Increasing vulnerability of plants to a variety of stresses such as drought, salt and extreme temperatures poses a global threat to sustained growth and productivity of major crops. Of these stresses, drought represents a considerable threat to plant growth and development. In view of this, developing staple food cultivars with improved drought tolerance emerges as the most sustainable solution toward improving crop productivity in a scenario of climate change. In parallel, unraveling the genetic architecture and the targeted identification of molecular networks using modern “OMICS” analyses, that can underpin drought tolerance mechanisms, is urgently required. Importantly, integrated studies intending to elucidate complex mechanisms can bridge the gap existing in our current knowledge about drought stress tolerance in plants. It is now well established that drought tolerance is regulated by several genes, including transcription factors (TFs) that enable plants to withstand unfavorable conditions, and these remain potential genomic candidates for their wide application in crop breeding. These TFs represent the key molecular switches orchestrating the regulation of plant developmental processes in response to a variety of stresses. The current review aims to offer a deeper understanding of TFs engaged in regulating plant’s response under drought stress and to devise potential strategies to improve plant tolerance against drought.

Plants are subjected to a wide range of environmental stresses which reduces and limits the productivity of agricultural crops. Two types of environmental stresses are encountered to plants which can be categorized as (1) Abiotic stress and (2) Biotic stress. The abiotic stress causes the loss of major crop plants worldwide and includes radiation, salinity, floods, drought, extremes in temperature, heavy metals, etc. On the other hand, attacks by various pathogens such as fungi, bacteria, oomycetes, nematodes and herbivores are included in biotic stresses. As plants are sessile in nature, they have no choice to escape from these environmental cues. Plants have developed various mechanisms in order to overcome these threats of biotic and abiotic stresses. They sense the external stress environment, get stimulated and then generate appropriate cellular responses. They do this by stimuli received from the sensors located on the cell surface or cytoplasm and transferred to the transcriptional machinery situated in the nucleus, with the help of various signal transduction pathways. This leads to differential transcriptional changes making the plant tolerant against the stress. The signaling pathways act as a connecting link and play an important role between sensing the stress environment and generating an appropriate biochemical and physiological response.

Extreme temperatures are considered one of the main constraints that limit the growth and development of rice. We elucidated the root and shoot developmental plasticity of 64 rice genotypes during early seedling establishment, using the sunlit plant growth chambers at 22/14 (low), 30/22 (optimum), and 38/30 °C (high) day/night temperatures. Low temperature severely inhibited 23 traits, such as shoot (68%), root (57%), and physiological (35%) attributes. On the contrary, the high temperature positively affected most of the shoot (48%) and root (31%) traits, except root diameter and root/shoot ratio, compared with the optimum. Alternatively, leaf chlorophyll fluorescence-associated parameters declined under low (34%) and high (8%) temperatures. A weak correlation between cumulative high-temperature response index (CHTRI) and cumulative low-temperature response index (CLTRI) indicates the operation of different low- and high-temperature tolerance mechanisms at the early seedling stage. Groups of distinct rice genotypes associated with low or high-temperature tolerance were selected based on CHTRI and CLTRI. The genotypes that commonly performed well under low and high temperatures (IR65600-81-5-2-3, CT18593-1-7-2-2-5, RU1504114, RU1504122, Bowman, and INIA Tacuari) will be valuable genetic resources for breeders in developing early-season high- and low-temperature-tolerant genotypes for a broad range of both tropical and temperate rice-growing environments.

Bunium persicum (Boiss), B. Fedtsch or Black cumin, is an economically important medicinal spice that is commonly used as a flavour enhancer and preservative in different food systems. It has also been used in Unani, Iranian, and Indian systems of traditional medicine. A member of the Apiaceae family, it possesses myriad phytochemicals, mainly cuminaldehyde, α-terpinene-7-al, γ-terpinene-7-al, γ-terpinene, ρ-cymene, β-Pinene, etc. and endows various proven therapeutic properties including antioxidant, antimicrobial, anti-inflammatory, lipid/glucose lowering activity, anti-carcinogenic activities, etc. This plant grows in the wild in specific areas and is scarcely available and over-exploited; hence, its conservation (both, in vitro and in situ) is a major concern. Besides, negligible work has been done for molecular characterisation, identification and development of promising high yielding cultivars/varieties of this valuable plant. With the aim to attract the attention of potential stakeholders towards the immense potential and infinite qualities of black cumin, this review provides an insight in to the phytochemistry, economic importance, including food and therapeutic uses; morphological, biochemical, and molecular characteristics of Bunium persicum, along with the efforts towards its conservation and a way forward. Abbreviations BPEO: Bunium persicum essential oil; BPE: B. persicum extract; MPEO: Mentha piperita essential oil; DPPH: 2,2-Diphenyl-1-picrylhydrazyl; TBA: Thiobarbituric acid; TPC: Total phenolic content; LD₅₀: Lethal dose; IC₅₀: Half maximal inhibitory concentration; BHT: Butylated hydroxy toluene; BHA: Butylated hydroxy anisole; ABTS: 2,2ʹ-Azino-bis (3-ethyl benzo thiazoline-6-sulphonic acid); MICs: Minimum inhibitory concentrations; BSA: Bovine serum albumin; MS: Murashige and Skoog Medium; MSN: Murashige and Skoog medium with Nitsch Vitamins; B₅: Gamborg’s Medium; 2,4-D: 2,4-dichlorophenoxyacetic acid; Kin: Kinetin; JA: Jasmonic acid; IAA: Indole-3-acetic acid; BAP: 6-Benzylaminopurine; IBA: Indole-3-Butyric Acid; TDZ: Thidiazuron; GA₃: Gibberellic Acid; ABA: Abscisic Acid.

The present investigation was performed to evaluate the variability of the essential oil composition present in the seed extract of Kala zeera (Bunium persicum Bioss.) obtained from different geographical zones of Northwestern-Himalayan using Gas Chromatography-Mass Spectrum (GC-MS). The results of the GC-MS analysis revealed significant differences in the essential oil content. Significant variability was observed in the chemical constituents of the essential oils mainly for p-cymene, D-limonene, Gamma-terpinene, Cumic aldehyde and 1, 4-p-menthadien-7-al. Among these compounds, the highest average percentage across the locations was observed for gamma-terpinene (32.08%) which was followed by cumic aldehyde (25.07%), and 1, 4-p-menthadien-7-al (15.45%). Principal component analysis (PCA) also grouped the 4 highly significant compounds i.e., p-Cymene, Gamma-Terpinene, Cumic aldehyde, and 1,4-p-Menthadien-7-al into same cluster which are mainly distributed in Shalimar Kalazeera-1, and Atholi Kishtwar zones. The highest value of gamma-terpinene was recorded in Atholi accession (40.66%). However, among climatic zones Zabarwan Srinagar and Shalimar Kalazeera-1 was found to have highly positive significant correlation (0.99). The cophenetic correlation coefficient (c) was found to be 0.8334 during hierarchical clustering for 12 essential oil compounds showing that our results are highly correlated. Network analysis also showed the overlapping pattern and similar interaction between the 12 compounds as shown by hierarchical clustering analysis. From the results, it could be concluded that existence of variability among the various bioactive compounds of B. persicum which are probably to be incorporated to the potential list of drugs and may serve as good genetic source for various modern breeding programs.