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Title: Physio-Morphic and Biochemical Characterization of Wheat Varieties in Response to Silver Nanoparticles Against Heat Stress
Authors: Iqbal, Muhammad
Keywords: Plant Sciences
Issue Date: 2021
Publisher: PMAS-Arid Agriculture University, Rawalpindi.
Abstract: Nanotechnology being the science of modern era has diverse applications in different fields like biology, physics and chemistry. This science deals with the production of minute particles termed as nanoparticles (NPs) having dimension between 1-100 nm. Currently different types of NPs are being synthesized. Among them, silver nanoparticles (AgNPs) are of major importance due to their unique properties. Pakistan is an agricultural country and agriculture contributes 18.5 % in GDP. Wheat is an important staple food crop of Pakistan. Wheat contributs 8.9 % value added in agriculture and 1.6 % of GDP. Wheat crop showed marginal increase of 0.5 % to 25.195 million tonnes over last year’s production of 25.076 million tonnes. Average yield of wheat in Pakistan is less as compared to the developed countries. Pakistan ranked 8th in world on basis of wheat production. The low yield of wheat is due to various biotic and abiotic stresses, which adversely affect the qualitative and quantitative attributes of wheat. Among these stresses, the heat stress is very important limiting factor affecting morphological, physiological, biochemical attributes which leads to yield loss in wheat. A sum total of 20-30 % reduction in wheat yield is due to heat stress. The major objective of present study was to find the potential role of green synthesized AgNPs on morphological growth, physiological and biochemical attributes and yield efficacy of wheat varieties against heat stress. Three wheat varieties Chakwal-50, NARC 2011 and Pakistan-2013, obtained from BARI Chakwal and CSI-NARC Islamabad were tested in current study. AgNPs were synthesized by using Moringa oleifera leaves extract as the main reducing and stabilising agent. The synthesized AgNPs were characterized through UV-Visible spectroscopy, SEM, TEM, AFM, EDX, XRD, FTIR and X-ray photon spectroscopy. Different concentrations (25, 50, 75, and 100 ppm) of green synthesized AgNPs were exogenously applied to wheat plants at heading stage followed by application of heat stress under controlled conditions. It was observed that the 50 ppm concentration of AgNPs was found as optimum concentration for producing thermotolerance in wheat plants against heat stress by improving morphological, physiological, biochemical and yield attributes of all tested varieties. Significant 213 improvement in morphological parameters (Plant height, shoot length, PFW & PDW and leaf area), physiological parameters (RWC, MSI, WP, OP and chlorophyll contents) and biochemical attributes both enzymatic (SOD, POD, and CAT) and non-enzymatic (TPC, TFC, Soluble sugars, Proline and MDA) attributes were observed in all tested varieties in response to 50 ppm treatment of AgNPs against heat stress. Yield parameters (SL, GNPS, 100-GW and YPP), and grain quality (Ca, K, Cu, Fe and Zn) parameters were significantly enhanced when wheat plants were treated with 50 ppm concentration of AgNPs. Proteome analysis from seeds of wheat varieties was also done through LC MS and functional categorization of proteins were done through MapMan Bin Codes Software. It was found that heat shock proteins (HSP17.4, HSP70 and HSP90-5) were up-regulated and hsp90-1 were down-regulated in wheat varieties in response to 50 ppm treatment of AgNPs against heat stress. Similarly, plant defense related proteins were up-regulated, and stress related proteins were down regulated in response to 50 ppm treatment of AgNPs against heat stress. Transcription factors were also analyzed from obtained proteome data by using plant transcription factor database ( and wheat transcription factor database ( Transcription factors (APRR7, TCPG and EIF2B) were up-regulated and transcription factor (HAT4, DEAH9 and BH125) was down-regulated in wheat varieties against heat stress. However, the transcription factors (EF2B, MD37C and PRP8A) were up-regulated and transcription factors (ERF99, TCPQ and EF1D2) were down-regulated in wheat varieties in response to 50 ppm treatment of AgNPs against heat stress. Overall, pronounced results were observed in wheat variety Pakistan-2013 followed by Chakwal-50 and NARC-2011 confirming increase thermotolerance due to AgNPs application against heat stress. So, it can be concluded that green synthesized AgNPs have the potential to enhance the thermotolerance by improving mporphological growth, physiological, biochemical attributes, yield and grain quality in plants of wheat varieties against heat stress. Likewise, AgNPs also enhanced tolerance in wheat plants of all variesties by endorcing more production 214 of plant defense related proteins, heat shock proteins and key transcription factors against heat stress. Further studies related to in-silico annotation and chromosomes mining are required to explore the uncharacterized genes in wheat varieties due to AgNPs application against heat stress. Comprehensive study is also required to understand AgNPs oriented morphological, physiological, biochemical changes and yield analysis in wheat varieties against heat stress at field level on large scale.
Gov't Doc #: 23042
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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