Browsing by Author "Nair, Athira Mohandas"

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    Arabidopsis SWEET12 contributes to the regulation of sugar allocation and defense responses during interaction with Serendipita indica
    (Oxford University Press, 2026) Jogawat, Abhimanyu; Sanyasi, Madhan; Menon, Sidhardh H; Goyal, Divya; Nair, Athira Mohandas; Vadassery, Jyothilakshmi
    Carbon availability is a central determinant of beneficial plant–fungal associations, and sugar transporters are key levers of this exchange. SWEETs (SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER) are involved in transporting various kinds of sugars in plants; however, their functional roles in fungal symbiosis are not sufficiently explored. In this study, we investigate the functional relevance of Arabidopsis SWEETs in the interaction with endophytic fungi, Serendipita indica. Transcript profiling of SWEET genes in response to S. indica and its major elicitor, cellotriose, revealed early root-specific induction of SWEET12. Using a SWEET12 loss-of-function mutant, we demonstrate that the absence of SWEET12 disrupts the major outcomes of mutualism including growth promotion, balanced colonization, sugar allocation, and the accumulation of defense phytohormones (JA and SA). Transcriptome profiling further reveals that SWEET12 buffers whole-plant responses by coordinating genes linked to carbohydrate, nitrogen, and lipid metabolism, and by tuning defense signalling and nutrient transporter networks. Our findings indicate that SWEET12 is essential for balancing fungal colonization and host defense, thereby promoting plant growth. SWEET12 does so by acting as sugar valve that meters sugar release to the apoplast, enabling the fungus to access carbon while preserving host sugar homeostasis and immune competence.
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    Surviving the odds: from perception to survival of fungal phytopathogens under host-generated oxidative burst
    (Elsevier B.V., 2021) Singh, Yeshveer; Nair, Athira Mohandas; Verma, Praveen K.
    Fungal phytopathogens pose a serious threat to global crop production. Only a handful of strategies are available to combat these fungal infections, and the increasing incidence of fungicide resistance is making the situation worse. Hence, the molecular understanding of plant–fungus interactions remains a primary focus of plant pathology. One of the hallmarks of host–pathogen interactions is the overproduction of reactive oxygen species (ROS) as a plant defense mechanism, collectively termed the oxidative burst. In general, high accumulation of ROS restricts the growth of pathogenic organisms by causing localized cell death around the site of infection. To survive the oxidative burst and achieve successful host colonization, fungal phytopathogens employ intricate mechanisms for ROS perception, ROS neutralization, and protection from ROS-mediated damage. Together, these countermeasures maintain the physiological redox homeostasis that is essential for cell viability. In addition to intracellular antioxidant systems, phytopathogenic fungi also deploy interesting effector-mediated mechanisms for extracellular ROS modulation. This aspect of plant–pathogen interactions is significantly under-studied and provides enormous scope for future research. These adaptive responses, broadly categorized into ‘‘escape’’ and ‘‘exploitation’’ mechanisms, are poorly understood. In this review, we discuss the oxidative stress response of filamentous fungi, their perception signaling, and recent insights that provide a comprehensive understanding of the distinct survival mechanisms of fungal pathogens in response to the host-generated oxidative burst.