Lipoxygenases: The gatekeepers in plant resilience against biotic stress

Climate change and extreme environmental conditions are recognized as the most challenging threats to agricultural systems, leading to significant limitations in crop production and yield worldwide. It is a big concern to increase or maintain crop productivity under changing climate conditions to cater for increasing food demand. Among abiotic stresses, salinity, drought and extreme heat are the most common stresses. Abiotic stresses contribute to reducing crop plant production by 50% or more. Like the effects of abiotic stress, constant exposure to biotic stresses—which include pathogen infections and pest and insect attacks—contribute to a major drop in crop productivity and wastage of crops. There is also constant pressure from extreme weather conditions due to climate change and the incidence of biotic stresses. There is a great need to develop biotic and abiotic stress resilience in crops to mitigate the adverse effects of stresses. Such resilience can be achieved through development and adoption of eco-friendly approaches in agricultural systems for crop sustainability and food security. The focus on plant–microbe interactions has attracted more attention in recent years for inducing plant resistance and defence against abiotic and biotic stresses. Plant growth–promoting rhizobacteria facilitate abiotic stress resilience in plants by several strategies through activation of plant growth regulators (which include ethylene, auxin (indole-3-acetic acid)), activity of enzymes such as 1-aminocyclopropane-1-carboxylate (ACC)–deaminase and production of bacterial products such as exopolysaccharide. Diverse plant–microbe interactions in the rhizosphere also help to regulate plant defence pathways under adverse conditions through induction of systematic resistance or systemic acquired resistance. Moreover, other strategies such as microbial antagonism through production of several compounds such as antibiotics, siderophores, bacteriocins and secondary metabolites further boost disease resistance in plants.

Plants are continuously challenged by living organisms (biotic stress) and environmental factors (abiotic stress) throughout their lifecycle. Biotic stress factors, such as phytopathogens and pests, along with abiotic challenges like drought, salinity, high temperature and heavy metal contamination, pose significant risk to crop productivity and global food security. These stresses can negatively impact crop growth by altering the rhizosphere environment and disrupting essential cellular and biochemical mechanisms. Understanding the composition, structure and function of the plant microbiome and how it helps plants withstand stress, is crucial. This knowledge could lead to the development of strategies to reduce stress in crops and breed stress-tolerant varieties. Plant-associated microbiomes have the potential to protect plants from biotic and abiotic stresses by enhancing their natural immune responses, either directly or indirectly. They also improve photosynthetic efficiency, promote plant growth, aid in nutrient absorption and synthesise beneficial compounds, hormones and enzymes that increase productivity and stress tolerance in plants. Pseudomonas species that produce DAPG have gained significant interest for their effectiveness in suppressing a wide range of soil-borne plant diseases, such as wheat take-all, tobacco black root rot and damping-off in sugar beet. They are also recognized as key contributors to the natural disease-suppressive properties of various soils worldwide. Insights into how the plant microbiome interacts with biotic and abiotic stresses can help in creating innovative bioinoculants. In conclusion, this review highlights the importance of microbial communities in supporting plant health and productivity under stress conditions, showcasing the microbiome-mediated mechanisms that enhance plant resilience to both biotic and abiotic stressors.

As global climates shift, plants are increasingly exposed to biotic and abiotic stresses that adversely affect their growth and development, ultimately reducing agricultural productivity. To counter these stresses, plants produce secondary metabolites (SMs), which are critical biochemical and essential compounds that serve as primary defense mechanisms. These diverse compounds, such as alkaloids, flavonoids, phenolic compounds, and nitrogen/sulfur-containing compounds, act as natural protectants against herbivores, pathogens, and oxidative stress. Despite the well-documented protective roles of SMs, the precise mechanisms by which environmental factors modulate their accumulation under different stress conditions are not fully understood. This review provides comprehensive insights into the recent advances in understanding the functions of SMs in plant defense against abiotic and biotic stresses, emphasizing their regulatory networks and biosynthetic pathways. Furthermore, we explored the unique contributions of individual SM classes to stress responses while integrating the findings across the entire spectrum of SM diversity, providing a comprehensive understanding of their roles in plant resilience under multiple stress conditions. Finally, we highlight the emerging strategies for harnessing SMs to improve crop resilience through genetic engineering and present novel solutions to enhance agricultural sustainability in a changing climate.

The escalating concerns of environmental protection and global food security are exacerbated by biotic and abiotic stresses, including drought, heat waves, cold shocks, and flooding, all of these significantly reduce crop yields and threaten food supply. Climate change amplifies these challenges, imposing a severe impact on agricultural productivity and food security globally. To address these challenges, it is crucial to enhance food production through the development of climate resilient crops, with a focus on crops that are resistant to both abiotic and biotic stresses. This can be achieved through conventional breeding, biotechnology, and advanced omics techniques such as transcriptomics, proteomics, and metabolomics. These approaches have illuminated key genes, proteins, and metabolic pathways that are critical for improving crop resilience. Sustainable farming practices, including intercropping, agroforestry, and the use of biofertilizers and biochar, are also key strategies for improving soil structure and water retention. Furthermore, supportive policies such as agricultural extension services, collaboration between public and private sectors, and farmer education on climate resilient crops are essential for fostering climate resilience in agriculture. This review consolidates current knowledge and highlights the role of these strategies in tackling food insecurity, with a focus on the genomic innovations that underpin climate resilience in plants.

lncRNAs and epigenetics regulate plant's resilience against biotic stresses

Plants are continuously exposed to environmental abiotic and biotic stressors that can significantly impact their growth, development, productivity, and lifespan. However, plants have developed exceptionally complex signaling pathways that enable their ability to sense, transduce, and respond to these diverse stress stimuli. Salicylates (SA) and jasmonates (JA) are two key phytohormones that significantly influence plant adaptation to environmental and biotic stressors, pivotal in enhancing stress resilience. The interaction and crosstalk between SA and JA signaling cascades are essential for orchestrating appropriate physiological and biochemical responses to biotic (e.g., pathogen attack, herbivory) and abiotic (e.g., oxidative stress, drought, temperature extremes, UV radiation, salinity, heavy metal toxicity) stresses. Salicylates are primarily recognized for being involved in systemic acquired resistance (SAR) against biotic stressors like pathogens. Conversely, jasmonates are well-documented in their function in defenses aimed at herbivorous insects and in mitigating the outcomes of abiotic conditions such as salinity and drought. However, the crosstalk between SAs and JAs is complex, involving both synergistic and antagonistic interactions that finely tune the natural defensive mechanism of the plant toward both biotic and abiotic stresses. This comprehensive review summarizes the most recent research on how SA and JA biosynthesis, signaling, and interactions govern diverse stress adaptive mechanisms in plants. It covers emerging evidence on the importance of SA-JA crosstalk in regulating physiological, biochemical, and molecular adaptations to combined biotic and abiotic stresses.

1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is one of the most beneficial traits of plant growth promoting (PGP) rhizobacteria responsible for protecting the plants from detrimental effects of abiotic and biotic stress. The strain S3 with ACC deaminase activity (724.56 nmol α-ketobutyrate mg−1 protein hr−1) was isolated from rhizospheric soil of turmeric (Curcuma longa), a medicinal plant, growing in Motihari district of Indian state, Bihar. The halotolerant strain S3, exhibited optimum growth at 8% (w/v) NaCl. It also exhibited multiple PGP traits such as indole acetic acid production (37.71 μg mL−1), phosphate solubilization (69.68 mg L−1), siderophore, hydrocyanic acid (HCN) and ammonia production as well as revealed antagonism against Rhizoctonia solani. The potential of isolated strain to alleviate salinity stress in tomato plants was investigated through pots trials by inoculating strain S3 through-seed bacterization, soil drenching, root dipping as well as seed treatment + soil drenching. The strain S3 inoculated through seed treatment and soil drenching method led to improved morphological attributes (root/shoot length, root/shoot fresh weight and root/shoot dry weight), photosynthetic pigment content, increased accumulation of osmolytes (proline and total soluble sugar), enhanced activities of antioxidants (Catalase and Peroxidase) and phenolic content in salt stressed tomato plants. The biochemical characterisation, FAMEs analysis and 16S rRNA gene sequencing revealed that strain S3 belongs to the genus Pseudomonas. The overall findings of the study revealed that Pseudomonas sp. strain S3 can be explored as an effective plant growth promoter which stimulate growth and improve resilience in tomato plants under saline condition.

What inspired your interest in plant science?I consider plants to be the most important and beautiful living things on the Earth.I grew up in the southern part of India, in the countryside village of Dharmavaram which is in the Andhra Pradesh state.During my school years, I was aware of various varieties of plants such as mango, custard apple and several exotic palms.When I was a child, I would grow vegetables and observe their development, and my family members still remember those days.Some of my school friends were from farming communities and I used to go to their fields and observe their crops and trees.Plants provide us with food, fodder, medicines, textiles, timber, oxygen.In a nutshell, they are ever-present in our daily lives!Starting from germination through to maturity, flowering and senescence, all plant science research is very interesting.Since plants are an integral part of our lives and give us so much, we need to protect them from biotic and abiotic stresses and improve them.Plant science is fascinating as it deals with a vast amount of biology and there is huge scope to develop crop plants to obtain high yielding varieties to ensure food security.Since my PhD, the analysis of plant metabolism, and of adaptive responses to hypoxia, has been my long lasting interest in plant science.

Abiotic and biotic stresses, whether occurring individually or in combination, have profound effects on plant growth, development and overall productivity. Abiotic stresses such as drought, salinity and extreme temperatures disrupt physiological processes, while biotic stresses from pathogens, pests and herbivores impair plant defenses and nutrient dynamics. When these stressors act simultaneously, they interact in complex ways, often exacerbating damage and creating unique challenges for plants. Research has shown that plants employ sophisticated signalling networks involving hormones such as abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA) and ethylene to coordinate responses to these stress combinations. These signalling pathways can have synergistic or antagonistic effects on stress tolerance, depending on the nature and timing of the stresses. Recent advancements in plant genetics, metabolomics, transcriptomics and genome-editing tools such as CRISPR-Cas (clustered regularly interspaced short palindromic repeats) are providing new insights into how plants adapt to dynamic environments and cope with concurrent stresses. Additionally, microbial inoculations, including arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR), are emerging as effective strategies to mitigate stress impacts by enhancing nutrient uptake, regulating hormone levels and improving overall plant resilience. This review emphasizes the need for an integrated approach to understanding the interactions between biotic and abiotic stressors. It highlights innovative strategies such as microbial applications, advanced breeding programs and biotechnological interventions to improve stress tolerance. Addressing these challenges is critical for developing resilient crop varieties capable of withstanding the impacts of climate change and ensuring sustainable agricultural productivity.

Millets, commonly referred to as the "future crop," provide a practical solution for addressing hunger and reducing the impact of climate change. The nutritional and physiological well-being of soil is crucial for the survival and resilience of plants while countering environmental stressors, both abiotic and biotic, that arise from the current climate change scenario. The health and production of millet are directly influenced by the soil microbial community. Millets have several plant growth-promoting rhizobacteria such as Pseudomonas, Azotobacter, Bacillus, Rhizobium, and fungi like Penicillium sp., that increase nutrient uptake, growth, and productivity and protect against abiotic and biotic stressors. Rhizobacteria enhance plant productivity by many mechanisms, including the release of plant hormones and secondary metabolic compounds, the conversion of nutrients into soluble forms, the ability to fix nitrogen, and the provision of resistance to both biotic and abiotic stresses. The microbial populations in the rhizosphere have a significant impact on the growth and production of millet such as enhancing soil fertility and plant nourishment. Additionally, arbuscular mycorrhizal fungi invade the roots of millets. The taxon Glomus is the most prevalent in association with millet plant soil, followed by Acaulospora, Funneliformis, and Rhizophagus. The symbiotic relationship between arbuscular mycorrhizal fungi and millet plants improves plant growth and nutrient absorption under diverse soil and environmental circumstances, including challenging abiotic factors like drought and salinity.

The holobiont paradigm, conceptualizing host-microbiome assemblages as functionally integrated entities, has fundamentally altered interpretations of adaptive responses to environmental pressures spanning multiple organizational levels. This review synthesizes the current knowledge on microbiome-host coevolution, focusing on three key aspects. First, it examines the evolutionary origins of holobionts from primordial microbial consortia. Second, it considers the mechanistic basis of microbiome-mediated stress resilience in plants and animals. Finally, it explores the ecological implications of inter-holobiont interactions. We highlight how early microbial alliances (protomicrobiomes) laid the groundwork for eukaryotic complexity through metabolic cooperation, with modern holobionts retaining this plasticity to confront abiotic and biotic stressors. In plants, compartment-specific microbiomes (e.g., rhizosphere, phyllosphere) enhance drought tolerance or nutrient acquisition, while in animals, the gut microbiome modulates neuroendocrine and immune functions via multi-organ axes (gut-brain, gut-liver, etc.). Critically, we emphasize the role of microbial metabolites (e.g., short-chain fatty acids, VOCs) as universal signaling molecules that coordinate holobiont responses to environmental change. Emerging strategies, like microbiome engineering and probiotics, are discussed as tools to augment stress resilience in agriculture and medicine. By framing adaptation as a collective trait of the holobiont, this work bridges evolutionary biology, microbiology, and ecology to offer a unified perspective on stress biology.

Secondary metabolites are the major defense elements of plants against biotic and abiotic stress conditions. They are diverse and valuable natural products induced by a variety of environmental and developmental cues. In recent years, NO has been successfully used as elicitor to stimulate secondary metabolite accumulation in plants. Emerging evidence has established the significant role of NO in plant growth and defense responses in plants. Several abiotic and biotic stress factors can induce NO-mediated regulation of the biosynthetic pathways of metabolites that can consequently alter their biological reaction toward the given stress. Moreover, exogenous treatments with NO donors also enhanced the accumulation of secondary metabolites including phenolics, flavonoids, and caffeic acid derivatives in several species suggesting the importance of NO accumulation for the secondary metabolic production. Complete elucidation of its role in the production of such secondary metabolites which are pharmaceutically significant is very essential for improving the large-scale commercial production and enhancing stress resilience in plants. Although several reports suggested the induction of secondary metabolites and NO against a range of stress factors, to establish link between NO and secondary metabolites under stress needs a deeper investigation. This compilation chiefly summarize NO biosynthesis, signaling, and functions under abiotic stress in plants highlighting what is currently known about secondary metabolite induction by NO in plants.

Fascinating impact of silicon and silicon transporters in plants: A review

In the face of complex biotic and abiotic stresses, modern agriculture seeks innovative solutions to ensure sustainable crop production. Plant Growth-Promoting Rhizobacteria (PGPR) emerges as powerful allies, offering a sustainable approach to fortifying plant defense mechanisms. This review delves into harnessing PGPR-mediated defense priming to combat both biotic and abiotic stresses in agriculture. Defense priming, a sophisticated mechanism acquired through exposure to primary stimuli, empowers plants to mount quicker and more resilient defense responses against subsequent challenges. PGPR induce a pre-conditioned state of heightened alertness, enabling rapid and robust defense responses upon stress encounters. This paradigm not only enhances plant resilience to pathogens and environmental stressors but also promotes sustainable practices by reducing chemical inputs. The review critically evaluates the mechanisms underlying PGPR-mediated priming, emphasizing its potential to modulate plant physiology, metabolite production, increased antioxidants enzymes, defense related enzymes activities and enhance stress tolerance. It further explores how PGPR can improve plant responses to a spectrum of stressors. This review also highlights PGPR-mediated defense priming as a cost-effective, enduring, chemical-free, and sustainable method for managing abiotic and biotic stresses in agriculture. Implementing this strategy offers effective crop protection with minimal fitness and environmental costs, even in harsh conditions.

Grapevine (Vitis vinifera L.) is a globally significant crop increasingly affected by a variety of biotic and abiotic stresses. Plant biostimulants offer a promising approach to enhance plant resilience by modulating key physiological and metabolic processes. This study aimed to demonstrate that the preventive application of a Fabaceae-based biostimulant can prime grapevine defense pathways, thereby improving plants’ ability to endure potential stress conditions. Indeed, resistance to both biotic and abiotic stresses in plants involves common pathways, including Ca2+ and ROS signaling, MAPK cascades, hormone cross-talk, transcription factor activation, and induction of defense genes. Grapevine leaves were subjected to high-throughput transcriptomic analysis coupled with qPCR validation 6 and 24 h following treatment application. Differentially expressed genes were visualized using MapMan to identify the major metabolic and signaling pathways responsive to the treatment. This integrative analysis revealed several defense-related pathways triggered by the biostimulant, with representative protein families showing both up- and downregulation across key functional categories. Overall, the results indicate that a wider array of pathways associated with stress tolerance and growth regulation were stimulated in treated plants compared to untreated controls. These findings support the conclusion that a preventive biostimulant application can effectively prime grapevine metabolism, enhancing its preparation to cope with forthcoming environmental challenges.