Authors:Reham M. Nada; Gaber M. Abogadallah Abstract: We tested the hypothesis that high root/shoot (R/S) in rice improves plant growth and yield when the shoot sink is expandable, and that in a genotype with exaggerated R/S ratio, the shoot growth is not limited by root resources. This study involved the three rice genotypes, Giza 178, PM12, and Moroberekan with a range of R/S ratios and shoot sink sizes. Root regrowth after trimming or high- and low-nitrogen treatments revealed that Moroberekan has consistently high root-favoured biomass partitioning than Giza 178 or PM12. Increasing the R/S ratios by detillering improved the culm growth in Giza 178 and PM12 (by 43.4 and 17.7% of control, respectively) but not Moroberekan, indicating that PM12 was closer to achieving its growth potential than Giza 178 but Moroberekan was operating at maximal shoot growth potential because of high R/S ratio and small sink size. Under drought, shoot growth, gas exchange, and grain yield correlated strongly with R/S ratio and root length density (RLD) in the droughted but not the well-watered plants. We further hypothesized that R/S ratio of Moroberekan was in excess of shoot requirement for optimum growth. Crossing Moroberekan to PM12 generated three F1 hybrids with intermediate R/S ratios but higher growth, gas exchange, and yield than either parent. We conclude that increasing the R/S ratio improved growth and yield in PM12 but not Moroberekan, because the shoot sink size was expandable in PM12. Moreover, lower R/S ratios than that of Moroberekan could support higher shoot growth if shoot sink is expandable. PubDate: 2018-05-31 DOI: 10.1007/s11738-018-2697-5 Issue No:Vol. 40, No. 6 (2018)
Authors:Aytunç Yildizli; Sertan Çevik; Serpil Ünyayar Abstract: Drought-stressed plants accumulate cyclitols such as myo-inositol, pinitol, quercitol in the cytosol. These solutes (compatible solutes) protect plants from stress effects. Synthetic myo-inositol was used in the investigation of drought stress tolerance in pepper plants. Hydrogen peroxide (H2O2), membrane damage, ascorbate peroxidase (AP), catalase (CAT), proline and calcium increased in plants under drought conditions. Water status, calcium level, glutathione reductase activities increased in myo-inositol treated Capsicum annuum L. (pepper) under drought stress. Exogenous myo-inositol significantly decreased H2O2, membrane damage and proline levels and AP (except for 5 µM) and CAT activity, compared with untreated plants. Myo-inositol can play a role as effective as proline in signal transduction and in regulating concentrations of reactive oxygen species within tolerable ranges and in maintaining cell turgor by binding water molecules. Myo-inositol may become a useful instrument to eliminate the negative effects of drought environments. PubDate: 2018-05-29 DOI: 10.1007/s11738-018-2690-z Issue No:Vol. 40, No. 6 (2018)
Authors:Salima Benazzouk; Zahr-Eddine Djazouli; Stanley Lutts Abstract: To determine the effects of vermicompost leachate (VCL) on resistance to salt stress in plants, young tomato seedlings (Solanum lycopersicum, cv. Ailsa Craig) were exposed to salinity (150 mM NaCl addition to nutrient solution) for 7 days after or during 6 mL L− 1 VCL application. Salt stress significantly decreased leaf fresh and dry weights, reduced leaf water content, significantly increased root and leaf Na+ concentrations, and decreased K+ concentrations. Salt stress decreased stomatal conductance (gs), net photosynthesis (A), instantaneous transpiration (E), maximal efficiency of PSII photochemistry in the dark-adapted state (Fv/Fm), photochemical quenching (qP), and actual PSII photochemical efficiency (ΦPSII). VCL applied during salt stress increased leaf fresh weight and gs, but did not reduce leaf osmotic potential, despite increased proline content in salt-treated plants. VCL reduced Na+ concentrations in leaves (by 21.4%), but increased them in roots (by 16.9%). VCL pre-treatment followed by salt stress was more efficient than VCL concomitant to salt stress, since VCL pre-treatment provided the greatest osmotic adjustment recorded, with maintenance of net photosynthesis and K+/Na+ ratios following salt stress. VCL pre-treatment also led to the highest proline content in leaves (50 µmol g− 1 FW) and the highest sugar content in roots (9.2 µmol g− 1 FW). Fluorescence-related parameters confirmed that VCL pre-treatment of salt-stressed plants showed higher PSII stability and efficiency compared to plants under concomitant VCL and salt stress. Therefore, VCL represents an efficient protective agent for improvement of salt-stress resistance in tomato. PubDate: 2018-05-26 DOI: 10.1007/s11738-018-2696-6 Issue No:Vol. 40, No. 6 (2018)
Authors:Jesús R. Torres-García; J. Antonio Tafoya-Razo; Sabina Velázquez-Márquez; Axel Tiessen Abstract: Plant herbicides inhibit specific enzymes of biosynthetic metabolism, such as acetyl-coenzyme A carboxylase (ACCase) and acetolactate synthase (ALS). Herbicide resistance can be caused by point mutations at the binding domains, catalytic sites and other regions within multimeric enzymes. Direct-injection electrospray mass spectrometry was used for high-throughput metabolic fingerprinting for finding significant differences among biotypes in response to herbicide application. A Mexican biotype of wild oat (Avena fatua) that displays multiple resistances to ACCase- and ALS-inhibiting herbicides was characterized. The dose–response test showed that the double-resistant biotype had a resistance index of 3.58 for pinoxaden and 3.53 for mesosulfuron-methyl. Resistance was accompanied by characteristic mutations at the site of action: an I-1781-L substitution occurred in the ACCase enzyme and an S-653-N mutation was identified within the ALS enzyme. Other mutations were also detected in the genes of the Mexican biotypes. The ionomic fingerprint showed that the multiple-resistant biotype had a markedly different metabolic pattern under control conditions and that this difference was accentuated after herbicide treatment. This demonstrates that single changes of amino acid sequences can produce several holistic modifications in the metabolism of resistant plants compared to susceptible plants. We conclude that in addition to genetic resistance, additional mechanisms of metabolic adaptation and detoxification can occur in multiple-resistant weed plants. PubDate: 2018-05-25 DOI: 10.1007/s11738-018-2691-y Issue No:Vol. 40, No. 6 (2018)
Authors:Servet Aras; Şeyma Arıkan; Muzaffer İpek; Ahmet Eşitken; Lütfi Pırlak; Mesude Figen Dönmez; Metin Turan Abstract: Iron chlorosis in the calcareous soils is one most important stress factors worldwide that limits photosynthesis and decreases fruit yield and quality. Certain soil rhizobacteria produce organic compounds such as plant acids and they may reduce the soil rhizosphere pH and affect ferric chelate reductase (FC-R) activity in root. However, there is no knowledge regarding changes in organic acids content and FC-R activities of leaf due to rhizobacterial root inoculation. Therefore, the efficiency of six plant growth promoting rhizobacteria (PGPR) were tested on apple cv. Braeburn on M9 and MM106 rootstocks. The results of the experiment showed leaf organic acid contents, iron quantity of soil, root and leaf and root and leaf FC-R activity were significantly affected via rhizobacteria applications in apple plants. In MM106 and M9, there was a remarkable increase in Fe in M3 inoculated soil by 95 and 89%, respectively, compared to control. Average increases in citric, malic, malonic, butyric and lactic acid in the leaf were obtained from rhizobacterial root inoculations of 25.1, 21.8, 29.6, 18.0 and 18.2% in Braeburn/MM106, respectively. In Braeburn/M9, MFDCa1 application increased all organic acid concentrations compared to the control. MFDCa2 treatment caused the maximum leaf FC-R activity in Braeburn on M9 and MM106 (60.9 and 50.3 nmol Fe+2 g−1 FW h−1, respectively) while the least values were determined in the control (33.5 and 29.9 nmol Fe+2 g−1 FW h−1, respectively). This study showed the bacterial strains tested in our study may be used as a biofertilizer instead of Fe fertilizers. PubDate: 2018-05-25 DOI: 10.1007/s11738-018-2693-9 Issue No:Vol. 40, No. 6 (2018)
Authors:Melissa Arguedas; Daviel Gómez; Lázaro Hernández; Florent Engelmann; Raffaele Garramone; Inaudis Cejas; Lourdes Yabor; Marcos Edel Martínez-Montero; José Carlos Lorenzo Abstract: We recorded the crypreservation effects (direct immersion) on various parameters of early germination stages of maize seeds (0, 7 and 14 days). Percentages of germination; fresh mass of different seedling parts; levels of chlorophyll pigments (a, b); carotenoids; malondialdehyde; other aldehydes; phenolics (cell wall-linked, free) and proteins were determined. Various statistically significant effects of seed exposure to liquid nitrogen (LN) were recorded. Maize seeds did not seem to be affected by LN exposure either visually or regarding fresh weight or germination rate. However, delayed growth was observed in seedlings recovered from cryopreserved seeds. This trend indicated an increase in the effect of seed cryopreservation on growing plants. The most significant effects of LN exposure were recorded in the combined fresh weight of stems and leaves at day 7 of germination and in fresh weights of roots, stems and leaves at day 14. At the biochemical level, numerous indicators varied following LN exposure, but the most significant effects were recorded in carotenoids, malondialdehyde and other aldehyde contents. LN exposure modified 50.0% of indicators in cotyledons, 48.1% in stems and leaves, 38.8% in roots and 11.1% in seeds. LN storage modified 11.1% of the variables measured at day 0 of germination, 37.0% at day 7, and 52.7% at day 14. Field performance of cryostored seed-derived plants should be evaluated to measure the durability of the changes observed. PubDate: 2018-05-24 DOI: 10.1007/s11738-018-2695-7 Issue No:Vol. 40, No. 6 (2018)
Authors:Mona Safari; Zahra Oraghi Ardebili; Alireza Iranbakhsh Abstract: Taking account of heat shock factor A4A (HSFA4A) as a hydrogen peroxide sensor, anti-apoptosis agent, and crosslink component with critical signaling cascades, the current study was carried out to monitor possible changes in expression of this gene as well as some other important characteristics in wheat plants exposed to selenium nano-particle (nSe). Wheat seedlings were treated with nSe (0, 5, 10, and 50 mgl−1). In germinating stage, plant fresh weights were reduced in nSe-treated seedlings, among which the nSe of 50 provoked roots turned brown. The nSe triggered the increases in the expressions of HSFA4A, in the plate. In the pot condition, shoot fresh weights in nSe-supplemented seedlings were decreased by approximately 22%. The nSe of 5 and 10 mgl−1, respectively induced the expression of HSFA4A by 3.4- and 9.15-folds, contrasted with nSe50. Increasing times of sprays caused the dramatic reductions of the expression of HSFA4A in the nSe-supplemented groups. Moreover, the treatment of nSe stimulated expression of high molecular weight glutenin subunit 1Bx (Glu-1Bx) by fourfold, over the control. While the dramatic decrease in the expression of Glu-1Bx was recorded with increasing times of spray. Nitrate reductase activities were significantly improved by approximately 47% in nSe-fortified seedlings. Also, the foliar supplementation of nSe of 5 mgl−1 provoked the significant inductions in peroxidase activity by 8%, whereas two other nSe treatments declined it. It may be stated that the nSe may modify the expression of HSFA4A, thereby triggering specific signaling and altering metabolism. PubDate: 2018-05-23 DOI: 10.1007/s11738-018-2694-8 Issue No:Vol. 40, No. 6 (2018)
Authors:Naouraz M’barki; Hechmi Chehab; Feten Aissaoui; Olfa Dabbaghi; Faouzi Attia; Zoubeir Mahjoub; Salwa Laamari; Badreddine Chihaoui; Tommaso del Giudice; Abdelmajid Jemai; Dalenda Boujnah; Beligh Mechri Abstract: Abiotic stresses present a real environmental problem in agriculture field. In our paper, we examine the significance of arbuscular mycorrhizal fungi (AMF) and soil amendment with water retaining superpolymers (hydrogel) on growth and physiology performance of olive plantlets. Our experiment was carried out in nursery conditions, to test the impact of hydrogel (TH) and mycorrhizal fungi (TM), used individually or combined (THM), and compare them with non inoculated plants (TC), to understand and reduce the water stress damage in olive plantlets (cv. Chemlali). We also evaluate interactions between hydrogel, mycorrhizal treatments and water regimes. Results of mycorrhization (M%) show that roots colonized by Rhizophagus irregularis of well-watered plants were about 40.87%. In combined treatment (THM), M% was about 32.14%. Compared to TC treatment, TM treatment enhances significantly the dry weights of the whole plant under the two water regimes. The TM treatment had the highest relative water content (66.50%) and Chl (a + b) (0.83 mg g− 1) in stressed conditions. We found also that under water stress, the maximal quantum efficiency of the photosystem II measurements in leaves were significantly improved by 50.70% in TH treatment compared to control. For phenolic contents, TH treatment decreased significantly total phenols by 50.10% compared to TC. Our study gives evidence that the use of AMF and the hydrogel separately or in combination may enhance the capacity to avoid drought damages of olive plantlets and improve olive performances. PubDate: 2018-05-22 DOI: 10.1007/s11738-018-2692-x Issue No:Vol. 40, No. 6 (2018)
Authors:Mingxi Liu; Xin Song; Yiwei Jiang Abstract: Growth, ionic responses, and expression of candidate genes to salinity stress were examined in two perennial ryegrass accessions differing in salinity tolerance. The salinity tolerant (PI265349) and sensitive accessions (PI231595) were subjected to 75-mM NaCl for 14 days in a growth chamber. Across two accessions, salinity stress increased shoot dry weight and concentrations of malondialdehyde (MDA) and Na+ in the shoots and roots, but decreased shoot Ca2+ and root K+ concentrations. Salinity stress also increased root expressions of SOS1, PIP1, and TIP1. Plant height and chlorophyll content were unaffected by salinity stress in the tolerant accession but significantly decreased in the sensitive accession. Shoot MDA content did not change in the tolerant accession but increased in the sensitive accession. A more dramatic increase in Na+ was found in the roots of the sensitive accession. Relative to the control, salinity stress reduced expression of SOS1, NHX1, PIP1, and TIP1 in the shoots but increased expression of these genes in the roots of the tolerant accession. Expression levels of SOS1 increased in the roots and expression of NHX1 increased in the shoots but decreased in the roots of the sensitive accession under salinity stress. A decline in PIP1 expression in the shoots and dramatic increases in TIP expression in both shoots and roots were found in the sensitive accession under salinity stress. The results suggested maintenance of plant growth and leaf chlorophyll content, lesser Na+ accumulation in the roots, and lower lipid peroxidation in the shoots which could be associated with salinity tolerance. The decreased expressions of SOS1, NHX1, and TIP1 in the shoots, and increased expressions of NHX1 and PIP1 in the roots might also be related to salinity tolerance in perennial ryegrass. PubDate: 2018-05-21 DOI: 10.1007/s11738-018-2687-7 Issue No:Vol. 40, No. 6 (2018)
Authors:Xiang Jiao; Huichun Zhang; Jiaqiang Zheng; Yue Yin; Guosu Wang; Ying Chen; Jun Yu; Yufeng Ge Abstract: As a model organism, modeling and analysis of the phenotype of Arabidopsis thaliana (A. thaliana) leaves for a given genotype can help us better understand leaf growth regulation. A. thaliana leaves growth trajectories are to be nonlinear and the leaves contribute most to the above-ground biomass. Therefore, analysis of their change regulation and development of nonlinear growth models can better understand the phenotypic characteristics of leaves (e.g., leaf size) at different growth stages. In this study, every individual leaf size of A. thaliana rosette leaves was measured during their whole life cycle using non-destructive imaging measurement. And three growth models (Gompertz model, logistic model and Von Bertalanffy model) were analyzed to quantify the rosette leaves growth process of A. thaliana. Both graphical (plots of standardized residuals) and numerical measures (AIC, R2 and RMSE) were used to evaluate the fitted models. The results showed that the logistic model fitted better in describing the growth of A. thaliana leaves compared to Gompertz model and Von Bertalanffy model, as it gave higher R2 and lower AIC and RMSE for the leaves of A. thaliana at different growth stages (i.e., early leaf, mid-term leaf and late leaf). PubDate: 2018-05-21 DOI: 10.1007/s11738-018-2686-8 Issue No:Vol. 40, No. 6 (2018)
Authors:Abdul Latif Khan; Ahmed Al-Harrasi; Raheem Shahzad; Qari Muhammad Imran; Byung-Wook Yun; Yoon-Ha Kim; Sang-Mo Kang; Ahmed Al-Rawahi; In-Jung Lee Abstract: Boswellia sacra is an economically and ecologically important frankincense-producing tree, which is wounded to extract the aromatic resin. However, the underlying physiological mechanisms following this wounding stress are unknown. Our current goal was to elucidate the regulation of key physio-molecular determinants of wounded and preserved B. sacra populations. Wounding caused a twofold increase in calcium/magnesium content and a reduction in essential macronutrient (nitrogen) levels. Total amino acids were also reduced 1.74-fold; however, the levels of γ-amino butyric acid, hydroxyl-proline, and β-alanine were significantly higher (1- to 2.2-fold). In contrast, the fatty acids (linolenic, palmitic, stearic, and linoleic acids) were significantly higher in the preserved trees. Endogenous jasmonic acid (JA) was also significantly higher (67%) in the wounded trees, as was the expression of the JA-related genes allene oxide synthase and allene oxide cyclase. A similar twofold increase in stress-responsive abscisic acid was observed in the wounded trees. However, salicylic acid was down-regulated, and the pathogenesis-related genes PR1 and PR3 exhibited varying responses in the wounded plants. The presence of physiologically active (GA1, GA4, and GA3) and inactive (GA12, GA19, and GA20) gibberellins in both the wounded and control trees revealed similarity with the known GA biosynthesis in B. sacra. Both GA4 and GA3 were each significantly synthesized, which were buoyed by the increased expressions of ent-copalyl diphosphate synthase, cytochrome P450 monooxygenases, and gibberellin 20 oxidases under wounding stress. In conclusion, B. sacra responds to extraction of resin by regulating essential endogenous hormones and related transcripts, which in return retard tree growth and development. PubDate: 2018-05-21 DOI: 10.1007/s11738-018-2688-6 Issue No:Vol. 40, No. 6 (2018)
Authors:Ira Vashisht; Tarun Pal; Ankush Bansal; Rajinder Singh Chauhan Abstract: Picroside-I (P-I) is an iridoid glycoside of Picrorhiza kurroa, a perennial medicinal herb native to North-Western Himalayas, used in the preparation of herbal drug formulations. Natural habitat shoots (PKSS) produce significantly higher P-I content as compared to in vitro shoots (PKS-15 and PKS-25). Although temperature and culture conditions are known to play a major role in influencing P-I biosynthesis in different shoots of P. kurroa, the molecular mechanisms behind signal perception of variable environments are completely unknown. Kinases have been considered as key signaling proteins which control cellular processes involved in adaptability under diverse environments, thereby affecting downstream primary and secondary metabolic pathways. The current study investigated the association of kinases with P-I production and shoot biomass in P. kurroa. Transcriptome mining and in silico transcript abundance in three shoot tissues revealed differentially expressed kinases under high and low P-I accumulating conditions. A total of 521, 473 and 346 transcripts encoding kinases were identified in PKS-25, PKS-15 and PKSS tissues, respectively. Gene expression analysis of 43 selected genes in differential P-I content shoot tissues and genotypes revealed key processes regulated by kinases which might be associated with P-I biosynthesis. Expression of 16 kinases genes involved in plant–pathogen interactions, abiotic stress, wounding, hormonal response and carbohydrate metabolism was observed to be up-regulated in high P-I accumulating conditions, indicating their possible role in eliciting P-I biosynthesis in P. kurroa. Analysis of kinases along with genes involved in controlling shoot biomass productivity revealed that auxin response plays a major role in affecting biomass productivity in in vitro shoots of P. kurroa. This study provides a basic understanding of physiological processes affected under variable environmental conditions leading to differential biosynthesis of P-I in P. kurroa. PubDate: 2018-05-21 DOI: 10.1007/s11738-018-2689-5 Issue No:Vol. 40, No. 6 (2018)
Authors:Andressa C. S. Nakagawa; Haruka Itoyama; Yuri Ariyoshi; Nobuyuki Ario; Yuki Tomita; Yukari Kondo; Mari Iwaya-Inoue; Yushi Ishibashi Abstract: Soybean seeds have high lipid and protein contents. Adverse environmental conditions restrict seed yield and quality. We examined the changes in storage compounds caused by drought stress from R5 stage (beginning seed growth stage). Under drought stress, contents of lipid in seed were remarkably low compared to control at 24 and 29 days after treatment. Protein contents in seed were immediately decreased after water deficit treatment. On the other hand, soluble sugar contents in seed were increased by drought stress. Drought stress decreased the expression of genes involved in lipid biosynthesis (PK, BCCP2, and KAS1) and increased the genes expression involved in lipid degradation (ACX2, MS, and PEPCK). These results suggest that the increasing of sugar content in seed under drought stress was complemented by degradation of lipids. The expressions of genes encoding storage protein (Gy4 and β-conglycinin) were also decreased by drought stress. This study showed how drought stress during seed filling affects seed quality, especially lipid and protein contents, that may facilitate further research on seed storage compounds metabolism under environmental stresses. PubDate: 2018-05-15 DOI: 10.1007/s11738-018-2683-y Issue No:Vol. 40, No. 6 (2018)
Authors:Ali Noman; Qasim Ali; Jazia Naseem; M. Tariq Javed; Hina Kanwal; Waqar Islam; Muhammad Aqeel; Noreen Khalid; Sara Zafar; Muhammad Tayyeb; Naeem Iqbal; Mahmooda Buriro; Junaid Maqsood; Samreena Shahid Abstract: The present study investigated the role of sugar beet extract (SBE) as a bio-stimulant to ameliorate the adverse effects of drought on seed germination and growth of wheat (Triticum aestivum L.). Different concentrations of SBE (0, 10, 20, 30, 40 and 50%) were used for priming the wheat seeds. The experiment was conducted in laboratory (PEG-8000 was used to create water stress) as well as under natural environmental conditions (using soil with 100 and 60% field capacity). Significant ameliorating effects of seed priming with SBE were recorded on different germination attributes, i.e., time to 50% emergence (E50), germination index (GI), mean emergence time (MET), germination percentage (G%), coefficient of uniformity of emergence (CUE) and germination energy (GE) under water stress. Without priming, the plants exhibited symptoms of water stress like decreased biomass, reduction in photosynthetic pigments, e.g., chlorophyll, carotenoids. Seed pre-conditioning with SBE improved the plant growth, photosynthetic pigments, antioxidants’ activities and nutrient homeostasis of plants facing water deficit and grown under well-watered conditions. The maximum increase in biomass, content of chlorophyll, carotenoids and activities of superoxide dismutase (SOD) and peroxidase (POD) was 13.4, 8.5, 11.9, 7.6, 13.6, 42.0, 19.8%, respectively, with SBE seed priming under water stress. In conclusion, SBE seed priming effectively reduced the negativities of water stress on seed germination which resulted in better plant growth in terms of enhanced biomass, photosynthetic pigments, antioxidant defense mechanism and better nutrient homeostasis. Overall, the findings suggest that seed pre-conditioning with SBE as a bio-stimulant will be helpful for better crop stand establishment under low field capacity, especially in semi-arid and arid agricultural fields. PubDate: 2018-05-15 DOI: 10.1007/s11738-018-2681-0 Issue No:Vol. 40, No. 6 (2018)
Authors:Yi Mei; Jun Guo; Ning Ding; Yun-Fen Liu; Xiao-Jun Su; Yan-Xia Zu; Yong-Cheng Wu; Jia-Qiu Zheng; Wei-Wei Wang Abstract: Radish is a common crop and vulnerable to high temperature. Pretreatment with spermidine could effectively elevate the resistance of radish to high temperature. Up to date, the underlying mechanisms remain unknown. In the present study, radish seedlings were pretreated with spermidine and then exposed to high temperature. The leaves were collected for transcriptome sequencing and the results were compared with samples only exposed to high temperature and samples consistently cultured at normal temperature. The differentially expressed genes were identified and validated using real-time quantitative PCR. Finally, the results revealed that pretreatment with spermidine significantly up-regulated the transcription level of anti-oxidation enzymes, heat-shock proteins, and proteins involved in the photosynthetic process, in comparison with treatments with high temperature and room temperature, suggesting that pretreatment with spermidine increased heat tolerance in radish probably through minimizing the harms caused by peroxidation, accelerating the corrections or degradation of misfolded proteins, and promoting photosynthesis. These findings preliminarily uncovered the molecular mechanisms underlying the spermidine-promoted heat resistance in radish. PubDate: 2018-05-12 DOI: 10.1007/s11738-018-2679-7 Issue No:Vol. 40, No. 6 (2018)
Authors:Jian-jie Gao; Yu-ru Sun; Bo Zhu; Ri-He Peng; Bo Wang; Li-Juan Wang; Zhen-Jun Li; Lei Chen; Quan-Hong Yao Abstract: d-Sorbitol-6-phosphate 2-dehydrogenase (S6PDH, E.C. 1.1.1.140) catalyzes the NADH-dependent conversion of d-fructose 6-phosphate (F6P) to d-sorbitol 6-phosphate (S6P). In this work, recombination and characterization of Haloarcula marismortui d-sorbitol-6-phosphate 2-dehydrogenase are reported. Haloarcula marismortui d-sorbitol-6-phosphate 2-dehydrogenase was expressed in P. pastoris and Arabidopsis thaliana. Enzyme assay indicated that HmS6PDH catalyzes the reduction of d-fructose 6-phosphate to d-sorbitol 6-phosphate and HmS6PDH activity was enhanced by NaCl. Furthermore, transgenic A. thaliana ectopic expressing HmS6PDH accumulate more sorbitol under salt stress. These results suggest that the ectopic expression of HmS6PDH in plants can facilitate future studies regarding the engineering and breeding of salt-tolerant crops. PubDate: 2018-05-11 DOI: 10.1007/s11738-018-2668-x Issue No:Vol. 40, No. 6 (2018)
Authors:Lídia da Silva Pereira; Viviane Veiga do Nascimento; Suzanna de Fátima Ferreira Ribeiro; Rosana Rodrigues; Katia Valevski Sales Fernandes; André de Oliveira Carvalho; Ilka Maria Vasconcelos; Cíntia dos Santos Bento; Cláudia Pombo Sudré; Umberto Zottich; Valdirene Moreira Gomes Abstract: This study aimed to detect and characterize antimicrobial proteins, especially antimicrobial peptides (AMPs) from leaves and roots of Capsicum annuum and to evaluate their inhibitory activities against different phytopathogenic fungi and the bacterium Xanthomonas euvesicatoria. Two methodologies were used for the extraction of peptides from leaves and roots of C. annuum: acid and ethanolic extraction. Extracts were subjected to reversed-phase chromatography on HPLC. The extraction and purification procedures were analysed by uni- and bi-dimensional electrophoresis in tricine gels. Our results show that alcoholic and acid extracts from both tissues can inhibit the growth of the phytopathogenics fungi C. lindemuthianum and C. gloeosporioides. The acid extracts from both tissues are active against X. euvesicatoria and only leaf extracts displayed specific inhibitory activity towards trypsin and α-amylase activity. The data compiled here aim to contribute to establish the multiplicity of potential uses of plant AMPs for the control of pests and pathogens of agricultural relevance. PubDate: 2018-05-11 DOI: 10.1007/s11738-018-2685-9 Issue No:Vol. 40, No. 6 (2018)
Authors:Ornusa Khamsuk; Weerasin Sonjaroon; Srisom Suwanwong; Kanapol Jutamanee; Apichart Suksamrarn Abstract: Drought is major stress that severely reduces plant growth and productivity. To improve drought tolerance, an exogenous brassinosteroids (BRs) has been used effectively in the field condition. However, the application of BRs is expensive due to the scarcity of natural BRs and the multistep synthesis of BRs. In an attempt to reduce the cost, 7,8-dihydro-8α-20-hydroxyecdysone (DHECD) has been proposed to function as an imitation of 24-epibrassinolide (EBR). In this study, chili pepper plants (Capsicum annuum L. var. frutescens (L.) Kuntze) were sprayed with DHECD, EBR at 1 µM or distilled water (control). Plants were subjected to severe water stress (25% pot water capacity) for 5 days and their physiological effects and yield were investigated. The result showed that the applications of DHECD and EBR before the beginning of water stress could improve leaf water status determined by relative water content in plants grown under drought condition. The electrolyte leakage, lipid peroxidation level, and H2O2 production were significantly declined, while the accumulations of proline and total soluble sugar were increased in the treated plants. Moreover, the net photosynthesis (PN) was elevated due to the increases of stomatal conductance (gs) and intercellular CO2 concentration (Ci) after BR pretreatments under drought. In addition, applications of DHECD and EBR maintained all chlorophyll fluorescence parameters; Fv/Fm, Fv′/Fm′, ΦPSII, qP, and ETR, to remain the photosynthesis. As a result, shoot biomass, fruit yield and capsaicin level were considerably enhanced in the treated plants. DHECD showed better performance to maintain membrane integrity; however, EBR had more effect on the osmotic maintenance. The result also showed that pretreatment with BRs had little or no effect on well-watered plants. The study concluded that DHECD and EBR alleviated the impact of drought on physiological responses and consequently minimized yield loss. PubDate: 2018-05-11 DOI: 10.1007/s11738-018-2682-z Issue No:Vol. 40, No. 6 (2018)
Authors:Hanafey F. Maswada; M. Djanaguiraman; P. V. V. Prasad Abstract: Experiment was conducted to identify the impacts of the salinity acclimation process on the photosynthetic efficiency, osmotic adjustment, membrane integrity, and yield components in two wheat cultivars differing in their salinity tolerance. The design of the experiment was factorial randomized block, where genotype is factor 1 and acclimation treatments represent factor 2. Genotypes were grown from emergence to 30 days after sowing (DAS) by irrigating with tap water [electrical conductivity (EC) of 0.776 dS m−1]. Thereafter, both the genotypes were divided into two groups and exposed to either irrigation with sublethal level of salinity EC of 2.09 or 3.76 dS m−1 for 21 days. At booting stage (65 DAS), both groups were subjected to lethal level of salinity stress EC of 12 dS m−1 for 21 days, followed by irrigation with tap water till maturity. Non-acclimated plants were irrigated with tap water from emergence to 65 days, then directly irrigated with lethal level of salinity for 21 days, followed by irrigation with tap water till maturity. The control plants were continuously irrigated with tap water from emergence until maturity. The non-acclimated plants had decreased electron transport rates at the donor and acceptor side of PSII and PSI in Giza 168, and decreased electron transport rates at PSII acceptor side in Sakha 8 compared to control plants. In both genotypes, the non-acclimated plants had decreased chlorophyll a, b, carotenoid, proline and total soluble sugar concentration, relative water content, membrane stability index, yield and yield components compared with acclimated plants. While, osmotic potential and lipid peroxidation showed an opposite trend. Overall, acclimation treatment (EC of 2.09 dS m−1) during vegetative stage alleviated the inhibitory effects of lethal level of salinity stress at booting stage through enhanced photosynthetic efficiency and osmotic adjustment, resulting in increased membrane integrity, biomass production and grain yield than in non-acclimated plants. PubDate: 2018-05-09 DOI: 10.1007/s11738-018-2684-x Issue No:Vol. 40, No. 6 (2018)
Authors:Wei She; Guoxian Cui; Xueling Li; Xiaohui Su; Yucheng Jie; Ruifang Yang Abstract: Zn and Fe are essential nutritional elements in plants and play important roles in various physiological processes of plants. Zn and Fe are chemically similar to cadmium (Cd); therefore, Zn and Fe may mediate Cd-induced physiological or metabolic changes in plants. In order to evaluate the interaction between Cd, Zn and Fe, we conducted a hydroponics experiment to determine the plant biomass, photosynthetic characteristics, and Cd accumulation of ten ramie cultivars under Zn/Fe-sufficient or Zn/Fe-deficient conditions in the presence of 32 µM CdCl2. Ramie varied among cultivars in morpho-physiological response to Cd stress as well as Cd accumulation, translocation and distribution. Zn and Fe deficiency increased the concentration and amount of Cd in plant organs, but decreased TFstem to leaf and TFroot to stem. Cultivars with more Cd in roots and shoots showed smaller increase in Cd accumulation under Zn and Fe-deficiency stress. Xiangzhu 7 and Duobeiti 1 showed a higher capacity of Cd accumulation in their shoots. Zn and Fe deficiency decreased Pn, but increased Ci, Gs, and E in most cultivars. The difference in Cd translocation among ramie cultivars was mainly ascribed to the difference in plant transpiration. PubDate: 2018-05-08 DOI: 10.1007/s11738-018-2670-3 Issue No:Vol. 40, No. 6 (2018)
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