Browsing by Author "Jaiswal, Rekha"

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Differential regulation of nitric oxide mediated by phytoglobin1 plays a role in resistance during Botrytis cinerea infection in Arabidopsis thaliana
(Springer Nature Publishing AG, 2026) Jaiswal, Rekha; Saini, Deepak; Swain, Jagannath; Gupta, Kapuganti Jagadis
Botrytis cinerea is a prominent necrotrophic pathogen responsible for gray mold disease, affecting a wide range of plant species, including economically vital crops such as tomatoes, grapes, strawberries, etc. Nitric oxide (NO) is considered as a crucial player in plant responses to biotic stress. NO homeostasis is regulated by phytoglobin (Pgb1), a potential scavenger of NO. However, the role of the Pgb1-NO cycle in regulating defense response against B. cinerea remains largely unknown. In the current study, we investigated the defense response of Arabidopsis thaliana against B. cinerea infection using antisense (Pgb1 AS) and overexpression (Pgb1 OE) lines, which produce differential levels of NO. The Pgb1 AS line accumulated higher NO levels and conferred resistance against B. cinerea infection, with reduced ROS levels, reduced cell death, and increased stomatal closure. Conversely, Pgb1 OE showed reduced NO levels accompanied by increased susceptibility. The elevated NO level in Pgb1 AS was associated with increased nitrate reductase (NR) activity and upregulation of NIA1 and NIA2 gene expression. Interestingly, ethylene-mediated defense pathway genes such as ERF1, ACS2, and ACS6 were upregulated while pathogen-related genes such as PR1, PR2, PR5, and NPR1 were downregulated in Pgb1 AS line. The elevated expression of ethylene genes corresponded with the higher ethylene levels in Pgb1 AS. Overall, our results confirmed the crucial role of phytoglobin-modulated NO in defense against B. cinerea infection by activating the ethylene-mediated defense pathway.
The emerging roles of nitric oxide and its associated scavengers-phytoglobins-in plant symbiotic interactions
(Oxford University Press, 2024) Pathak, Pradeep Kumar; Yadav, Nidhi; Kaladhar, Vemula Chandra; Jaiswal, Rekha; Kumari, Aprajita; Igamberdiev, Abir U.; Loake, Gary J.; Gupta, Kapuganti Jagadis
A key feature in the establishment of symbiosis between plants and microbes is the maintenance of the balance between the production of the small redox-related molecule, nitric oxide (NO), and its cognate scavenging pathways. During the establishment of symbiosis, a transition from a normoxic to a microoxic environment often takes place, triggering the production of NO from nitrite via a reductive production pathway. Plant hemoglobins [phytoglobins (Phytogbs)] are a central tenant of NO scavenging, with NO homeostasis maintained via the Phytogb–NO cycle. While the first plant hemoglobin (leghemoglobin), associated with the symbiotic relationship between leguminous plants and bacterial Rhizobium species, was discovered in 1939, most other plant hemoglobins, identified only in the 1990s, were considered as non-symbiotic. From recent studies, it is becoming evident that the role of Phytogbs1 in the establishment and maintenance of plant–bacterial and plant–fungal symbiosis is also essential in roots. Consequently, the division of plant hemoglobins into symbiotic and non-symbiotic groups becomes less justified. While the main function of Phytogbs1 is related to the regulation of NO levels, participation of these proteins in the establishment of symbiotic relationships between plants and microorganisms represents another important dimension among the other processes in which these key redox-regulatory proteins play a central role.
Method for the measurement of ethylene during hypoxia in rice plants
(Springer Nature Publishing AG, 2025) Jaiswal, Rekha; Gupta, Kapuganti Jagadis; Praveen, Afsana
Ethylene is a versatile phytohormone that is involved in the regulation of both growth and development such as senescence, and also it can act as a signaling hormone during hypoxia. Ethylene acts alone or in interaction with different phytohormones and proteins to regulate numerous cellular processes. Accumulating evidence suggest that endogenous ethylene production and emission into atmosphere are modulated by various biotic and abiotic stresses. Since it is a gaseous hormone, a precise detection, particularly under low-oxygen (hypoxic) conditions, is important for understanding its role in regulatory processes and stress signaling pathways. Currently, measurement practices such as gas chromatography, electrochemical sensing, and optical sensing are widely employed to detect ethylene. These methods are distinct from each other in terms of sensitivity, time response, selectivity, and cost. However, each method has its own advantages and limitations. Gas chromatography (GC) is one of the best techniques that is applied for the separation and measurement of ethylene due to its volatile and supersensitive nature. In this chapter, we describe a detailed GC-based procedure specifically optimized for measuring ethylene levels during hypoxic stress application in (Oryza sativa) rice plants.
Method for the measurement of ethylene during pathogen infection in arabidopsis
(Springer Nature Publishing AG, 2025) Jaiswal, Rekha; Gupta, Kapuganti Jagadis; Praveen, Afsana
Ethylene is a gaseous phytohormone that plays an important role as a signaling molecule during pathogen attack, influencing disease resistance and defense responses in plants. A precise measurement of ethylene production upon pathogen challenge is essential to elucidate its role in plant–pathogen interactions. Gas chromatography (GC) is among the most accurate and sensitive techniques for detecting and quantifying ethylene emissions due to its selectivity and effectiveness with gaseous molecules. In this chapter, we provide a detailed procedure employing GC specifically adapted for measuring ethylene levels during pathogen infection (Botrytis cinerea) in Arabidopsis leaflets. Arabidopsis leaflets infected by the necrotrophic pathogen Botrytis cinerea exhibit increased ethylene emission, facilitating the activation of defense pathways and secondary metabolites such as camalexin. The present GC method captures ethylene dynamics at early infection stages, ensuring precise quantification critical for dissecting the molecular mechanisms of plant immunity.