An overview on miRNA-encoded peptides in plant biology research.

MicroRNAs (miRNAs) are short (21-23 nt) regulatory RNA molecules present in plants and animals which are known for regulating the mRNA target gene expression either by cleavage or translational repression. With the advancements in miRNAs research in plants towards their biogenesis and applications has directed the recent discovery of pri-miRNAs encoding functional peptides or microRNA peptides (miPEPs). These miPEPs are encoded by 5' of pri-miRs containing short ORFs (miORFs). miPEPs are known to enhance the activity of their associated miRNAs by increasing their accumulation and hence downregulating the target genes. Since miPEPs are very specific for each miRNA, they are considered as novel and effective tools for improving traits of interest for plant growth promotion and plant-microbe interaction. Entire peptidome research is the need of the hour. This review thus summarizes recent advancements in miPEP research and its applications as a technology with important agronomical implications with miRNAs augmentation.

Biotechnological strategies for enhancing heavy metal tolerance in neglected and underutilized legume crops: A comprehensive review.

Contamination of agricultural land and water by heavy metals due to rapid industrialization and urbanization including various natural processes have become one of the major constraints to crop growth and productivity. Several studies have reported that to counteract heavy metal stress, plants should be able to maneuver various physiological, biochemical and molecular processes to improve their growth and development under heavy metal stress. With the advent of modern biotechnological tools and techniques it is now possible to tailor legume and other plants overexpressing stress-induced genes, transcription factors, proteins, and metabolites that are directly involved in heavy metal stress tolerance. This review provides an in-depth overview of various biotechnological approaches and/or strategies that can be used for enhancing detoxification of the heavy metals by stimulating phytoremediation processes. Synthetic biology tools involved in the engineering of legume and other crop plants against heavy metal stress tolerance are also discussed herewith some pioneering examples where synthetic biology tools that have been used to modify plants for specific traits. Also, CRISPR based genetic engineering of plants, including their role in modulating the expression of several genes/ transcription factors in the improvement of abiotic stress tolerance and phytoremediation ability using knockdown and knockout strategies has also been critically discussed.

microRNA 166: an evolutionarily conserved stress biomarker in land plants targeting HD-ZIP family.

MicroRNAs (miRNAs) are significant class of noncoding RNAs having analytical investigating and modulatory roles in various signaling mechanisms in plants related to growth, development and environmental stress. Conserved miRNAs are an affirmation of land plants evolution and adaptation. They are a proof of indispensable roles of endogenous gene modulators that mediate plant survival on land. Out of such conserved miRNA families, is one core miRNA known as miR166 that is highly conserved among land plants. This particular miRNA is known to primarily target HD ZIP-III transcription factors. miR166 has roles in various developmental processes, as well as regulatory roles against biotic and abiotic stresses in major crop plants. Major developmental roles indirectly modulated by miR166 include shoot apical meristem and vascular differentiation, leaf and root development. In terms of abiotic stress, it has decisive regulatory roles under drought, salinity, and temperature along with biotic stress management. miR166 and its target genes are also known for their beneficial synergy with microorganisms in leguminous crops in relation to lateral roots and nodule development. Hence it is important to study the roles of miR166 in different crop plants to understand its defensive roles against environmental stresses and improve plant productivity by reprogramming several gene functions at molecular levels. This review is hence a summary of different regulatory roles of miR166 with its target HD-ZIP III and its modulatory and fine tuning against different environmental stresses in various plants.

Response of Lablab purpureus L. to high temperature stress and role of exogenous protectants in mitigating high temperature induced oxidative damages.

Present study was conducted to explore the role of exogenous salicylic acid (SA), sodium nitroprusside (SNP), abscisic acid (ABA) and proline (PRO) in mitigating high-temperature (HT) induced oxidative stress in different Lablab purpureus L. cultivars. The attempt was made to examine whether these phytohormones, when applied exogenously, were able to regulate plant morpho-physiological behavior by modulating genes and proteins involved in antioxidant defense system. The HT stress induced membrane damage, degraded chlorophyll, generated redox metabolites and significantly reduced growth and biomass in all the cultivars. Among all the four treatments, foliar application of SA and SNP were most effective in the regulation of growth and physiological processes of the cultivars compared to ABA and PRO applications. Thus, signifying the protective role of SA and SNP in mitigation of HT induced oxidative stress and conferring HT stress tolerance in the cultivars. Gene expression and leaf proteome analysis revealed that these phytohormones were also involved in regulation of defense related gene expression, stress inducible proteins and de novo synthesis of specific proteins under HT stress. The experimental findings depict that foliar applications of SA and SNP enhances HT stress tolerance in lablab cultivars by modulating antioxidant defense system and by regulating bio-physical growth more effectively as compared to ABA and PRO application.

Cultivar specific variations in antioxidative defense system, genome and proteome of two tropical rice cultivars against ambient and elevated ozone.

For the past few decades continuous increase in the levels of tropospheric ozone (O3) concentrations is posing to be a threat for agricultural productivity. Two high yielding tropical rice cultivars (Malviya dhan 36 and Shivani) were evaluated against different concentrations of O3 under field conditions. Experimental design included filtered chambers, non-filtered chambers having ambient O3 and 10 and 20ppb elevated O3 above the ambient. Study was conducted to assess differential response if any in induction of antioxidative defense system, genome stability, leaf proteome, yield and quality of the product in both the test cultivars. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) were induced under ambient and elevated levels of O3. Native polyacrylamide gel electrophoresis (PAGE) of SOD, CAT and POD also displayed increased enzymatic activity along with associated alterations in specific isoforms. Ascorbic acid, thiols and phenolics were also stimulated at ambient and elevated O3. Structural alterations in DNA of rice plants due to O3 affecting its genome template stability (GTS) was examined using RAPD technique. 2-D PAGE revealed 25 differential spots in Malviya dhan 36 and 36 spots in Shivani after O3 treatment with reductions in RuBisCO subunits. Reductions in yield and change in the quality of grains were also noticed.

Effect of elevated ozone on the antioxidant response, genomic stability, DNA methylation pattern and yield in three species of Abelmoschus having different ploidy levels.

The majority of polyploids can withstand many stresses better than their monoploid counterparts; however, there is no proven mechanism that can fully explain the level of tolerance at the biochemical and molecular levels. Here, we make an effort to provide an explanation for this intriguing but perplexing issue using the antioxidant responses, genomic stability, DNA methylation pattern and yield in relation to ploidy level under the elevated level of ozone in Abelmoschus cytotypes. The outcome of this study inferred that the elevated ozone causes an increase in reactive oxygen species leading to enhanced lipid peroxidation, DNA damage and DNA de-methylation in all the Abelmoschus cytotypes. The monoploid cytotype of Abelmoschus, that is Abelmoschus moschatus L., experienced the highest oxidative stress under elevated O3, resulting in maximum DNA damage and DNA de-methylation leading to the maximum reduction in yield. While the diploid (Abelmoschus esculentus L.) and triploid (Abelmoschus caillei A. Chev.) cytotypes of Abelmoschus with lower oxidative stress result in lesser DNA damage and DNA de-methylation which ultimately leads to lower yield reduction. The result of this experiment explicitly revealed that polyploidy confers better adaptability in the case of Abelmoschus cytotypes under ozone stress. This study can further be used as a base to understand the mechanism behind the ploidy-induced stress tolerance in other plants mediated by gene dosage effect.

Arsenic-induced changes in morphological, physiological, and biochemical attributes and artemisinin biosynthesis in Artemisia annua, an antimalarial plant.

Present study is the first to explore physiological, biochemical and molecular changes in the medicinal plant Artemisia annua under arsenic (As) stress. A. annua grown hydroponically in a nutrient solution was spiked with increasing doses of As (0, 1,500, 3,000 and 4,500 µg l(-1)) for 7 days. Plants accumulated As in a dose dependent manner with bioconcentration factor 13.4 and translocation factor 0.97. While a similar trend of As accumulation was observed under soil culture experiments, the transfer factor went up to 2.1, depicting high efficiency of As translocation from roots to shoots by A. annua. Plants raised in 0-3,000 µg l(-1) As containing nutrient solution registered increase in root length, biomass, and carotenoid contents without any visual toxicity symptoms. A dose dependent increase in the activities of enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase and guaiacol peroxidase followed by a gradual decline at higher concentrations suggested their role in alleviating oxidative stress. Significant increase in the levels of thiols, GSH, and pcs gene transcript up to 3,000 µg l(-1) As attested their roles in As detoxification. Enhanced artemisinin production (an antimalarial compound) under As stress and upregulation of the transcripts (measured by RT-PCR) of the genes HMGR, FDS, ADS, and CYP71AV1 involved in artemisinin biosynthesis reaffirmed induction of artemisinin biosynthesis in A. annua under As stress. The results of the present study vividly suggested that A. annua has considerable As tolerance, and thus can be successfully cultivated in As contaminated fields.

Interactive role of salicylic acid and nitric oxide on transcriptional reprogramming for high temperature tolerance in lablab purpureus L.: Structural and functional insights using computational approaches.

Salicylic acid (SA) and nitric oxide (NO) are considered as putative plant growth regulators that are involved in the regulation of an array of plant's growth and developmental functions under environmental fluctuations when applied at lower concentrations. The possible involvement of NO in SA induced attenuation of high temperature (HT) induced oxidative stress in plants is however, still vague and need to be explored. Therefore, the present study aimed to investigates the biochemical and physiological changes induced by foliar spray of SA and NO combinations to ameliorate HT induced oxidative stress in Lablab purpureus L. Foliar application of combined SA and NO significantly improved relative water content (27.8 %), photosynthetic pigment content (67.2 %), membrane stability (45 %), proline content (1.0 %), expression of enzymatic antioxidants (7.1-18 %) along with pod yield (1.0 %). Heat Shock Factors (HSFs) play crucial roles in plants abiotic stress tolerance, however there structural and functional classifications in L. purpureus L. is still unknown. So, In-silico approach was also used for functional characterization and homology modelling of HSFs in L. purpureus. The experimental findings depicted that combine effect of SA and NO enhances tolerance in HT stressed L. purpureus L. plants by regulating physiological functions, antioxidants, expression and regulation of stress-responsive genes via transcriptional regulation of heat shock factor.

Green and cost effective synthesis of silver nanoparticles from endangered medicinal plant Withania coagulans and their potential biomedical properties.

Silver nanoparticles (AgNPs) have great potential for their mechanistic role in biomedical researches. Recently, green biosynthetic approaches have been received much attention in plant science for nanoparticles production. Therefore, in the present study AgNPs have been synthesized utilizing in-vitro grown leaf extract of anti-diabetic medicinal plant Withania coagulans Dunal by the reduction of silver nitrate solution. W. coagulans synthesized silver nanoparticles (WcAgNPs) were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, X-ray powder diffraction and Fourier transform Infra-Red spectroscopy. All cumulative results showed that WcAgNPs were ~14 nm in size having spherical shape with face centered cubic structure. High performance liquid chromatography confirmed the involvement of withanolides in AgNPs synthesis as a reducing/capping agent. Synthesized WcAgNPs showed greater antioxidative potential when compared with W. coagulans leaf extract. WcAgNPs have efficient antimicrobial potential and suppresses the growth of both gram positive and gram negative bacteria. In our finding we also observed cytotoxicity of WcAgNPs against SiHa (cervical cancerous, hyper-triploid) cell lines and apoptosis in SiHa cells after 48 hour incubation with 13.74 µg ml-1 (IC50) concentration of WcAgNPs. As results suggested, this is the first report which explain that W. coagulans leaf extract have potential as bio-reducing agent for synthesis of silver nanoparticles, which can be exploited as anti-oxidant, antimicrobial and anti-cancerous agent and depicting an effective way for utilizing bioactive resources in restoration of medicinal properties of this plant with high efficacy.

Salicylic acid and nitric oxide alleviate high temperature induced oxidative damage in Lablab purpureus L plants by regulating bio-physical processes and DNA methylation.

Salicylic acid (SA) and sodium nitroprusside (SNP, NO donor) modulates plant growth and development processes and recent findings have also revealed their involvement in the regulation of epigenetic factors under stress condition. In the present study, some of these factors were comparatively studied in hyacinth bean plants subjected to high temperature (HT) environment (40-42 °C) with and without exogenous application of SA and SNP under field condition. Exogenous application of SA and SNP substantially modulated the growth and biophysical process of hyacinth bean plants under HT environment. Exogenous application of SA and SNP also remarkably regulated the activities of antioxidant enzymes, modulated mRNA level of certain enzymes, improves plant water relation, enhance photosynthesis and thereby increasing plant defence under HT. Coupled restriction enzyme digestion-random amplification (CRED-RA) technique revealed that many methylation changes were "dose dependent" and HT significantly increased DNA damages as evidenced by both increase and decrease in bands profiles, methylation and de-methylation pattern. Thus, the result of the present study clearly shows that exogenous SA and SNP regulates DNA methylation pattern, modulates stress-responsive genes and can impart transient HT tolerance by synchronizing growth and physiological acclimatization of plants, thus narrowing the gaps between physio-biochemical and molecular events in addressing HT tolerance.

Protective effect of Pueraria tuberosa DC. embedded biscuit on cisplatin-induced nephrotoxicity in mice.

Recently, the nephroprotective property of Pueraria tuberosa DC. tuber (PT) has been reported by our group. Here, PT-embedded biscuits were prepared and tested on cisplatin-induced nephrotoxicity in Swiss albino mice. The PT powder was characterized by RAPD (random amplified polymorphic DNA) to ascertain its authenticity and PT biscuits were prepared in different concentrations (1, 2, or 4 g of PT powder). These biscuits were given as diet for a total of 10 days, but on the 7th day cisplatin injection (8 mg/kg bw, i.p.) was given. On the 10th day animals were killed to collect kidneys for assessment of antioxidant status. Blood samples were collected on both the 7th and 10th days for assessment of liver and kidney functions. In mice, PT biscuit showed significant protection against cisplatin-induced nephrotoxicity, but there was a transient rise in alanine aminotransferase and aspartate aminotransferase at the dose of 4 g PT biscuit. Therefore, it is suggested that PT biscuit might be an effective food supplement for cancer patients undergoing cisplatin-chemotherapy. However, periodical liver function monitoring is required, especially when PT is used for longer periods or at higher doses.