Pinero, Maria CarmenOtalora, GinesCollado-Gonzalez, JacintaLopez-Marin, Josefa...
8页
查看更多>>摘要：Se has beneficial effects on plants， through the stimulation of plant productivity， the reduction of abiotic stresses， and the improvement in N metabolism。 Therefore， we investigated the effect of the foliar application of different concentrations of Se (0， 4， 8 and 16 mu mol L-1) on lettuce plants grown in an aquaponics system (fish water) compared with a control (conventional soilless fertigation)。 The NO3- concentration supplied by the fish water was 47% of the control solution。 The results showed a reduction in the fresh weight of lettuce plants irrigated with the fish water mixture treatment， along with an increase in sugar concentration。 However， the application of Se at 4 and 16 mu mol L-1， prompted a relief of this stress， reducing both lipid peroxidation and the sugar content， and increasing the nitrate concentration。 In addition， in the case of the highest concentration of Se (16 mu mol L-1)， the values of nitrate were comparable those control plants。 We show the importance of sprayed Se in increasing the efficiency of N utilization， in addition to lessening environmental issues for aquaponics culture。
查看更多>>摘要：The regulation of gamma-aminobutyric acid (GABA) on plant anti-oxygenation and programmed cell death (PCD) in fresh-cut pumpkins was investigated。 Exogenous GABA positively promoted GABA accumulation and alleviated oxidant damage in pumpkins tissue。 Pumpkins treated with GABA showed lower electrolyte leakage， reactive oxygen species (ROS) and MDA content， while higher activities of superoxide dismutase (SOD)， catalase (CAT)， peroxidase (POD)， and ascorbate peroxidase (APX) as compared to the non-treated tissues。 Our results also found that GABA treatment retarded DNA degradation and cytochrome c release and delayed the apoptosis of pumpkin cells。 On the other hand， the inhibitor of GABA generation， 3-mercaptopropionic acid (3-MP) treatment not only accelerated oxidant damage， but also induced cell death involving chromatin condensation， DNA ladder and cytochrome c releasing。 Taken together， our present research indicated that exogenous GABA could alleviate the wound-induced oxidative stress and PCD occurrence in fresh-cut pumpkins。
Pirzadah, Tanveer BilalHakeem, Khalid RehmanAlharby, Hesham F.
10页
查看更多>>摘要：Calcium (Ca) being macronutrient plays a prominent role in signal transduction during various abiotic stresses。 However， their involvements to alleviate heavy metal stress in plants remain evasive。 In the present investigation， we found that application of exogenous Ca to Cd-stressed common buckwheat plants reversed the toxic effects of Cd by enhancing root and shoot length， biomass accumulation and reduced Cd-uptake as revealed by the translocation factor (< 1)， indicating more Cd is restrained in the roots。 Moreover， present data also revealed that exogenous Ca significantly alleviated the Cd-induced oxidative damage by enhancing proline by 66。12% and 47。20% respectively in roots and shoots than control。 The decline in the total chlorophyll content upon Ca application in Cd-treated plants was found less (38。96%) compared to buckwheat plants treated with Cd-stress alone (80。2%)。 APX and POD activities increased by 1。97 and 1。44 times in shoots， respectively， and increased by 2。81and 1。33 times in roots， respectively compared to the Cd-treated plants alone。 The mineral content (Ca， K， Mg， Fe， P and S) that were suppressed in Cd-treated plants in both root and shoot were restored upon exogenous Ca application。 Further， the correlation analysis showed significant positive correlation among proline and GSH synthesis in the Ca + Cd treatment。 The correlations of Ca revealed to be positive with enhanced levels of APX and POD activity。 Our data showed that exogenous application of Ca minimizes the Cd-toxicity and modulates the physiological and biochemical pathway in common buckwheat to withstand Cd-induced oxidative stress。
查看更多>>摘要：Leaf senescence occurs as the last developmental phase of leaf。 The initiation and progression of leaf senescence is highly regulated by a plethora of internal developmental signals and environmental stimuli。 Being an important class of phytohormones， jasmonates (JAs) are shown to induce premature leaf senescence in tomato (Solanum lycopersicum)， nevertheless， the underlying mechanisms remain enigmatic。 Here， we report that tomato MYC2， a key factor in the JA signal transduction， functions in JA-induced tomato leaf senescence by promoting chlorophyll degradation and inhibiting photosynthetic carbon fixation。 We found that exogenous application of MeJA reduced chlorophyll content， decreased carbon assimilation rates and disrupted membrane integrity。 We further demonstrated using SlMYC2-RNAi tomato plants that SlMYC2 enhanced the expression of SlPAO， which encodes a chlorophyll degradation enzyme， but suppressed the expression of SlRCA and SlSBPASE， both of which are required for photosynthesis and growth in plants。 Dual-luciferase assay confirmed that SlMYC2 activated the transcription of SlPAO， but inhibited the transcription of SlRCA and SlSBPASE。 Furthermore， repression of SlRCA led to typical features associated with leaf senescence in tomato。 Taken together， these results favor that tomato MYC2 acts positively in the regulation of JA-dependent tomato leaf senescence。 The results extend our mechanistic understanding of JA-induced senescence in an important horticultural crop。
查看更多>>摘要：The Arabidopsis knockout mutant lacking both the cytosolic disproportionating enzyme 2 (DPE2) and the plastidial phosphorylase (PHS1) had a dwarf-growth phenotype， a reduced and uneven distribution of starch within the plant rosettes， and a lower starch granule number per chloroplast under standard growth conditions。 In contrast， a triple mutant impaired in starch degradation by its additional lack of the glucan， water dikinase (GWD) showed improved plant growth， a starch-excess phenotype， and a homogeneous starch distribution。 Furthermore， the number of starch granules per chloroplast was increased and was similar to the wild type。 We concluded that ongoing starch degradation is mainly responsible for the observed phenotype of dpe2/phs1。 Next， we generated two further triple mutants lacking either the phosphoglucan， water dikinase (PWD)， or the disproportionating enzyme 1 (DPE1) in the background of the double mutant。 Analysis of the starch metabolism revealed that even minor ongoing starch degradation observed in dpe2/phs1/pwd maintained the double mutant phenotype。 In contrast， an additional blockage in the glucose pathway of starch breakdown， as in dpe2/phs1/ dpe1， resulted in a nearly starch-free phenotype and massive chloroplast degradation。 The characterized mutants were discussed in the context of starch granule formation。
Groppa, Maria DanielaZawoznik, Myriam SaraBenavides, Maria PatriciaIannone, Maria Florencia...
8页
查看更多>>摘要：Nanoparticles (NPs)-based growth stimulators have promising usage in agriculture。 This research analyzed the impact of citric acid-coated magnetite nanoparticles (Fe3O4-NPs; 50 mg Fe L-1) added once at pre-sowing on soybean and alfalfa seedlings growing in association with their corresponding microsymbiont partners， Bradyrhizobium japonicum and Sinorhizobium meliloti; also on the in vitro growth rate of these microorganisms。 FeEDTA (50 mg Fe L-1) was used as a comparator。& nbsp;Fe3O4-NPs significantly augmented the growth rate constant (7-17%) and extracellular polysaccharides production of both microsymbionts (B。 japonicum: 2-fold; S。 meliloti: 43%)， which probably favored bacterial adhesion to the root hairs。& nbsp;In both legumes， Fe3O4-NPs increased chlorophyll content (up to 56% in soybean) and improved plant growth， evidenced by a greater root biomass system (80-90% higher than the control)， and increased shoot biomass (30-40%)。 Besides， Fe3O4-NPs addition resulted in earlier nodule formation and enhanced nodule biomass (about 2。5-fold in both species)。 Nodules were mainly located in the crown of the root in the NP50 treatment， while they were evenly distributed along lateral roots in the control and the comparator。 Fe3O4-NPs also augmented significantly nodule leghemoglobin content (~50-70%) and total N in legumes' shoots (ca。 20%)。 CAT activity increased only under NP50 treatment and no symptoms of oxidative damage were evidenced。 In this work， we found that besides not being toxic neither to soybean and alfalfa plants nor to their microsymbiont partners， Fe3O4-NPs do not exert adverse effects on the symbioses establishment; oppositely， a more efficient nodulation pattern was verified in both plant species。
查看更多>>摘要：Plant metacaspases were evolved in parallel to well-characterized animal counterpart caspases and retained the similar histidine-cysteine catalytic dyad， leading to functional congruity between these endopeptidases。 Although phylogenetic relatedness of the catalytic domain and functional commonality placed these proteases in the caspase family， credible counterarguments predominantly about their distinct substrate specificity raised doubts about the classification。 Metacaspases are involved in regulating the PCD during development as well as in senescence。 Balancing acts of metacaspase activity also dictate cell fate during defense upon the perception of adverse environmental cues。 Accordingly， their activity is tightly regulated， while suppressing spurious activation， by a combination of genetic and post-translational modifications。 Structural insights from recent studies provided vital clues on the functionality。 This comprehensive review aims to explore the origin of plant metacaspases， and their regulatory and functional diversity in different plants while discussing their analogy to mammalian caspases。 Besides， we have presented various modern methodologies for analyzing the proteolytic activity of these indispensable molecules in the healthy or stressed life of a plant。 The review would serve as a repository of all the available pieces of evidence indicating metacaspases as the key regulator of PCD across the plant kingdom and highlight the prospect of studying metacaspases for their inclusion in a crop improvement program。
查看更多>>摘要：The present study focuses on protection of emerging Alternaria leaf spot disease of chilli by application of chi -tosan nanoparticles (CNP)。 CNP was prepared by ionotropic gelation method and characterized。 Antifungal potential of CNP was also checked against Alternaria alternata and its mechanisms were unraveled。 Foliar application of CNP (0。001%) improved plant innate immunity in two chilli cultivars (one tolerant and one susceptible) by inducing the activities of different defense related enzymes along with total phenol and flavonoid。 CNP application also induced callose deposition and reduced cell death in both the cultivar。 Signaling molecule nitric oxide (NO) also augmented in CNP treated sets which were confirmed by both biochemical and micro-scopic data。 In order to find out involvement of NO in CNP induced innate immunity in chilli cultivars， both NO surplus and NO depleted conditions were artificially created and defense responses were recorded。 It was interesting to note that CNP mediated enhancement of defense responses in chilli plants was compromised in NO depleted condition。 These results signify possible involvement of NO in CNP induced defense responses in chilli plants。 It is evident from our results that CNP can be used to protect chilli plants against this fungal disease to develop a sustainable management strategy。
查看更多>>摘要：The calcium-sensing receptor (CAS)， as a chloroplast thylakoid membrane protein， is involved in the process of external Ca2+-induced cytosolic Ca2+ increase in plants。 However， the underlying mechanism regulating this process is lacking。 Furthermore， recent evidence suggests that CAS may perform additional roles in plants。 Here， we provided an update covering the multiple roles of CAS in stomatal movement regulation and Ca signaling in plants。 We also analyzed the possible phosphorylation mechanism of CAS by light and discuss the role of CAS in abiotic stress (drought， salt stress) and biotic stresses (plant immune signaling)。 Finally， we proposed a perspective for future experiments that are required to fill gaps in our understanding of the biological function of CAS in plants。
查看更多>>摘要：Nijmegen breakage syndrome 1 (NBS1) protein is a core member of the MRE11-RAD50-NBS1 (MRN) complex that plays a crucial role in DNA damage sensing and repair in plants。 Here we report that NBS1 from moss Physcomitrium patens reduces oxidative damage by lowering the cellular ROS in addition to its known role in oxidative DNA damage recovery。 Real-time transcript analysis showed up-regulation of the PpNBS1 transcript under different stress conditions。 Bacterial cells showed better cell survivability upon over-expressing PpNBS1 protein as compared to untransformed cells。 Likewise， overexpression of PpNBS1 in tobacco plants provides improved protection against oxidative damage and exhibited a lesser amount of ROS upon exposure to oxidative stress。 Moreover， PpNBS1 contributes to the antioxidant defense mechanism by positively regulating the expression of the antioxidant genes under stress conditions in transgenic tobacco plants。 PpNBS1 expressing transgenic tobacco plants resulted in lesser membrane damage， lower lipid peroxidation level， and higher chlorophyll content under stress conditions。 Taken together， we conclude in addition to its known role as DNA damage sensor， PpNBS1 also plays a definite role in oxidative stress mitigation by minimizing ROS accumulation in the cell。
NSTL
Elsevier