Browsing by Author "Chhatwal, Himani"

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Broadening the epigenetic horizon of abiotic stress response in plants
(Springer Nature Publishing AG, 2024) Chhatwal, Himani; Naik, Jogindra; Pandey, Ashutosh; Trivedi, Prabodh Kumar
Plants, unlike animals, cannot move from one place to another and have to face different climatic disturbances wherever they are growing. So, they have innumerable built-in mechanisms to adapt to various abiotic stressful conditions like drought, heat, cold, and salinity. The changing environmental conditions influence the expression patterns of genes. Epigenetics involves heritable changes in DNA bases or histone proteins, which ultimately create different conformational states of chromatin. The regulatory enzymes of epigenetic modifications are grouped as writers, readers and erasers, which add, recognize and remove the epigenetic marks, respectively. Here, we provide a comprehensive overview of the mechanism of DNA methylation by the RdDM pathway, its maintenance and removal, and different histone modification categories like acetylation, methylation, phosphorylation and ubiquitination. This review further discusses in detail the crucial role these modifications play in adapting to major abiotic stresses and how plants preserve these experiences as stress memory to respond to recurring stresses. It emphasizes the role of epigenetic modifications as a crucial mechanism for building plant’s tolerance and how it can be an important research priority to improve plant growth and development under abiotic stress conditions.
CaLAP1 and CaLAP2 orchestrate anthocyanin biosynthesis in the seed coat of Cicer arietinum
(Springer Nature Publishing AG, 2024) Singh, Samar; Pal, Lalita; Rajput, Ruchika; Chhatwal, Himani; Singh, Nidhi; Chattopadhyay, Debasis; Pandey, Ashutosh
The seed coat color is a major economic trait in leguminous crop chickpea (Cicer arietinum). Anthocyanins and proanthocyanidins (PAs) are two classes of flavonoids that mainly contribute to the flower, seed coat and color of Desi chickpea cultivars. Throughout the land plant lineage, the accumulation of anthocyanins and PAs is regulated by MYB and bHLH transcription factors (TFs), which form an MBW (MYB, bHLH, and WD40) complex. Here, we report two R2R3-MYB TFs in chickpea belonging to the anthocyanin-specific subgroup-6, CaLAP1 (Legume Anthocyanin Production 1), and CaLAP2 (Legume Anthocyanin Production 2), which are mainly expressed in the flowers and developmental stages of the seeds. CaLAP1 and CaLAP2 interact with TT8-like CabHLH1 and WD40, forming the MBW complex, and bind to the promoter sequences of anthocyanin- and PA biosynthetic genes CaCHS6, CaDFR2, CaANS, and CaANR, leading to anthocyanins and PA accumulation in the seed coat of chickpea. Moreover, these CaLAPs partially complement the anthocyanin-deficient phenotype in the Arabidopsis thaliana sextuple mutant seedlings. Overexpression of CaLAPs in chickpea resulted in significantly higher expression of anthocyanin and PA biosynthetic genes leading to a darker seed coat color with higher accumulation of anthocyanin and PA. Our findings show that CaLAPs positively modulate anthocyanin and PA content in seed coats, which might influence plant development and resistance to various biotic and abiotic stresses.
Climate change impact on human health
(CABI, 2024) Singh, Samar; Chhatwal, Himani; Pandey, Ashutosh
Variations in environmental conditions caused by natural or anthropogenic activities have been exhibiting their impacts on climate change in the form of heat waves, drought, acid rain, floods, and storms throughout the decades. The resulting climate change has perturbated the interrelated threats to the ecosystem. Climate change affects human health, causing mental illness, undernutrition, and cardiovascular, respiratory, and infectious diseases. This outcome is observed in terms of worldwide disturbance in social dynamics such as health status, socioeconomic status, and public health infrastructure. This chapter explores the adverse climate conditions and highlights footprints on human health. Strategies to reduce the catastrophic impact of climate change on humans have been discussed in the latter sections.
Deciphering the complexity of terpenoid biosynthesis and its multi-level regulatory mechanism in plants
(Springer Nature Publishing AG, 2024) Singh, Samar; Chhatwal, Himani; Pandey, Ashutosh
Terpenoids are one of the essential plant metabolites which are known to play vital roles in plants' primary growth and development including protection from biotic and abiotic stresses. They have huge structural diversity and are known to provide various health benefits, flavors, fragrances, essential oils, cosmetics, pigments, insecticides, etc. The biosynthesis of terpenoids by mevalonic acid (MVA) and methylerythritol pathway (MEP) occurs inside the cytoplasm and the chloroplast, respectively. Here, we provide a comprehensive overview of synthesis, metabolic, and regulatory pathways of terpenoid, their different classes and ecological roles. We also discuss in detail the key transcription factors (TFs) like WRKY, AP2/ERF, bHLH, MYB, NAC, and bZIP which reprogram and modulate the terpenoid pathway in plants. It also includes the post-transcriptional and post-translational modifications of these pathways. The post-transcriptional regulation by microRNA plays a critical role in the synthesis and regulation of the terpenoid. MAP kinases also regulate the stability of biosynthetic enzymes and transcription factors to regulate terpenoid biosynthesis. High-throughput sequencing technology and functional genomics have further strengthened our understanding of this pathway and associated regulatory genes which control it. As a future perspective, modifying these transcription factors via various strategies holds promise for improvement of agricultural crop plants in terms of nutritional enrichment, stress responsiveness, and resistance.
Hotspots associated with climate change and food security risks
(CABI, 2024) Chhatwal, Himani; Singh, Samar; Pandey, Ashutosh
Climate change is an emerging problem, threatening nations at a global stage. Our knowledge about the impact of climate change on agriculture has grown over the past two decades, but recently, it has been found that its effects are even more deep-rooted. Anthropogenic and natural activities are increasing global temperatures at an alarming rate, affecting crop productivity. Extreme weather events will impact food supply, stability, and access. In the current times of increasing population, when wholesome food production is a global concern, climate change becomes an inevitable issue that no nation can escape from. This chapter highlights the major hotspots of the world which face an immediate threat from climate change. It also covers the perils of changing climate on the food production system and the adaptation strategies to overcome it. The need is to focus on developing immediate solutions to develop a sustainable food supply in the future.