Unfolding molecular switches in plant heat stress resistance: A comprehensive review.

KEY MESSAGE: Plant heat stress response is a multi-factorial trait that is precisely regulated by the complex web of transcription factors from various families that modulate heat stress responsive gene expression. Global warming due to climate change affects plant growth and development throughout its life cycle. Adds to this, the frequent occurrence of heat waves is drastically reducing the global crop yield. Molecular plant scientists can help crop breeders by providing genetic markers associated with stress resistance. Plant heat stress response (HSR), however, is a multi-factorial trait and using a single stress resistance trait might not be ideal to develop thermotolerant crops. Transcription factors participate in regulation of plant biological processes and environmental stress responses. Recent studies have revealed that plant HSR is precisely regulated by the complex web of transcription factors from various families. These transcription factors enhance plant heat stress tolerance by regulating the expression level of several stress-responsive genes independently or in cross talk with different other transcription factors. This review explores how signaling pathways triggered by heat stress are regulated by multiple transcription factor families. To our knowledge, we for the first time analyze the role of major transcription factor families in plant HSR along with their regulatory mechanisms. In the end, we will also discuss the potential of emerging technologies to improve thermotolerance in plants.

Molecular mechanisms of plant tolerance to heat stress: current landscape and future perspectives.

KEY MESSAGE: We summarize recent studies focusing on the molecular basis of plant heat stress response (HSR), how HSR leads to thermotolerance, and promote plant adaptation to recurring heat stress events. The global crop productivity is facing unprecedented threats due to climate change as high temperature negatively influences plant growth and metabolism. Owing to their sessile nature, plants have developed complex signaling networks which enable them to perceive changes in ambient temperature. This in turn activates a suite of molecular changes that promote plant survival and reproduction under adverse conditions. Deciphering these mechanisms is an important task, as this could facilitate development of molecular markers, which could be ultimately used to breed thermotolerant crop cultivars. In current article, we summarize mechanisms involve in plant heat stress acclimation with special emphasis on advances related to heat stress perception, heat-induced signaling, heat stress-responsive gene expression and thermomemory that promote plant adaptation to short- and long-term-recurring heat-stress events. In the end, we will discuss impact of emerging technologies that could facilitate the development of heat stress-tolerant crop cultivars.

Assessment of phytochemicals, antioxidant, anti-hemolytic, anti-inflammatory and anti-cancer potential of flowers, leaves and stem extracts of.

OBJECTIVE: To evaluate phytochemicals and in vitro biological potential of flowers, leaves and stem extracts of Rosa arvensis. METHODS: Presence of twenty secondary metabolites was confirmed and then phenolic and flavonoid contents were quantified spectrophotometrically. Fourier Transform Infrared spectroscopy was conducted to ascertain functional groups and antioxidant potential was examined using 2,2-diphenyl-1-picrylhydrazyl scavenging activity, total antioxidant capacity and total reducing power assays. Human erythrocytes were used to assess anti-hemolytic activity and five bacterial strains were examined to determine antibacterial potential of plant extracts. Radish seeds were used to perform phytotoxic activity and cytotoxic potential was evaluated via brine shrimps and PC3 cell lines. RESULTS: Highest phenolic contents were detected in the methanolic extract of Rosa arvensis flower (RAFM) [(151.635 ± 0.005) gallic acid equivalent mg/g] and highest flavonoid contents in the chloroform leaf extract (RALC) [(108.228 ± 0.004) quercetin equivalent mg/g]. Fourier-transform infrared spectroscopy analysis showed the presence of wide range of functional groups. The antioxidant assays indicated highest DPPH scavenging activity [IC50 (23.5 ± 0.6) µg/mL] in the methanolic stem extract (RASM), highest total antioxidant capacity [(265.1 ± 0.9) µg/mL] in RAFM and highest reducing potential [(209.9 ± 0.6) µg/mL] in leaf extract (RALM). Highest anti-hemolytic activity [(90.0 ± 0.5) µg/mL] was recorded in RAFM and brine shrimp cytotoxicity potential [(52.3 ± 0.3) µg/mL] in RASM. The antimicrobial activity was detected highest [(21.1 ± 0.5) mm inhibition zones] in RALM against Streptococcus aureus. In the end, anti-inflammatory and anti-cancer activity results depicted less than 50 % inhibition in the methanolic extracts. CONCLUSIONS: Our findings will be helpful in designing pharmaceutical regimens and therefore, more studies can be recommended to isolate and characterize compounds associated with the biological activities of Rosa arvensis.

In-silico analysis and transformation of OsMYB48 transcription factor driven by CaMV35S promoter in model plant - Nicotiana tabacum L. conferring abiotic stress tolerance.

Global crop yield has been affected by a number of abiotic stresses. Heat, salinity, and drought stress are at the top of the list as serious environmental growth-limiting factors. To enhance crop productivity, molecular approaches have been used to determine the key regulators affecting stress-related phenomena. MYB transcription factors (TF) have been reported as one of the promising defensive proteins against the unfavorable conditions that plants must face. Different roles of MYB TFs have been suggested such as regulation of cellular growth and differentiation, hormonal signaling, mediating abiotic stress responses, etc. To gain significant insights, a comprehensive in-silico analysis of OsMYB TF was carried out in comparison with 21 dicot MYB TFs and 10 monocot MYB TFs. Their chromosomal location, gene structure, protein domain, and motifs were analyzed. The phylogenetic relationship was also studied, which resulted in the classification of proteins into four basic groups: groups A, B, C, and D. The protein motif analysis identified several conserved sequences responsible for cellular activities. The gene structure analysis suggested that proteins that were present in the same class, showed similar intron-exon structures. Promoter analysis revealed major cis-acting elements that were found to be responsible for hormonal signaling and initiating a response to abiotic stress and light-induced mechanisms. The transformation of OsMYB TF into tobacco was carried out using the Agrobacterium-mediated transformation method, to further analyze the expression level of a gene in different plant parts, under stress conditions. To summarize, the current studies shed light on the evolution and role of OsMYB TF in plants. Future investigations should focus on elucidating the functional roles of MYB transcription factors in abiotic stress tolerance through targeted genetic modification and CRISPR/Cas9-mediated genome editing. The application of omics approaches and systems biology will be indispensable in delineating the regulatory networks orchestrated by MYB TFs, facilitating the development of crop genotypes with enhanced resilience to environmental stressors. Rigorous field validation of these genetically engineered or edited crops is imperative to ascertain their utility in promoting sustainable agricultural practices.

Deciphering chemical profiling, pharmacological responses and potential bioactive constituents of Saussurea lappa Decne. Extracts through in vitro approaches.

Despite advancement in modern medicines, plant derived medicines have still wide range utilities as they have less side effects and are cheap and biocompitable. Sassurea lappa is an extensively used plant in traditional medicinal formulations. Plant roots are used to cure various diseases including cancer, rheumatic pain, abdominal and nervous disorders. The present study was aimed for the evalution of biological potentials of methanolic and chloroform extracts of Saussurea lappa root, leaf, seed and flower. The methanolic and chloroform extracts were subjected to qualitative and quantitative phytochemical analyses. Identification of functional groups was performed using Fourier Transform infrared (FT-IR) spectroscopy. Antioxidant potential was determined via diphenyl-1-picrylhydrazyl (DPPH), total reducing power (TRP) and total antioxidant capacity (TAC) method, anti-hemolytic potential was conducted on human RBCs, antibacterial activity was evaluated against six American type culture collection (ATCC) and three multi drug resistance (MDR) strains, cytotoxic and phytotoxic potentials were evaluated through brine shrimp lethality assay and raddish seed assay respectively. Experiments were performed in triplicates and analysis of variance (ANOVA) was applied using statistics version-8.1. Phytochemical analysis revealed the presence of sixteen secondary metabolites. Fourteen functional groups were identified through FTIR. S. lappa root methanolic (SLRM) showed maximum antioxidant activity index (AAI-79.42%) whereas chloroform extract of leaves (SLLC) gave highest antibacterial activity with maximum zone of inhibition (ZOI) against Pseudomonas aeruginosa (21.4 mm). Maximum cytotoxicity was observed for SLRM with lethal dose concentration (LC50) of 58.8 µg/mL. However, root extracts showed significant phytotoxicity (15% germination). The current study investigated that bioactive compounds present in S. lappa leaves, seed, flower and roots were responsible for enhanced biological potentials. Further studies on isolation and characterization of these bioactive compounds may help in drug development. In future, we recommend different in-vitro and in-vivo studies to further confirm it biopharmacological potencies.

A pilot study of the Leicester ED medical infrared imaging protocol in fever and sepsis.

BACKGROUND: Medical Infrared Imaging (MII) is an investigative method that can be potentially used in emergency care to non-invasively detect thermal signatures associated with change in blood flow. We have developed a protocol for the use of MII in the Emergency Department (ED) and shown that it is feasible. To derive initial data for sample size calculations, we performed an exploratory study in patients with fever and sepsis. METHODS: The Leicester MII protocol was used to image the temperature patterns along the arm among three patient groups (control, fever and sepsis) of a total 56 patients. Anatomical markers were used to divide this gradient into upper arm, forearm, hand and finger regions. Variations in measurements within and between these regions were described. RESULTS: The thermal gradient down the arm was successfully extracted in all patients. The distribution of values in each region of the arm was described in control, fever and sepsis patients. There was a significant gradient between upper arm and finger in controls (2.75, p < 0.0001), but no gradient in fever (p = 0.944) or sepsis (p = 0.710). This was reflected in the finger/arm difference, which was of -2.74°C (±3.50) in controls, -0.39C (±2.48) in fever, and -1.80°C (±3.09) in sepsis. CONCLUSIONS: This study found different thermal gradients along the arm in control and febrile groups, and defined the degree of individual variation. It is likely that the difference between upper arm temperature and finger temperature (representing the temperature gradient down the arm) may be more useful than absolute measurements in future studies.