Lateral rooting confers essential plasticity to root system architecture, ensuring efficient growth and stress adaptations. Auxin has long been associated with lateral root development, but the intricate regulatory mechanism remains elusive. Here, we show that ABI3, a B3-domain transcription factor, controls lateral root formation by intercepting auxin response in Arabidopsis thaliana. ABI3 deletion promotes lateral rooting, characterised by higher primordia number, density, accelerated emergence and enhanced auxin response, compared to wild-type. While optimum auxin is known to promote lateral rooting, excess auxin inhibits it. We show that auxin concentrations that impair lateral root development augment ABI3 expression. Transactivation assay and ChIP-based results indicate that the auxin-responsive factor ARF19 weakly induces ABI3 expression, probably as part of a secondary auxin response, coupled with ABI3-mediated autoactivation, resulting in higher transcriptional output. ABI3 functions as a transcriptional repressor of MYC2. MYC2 affects auxin biosynthesis and signalling through ERF109 and ASA1, followed by the downstream module of ARF7/19-LBD29, to ensure efficient lateral root development. ABI3-mediated repression of MYC2 acts to attenuate this pathway, restricting lateral root formation. Absence of ABI3 thus augments auxin signalling through MYC2, effectively promoting enhanced lateral root proliferation. ABI3, therefore, functions as a critical regulator that fine-tunes auxin signalling to balance lateral root growth.

Root growth and modulation in plants is a highly dynamic yet strictly regulated process. Primary root development in Arabidopsis for example, is an intricate balance between cell division in the meristematic zone and cell elongation in the elongation zone, followed by subsequent differentiation. This process involves an orchestrated series of events that depend on environmental and developmental cues. Regulation is imparted by a complex network of hormone signaling primarily involving auxin, in crosstalk with cytokinin, abscisic acid, jasmonic acid, ethylene and others. In course of evolution, plants have developed an incredible array of mechanisms to address water scarcity, including modulation of root system architecture. During low to moderate water deficiency plants, adopt a “searching-for-water” strategy evoking growth-promoting responses. This is marked by elongation of the primary root for water exploration in deeper soil layers. However, during severe drought stress, plants resort to a “stop growth” strategy and restrict root growth, to conserve resources and energy for survival. The balance between these adaptive responses is critically regulated by key phytohormones which interact synergistically or antagonistically, to control root growth under varying levels of water shortage. Understanding these adaptation strategies as to how plants integrate environmental cues and associated hormone signaling to influence root growth generates a wide range of possibilities for agricultural innovation. This article aims to provide an overview of the mechanisms acquired by the root system at the morphological, physiological, and molecular levels, under optimum growth conditions and in response to varying degrees of water paucity. The root system architecture and its modulation under various developmental and environmental cues, is a manifestation of complex hormonal signalling. It involves reprogramming gene expression and consequent timely morphological changes.

Background: COPD (chronic obstructive pulmonary disease) is a serious health problem worldwide. Present treatments are insufficient and have severe side effects. There is a critical shortage of possible alternative treatments. Medicinal herbs are the most traditional and widely used therapy for treating a wide range of human illnesses around the world. In several countries, different plants are used to treat COPD.Purpose: In this review, we have discussed several known cellular and molecular components implicated in COPD and how plant-derived chemicals might modulate them.Methods: We have discussed how COVID-19 is associated with COPD mortality and severity along with the phytochemical roles of a few plants in the treatment of COPD. In addition, two tables have been included; the first summarizes different plants used for the treatment of COPD, and the second table consists of different kinds of phytochemicals extracted from plants, which are used to inhibit inflammation in the lungs.Conclusion: Various plants have been found to have medicinal properties against COPD. Many plant extracts and components may be used as novel disease-modifying drugs for lung inflammatory diseases.

Plants combat dehydration stress through different strategies including root architectural changes. Here we show that when exposed to varying levels of dehydration stress, primary root growth in Arabidopsis is modulated by regulating root meristem activity. Abscisic acid (ABA) in concert with auxin signalling adjust primary root growth according to stress levels. ABSCISIC ACID INSENSITIVE 3 (ABI3), an ABA-responsive transcription factor, stands at the intersection of ABA and auxin signalling and fine-tunes primary root growth in response to dehydration stress. Under low ABA or dehydration stress, induction of ABI3 expression promotes auxin signalling by decreasing expression of SHY2, a negative regulator of auxin response. This further enhances the expression of auxin transporter gene PIN1 and cell cycle gene CYCB1;1, resulting in an increase in primary root meristem size and root length. Higher levels of dehydration stress or ABA repress ABI3 expression and promote ABSCISIC ACID INSENSITIVE 5 (ABI5) expression. This elevates SHY2 expression, thereby impairing primary root meristem activity and retarding root growth. Notably, ABI5 can promote SHY2 expression only in the absence of ABI3. Such ABA concentration-dependent expression of ABI3 therefore functions as a regulatory sensor of dehydration stress levels and orchestrates primary root growth by coordinating its downstream regulation.

Post-embryonic primary root growth is effectively an interplay of several hormone signalling pathways. Here, we show that the ABA-responsive transcription factor ABI3 controls primary root growth through the regulation of JA signalling molecule JAZ1 along with ABA-responsive factor ABI1. In the absence of ABI3, the primary root elongation zone is shortened with significantly reduced cell length. Expression analyses and ChIP-based assays indicate that ABI3 negatively regulates JAZ1 expression by occupying its upstream regulatory sequence and enriching repressive histone modification mark H3K27 trimethylation, thereby occluding RNAPII occupancy. Previous studies have shown that JAZ1 interacts with ABI1, the protein phosphatase 2C, that works during ABA signalling. Our results indicate that in the absence of ABI3, when JAZ1 expression levels are high, the ABI1 protein shows increased stability, compared to when JAZ1 is absent, or ABI3 is overexpressed. Consequently, in the abi3-6 mutant, due to the higher stability of ABI1, reduced phosphorylation of plasma membrane H+-ATPase (AHA2) occurs. HPTS staining further indicated that abi3-6 root cell apoplasts show reduced protonation, compared to wild-type and ABI3 overexpressing seedlings. Such impeded proton extrusion negatively affects cell length in the primary root elongation zone. ABI3 therefore controls cell elongation in the primary root by affecting the ABI1-dependent protonation of root cell apoplasts. In summary, ABI3 controls the expression of JAZ1 and in turn modulates the function of ABI1 to regulate cell length in the elongation zone during primary root growth.

The need for better productivity, improvement, and protection of crops from a majority of diseases has become essential. One such role is played by small RNAs (sRNAs), which are sequenced via different techniques. This entire mechanism is conducted via the regulation or silencing of plants. SRNAs are associated with proteins, namely, ribonucleoprotein (RNP), Argonaute (AGO), and Dicer-like proteins (DCL). Due to this, the expression level of other genes can be regulated. In terms of classification, sub-classes of sRNA give protection against viral pathogens via SRGE mechanisms. The discovery of novel miRNAs is possible with sRNA deep sequencing, which enhances the ability to resist different types of stress conditions. With this technique, major crops such as pearl millet and wheat have attained tolerance against salinity, and tomato and wheat attained tolerance to drought by the action of different types of sRNAs. Taking this into consideration, this chapter elaborates and emphasizes the roles of sRNAs in improving crops against drought, salinity, and pollen fertility.

Piperine and piperidine are the two major alkaloids extracted from black pepper (Piper nigrum); piperidine is a heterocyclic moiety that has the molecular formula (CH2)5NH. Over the years, many therapeutic properties including anticancer potential of these two compounds have been observed. Piperine has therapeutic potential against cancers such as breast cancer, ovarian cancer, gastric cancer, gliomal cancer, lung cancer, oral squamous, chronic pancreatitis, prostate cancer, rectal cancer, cervical cancer, and leukemia. Whereas, piperidine acts as a potential clinical agent against cancers, such as breast cancer, prostate cancer, colon cancer, lung cancer, and ovarian cancer, when treated alone or in combination with some novel drugs. Several crucial signalling pathways essential for the establishment of cancers such as STAT-3, NF-κB, PI3k/Aκt, JNK/p38-MAPK, TGF-ß/SMAD, Smac/DIABLO, p-IκB etc., are regulated by these two phytochemicals. Both of these phytochemicals lead to inhibition of cell migration and help in cell cycle arrest to inhibit survivability of cancer cells. The current review highlights the pharmaceutical relevance of both piperine and piperidine against different types of cancers.

The rice and wheat agricultural system is the primary source of food for billions across the world. However, the productivity and long-term sustainability of rice and wheat are threatened by a large number of abiotic stresses, especially salinity stress. Salinity has a significant impact on plant development and productivity and is one of the leading causes of crop yield losses in agricultural soils worldwide. Over the last few decades, several attempts have been undertaken to enhance salinity stress tolerance, most of which have relied on traditional or molecular breeding approaches. These approaches have so far been insufficient in addressing the issues of abiotic stress. However, due to the availability of genome sequences for cereal crops like rice and wheat and the development of genome editing techniques like clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein9 (Cas9), it is now possible to "edit" genes and influence key traits. Here, we review the application of the CRISPR/Cas9 system in both rice (Oryza sativa L.) and wheat (Triticum aestivum L.) to develop salinity tolerant cultivars. The CRISPR/Cas genome editing toolkit holds great promise of producing cereal crops tolerant to salt stress to increase agriculture resilience with a strong impact on the environment and public health.

Plants produce a large number of secondary metabolites, known as phytometabolites that may be employed as medicines, dyes, poisons, and insecticides in the field of medicine, agriculture, and industrial use, respectively. The rise of genome management approaches has promised a factual revolution in genetic engineering. Targeted genome editing in living entities permits the understanding of the biological systems very clearly, and also sanctions to address a wide-ranging objective in the direction of improving features of plant and their yields. The last few years have introduced a number of unique genome editing systems, including transcription activator-like effector nucleases, zinc finger nucleases, and miRNA-regulated clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9). Genome editing systems have helped in the transformation of metabolic engineering, allowing researchers to modify biosynthetic pathways of different secondary metabolites. Given the growing relevance of editing genomes in plant research, the exciting novel methods are briefly reviewed in this chapter. Also, this chapter highlights recent discoveries on the CRISPR-based modification of natural products in different medicinal plants.

Global agricultural demand and the impact of fluctuating climatic conditions including global warming have catastrophically limited crop productivity and immensely outstretched the market value of agricultural products leading to acute inflation. The effect of desiccation or drought stress in plants is manifested at three levels viz. morphological, biochemical, and molecular and plants possess their own molecular and signaling arsenal to combat or ameliorate various stresses. For decades, stress-tolerant cultivars have been investigated and modulation of polyamine (PA) signaling was found to play a major role in attenuating environmental stresses including drought as major abiotic stress. PA metabolism pathways with their ability to crosstalk with both primary and secondary metabolic pathways have been correlated with several other responses such as seed germination, plant growth, development, defense, hormonal regulation, stress tolerance, and crop yield. Recent transcriptomic and metabolomic approaches have expanded the knowledge on the regulation of stress-induced biochemical, molecular, and physiological alterations. To fully comprehend the intricate biochemical network of plant stress physiology, it is necessary to identify exact responses against specific stress stimuli, interpret concurrent epigenetic alterations, and use molecular switching. The present review encompasses recent updates on drought tolerance mechanisms mediated by diverse polyamines playing significant roles in metabolic regulation, oxidative stress management, and systematic stress-reversal signaling. Besides, the drought stress-reversal role of polyamines and their cross-talks with other signaling molecules have also been documented. Gene, enzyme, and transcription factor (TF) functional features were retrieved from the published papers involving transgenic or mutant plants with over-expression or loss-of-function investigations.

Neoechinulins are fungal and plant-derived chemicals extracted from Microsporum sp., Eurotium rubrum, Aspergillus sp., etc. Two analogues of neoechinulin, i.e., A and B, exerted extensive pharmacological properties described in this review. Neoechinulin is an indole alkaloid and has a double bond between C8/C9, which tends to contribute to its cytoprotective nature. Neoechinulin A exhibits protection to PC12 cells against nitrosative stress via increasing NAD(P)H reserve capacity and decreasing cellular GSH levels. It also confers protection via rescuing PC12 cells from rotenone-induced stress by lowering LDH leakage. This compound has great positive potential against neurodegenerative diseases by inhibiting SIN-1 induced cell death in neuronal cells. Together with these, neoechinulin A tends to inhibit Aβ42-induced microglial activation and confers protection against neuroinflammation. Alongside, it also inhibits cervical cancer cells by caspase-dependent apoptosis and via upregulation of apoptosis inducing genes like Bax, it suppresses LPS-induced inflammation in RAW264.7 macrophages and acts as an antidepressant. Whereas, another analogue, Neoechinulin B tends to interfere with the cellular mechanism thereby, inhibiting the entry of influenza A virus and it targets Liver X receptor (LXR) and decreases the infection rate of Hepatitis C. The present review describes the pharmaceutical properties of neoechinulins with notes on their molecular, cellular, and functional basis and their therapeutic properties.

Phytohormones play significant roles in plants for its growth and development. These phytohormones have been identified to regulate stress tolerance in plants. Gibberellic acid is one such phytohormones which carries out several important roles, GA crosstalk with many other phytohormones like ethylene, jasmonic acid, brassinosteroids, strigolactones which further leads to increased tolerance to stresses such as drought, salinity, extreme temperature, etc. This chapter focuses in the signalling mechanism of GA along with its crosstalk with other related phytohormones in different plants.