Sowbiya Muneer

Bio: Sowbiya Muneer is an academic researcher from VIT University. The author has contributed to research in topics: Photosynthesis & Salinity. The author has an hindex of 19, co-authored 60 publications receiving 1117 citations. Previous affiliations of Sowbiya Muneer include Gyeongsang National University & Jamia Millia Islamia.

Role of Circadian Rhythms in Major Plant Metabolic and Signaling Pathways

Abstract: Plants require an endogenous regulatory network and mechanism to cope with diurnal environmental changes and compensate for their sessile nature. Plants use the circadian clock to anticipate diurnal changes. Circadian rhythm predicts a 24-h cycle with 16 h of light and 8 h of darkness in response to abiotic and biotic factors as well as the appropriate temperature. For a plant’s fitness, proper growth, and development, these rhythms synchronize the diurnal photoperiodic changes. Input pathway, central oscillator, and output pathway are the three components that make up the endogenous clock. There are also transcriptional and translational feedback loops (TTFLs) in the clock, which are dependent on the results of gene expression. Several physiological processes, such as stress acclimatization, hormone signaling, morphogenesis, carbon metabolism, and defense response, are currently being investigated for their interactions with the circadian clock using phenotypic, genomic, and metabolic studies. This review examines the role of circadian rhythms in the regulation of plant metabolic pathways, such as photosynthesis and carbon metabolism, as well as developmental and degenerative processes, such as flowering and senescence. Furthermore, we summarized signaling pathways related to circadian rhythms, such as defense response and gene regulatory pathways.

Involvement of Fe nutrition in modulating oxidative stress and the expression of stress responsive proteins in leaves of Vigna radiata L.

Abstract: Cadmium (Cd) is deleterious to all forms of life which in plants has competition with iron (Fe) for root uptake. This study investigated the protective role of iron (Fe) and its interaction with cadmium (Cd) in leaves of Vigna radiata L. (Green gram). To characterize the significance of Fe nutrition under Cd exposure, biochemical and gel based proteomic analysis was performed in the leaves of Vigna radiata exposed to Fe and Cd combined treatments: Fe-sufficient (+Fe/-Cd), and Fe-deficient (-Fe/-Cd) soils by comparing them with -Fe/+Cd treated plants and with non Cd exposed (+Fe/-Cd) plants. -Fe/-Cd led to an elevation in lipid peroxidation (TBARS) which was further increased in -Fe/+Cd plants. However, in +Fe/+Cd plants oxidative stress in terms of TBARS was minimized by 30%. Biochemical parameters such as total chlorophyll, total ascorbate and glutathione concentration reduced in -Fe/-Cd plants which was more reduced in -Fe/+Cd plants, whereas increased in +Fe/+Cd plants. Enzymatic activities such as APX, SOD, CAT, and GR activities were reduced in -Fe/-Cd plants which was more severe in -Fe/+Cd plants and in -Fe/+Cd enzyme assays were increased. Furthermore, proteomic analysis revealed 238 spots were reproducibly detected on 2D gels of all the four treatments among which 40 proteins were differentially expressed. Eight proteins of interest from differentially expressed proteins were identified and were classified as photosynthetic pigments, chloroplast precursor, stress responsive proteins, protein destination and secondary metabolism. These results indicate that Fe nutrition is involved in alleviating oxidative stress and expression of stress responsive proteins under Cd-stress.

Proteomics of nitrogen fixing nodules under various environmental stresses.

Abstract: Proteomics is an ideal tool to study the interaction of root nodules and their symbiotic bacteria as it provides a broad overview of proteins produced by both partners during their constant signal exchange and allows the signal transduction path ways following photophosphorylation. Iron containing proteins play a key role in symbiotic nitrogen fixation that occurs in a nodule-a specialized structure present on roots. Several proteins like those related to SNF (symbiotic nitrogen fixation), predominantly components of nitrogenase complexes, such as 'nifD', 'nifH', 'nifK', nitrogen regulatory protein II (GlnB) and PIIA (PtsN), and urease accessory protein (UreE) have been found to be affected by abiotic stress. Nodules are better equipped with all kinds of antioxidant systems (i.e., ascorbate-glutathione pathway or Superoxide dismutase) which have been formed to show a decline under stress conditions. The present review article aims to investigate the nodule physiology, the effect of different abiotic stress on nodule proteins comprehensive account of these stress-responsive proteins and their role in combating stress in legume nodules. This will help to elucidate which specific key proteins are affected by abiotic stress. As such, it will greatly facilitate understanding resistance or stress tolerance mechanism and hence improvement in crop resistance.

Ethylene regulates sulfur acquisition by regulating the expression of sulfate transporter genes in oilseed rape.

Abstract: To manage nutrient deficiencies, plants develop both morphological and physiological responses The studies on the regulation of these responses are limited; however, certain hormones and signaling components have been largely implicated Several studies depicted ethylene as a regulator of the response of some nutrient deficiencies like iron, phosphorous and potassium The present study focused on the response of sulfur in the presence and absence of ethylene The experiments were performed in hydroponic nutrient media, using oilseed rape grown with or without sulfur deficiency and ethylene treatments for 10 days The ACC oxidase and ACC synthase were observed significantly reduced in sulfur-deficient plants treated with ethylene compared to control The biomass and photosynthetic parameters, including the expression of multicomplex thylakoidal proteins showed a significant increase in sulfur deficient plants supplemented with ethylene The enzymes related to sulfur regulation such as sulfate adenyltransferase, glutamine synthetase and O-acetylserine (thiol)lyase also showed similar results as shown by the morphological data The relative expression of the sulfur transporter genes BnSultr1, 1, BnSultr1, 2, BnSultr4,1, BnSultr 4,2, ATP sulfurylase and OASTL increased in sulfur-deficient plants, whereas their expression decreased when ethylene was given to the plants Fe and S nutritional correlations are already known; therefore, Fe-transporters like IRT1 and FRO1 were also evaluated, and similar results as for the sulfur transporter genes were observed The overall results indicated that ethylene regulates sulfur acquisition by regulating the expression of sulfur transporter genes in oilseed rape (Brassica napus)

Application of NIR-Spectroscopy to predict the harvesting maturity, fruit ripening and storage ability of Ca-chitosan treated baby kiwifruit

Abstract: In this study, near infrared (NIR) spectroscopy was performed to establish a non-destructive method to predict the harvesting maturity, fruit ripening and storage ability of Ca-chitosan treated baby kiwifruit. Destructive measurements of firmness, dry matter (DM), soluble solids content (SSC), and acidity was performed. The calibration range investigated for dry matter content (DM) and SSC using NIR reflectance spectrums were observed at 729-975 nm wavelengths. NIR predictions of those quality factors were calculated using the modified partial least square regression method. The predicted R2 value for DM and SSC was 0.73, and the standard error deviation (SED) value was greater than 2. The correlation between the actual value and predicted model of DM were r = 0.74. The correlation between the predicted DM content and the actual SSC, using SSC model was r = 0.65. The correlation between the predicted value of SSC and the actual value of SSC (baby kiwifruits ripen with ethylene) was r = 0.48, which was lower than the actual SSC model. Further, Ca-chitosan pre-harvest treatment on baby kiwifruit showed considerable effects on baby kiwifruit quality. The actual DM content of untreated fruits was 21.4% and it was 22.3% in Ca-chitosan treated fruits. Also, the predicted DM content was significantly high in Ca-chitosan treated fruits (22.7%) compared to untreated fruits. NIR spectroscopy is an effective and efficient method to measure DM and SSC to determine the fruit harvest maturity hence, date of harvest and storability for quality baby kiwifruits from the marketing point of view. Key words: Ca-chitosan, firmness, harvest index, maturation, nondestructive measurement.

Phytoremediation : 植物による環境/土壌浄化

Abstract: In addition to the often-cited advantages of using Arabidopsis thaliana as a model system in plant biological research (1), Arabidopsis has many additional characteristics that make it an attractive experimental organism for studying lea d (Pb) accumulation and tolerance in plants. These include its fortuitous familial relationship to many known metal hyperaccumulators (Brassicaceae), as well as similar Pbaccumulation patterns to most other plants. Using nutrient-agar plates, hydroponic culture, and Pb-contaminated soils as growth media, we found significant variation in Arabidopsis thaliana ecotypes in accumulation and tolerance of Pb. In addition, we have found that Pb accumulation is not obligatorily linked with Pb tolerance, suggesti ng that different genetic factors control these two processes. We also screened ethyl methanesulfonate-mutagenized M2 populations and identified several Pb-accumulating mutants. Current characterization of these mutants indicates that their phenotypes are likely due to alteration of general metal ion uptake or translocation processes since these mutants also accumulate many other metals in shoots. We expect that further characterization of the ecotypes and mutants will shed light on the basic genetic and physiological underpinnings of plant-based Pb remediation. 7. Aromatic nitroreduction of acifluorfen in soils, rhizospheres, and pure cultures of rhizobacteria. Zablotowicz, R. M., Locke, M. A., and Hoagland, R. E. Phytoremediation of soil and water contaminants. Washington, DC : American Chemical Society, 1997. p. 38-53. NAL Call #: QD1.A45-no.664 Abstract: Reduction of nitroaromatic compounds to their corresponding amino derivatives is one of several pathways in the degradation of nitroxenobiotics. Our studies with the nitrodiphenyl ether herbicide acifluorfen showed rapid metabolism to am inoacifluorfen followed by incorporation into unextractable soil components in both soil and rhizosphere suspensions. Aminoacifluorfen was formed more rapidly in rhizospheres compared to soil, which can be attributed to higher microbial populations, espec ially of Gram-negative bacteria. We identified several strains of Pseudomonas fluorescens that possess nitroreductase activity capable of converting acifluorfen to aminoacifluorfen. Factors affecting acifluorfen nitroreductase activity in pure cultures an d cell-free extracts, and other catabolic transformations of acifluorfen, ether bond cleavage, are discussed. Plant rhizospheres should be conducive for aromatic nitroreduction. Nitroreduction by rhizobacteria is an important catabolic pathway for the ini tial degradation of various nitroherbicides and other nitroaromatic compounds in soils under Reduction of nitroaromatic compounds to their corresponding amino derivatives is one of several pathways in the degradation of nitroxenobiotics. Our studies with the nitrodiphenyl ether herbicide acifluorfen showed rapid metabolism to am inoacifluorfen followed by incorporation into unextractable soil components in both soil and rhizosphere suspensions. Aminoacifluorfen was formed more rapidly in rhizospheres compared to soil, which can be attributed to higher microbial populations, espec ially of Gram-negative bacteria. We identified several strains of Pseudomonas fluorescens that possess nitroreductase activity capable of converting acifluorfen to aminoacifluorfen. Factors affecting acifluorfen nitroreductase activity in pure cultures an d cell-free extracts, and other catabolic transformations of acifluorfen, ether bond cleavage, are discussed. Plant rhizospheres should be conducive for aromatic nitroreduction. Nitroreduction by rhizobacteria is an important catabolic pathway for the ini tial degradation of various nitroherbicides and other nitroaromatic compounds in soils under phytoremediation management. 8. Ascorbate: a biomarker of herbicide stress in wetland plants. Lytle, T. F. and Lytle, J. S. Phytoremediation of soil and water contaminants. Washington, DC : American Chemical Society, 1997. p. 106-113. NAL Call #: QD1.A45-no.664 Abstract: In laboratory exposures of wetland plants to low herbicide levels (<0.1 micrograms/mL), some plants showed increased total ascorbic acid suggesting a stimulatory effect on ascorbic acid synthesis occurred; at higher herbicide conce ntrations (greater than or equal to 0.1 micrograms/mL) a notable decline in total ascorbic acid and increase in the oxidized form, dehydroascorbic acid occurred. Vigna luteola and Sesbania vesicaria were exposed for 7 and 21 days respectively to atrazine (0.05 to 1 microgram/mL); Spartina alterniflora 28 days at 0.1 micrograms/mL trifluralin; Hibiscus moscheutos 14 days at 0.1 and 1 microgram/mL metolachlor in fresh and brackish water. The greatest increase following low dosage occurred with S. alterniflo ra, increasing from <600 micrograms/g wet wt. total ascorbic acid to >1000 micrograms/g. Ascorbic acid may be a promising biomarker of estuarine plants exposed to herbicide runoff; stimulation of ascorbic acid synthesis may enable some wetland plant s used in phytoremediation to cope with low levels of these compounds. In laboratory exposures of wetland plants to low herbicide levels (<0.1 micrograms/mL), some plants showed increased total ascorbic acid suggesting a stimulatory effect on ascorbic acid synthesis occurred; at higher herbicide conce ntrations (greater than or equal to 0.1 micrograms/mL) a notable decline in total ascorbic acid and increase in the oxidized form, dehydroascorbic acid occurred. Vigna luteola and Sesbania vesicaria were exposed for 7 and 21 days respectively to atrazine (0.05 to 1 microgram/mL); Spartina alterniflora 28 days at 0.1 micrograms/mL trifluralin; Hibiscus moscheutos 14 days at 0.1 and 1 microgram/mL metolachlor in fresh and brackish water. The greatest increase following low dosage occurred with S. alterniflo ra, increasing from <600 micrograms/g wet wt. total ascorbic acid to >1000 micrograms/g. Ascorbic acid may be a promising biomarker of estuarine plants exposed to herbicide runoff; stimulation of ascorbic acid synthesis may enable some wetland plant s used in phytoremediation to cope with low levels of these compounds. 9. Atmospheric nitrogenous compounds and ozone--is NO(x) fixation by plants a possible solution. Wellburn, A. R. New phytol. 139: 1 pp. 5-9. (May 1998). NAL Call #: 450-N42 Descriptors: ozoneair-pollution nitrogen-dioxide nitric-oxide air-quality tolerancebioremediationacclimatizationnutrient-sources nutrient-uptake plantscultivarsgenetic-variation literature-reviews 10. Atrazine degradation in pesticide-contaminated soils: phytoremediation potential. Kruger, E. L., Anhalt, J. C., Sorenson, D., Nelson, B., Chouhy, A. L., Anderson, T. A., and Coats, J. R. Phytoremediation of soil and water contaminants. Washington, DC : American Chemical Society, 1997. p. 54-64. NAL Call #: QD1.A45-no. 664 Abstract: Studies were conducted in the laboratory to determine the fate of atrazine in pesticide-contaminated soils from agrochemical dealer sites. No significant differences in atrazine concentrations occurred in soils treated with atrazine i ndividually or combinations with metolachlor and trifluralin. In a screening study carried out in soils from four agrochemical dealer sites, rapid mineralization of atrazine occurred in three out of eight soils tested, with the greatest amount occurring i n Bravo rhizosphere soil (35% of the applied atrazine after 9 weeks). Suppression of atrazine mineralization in the Bravo rhizosphere soil did not occur with the addition of high concentrations of herbicide mixtures, but instead was increased. Plants had a positive impact on dissipation of aged Studies were conducted in the laboratory to determine the fate of atrazine in pesticide-contaminated soils from agrochemical dealer sites. No significant differences in atrazine concentrations occurred in soils treated with atrazine i ndividually or combinations with metolachlor and trifluralin. In a screening study carried out in soils from four agrochemical dealer sites, rapid mineralization of atrazine occurred in three out of eight soils tested, with the greatest amount occurring i n Bravo rhizosphere soil (35% of the applied atrazine after 9 weeks). Suppression of atrazine mineralization in the Bravo rhizosphere soil did not occur with the addition of high concentrations of herbicide mixtures, but instead was increased. Plants had a positive impact on dissipation of aged atrazine in soil, with significantly less atrazine extractable from Kochia-vegetated soils than from nonvegetated soils. 11. Bacterial inoculants of forage grasses that enhance degradation of 2-chlorobenzoic acid in soil. Siciliano, S. D. and Germida, J. J. Environ toxicol chem. 16: 6 pp. 1098-1104. (June 1997). NAL Call #: QH545.A1E58 Descriptors: polluted-soils bioremediationAbstract: Biological remediation of contaminated soil is an effective method of reducing risk to human and ecosystem health. Bacteria and plants might be used to enhance remediation of soil pollutants in situ. This study assessed the potential of bacteria (12 isolates), plants (16 forage grasses), and plant-bacteria associations (selected pairings) to remediate 2-chlorobenzoic acid (2CBA)-contaminated soil. Initially, grass viability was assessed in 2CBA-contaminated soil. Soil was contaminated wi th 2CBA, forage grasses were grown under growth chamber conditions for 42 or 60 d, and the 2CBA concentration in soil was determined by gas chromatography. Only five of 16 forage grasses grew in 2CBA-treated (816 mg/kg) soil. Growth of Bromus inermis had no effect on 2CBA concentration, whereas Agropyron intermedium, B. biebersteinii, A. riparum, and Elymus dauricus decreased 2CBA relative to nonplanted control soil by 32 to 42%. The 12 bacteria isolates were screened for their ability to promote the germ ination of the five grasses in 2CBA-contaminated soil. Inoculation of A. riparum with Pseudomonas aeruginos

Soil Salinity: Effect on Vegetable Crop Growth. Management Practices to Prevent and Mitigate Soil Salinization

Abstract: Salinity is a major problem affecting crop production all over the world: 20% of cultivated land in the world, and 33% of irrigated land, are salt-affected and degraded. This process can be accentuated by climate change, excessive use of groundwater (mainly if close to the sea), increasing use of low-quality water in irrigation, and massive introduction of irrigation associated with intensive farming. Excessive soil salinity reduces the productivity of many agricultural crops, including most vegetables, which are particularly sensitive throughout the ontogeny of the plant. The salinity threshold (ECt) of the majority of vegetable crops is low (ranging from 1 to 2.5 dS m−1 in saturated soil extracts) and vegetable salt tolerance decreases when saline water is used for irrigation. The objective of this review is to discuss the effects of salinity on vegetable growth and how management practices (irrigation, drainage, and fertilization) can prevent soil and water salinization and mitigate the adverse effects of salinity.

Regulation of Ascorbate-Glutathione Pathway in Mitigating Oxidative Damage in Plants under Abiotic Stress

Abstract: Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and stressed condition. However, under unfavorable or adverse conditions, ROS production exceeds the capacity of the antioxidant defense system. Both non-enzymatic and enzymatic components of the antioxidant defense system either detoxify or scavenge ROS and mitigate their deleterious effects. The Ascorbate-Glutathione (AsA-GSH) pathway, also known as Asada–Halliwell pathway comprises of AsA, GSH, and four enzymes viz. ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, play a vital role in detoxifying ROS. Apart from ROS detoxification, they also interact with other defense systems in plants and protect the plants from various abiotic stress-induced damages. Several plant studies revealed that the upregulation or overexpression of AsA-GSH pathway enzymes and the enhancement of the AsA and GSH levels conferred plants better tolerance to abiotic stresses by reducing the ROS. In this review, we summarize the recent progress of the research on AsA-GSH pathway in terms of oxidative stress tolerance in plants. We also focus on the defense mechanisms as well as molecular interactions.