Ben; Mounawer Badri; Jugurta Chedded; Brahim Mouhouche; Laurent Gentzbittel; Aïssa Abdelguerfi Abstract: Abstract Fitness traits that determine the reproductive ability of individuals and the persistence of populations are affected by drought stress. Medicago truncatula that commonly encounters drought stress in its natural area, and for which large natural diversity and genetic tools are available, is a suitable species to investigate genetic determinism of fitness traits under stress. In a common garden, three successive cycles of short drought stress were applied after flowering, during the reproductive stage that is the most susceptible to drought for that species. Ten genotypes derived from natural populations and a mapping population were used to investigate the genetic determinism of vegetative and reproductive traits as components of fitness. A large genetic variation was observed and transgressive genotypes (more resistant or more susceptible than the parental genotypes) were found in the mapping population. Fitness traits were reduced by 5–74% in drought condition compared to well-watered condition. The most affected characters were total pod number per plant and total pod weight per plant. A total of 49 QTL, explaining between 6 and 38% of phenotypic variation for vegetative and reproductive fitness traits, were detected on all chromosomes except chromosome 6. A major QTL for flowering date (R 2 of 19 and 38%) that co-located with QTL for reproductive fitness traits were found on chromosome 7. In this study, no major QTL specific to drought-stressed or well-watered conditions were detected. We, thus, showed that QTL explaining fitness traits were numerous with small effects, in accordance with the genetic determinism of a complex trait. PubDate: 2017-09-12 DOI: 10.1007/s11738-017-2527-1 Issue No:Vol. 39, No. 10 (2017)
Authors:Xiao-Long Jiang; Xuan-Chun Piao; Ri Gao; Mei-Yu Jin; Jun Jiang; Xiang-Hua Jin; Mei-Lan Lian Abstract: Abstract Efficiently culturing adventitious roots (ARs) has become an alternative route for the protection and utilization of endangered plant resources. In the present study, to improve accumulation of bioactive compounds (polysaccharides, phenolics, and flavonoids) in AR cultures of endangered plant species—Oplopanax elatus—effects of methyl jasmonate (MeJA) and salicylic acid (SA) were investigated. The optimal concentration of MeJA was 200 μM and SA was 100 μM for enhancement of polysaccharide, phenolic, and flavonoid contents. In addition, MeJA (200 μM) was more suitable than SA (100 μM) for polysaccharide and flavonoid production, but both elicitors were equally favorable for phenolic production. During AR bioreactor culture, MeJA was as an elicitor to study the effect of its addition time and contact time. Contents of polysaccharides, phenolics, and flavonoids increased when MeJA was added to culture medium after 40 days of culture, but the increased degree was lower and the AR biomass significantly inhibited. However, when MeJA was added to culture medium after 30 days of culture, polysaccharide, phenolic, and flavonoid contents dramatically increased without AR biomass decrease; the maximum productivity of three bioactive compounds was found on day 8 after the MeJA treatment. Therefore, a novel elicitation method during bioreactor culture of O. elatus ARs was established in the present study, the method could be applied to commercial production of O. elatus products in the future. PubDate: 2017-09-09 DOI: 10.1007/s11738-017-2525-3 Issue No:Vol. 39, No. 10 (2017)
Authors:Andrea Luvisi; Alessandra Panattoni; Alberto Materazzi; Domenico Rizzo; Luigi De Bellis; Alessio Aprile; Erika Sabella; Enrico Rinaldelli Abstract: Abstract Early trans-plasma membrane behavior after in vivo mechanical inoculation of Nicotiana tabacum with Tobacco mosaic virus (TMV) was investigated and compared to virus quantification in leaf tissues. To identify early events related to virus/host interaction, the systemic virus TMV was used to infect lower leaves and tests were carried out on upper leaves which were not directly infected. Non-invasive microelectrodes were used to estimate trans-plasma membrane electron transport and membrane potential after artificial inoculum of virus, monitoring the plant for the following 15 days. Virus infection was assessed by ELISA and quantified by quantitative RT-PCR. Collected data showed that after 2-day post-inoculation (dpi), TMV was able to modify membrane parameters: transient hyperpolarization of trans-membrane potential was observed until 10 dpi, while redox activity in infected samples was higher compared to control until end of tests. Conversely, ELISA diagnostic test was not able to reveal the virus presence in tobacco leaves until 6 dpi, while leaf symptoms were manifested after 13 dpi. PubDate: 2017-09-09 DOI: 10.1007/s11738-017-2523-5 Issue No:Vol. 39, No. 10 (2017)
Authors:Zhongcheng Zhou; Muxian Han; Mei Hou; Xiaojing Deng; Rui Tian; Shuifa Min; Jinbo Zhang Abstract: Abstract Juglans regia ‘Yuanfeng’ is an elite walnut cultivar in China. Juglans cathayensis, a close relative species of Juglans regia originated from China, possesses some superior traits such as strong disease resistance and high fruit number per branch. So far, transcriptomes of either J. regia or J. cathayensis have not been studied and made available to public yet. In the present study, the transcriptomes of J. regia and J. cathayensis leaves were profiled using Illumina HiSeq 2000 platform. A total of 41,914 unigenes were obtained from the combined clean reads of J. regia and J. cathayensis with an average length of 1363 bp and 2529 differentially expressed genes (DEGs) were detected. Gene annotation analyses revealed that 38,483 unigenes (91.81%) were annotated in at least one of the five databases such as Gene Ontology (GO), etc. Meanwhile, the Ca, Mg, Fe, Zn, K and protein contents in the leaves of J. regia and J. cathayensis were compared and significant differences between J. regia and J. cathayensis in terms of the Ca, Mg, Fe and protein contents were discovered. In addition, DEGs associated with the Ca, Mg and Fe content variations between J. regia and J. cathayensis were investigated. Our comparative transcriptomes’ analysis between J. regia and J. cathayensis could provide a useful resource for genetic characterization and improvements of J. regia. PubDate: 2017-09-08 DOI: 10.1007/s11738-017-2504-8 Issue No:Vol. 39, No. 10 (2017)
Authors:Hui Cao; Xiaolin Ni; Caiyun Zhang; Wenshuo Shi; Yuxing Xu; Yueming Yan; Feixiong Zhang Abstract: Abstract Wortmannin is an efficient inhibitor of phosphatidylinositol 3-kinases that is involved in normal plant growth. In this study, we performed the global proteomic analysis of the effects of wortmannin on wheat primary roots during seed germination. Wortmannin significantly inhibited the growth of wheat primary roots in a macroscopic level, and damaged the fine structure of nucleoli and mitochondria in a microscopic level. In total, 75 differentially accumulated protein (DAP) spots representing 66 unique DAPs were identified by linear two-dimensional electrophoresis and tandem mass spectrometry. These DAPs were mainly related to detoxification and defense response, carbon metabolism, and amino acid metabolism. Principal component analysis indicated that wortmannin significantly induced the proteomic changes between the treatment and control groups. Protein–protein interaction analysis revealed a complex network centralized by the 14-3-3 protein which was significantly upregulated in both transcriptional and translational levels. Furthermore, some key DAPs, such as heat shock-related proteins, glyceraldehyde-3-phosphate dehydrogenase, isocitrate dehydrogenase, 5-methyltetrahydropteroyltriglutamate–homocysteine methyltransferase, and elongation factor, also showed significantly upregulated accumulation, indicating their key roles in cell homeostasis maintenance, energy supply, and protein biosynthesis. Results obtained from this study provided a new insight into the molecular mechanism of wheat primary root in response to wortmannin during seed germination. PubDate: 2017-09-08 DOI: 10.1007/s11738-017-2511-9 Issue No:Vol. 39, No. 10 (2017)
Authors:Jiasong Meng; Yao Jiang; Jun Tao Abstract: Abstract As a new α-linolenic acid (ALA) resource, there has been little known about the relationship between expression levels of fatty acid desaturase (FAD) genes during seed development and fatty acid (FA) composition in herbaceous peony (Paeonia lactiflora Pall.). In this study, oil content and FA composition of nine cultivars were measured at four different stages during seed development. Moreover, five genes including PlFAD2-1, PlFAD2-2, PlFAD3-2, PlFAD6 and PlFAD7 related to the ALA biosynthesis were isolated. Furthermore, the relative expression levels of these genes in seeds were investigated in two cultivars, that is, ‘PL1’ and ‘PL2’ with higher and lower ALA content, respectively. The results showed that oil content was from 17.03 ± 0.15 to 24.51 ± 0.15%; 15 kinds of FA were detected. However, the relative content of ALA was decreased during seed development. Although, the genes PlFAD2-1, PlFAD2-2, PlFAD3-2, PlFAD6 and PlFAD7 were all expressed during the seed development, the expression levels varied significantly. Most of the genes were expressed strongly in the early stage but weakly in the late stage except PlFAD6. Moreover, expression level of gene PlFAD2-2 was the highest while that of PlFAD7 was lowest at S1. In addition, the relative expression level of genes in ‘PL1’ (high ALA content) was higher than those in ‘PL2’ (low ALA content) during the early stage of the seed development apart from gene PlFAD6. This study provides a reliable theoretical basis for improving the contents of ALA by means of genetic engineering in the herbaceous peony seed oil. PubDate: 2017-09-07 DOI: 10.1007/s11738-017-2506-6 Issue No:Vol. 39, No. 10 (2017)
Authors:Harsimran Kaur; Rachana D. Bhardwaj; Satvir K. Grewal Abstract: Abstract In the present investigation, influence of exogenous phenolic acids on antioxidative defense system of salt stressed wheat seedlings was explored at the seventh day of growth. Electrical conductivity of 10 dS/m was used for imposing salt stress in two wheat cultivars showing contrasting behavior for salt tolerance. For observing stress mitigating effects of various phenolic acids, 20 ppm of ferulic, 10 ppm of caffeic, 10 ppm of p-coumaric, 5 ppm of salicylic, and 15 ppm of sinapic acids were selected for biochemical studies. Imposition of salinity stress reduced membrane stability as depicted by electrolyte leakage and reduction was more in sensitive cultivar HD2329 which was well correlated with its higher ROS accumulation in terms of H2O2 content and lipid peroxidation as MDA content. Exogenous application of phenolic acids reduced electrolyte leakage in NaCl-stressed seedlings of both the cultivars and maximum decrease was observed in the presence of sinapic acid, followed by caffeic, salicylic, ferulic, and p-coumaric acids. When phenolic acids were applied to salt stressed wheat seedlings, malondialdehyde content either decreased or remained unaffected in the shoots of both the cultivars, whereas hydrogen peroxide (H2O2) decreased in the roots and shoots of both cultivars maximally by caffeic and salicylic acids. Hydroxyl radical scavenging capacity of salt stressed seedlings increased to the maximum extent by the use of caffeic and sinapic acids. Catalase (CAT) and peroxidase activities were upregulated in the stressed shoots of salt-tolerant cultivar by the exogenous use of caffeic and sinapic acids. In comparison to stress, ascorbate peroxidase (APX) activity was also upregulated in stressed seedlings of both cultivars by exogenous use of caffeic and sinapic acids. In stressed seedlings of salt-sensitive cultivar, monodehydroascorbate reductase activity increased by exogenous use of caffeic, p-coumaric, salicylic, and sinapic acids. In roots of Kharchia local, use of ferulic, p-coumaric, and caffeic acids resulted into upregulation of glutathione reductase activity, whereas in salt-sensitive cultivar, only caffeic acid caused upregulation of this enzyme. Proline (Pro) content increased in HD2329 on addition of different exogenous phenolic acids in the medium, whereas in Kharchia local, addition of sinapic acid enhanced pro content. Glycine betaine (GB) content was increased by use of different phenolic acids in the stressed roots of Kharchia local. On the other hand, exogenous application of sinapic acid led to enhanced GB content in salt-sensitive cultivar. Based upon the fine regulation of CAT and APX activities and hydroxyl radical scavenging activity in relation to H2O2 content and electrolyte leakage, caffeic and sinapic acids may be regarded as the most efficient among the different phenolic acids in averting ROS-accrued oxidative damage in salt stressed wheat seedlings. PubDate: 2017-09-06 DOI: 10.1007/s11738-017-2521-7 Issue No:Vol. 39, No. 10 (2017)
Authors:Elsa Martineau; Jean-Christophe Domec; Alexandre Bosc; Masako Dannoura; Yves Gibon; Camille Bénard; Lionel Jordan-Meille Abstract: Abstract Climate changes are mainly characterized by an increase in air temperature and a decrease in rainfalls. Potassium (K) nutrition is generally considered to alleviate plants tolerance to water deficit, especially by improving photosynthesis and phloem transport of carbohydrates from leaves to roots. The main objective of this study was to measure the effect of K on sugar transport and allocation under water-stressed conditions on maize (Zea mays L.). Maize plants were grown in pots under different water and K treatments. We used 13CO2 pulse-labelling to determine carbon exportation from leaves with δ13C analysis, within 1 week. The diurnal sugar content in leaves was measured, and net carbon assimilation accessed. Water deficit strongly reduced plant growth, while K nutrition appeared to be efficient in attenuating these effects. K deficiency significantly decreased starch content in leaves under well-watered but not under water-stressed treatment. A leaf carbon mass balance showed that K increased sugar export on a daily time scale, while instantaneous δ13C measurements did not show any significant effect, partly because of the very rapid δ13C decline after labelling. Our home-made labelling chamber proved to be successful in monitoring diurnal changes in δ13C for a C4 plant with high photosynthetic rates and fast carbon export, and also in determining the effect of a K deficiency on sugar export. Our results highlight a need for research into carbon export on leaves of different ages in fast-growing crops under the combined effect of water and nutrient stress. PubDate: 2017-09-06 DOI: 10.1007/s11738-017-2515-5 Issue No:Vol. 39, No. 10 (2017)
Authors:S. N. Saxena; R. K. Kakani; L. K. Sharma; D. Agarwal; S. John; Y. Sharma Abstract: Abstract Fenugreek (Trigonella foenum-graecum L.) is a seed spice grown during winter season in North India mostly on conserve moisture of monsoon rains. An experiment was conducted to investigate the effect of moisture stress on seed yield, total oil, fatty acid composition, phenolic content, and antioxidant activity of 13 fenugreek genotypes with an objective to identify suitable genotypes for water-limiting conditions and judicious application of available irrigation water. Moisture stress was created by withholding irrigation in one set of genotypes at flowering and post-flowering stage. Moisture stress at post-flowering stage adversely affected seed yield of all genotypes. Genotype AFg-6 showed at par seed yield (7.7 g/plant) with non-stress (control) (7.5 g/plant), while genotype AM-327-3 produced more yield when moisture stress was given at flowering stage. Oil content under non-stress environment ranged from a minimum of 2.62% in genotype AFg-6 to a maximum of 5.31 in AM-327-3 which increased up to 3.15 and 5.42% when moisture stress was created at post-flowering stage. GC–MS profiling of seed oil revealed significant genotypic variation in fatty acid composition. Total phenolic, flavonoid, sapogenin, diosgenin content, and antioxidant capacity of methanol crude seed extract increased during moisture stress. Genotypes AFg-4, AFg-6, Hisar Sonali, and RMt-305 have been identified for limited water conditions. Results of analysis suggested that a significant genotypic variation in fatty acid composition of fenugreek genotypes may utilize in developing new cultivars and to introduce fenugreek seed oil for end-uses either sole use or blended with other vegetable oil. PubDate: 2017-09-06 DOI: 10.1007/s11738-017-2522-6 Issue No:Vol. 39, No. 10 (2017)
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