Subramanian Sankaranarayanan - Academia.edu (original) (raw)

Papers by Subramanian Sankaranarayanan

bioRxiv (Cold Spring Harbor Laboratory), Mar 18, 2024

bioRxiv (Cold Spring Harbor Laboratory), May 24, 2023

We present a green synthesis method of producing blue fluorescence emitting carbon nanoparticles ... more We present a green synthesis method of producing blue fluorescence emitting carbon nanoparticles (CNPs) through a simple and cost-effective single-step hydrothermal reaction. The synthesis utilized bract extracts and pollen grains from threeBougainvilleaspecies:B. spectabilis, B. alba, andB. buttiana. The CNPs exhibited photoluminescence, with the highest emission observed in the ultraviolet region. Atomic force microscopy analysis revealed that the size of synthesized CNPs ranged from 23 nm to 83 nm. Fourier transform infrared analysis provided a comprehensive understanding of the CNP’s surface functional groups, with carbon being the predominant group. X-ray diffraction analysis confirmed the amorphous nature of the synthesized CNPs. Zeta potential measurements indicated that the particles carried a negative charge, suggesting their colloidal stability. In experiments conducted withArabidopsis thalianaseedlings, CNPs derived fromB. albapollen grains were found to promote leaf area...

Frontiers in Plant Science, 2020

Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also f... more Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also function as important signaling molecules that regulate biotic and abiotic stress responses as well as plant growth and development. Recent studies have implicated ROS in various aspects of plant reproduction. In male gametophytes, ROS are associated with germline development as well as the developmentally associated programmed cell death of tapetal cells necessary for microspore development. ROS have a role in regulation of female gametophyte patterning and maintenance of embryo sac polarity. During pollination, ROS play roles in the generation of self-incompatibility response during pollen-pistil interaction, pollen tube growth, pollen tube burst for sperm release and fertilization. In this mini review, we provide an overview of ROS production and signaling in the context of plant reproductive development, from female and male gametophyte development to fertilization.

Members of the Brassicaceae family have the ability to regulate pollination events occurring on t... more Members of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including Glyoxalase I (GLO1) which is necessary for successful pollination. Suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCRb, AlSRKb and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility...

eLife, 2020

The pollen tube in a flowering plant grows in a direction that is influenced by the mechanical pr... more The pollen tube in a flowering plant grows in a direction that is influenced by the mechanical properties of the stigma papillae and the organization of structures called cortical microtubules inside these cells.

Pollen Tip Growth, 2017

Flowering plants use a polarized projection of the pollen grain called a pollen tube, to precisel... more Flowering plants use a polarized projection of the pollen grain called a pollen tube, to precisely deliver two sperm cells to the female gametes, which are deeply buried in the female gametophyte of the ovules for fertilization. The pollen tubes navigate a long route from the stigma, through the transmitting tract over a considerable amount of time before targeting the individual ovules. How is this precise cellular targeting achieved by the pollen tube? A lot of progress has been made toward identifying the sources of guidance cues that the pollen tube receives and the molecules that act as such guidance cues during its journey toward the ovule. In this chapter, we discuss these pollen tube guidance cues and also the latest tools in bio-imaging and microfluidics that would enable us to gain a better understanding of this process of directional growth for sperm delivery.

International journal of molecular sciences, Jan 24, 2017

The ubiquitous glyoxalase enzymatic pathway is involved in the detoxification of methylglyoxal (M... more The ubiquitous glyoxalase enzymatic pathway is involved in the detoxification of methylglyoxal (MG), a cytotoxic byproduct of glycolysis. The glyoxalase system has been more extensively studied in animals versus plants. Plant glyoxalases have been primarily associated with stress responses and their overexpression is known to impart tolerance to various abiotic stresses. In plants, glyoxalases exist as multigene families, and new roles for glyoxalases in various developmental and signaling pathways have started to emerge. Glyoxalase-based MG detoxification has now been shown to be important for pollination responses. During self-incompatibility response in Brassicaceae, MG is required to target compatibility factors for proteasomal degradation, while accumulation of glyoxalase leads to MG detoxification and efficient pollination. In this review, we discuss the importance of glyoxalase systems and their emerging biological roles in plants.

Nature materials, Jan 8, 2015

Self-assembly of nanoparticles at fluid interfaces has emerged as a simple yet efficient way to c... more Self-assembly of nanoparticles at fluid interfaces has emerged as a simple yet efficient way to create two-dimensional membranes with tunable properties. In these membranes, inorganic nanoparticles are coated with a shell of organic ligands that interlock as spacers and provide tensile strength. Although curvature due to gradients in lipid-bilayer composition and protein scaffolding is a key feature of many biological membranes, creating gradients in nanoparticle membranes has been difficult. Here, we show by X-ray scattering that nanoparticle membranes formed at air/water interfaces exhibit a small but significant ∼6 Å difference in average ligand-shell thickness between their two sides. This affects surface-enhanced Raman scattering and can be used to fold detached free-standing membranes into tubes by exposure to electron beams. Molecular dynamics simulations elucidate the roles of ligand coverage and mobility in producing and maintaining this asymmetry. Understanding this Janus-...

SummaryIn angiosperms, the process of pollination relies on species-specific interaction and sign... more SummaryIn angiosperms, the process of pollination relies on species-specific interaction and signaling between the male (pollen) and female (pistil) counterparts where the interplay between several pollen and stigma proteins decides the fate of the pollen. In Brassicaceae, the dry stigmatic papillary cells control pollen germination by releasing resources only to compatible pollen thereby allowing pollen to hydrate and germinate. Despite the identification of a number of stigmatic proteins that facilitate pollination responses, the signaling mechanisms that regulate functions of these proteins have remained unknown. Here we show that, in Arabidopsis, an extremely functionally redundant mitogen-activated protein kinase (MAPK) cascade is required for maintaining stigma receptivity to accept compatible pollen. Our genetic analyses demonstrate that in stigmas, five MAPK kinases (MKKs), MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible poll...

Trends in Plant Science, 2018

Current Biology, 2016

Highlights d AMOR makes pollen tubes competent to respond to LURE attractant peptides in Torenia ... more Highlights d AMOR makes pollen tubes competent to respond to LURE attractant peptides in Torenia d Arabinogalactan sugars, which are abundant in the ovary, are responsible for AMOR d A terminal disaccharide structure is necessary and sufficient for AMOR activity d The synthesized disaccharide, methyl-glucuronosyl galactose, shows AMOR activity

Plant signaling & behavior, Jan 4, 2015

Plants respond to limited soil nutrient availability by inducing more lateral roots (LR) to incre... more Plants respond to limited soil nutrient availability by inducing more lateral roots (LR) to increase the root surface area. At the cellular level, nutrient starvation triggers the process of autophagy through which bulk degradation of cellular materials is achieved to facilitate nutrient mobilization. Whether there is any link between the cellular autophagy and induction of LR had remained unknown. We recently showed that the S-Domain receptor Kinase (ARK2) and U Box/Armadillo Repeat-Containing E3 ligase (PUB9) module is required for lateral root formation under phosphate starvation in Arabidopsis thaliana.(1) We also showed that PUB9 localized to autophagic bodies following either activation by ARK2 or under phosphate starvation and ark2-1/pub9-1 plants displayed lateral root defects with inability to accumulate auxin in the root tips under phosphate starvation.(1) Supplementing exogenous auxin was sufficient to rescue the LR defects in ark2-1/pub9-1 mutant. Blocking of autophagic ...

Plant physiology, Jan 25, 2014

When plants encounter nutrient-limiting conditions in the soil, the root architecture is redesign... more When plants encounter nutrient-limiting conditions in the soil, the root architecture is redesigned to generate numerous lateral roots (LRs) that increase the surface area of roots, promoting efficient uptake of these deficient nutrients. Of the many essential nutrients, reduced availability of inorganic phosphate has a major impact on plant growth because of the requirement of inorganic phosphate for synthesis of organic molecules, such as nucleic acids, ATP, and phospholipids, that function in various crucial metabolic activities. In our screens to identify a potential role for the S-domain receptor kinase1-6 and its interacting downstream signaling partner, the Arabidopsis (Arabidopsis thaliana) plant U box/armadillo repeat-containing E3 ligase9 (AtPUB9), we identified a role for this module in regulating LR development under phosphate-starved conditions. Our results show that Arabidopsis double mutant plants lacking AtPUB9 and Arabidopsis Receptor Kinase2 (AtARK2; ark2-1/pub9-1)...

Plant Reproduction, 2014

We have previously proposed that Exo70A1 is required in the Brassicaceae stigma to control the ea... more We have previously proposed that Exo70A1 is required in the Brassicaceae stigma to control the early stages of pollen hydration and pollen tube penetration through the stigmatic surface, following compatible pollination. However, recent work has raised questions regarding Arabidopsis thaliana Exo70A1's expression in the stigma and its role in stigma receptivity to compatible pollen. Here, we verified the expression of Exo70A1 in stigmas from three Brassicaceae species and carefully re-examined Exo70A1's function in the stigmatic papillae. With previous studies showing that high relative humidity can rescue some pollination defects, essentially bypassing the control of pollen hydration by the Brassicaceae dry stigma, the effect of high humidity was investigated on pollinations with the Arabidopsis exo70A1-1 mutant. Pollinations under low relative humidity resulted in a complete failure of wild-type compatible pollen acceptance by the exo70A1-1 mutant stigma as we had previously seen. However, high relative humidity resulted in a partial rescue of the exo70A1-1 stigmatic papillar defect resulting is some wild-type compatible pollen acceptance and seed set. Thus, these results reaffirmed Exo70A1's proposed role in the stigma regulating compatible pollen hydration and pollen tube entry and demonstrate that high relative humidity can partially bypass these functions.

bioRxiv (Cold Spring Harbor Laboratory), Mar 18, 2024

bioRxiv (Cold Spring Harbor Laboratory), May 24, 2023

We present a green synthesis method of producing blue fluorescence emitting carbon nanoparticles ... more We present a green synthesis method of producing blue fluorescence emitting carbon nanoparticles (CNPs) through a simple and cost-effective single-step hydrothermal reaction. The synthesis utilized bract extracts and pollen grains from threeBougainvilleaspecies:B. spectabilis, B. alba, andB. buttiana. The CNPs exhibited photoluminescence, with the highest emission observed in the ultraviolet region. Atomic force microscopy analysis revealed that the size of synthesized CNPs ranged from 23 nm to 83 nm. Fourier transform infrared analysis provided a comprehensive understanding of the CNP’s surface functional groups, with carbon being the predominant group. X-ray diffraction analysis confirmed the amorphous nature of the synthesized CNPs. Zeta potential measurements indicated that the particles carried a negative charge, suggesting their colloidal stability. In experiments conducted withArabidopsis thalianaseedlings, CNPs derived fromB. albapollen grains were found to promote leaf area...

Frontiers in Plant Science, 2020

Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also f... more Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also function as important signaling molecules that regulate biotic and abiotic stress responses as well as plant growth and development. Recent studies have implicated ROS in various aspects of plant reproduction. In male gametophytes, ROS are associated with germline development as well as the developmentally associated programmed cell death of tapetal cells necessary for microspore development. ROS have a role in regulation of female gametophyte patterning and maintenance of embryo sac polarity. During pollination, ROS play roles in the generation of self-incompatibility response during pollen-pistil interaction, pollen tube growth, pollen tube burst for sperm release and fertilization. In this mini review, we provide an overview of ROS production and signaling in the context of plant reproductive development, from female and male gametophyte development to fertilization.

Members of the Brassicaceae family have the ability to regulate pollination events occurring on t... more Members of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including Glyoxalase I (GLO1) which is necessary for successful pollination. Suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCRb, AlSRKb and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility...

eLife, 2020

The pollen tube in a flowering plant grows in a direction that is influenced by the mechanical pr... more The pollen tube in a flowering plant grows in a direction that is influenced by the mechanical properties of the stigma papillae and the organization of structures called cortical microtubules inside these cells.

Pollen Tip Growth, 2017

Flowering plants use a polarized projection of the pollen grain called a pollen tube, to precisel... more Flowering plants use a polarized projection of the pollen grain called a pollen tube, to precisely deliver two sperm cells to the female gametes, which are deeply buried in the female gametophyte of the ovules for fertilization. The pollen tubes navigate a long route from the stigma, through the transmitting tract over a considerable amount of time before targeting the individual ovules. How is this precise cellular targeting achieved by the pollen tube? A lot of progress has been made toward identifying the sources of guidance cues that the pollen tube receives and the molecules that act as such guidance cues during its journey toward the ovule. In this chapter, we discuss these pollen tube guidance cues and also the latest tools in bio-imaging and microfluidics that would enable us to gain a better understanding of this process of directional growth for sperm delivery.

International journal of molecular sciences, Jan 24, 2017

The ubiquitous glyoxalase enzymatic pathway is involved in the detoxification of methylglyoxal (M... more The ubiquitous glyoxalase enzymatic pathway is involved in the detoxification of methylglyoxal (MG), a cytotoxic byproduct of glycolysis. The glyoxalase system has been more extensively studied in animals versus plants. Plant glyoxalases have been primarily associated with stress responses and their overexpression is known to impart tolerance to various abiotic stresses. In plants, glyoxalases exist as multigene families, and new roles for glyoxalases in various developmental and signaling pathways have started to emerge. Glyoxalase-based MG detoxification has now been shown to be important for pollination responses. During self-incompatibility response in Brassicaceae, MG is required to target compatibility factors for proteasomal degradation, while accumulation of glyoxalase leads to MG detoxification and efficient pollination. In this review, we discuss the importance of glyoxalase systems and their emerging biological roles in plants.

Nature materials, Jan 8, 2015

Self-assembly of nanoparticles at fluid interfaces has emerged as a simple yet efficient way to c... more Self-assembly of nanoparticles at fluid interfaces has emerged as a simple yet efficient way to create two-dimensional membranes with tunable properties. In these membranes, inorganic nanoparticles are coated with a shell of organic ligands that interlock as spacers and provide tensile strength. Although curvature due to gradients in lipid-bilayer composition and protein scaffolding is a key feature of many biological membranes, creating gradients in nanoparticle membranes has been difficult. Here, we show by X-ray scattering that nanoparticle membranes formed at air/water interfaces exhibit a small but significant ∼6 Å difference in average ligand-shell thickness between their two sides. This affects surface-enhanced Raman scattering and can be used to fold detached free-standing membranes into tubes by exposure to electron beams. Molecular dynamics simulations elucidate the roles of ligand coverage and mobility in producing and maintaining this asymmetry. Understanding this Janus-...

SummaryIn angiosperms, the process of pollination relies on species-specific interaction and sign... more SummaryIn angiosperms, the process of pollination relies on species-specific interaction and signaling between the male (pollen) and female (pistil) counterparts where the interplay between several pollen and stigma proteins decides the fate of the pollen. In Brassicaceae, the dry stigmatic papillary cells control pollen germination by releasing resources only to compatible pollen thereby allowing pollen to hydrate and germinate. Despite the identification of a number of stigmatic proteins that facilitate pollination responses, the signaling mechanisms that regulate functions of these proteins have remained unknown. Here we show that, in Arabidopsis, an extremely functionally redundant mitogen-activated protein kinase (MAPK) cascade is required for maintaining stigma receptivity to accept compatible pollen. Our genetic analyses demonstrate that in stigmas, five MAPK kinases (MKKs), MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible poll...

Trends in Plant Science, 2018

Current Biology, 2016

Highlights d AMOR makes pollen tubes competent to respond to LURE attractant peptides in Torenia ... more Highlights d AMOR makes pollen tubes competent to respond to LURE attractant peptides in Torenia d Arabinogalactan sugars, which are abundant in the ovary, are responsible for AMOR d A terminal disaccharide structure is necessary and sufficient for AMOR activity d The synthesized disaccharide, methyl-glucuronosyl galactose, shows AMOR activity

Plant signaling & behavior, Jan 4, 2015

Plants respond to limited soil nutrient availability by inducing more lateral roots (LR) to incre... more Plants respond to limited soil nutrient availability by inducing more lateral roots (LR) to increase the root surface area. At the cellular level, nutrient starvation triggers the process of autophagy through which bulk degradation of cellular materials is achieved to facilitate nutrient mobilization. Whether there is any link between the cellular autophagy and induction of LR had remained unknown. We recently showed that the S-Domain receptor Kinase (ARK2) and U Box/Armadillo Repeat-Containing E3 ligase (PUB9) module is required for lateral root formation under phosphate starvation in Arabidopsis thaliana.(1) We also showed that PUB9 localized to autophagic bodies following either activation by ARK2 or under phosphate starvation and ark2-1/pub9-1 plants displayed lateral root defects with inability to accumulate auxin in the root tips under phosphate starvation.(1) Supplementing exogenous auxin was sufficient to rescue the LR defects in ark2-1/pub9-1 mutant. Blocking of autophagic ...

Plant physiology, Jan 25, 2014

When plants encounter nutrient-limiting conditions in the soil, the root architecture is redesign... more When plants encounter nutrient-limiting conditions in the soil, the root architecture is redesigned to generate numerous lateral roots (LRs) that increase the surface area of roots, promoting efficient uptake of these deficient nutrients. Of the many essential nutrients, reduced availability of inorganic phosphate has a major impact on plant growth because of the requirement of inorganic phosphate for synthesis of organic molecules, such as nucleic acids, ATP, and phospholipids, that function in various crucial metabolic activities. In our screens to identify a potential role for the S-domain receptor kinase1-6 and its interacting downstream signaling partner, the Arabidopsis (Arabidopsis thaliana) plant U box/armadillo repeat-containing E3 ligase9 (AtPUB9), we identified a role for this module in regulating LR development under phosphate-starved conditions. Our results show that Arabidopsis double mutant plants lacking AtPUB9 and Arabidopsis Receptor Kinase2 (AtARK2; ark2-1/pub9-1)...

Plant Reproduction, 2014

We have previously proposed that Exo70A1 is required in the Brassicaceae stigma to control the ea... more We have previously proposed that Exo70A1 is required in the Brassicaceae stigma to control the early stages of pollen hydration and pollen tube penetration through the stigmatic surface, following compatible pollination. However, recent work has raised questions regarding Arabidopsis thaliana Exo70A1's expression in the stigma and its role in stigma receptivity to compatible pollen. Here, we verified the expression of Exo70A1 in stigmas from three Brassicaceae species and carefully re-examined Exo70A1's function in the stigmatic papillae. With previous studies showing that high relative humidity can rescue some pollination defects, essentially bypassing the control of pollen hydration by the Brassicaceae dry stigma, the effect of high humidity was investigated on pollinations with the Arabidopsis exo70A1-1 mutant. Pollinations under low relative humidity resulted in a complete failure of wild-type compatible pollen acceptance by the exo70A1-1 mutant stigma as we had previously seen. However, high relative humidity resulted in a partial rescue of the exo70A1-1 stigmatic papillar defect resulting is some wild-type compatible pollen acceptance and seed set. Thus, these results reaffirmed Exo70A1's proposed role in the stigma regulating compatible pollen hydration and pollen tube entry and demonstrate that high relative humidity can partially bypass these functions.