Phytofabricated gold nanoparticles as modulators of salt stress responses in spinach: implications for redox homeostasis, biochemical and physiological adaptation.

Introduction: The utilization of plant material for synthesizing nanoparticles effectively triggers physiological and biochemical responses in plants to combat abiotic stresses. Salt stress, particularly caused by NaCl, significantly affects plant morphology and physiology, leading to reduced crop yields. Understanding the mechanisms of salt tolerance is crucial for maintaining crop productivity. Methods: In this study, we examined the effects of 150 µM spinach-assisted gold nanoparticles (S-AuNPs) on various parameters related to seed germination, growth attributes, photosynthetic pigments, stomatal traits, ion concentrations, stress markers, antioxidants, metabolites, and nutritional contents of spinach plants irrigated with 50 mM NaCl. Results: Results showed that S-AuNPs enhanced chlorophyll levels, leading to improved light absorption, increased photosynthates production, higher sugar content, and stimulated plant growth under NaCl stress. Stomatal traits were improved, and partially closed stomata were reopened with S-AuNPs treatment, possibly due to K+/Na+ modulation, resulting in enhanced relative water content and stomatal conductance. ABA content decreased under S-AuNPs application, possibly due to K+ ion accumulation. S-AuNPs supplementation increased proline and flavonoid contents while reducing ROS accumulation and lipid peroxidation via activation of both non-enzymatic and enzymatic antioxidants. S-AuNPs also regulated the ionic ratio of K+/Na+, leading to decreased Na+ accumulation and increased levels of essential ions in spinach plants under NaCl irrigation. Discussion: Overall, these findings suggest that S-AuNPs significantly contribute to salt stress endurance in spinach plants by modulating various physiological attributes.

Genotyping SNPs in lignin biosynthesis gene (CAD1) and transcription factors (MYB1 and MYB2) exhibits association with wood density in teak (Tectona grandis L.f.).

BACKGROUND: Teak (Tectona grandis L.f.), an important source of tropical timber with immense economic value, is a highly outcrossing forest tree species. 150 unrelated accessions of teak (Tectona grandis L.f.) plus trees assembled as clones at National Teak Germplasm Bank, Chandrapur, Maharashtra, India was investigated for association mapping of candidate lignin biosynthesis gene (CAD1) and transcription factors (MYB1 and MYB2). METHODS AND RESULTS: The CAD1, MYB1 and MYB2 were amplified using specifically designed primers. The amplified sequences were then sequenced and genotyped for 112 SNPs/11 indels. We evaluated the association between SNPs and wood density in teak accessions using GLM and MLM statistical models, with Bonferroni correction applied. The teak accessions recorded an average wood density of 416.69 kg.m-3 (CV 4.97%) and comprised of three loosely structured admixed sub-populations (K = 3), containing 72.05% genetic variation within sub-populations with low intragenic LD (0-21% SNP pairs) at P < 0.05 and high LD decay (33-934 bp) at R2 = 0.1. GLM and MLM models discounting systematic biases (Q and K matrices) to avoid false discovery revealed five loci at rare variants (MAF 0.003) and three loci at common variants (MAF 0.05) to be significantly (P < 0.05) associated with the wood density. However, the stringent Bonferroni correction (4.06-7.04 × 10-4) yielded only a single associated locus (B1485C/A) from exon of MYB1 transcription factor, contributing to about 10.35% phenotypic variation in wood density trait. CONCLUSION: Scored SNP locus (B1485C/A) can be developed as a molecular probe for selection of improved planting stock with proven wood density trait for a large-scale teak plantation.

Post-harvest biology and recent advances of storage technologies in sugarcane.

Sugarcane deteriorates at a quick rate, just like other perishable crops. The quick loss of sucrose content in sugarcane from the time it is harvested has a significant impact on sugar recovery. This problem of post-harvest sucrose losses in sugarcane is a serious concern in cane-producing countries, as it not only leads to low sugar recovery in mills, but also to poor sugar refining. Unreasonable delays in cane transportation from the fields to the mill are frequently linked to a number of problems related to primary or secondary sucrose losses, all of which contribute to a significant reduction in cane weight and sugar recovery. In sugar mills, the processing of damaged or stale canes also presents a number of challenges, including increased viscosity due to dextran generation, formation of acetic acid, and dextrans due to Leuconostoc spp. invasion, and so on. The combination of all of these variables results in low sugar quality, resulting in significant losses for sugar mills. The primary and secondary losses caused by post-harvest sucrose degradation in sugarcane are enlisted. The employment of physico-chemical technologies in farmers' fields and sugar mills to control and minimize these losses has also been demonstrated.

Toward Integrated Multi-Omics Intervention: Rice Trait Improvement and Stress Management.

Rice (Oryza sativa) is an imperative staple crop for nearly half of the world's population. Challenging environmental conditions encompassing abiotic and biotic stresses negatively impact the quality and yield of rice. To assure food supply for the unprecedented ever-growing world population, the improvement of rice as a crop is of utmost importance. In this era, "omics" techniques have been comprehensively utilized to decipher the regulatory mechanisms and cellular intricacies in rice. Advancements in omics technologies have provided a strong platform for the reliable exploration of genetic resources involved in rice trait development. Omics disciplines like genomics, transcriptomics, proteomics, and metabolomics have significantly contributed toward the achievement of desired improvements in rice under optimal and stressful environments. The present review recapitulates the basic and applied multi-omics technologies in providing new orchestration toward the improvement of rice desirable traits. The article also provides a catalog of current scenario of omics applications in comprehending this imperative crop in relation to yield enhancement and various environmental stresses. Further, the appropriate databases in the field of data science to analyze big data, and retrieve relevant information vis-à-vis rice trait improvement and stress management are described.

Amplification, sequencing and characterization of pectin methyl esterase inhibitor 51 gene in Tectona grandis L.f.

Tectona grandis L.f. (Teak), a very important source of incomparable timber, withstands a wide range of tropical deciduous conditions. We achieved partial amplification of pectin methylesterase inhibitor 51 (PMEI) gene in teak by E. pilularis cinnamoyl Co-A reductase (CCR) gene specific primer. The amplified teak gene was of 750 bp, 79% identity and 97% query cover with PMEI of Sesamum indicum. The phylogenetic tree clustered the amplified gene with PMEI of database plant species, Erythranthe guttata and Sesamum indicum (87% bootstrap value). On conversion to amino acid sequence, the obtained protein comprised 237 amino acids. However, PMEI region spanned from 24 to 171 amino acids, 15.94 kDa molecular weight, 8.97 pI value and C697H1117N199O211S9 molecular formula with four conserved cysteine residues as disulfide bridges. 25.9 % protein residues were hydrophilic, 42.7% hydrophobic and 31.2% neutral. Teak 3D PMEI protein structure corresponded well with Arabidopsis thaliana and Actinidia deliciosa PMEIs. The gene maintains integrity of pectin component of middle lamella of primary cell wall and confers tolerance against various kinds of stresses. Teak conferred with overexpression of PMEI may secure a wide adaptability as well as luxuriant timber productivity and quality in adverse/ fluctuating/ scarce climatic and environmental conditions of tropical forests.

Nigella sativa callus treated with sodium azide exhibit augmented antioxidant activity and DNA damage inhibition.

Nigella sativa L. (NS) is an herbaceous plant, possessing phytochemicals of therapeutic importance. Thymoquinone is one of the active phytochemicals of NS that confers noteworthy antioxidant properties. Sodium azide, an agent of abiotic stress, can modulates antioxidant system in plants. In the present investigation, sodium azide (0, 5 µM, 10 µM, 20 µM, 50 µM, 100 µM and 200 µM) doses administered to the in vitro NS callus cultures for production/modification of secondary metabolites with augmented activity. 200 µM sodium azide treated NS callus exhibited maximum peroxidase activity (1.286 ± 0.101 nanokatal mg-1 protein) and polyphenol oxidase activity (1.590 ± 0.110 nanokatal mg-1 protein), while 100 µM sodium azide treated NS callus for optimum catalase activity (1.250 ± 0.105 nanokatal mg-1 protein). Further, 200 µM sodium azide treated NS callus obtained significantly the highest phenolics (3.666 ± 0.475 mg g-1 callus fresh weight), 20 µM sodium azide treated NS callus, the highest flavonoids (1.308 ± 0.082 mg g-1 callus fresh weight) and 100 µM sodium azide treated NS callus, the highest carotenes (1.273 ± 0.066 mg g-1 callus fresh weight). However, NS callus exhibited a decrease in thymoquinone yield/content vis-à-vis possible emergence of its analog with 5.3 min retention time and an increase in antioxidant property. Treatment with 200 µM sodium azide registered significantly the lowest percent yield of callus extract (4.6 ± 0.36 mg g-1 callus fresh weight) and thymoquinone yield (16.65 ± 2.52 µg g-1 callus fresh weight) and content (0.36 ± 0.07 mg g-1 callus dry weight) and the highest antioxidant activity (3.873 ± 0.402%), signifying a negative correlation of the former with the latter. DNA damage inhibition (24.3 ± 1.7%) was recorded significantly maximum at 200 µM sodium azide treatment. Sodium azide treated callus also recorded emergence of a new peak at 5.3 min retention time (possibly an analog of thymoquinone with augmented antioxidant activity) whose area exhibits significantly negative correlation with callus extract yield and thymoquinone yield/content and positive correlation with antioxidant activity and in vitro DNA damage inhibition. Thus, sodium azide treatment to NS callus confers possible production of secondary metabolites or thymoquinone analog (s) responsible for elevated antioxidant property and inhibition to DNA damage. The formation of potent antioxidants through sodium azide treatment to NS could be worthy for nutraceutical and pharmaceutical industries.

Plant Defense Responses to Biotic Stress and Its Interplay With Fluctuating Dark/Light Conditions.

Plants are subjected to a plethora of environmental cues that cause extreme losses to crop productivity. Due to fluctuating environmental conditions, plants encounter difficulties in attaining full genetic potential for growth and reproduction. One such environmental condition is the recurrent attack on plants by herbivores and microbial pathogens. To surmount such attacks, plants have developed a complex array of defense mechanisms. The defense mechanism can be either preformed, where toxic secondary metabolites are stored; or can be inducible, where defense is activated upon detection of an attack. Plants sense biotic stress conditions, activate the regulatory or transcriptional machinery, and eventually generate an appropriate response. Plant defense against pathogen attack is well understood, but the interplay and impact of different signals to generate defense responses against biotic stress still remain elusive. The impact of light and dark signals on biotic stress response is one such area to comprehend. Light and dark alterations not only regulate defense mechanisms impacting plant development and biochemistry but also bestow resistance against invading pathogens. The interaction between plant defense and dark/light environment activates a signaling cascade. This signaling cascade acts as a connecting link between perception of biotic stress, dark/light environment, and generation of an appropriate physiological or biochemical response. The present review highlights molecular responses arising from dark/light fluctuations vis-à-vis elicitation of defense mechanisms in plants.

Abiotic Stress and Reactive Oxygen Species: Generation, Signaling, and Defense Mechanisms.

Climate change is an invisible, silent killer with calamitous effects on living organisms. As the sessile organism, plants experience a diverse array of abiotic stresses during ontogenesis. The relentless climatic changes amplify the intensity and duration of stresses, making plants dwindle to survive. Plants convert 1-2% of consumed oxygen into reactive oxygen species (ROS), in particular, singlet oxygen (1O2), superoxide radical (O2•-), hydrogen peroxide (H2O2), hydroxyl radical (•OH), etc. as a byproduct of aerobic metabolism in different cell organelles such as chloroplast, mitochondria, etc. The regulatory network comprising enzymatic and non-enzymatic antioxidant systems tends to keep the magnitude of ROS within plant cells to a non-damaging level. However, under stress conditions, the production rate of ROS increases exponentially, exceeding the potential of antioxidant scavengers instigating oxidative burst, which affects biomolecules and disturbs cellular redox homeostasis. ROS are similar to a double-edged sword; and, when present below the threshold level, mediate redox signaling pathways that actuate plant growth, development, and acclimatization against stresses. The production of ROS in plant cells displays both detrimental and beneficial effects. However, exact pathways of ROS mediated stress alleviation are yet to be fully elucidated. Therefore, the review deposits information about the status of known sites of production, signaling mechanisms/pathways, effects, and management of ROS within plant cells under stress. In addition, the role played by advancement in modern techniques such as molecular priming, systems biology, phenomics, and crop modeling in preventing oxidative stress, as well as diverting ROS into signaling pathways has been canvassed.

Impact of chemical treatments on Leuconostoc bacteria from harvested stored cane/stale cane.

Post-harvest sucrose losses are always a critical problem for sugar industries. A predominant factor which is causing these post-harvest losses that affects sugar recovery is the bacterium Leuconostoc spp. This study aims to check the efficacy of certain chemical treatments in reducing the proliferation of this bacterium. Our study based on a Leuconostoc-specific media revealed that application of 0.5 % aqueous solution of benzalkonium chloride and sodium metasilicate (BKC + SMS), formaldehyde, glutaraldehyde, sodium chloride and pine oil showed significant reduction in zone of proliferation. Considering formaldehyde and glutaraldehyde as control, the most effective treatments were chemical formulations of benzalkonium chloride along with sodium metasilicate, pine oil and sodium chloride in checking the proliferation of this bacterium. The application of these treatments has an immense potential in the sugar industry for reducing post-harvest sugar losses.

Morphological assessment of water stressed sugarcane: A comparison of waterlogged and drought affected crop.

Abiotic stress is recurrent occurring problem for sugarcane crop in terms of hindrance in achieving good and high production. In India, drought coverage is 2.97 lakh ha while 2.5 lakh ha under coverage of waterlogging which is one of the reasons behind low cane production and productivity due to alteration in metabolism, growth and development of the plant either in direct or indirect way. Therefore, we investigated the comparison of morphological losses in drought and waterlogging sugarcanes. Morphological parameters assessed were leaf length, leaf width, leaf area, stalk diameter, cane height, cane weight, internodes number and average internodal length. Also, total root weight, dry matter production of stalk, leaves and roots were observed. Results showed that leaf length was marginally increased in drought canes but it was not so in case of waterlogged canes. Besides, there was decrease in total root weight of sugarcane affected by drought by 16.99% while there was increase by 10.06% in waterlogging affected canes in comparison to normal grown canes. In cane height and stalk diameter, decrease by 18.28%, 7.52%, respectively, in drought and 11.41%, marginal decrease, respectively, in waterlogged affected canes as compared to normally grown canes. Average internodal length was also found to increase in both drought as well as waterlogged canes by 39.02% and 36.60%, respectively, in comparison to normal grown canes. Number of internodes was decreased more in drought affected canes than in waterlogged canes. This study concluded that there are higher morphological losses in sugarcane in drought condition than in waterlogging conditions with respect to normal grown canes.

Minimization of post-harvest sucrose losses in drought affected sugarcane using chemical formulation.

Sugarcane is a significant crop for production of sugar and ethanol in the world. In present perspective, drought is one of the frequently occurring abiotic stresses hampering the productivity of sugarcane causing heavy losses in sugar recovery. Post-harvest sugarcane deterioration attains more importance. Measures have been recommended in harvested canes to prevent these losses in general and under drought conditions but application of chemical formulation has not yet been tested over drought effected ones. Thus, we tried to investigate the efficacy of chemical formulation [Benzalkonium chloride (BKC) + Sodium metasilicate (SMS)] on sucrose losses occurring in harvested canes grown under drought and normal conditions. Results showed that application of chemical formulation had higher effect on drought canes in comparison to normal grown canes. Loss in cane weight was reduced to 8.25% and 11% in drought treated and normal treated grown canes, respectively, after 240 h of harvest in comparison to their respective control. In sucrose content and Commercial cane sugars %, drought treated canes showed an effect of BKC + SMS by reducing the losses to 1.26 units and 1.42 units, respectively, whereas in normal ones, reduction was of 0.38 units and 0.10 units, respectively. Biochemical analysis revealed that in reducing sugars, reduction in increase were of 44.51% and 25.50% in drought and normal grown canes, respectively, after 240 h of harvest. Dextran and soluble acid invertase estimations revealed that after application of BKC + SMS, reduction of dextran and invertase activity were of 49.74%, 66.84%, respectively, and 33.92%, 42.75%, respectively, in drought and normal grown canes, respectively. Total microbial load, showed effectiveness of 25.01% in drought grown canes while 14.41% in normal grown ones after 240 h of harvest. Our study was planned to use the anti-bacterial efficiency of both the chemicals over harvested canes so that the major sucrose losses occurring due to microbial deterioration could be inhibited. The use of this chemical formulation proves to be an effective one over post-harvest sucrose losses, particularly in drought grown canes.

Biochemical synthesis of gold nanoparticles from leaf protein of Nicotiana tabacum L. cv. xanthi and their physiological, developmental, and ROS scavenging responses on tobacco plant under stress conditions.

The stress conditions imposed by the impact of metal and non-metal oxide nanoparticles over plant systems enhances the synthesis of reactive oxygen species (ROS), resulting in oxidative damage at cellular level. The objective of this study was to synthesise the gold nanoparticles (GNps) from the leaves protein of Nicotiana tabacum L. cv. xanthi, its characterisation, and response on plant physiology and ROS scavenging activity on plants after exposure to different stresses. The authors have treated N. tabacum L. cv. xanthi plants with 100, 200, 300, 400, and 500 ppm biochemically synthesised GNps and examined physiological as well as biochemical changes. Results showed that biochemically synthesised GNps exposure significantly increased the seed germination (P < 0.001), root (P < 0.001), shoot growth (P < 0.001), and antioxidant ability (P < 0.05) of plants depending on bioengineered GNPs concentrations. Low concentrations (200-300 ppm) of GNps boosted growth by ∼50% and significantly increase in photosynthetic parameters such as total chlorophyll content (P < 0.05), membrane ion leakage (P < 0.05) as well as malondialdehyde (P < 0.05) content with respect to untreated plants under stress conditions. The high concentration (400-500 ppm) of GNps affected these parameters in a negative manner. The total antioxidant activity was also elevated in the exposed plants in a dose-dependent manner.

Correlation between mtDNA complexity and mtDNA replication mode in developing cotyledon mitochondria during mung bean seed germination.

The currently accepted model of recombination-dependent replication (RDR) in plant mitochondrial DNA (mtDNA) does not clearly explain how RDR progresses and how highly complex mtDNA develops. This study aimed to investigate the correlation between RDR and mtDNA complexity during mitochondrial development in mung bean (Vigna radiata) seed, and the initiation and processing of RDR in plant mitochondria. Flow cytometry, pulsed-field gel electrophoresis, electron microscopy, real-time PCR and biochemical studies were used in this study. The highly dynamic changes in mtDNA complexity correspond to mtDNA RDR activity throughout mitochondrial development. With in vitro freeze-thaw treatment or prolonged in vivo cold incubation, the mtDNA rosette core disappeared and the rosette structure converted to a much longer linear DNA structure. D-loops, Holliday junctions and putative RDR forks often appeared near the rosette cores. We hypothesize that the rosette core may consist of condensed mtDNA and a replication starting sequence, and play an initial and central role in RDR. The satellite cores in the rosette structure may represent the re-initiation sites of mtDNA RDR in the same parental molecule, thereby forming highly complex and giant mitochondrial molecules, representing the RDR intermediates, in vivo.

Major bioactive metabolites from marine fungi: A Review.

Biologists and chemists of the world have been attracted towards marine natural products for the last five decades. Approximately 16,000 marine natural products have been isolated from marine organisms which have been reported in approximately 6,800 publications, proving marine microorganisms to be a invaluable source for the production of novel antibiotic, anti tumor, and anti inflammatory agents. The marine fungi particularly those associated with marine alga, sponge, invertebrates, and sediments appear to be a rich source for secondary metabolites, possessing Antibiotic, antiviral, antifungal and antiyeast activities. Besides, a few growth stimulant properties which may be useful in studies on wound healing, carcinogenic properties, and in the study of cancers are reported. Recent investigations on marine filamentous fungi looking for biologically active secondary metabolites indicate the tremendous potential of them as a source of new medicines. The present study reviews about some important bioactive metabolites reported from marine fungal strains which are anti bacterial, anti tumour and anti inflammatory in action. It highlights the chemistry and biological activity of the major bioactive alkaloids, polyketides, terpenoids, isoprenoid and non-isoprenoid compounds, quinones, isolated from marine fungi.

Leaf Senescence and GABA Shunt.

Leaf senescence is highly regulated and complex developmental process that involves degradation of macromolecules as well as its recycling. Senescence process involves loss of chlorophyll, degradation of proteins, nucleic acid, lipid and mobilization of nutrients through its transport to the growing parts, developing fruits and seeds. Nitrogen is the most important nutrient to be recycled in senescence process. GABA-transaminase (γ-aminobutyric acid) is found to play very important role in nitrogen recycling process through GABA-shunt. Therefore, it is of interest to review the significance of GABA shunt in leaf senescence.

An-Overview on invertase in sugarcane.

Saccharum officinarum is one of the most cultivated hybrid varieties among the sugarcane varieties. In sugarcane plant sucrose is the major carbohydrate which can be stored and transported. Different physiological and biochemical studies on this crop report that invertase activity and sucrose concentration some how are key limiting step in the process of sucrose accumulation. Significant efforts have been made in relation to the sucrose cycle by altering the sucrose phosphate synthetase, sucrose synthetase and invertase. In sugarcane two types of invertase enzymes have been reported on the basis of pH and cellular localization. Invertase breaks the sucrose into hexoses as a source of energy and carbon. It has also been reported that this enzyme is involved in the process of cell differentiation and plant development. Progress has been made for the understanding of invertase activity and its role in sugarcane plant. With the help of biotechnology it is possible to target the desired gene with genetic engineering approach to increase sucrose content by careful manipulation of invertase (enzyme) gene to increase the sucrose yield in sugarcane. Purpose of this mini review is to high-light the role of invertase in sugarcane and how to overcome sucrose recovery in sugarcane.