Biology subjects

Prasad, K.

Publications and source records attributed to Prasad, K..

4 recordsLinked to original sources

bioRxiv2020

Regulation of touch dependant de novo root regeneration in Arabidopsis

The versatile regeneration capability of leaves enable even a detached Arabidopsis leaf to yield two kinds of regenerative responses namely, wound healing at the cut end in form of callus formation or de novo root regeneration (DNRR). Using various experimental approaches, we show that the factor favouring DNRR over callus formation seems to be a mechanical cue, possibly touch, at the cut end of the detached leaf. Here, we show that the forced expression of a PLETHORA transcription factor can bypass the need for touch to initiate DNRR. Our findings provide a genetic frame-work for touch dependant DNRR and suggest that a core PLT transcription regulatory module acts in response to mechano-sensing stimuli.

plant biology↗

bioRxiv2020

Age, wound size and position of injury - dependent vascular regeneration assay in growing leaves

BackgroundRecurring damage to aerial organs of plants necessitates their prompt repair, particularly their vasculature. While vascular regeneration assay in aerial plant parts such as stem and inflorescence stalk are well established, those on leaf vasculature remained unexplored. Recently we established a new vascular regeneration assay in growing leaf and discovered the underlying molecular mechanism. ResultsHere we describe the detailed stepwise method of incision and the regeneration assay used for studying the leaf vascular regeneration. By using a combination of micro-surgical perturbations, brightfield microscopy and other experimental approaches, our new findings show that the regeneration efficiency decreases with aging of the leaf, and increases with the nearness of the wound towards the proximal end of the leaf. ConclusionThis easy-to-master vascular regeneration assay is an efficient and rapid method to study the mechanism of vascular regeneration in growing leaves. It can be readily adapted for other plant species and can be combined with cellular and molecular biology techniques.

plant biology↗

bioRxiv2020

Genome-Wide High Resolution Expression Map and Functions of Key Cell Fate Determinants Reveal the Dynamics of Crown Root Development in Rice

Shoot borne adventitious/crown roots (AR/CR) shape up the root architecture in grasses. Mechanisms underlying initiation and subsequent outgrowth of CR remain largely unknown. Here, we provide genome-wide modulation in the landscape of transcriptional signatures during distinct developmental stages of CR formation in highly derived grass species, rice. Our studies implicate the role of potential epigenetic modifiers, transcription factors and cell division regulators in priming the initiation of CR primordia followed by progressive activation of conserved transcription regulatory modules to ensure their outgrowth. In depth analysis of spatio-temporal expression patterns of key cell fate determinants and functional analyses of rice WUSCHEL RELATED HOMEOBOX10 (OsWOX10) and PLETHORA (OsPLT1) genes reveal their unprecedented role in controlling root architecture. We further show that OsPLT1 activates local auxin biosynthesis and forms an integral part of ERF3-OsWOX11-OsRR2 regulatory module during CR primordia development. Interestingly, OsPLT genes, when expressed in the transcriptional domain of root-borne lateral root primordia of Arabidopsis plt mutant, rescued their outgrowth demonstrating the conserved role of PLT genes in root primordia outgrowth irrespective of their developmental origin. Together, these findings unveil the molecular framework of cellular reprogramming during trans-differentiation of shoot tissue to root leading to culmination of robust root architecture in grass species which got evolutionary diverged from dicots.

plant biology↗

bioRxiv2019

Coconut inflorescence sap mediated synthesis of silver nanoparticles and its diverse antimicrobial properties

Green synthesis of nanoparticles (NPs) involves the use of diverse extracts of biological origin as substrates to synthesize nanoparticles and can overcome the hazards associated with chemical methods. Coconut inflorescence sap, which is unfermented phloem sap obtained by tapping of coconut inflorescence, is a rich source of sugars and secondary metabolites. In this study, coconut inflorescence sap was used to synthesize silver nanoparticles (AgNPs). We have initially undertaken metabolomic profiling of coconut inflorescence sap from West Coast Tall cultivar to delineate its individual components. Secondary metabolites constituted the major portion of the inflorescence sap along with sugars, lipids and, peptides. The concentration of silver nitrate, inflorescence sap and incubation temperature for synthesis of AgNPs were optimized. Incubating the reaction mixture at 40{degrees}C was found to enhance AgNP synthesis. The AgNPs synthesized were characterized using UV-Visible spectrophotometry, X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Antimicrobial property of AgNP was tested in tissue culture of arecanut (Areca catechu L.) where bacterial contamination (Bacillus pumilus) was a frequent occurrence. Significant reduction in the contamination was observed when plantlets were treated with aqueous solutions of 0.01, 0.02 and 0.03% of AgNPs for one hour. Notably, treatment with AgNPs did not affect growth and development of the arecanut plantlets. Cytotoxicity of AgNPs was quantified in HeLa cells. Viability (%) of HeLa cells declined significantly at 10 ppm concentration of AgNP and complete mortality was observed at 60 ppm. Antimicrobial properties of AgNPs synthesized from inflorescence sap were also evaluated and confirmed in human pathogenic bacteria viz., Salmonella sp., Vibrio parahaemolyticus, and Escherichia coli. The study concludes that unfermented inflorescence sap, with above neutral pH, serves as an excellent reducing agent to synthesize AgNPs from Ag+.\n\nO_FIG O_LINKSMALLFIG WIDTH=177 HEIGHT=200 SRC=\"FIGDIR/small/775940v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (64K):\norg.highwire.dtl.DTLVardef@3c3f1forg.highwire.dtl.DTLVardef@1540f6borg.highwire.dtl.DTLVardef@1c069aborg.highwire.dtl.DTLVardef@159772c_HPS_FORMAT_FIGEXP M_FIG Graphical abstract\n\nC_FIG

plant biology↗