Cedrus deodara is economically and ethnobotanically an important forest tree and is shown to be at decline in Northern areas of Pakistan in recent years mainly due to high concentration of Nitrogen in forests. Ectomycorrhizal (ECM) association forming fungi enables the forest trees to develop optimally by absorbing water from the rhizosphere through their absorptive hyphae and by making available the nutrients by mobilization of N and P from the organic substrates. This study was conducted to identify the ECM strains from C. deodara rhizosphere and to analyse the impact of high N load on the C. deodara seedlings to establish N critical load value for coniferous forests of Pakistan. Six new fungal strains were identified from the rhizosphere of C. deodara and were registered at GenBank (NCBI) as Emmia latemarginata strain ACE1, Aspergillus terreus strain ACE2, Purpureocillium lilacinum strain ACE3, Talaromyces pinophilus strain ACE4, A. fumigatus strain ACE5 and T. pinophilus strain ACE6 with accession numbers MH145426, MH145427, MH145428, MH145429, MH145430 and MH547115. Four out of six isolated strains were inoculated with seedlings of C. deodara singly and in consortium (CN) in combination with nitrogen load of 0 (C), 25 (T1), 50 (T2), 100 kg N ha−1 yr−1 (T3). Agronomic, physiological and gene expression studies for ExpansinA4 (EXPA4) and Cystatins (Cys) were made to analyse the impact of fungal strains in relation to high N stress. This study suggests a positive impact of T1 (25 kg N ha−1 yr−1) Nitrogen load and a negative impact of T3 (100 kg N ha−1 yr−1) on growth parameters and expression patterns of EXPA4 and Cys genes. Peroxidase (POX) activity decreased in the order ACE5 > ACE2 > C > ACE3 > ACE1 > CN. However, the results of Superoxide dismutase (SOD) showed decreasing trend in the order ACE5 > C > CN > ACE1 > ACE2 > ACE3. Strain ACE3 was shown to have a positive impact on the seedlings in terms of growth, physiology and expression of genes. Present study suggests that newly identified fungal strains showing positive impact on the growth and physiology of C. deodara could be used for the propagation of this economically important plant in Pakistan after pathogenicity test.

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Wheat (Triticum aestivum L.) is an important crop of the world and is considered as an essential food for one third of the world's population. Wheat yield and productivity are affected by many heavy metals including lead (Pb). In order to determine the genetic response of wheat against Pb stress, wheat was grown hydroponically with three different levels of Pb stress: 0, 75 and 225 µM. Total RNA was extracted from the leaves of two wheat cultivars 'Galaxy-13' and 'Punjab-11' in order to determine the expression of genes involved in detoxifying oxidative stress such as glutathione S-transferase (GST), glutathione reductase (GR), phospholipase Dα (PLDα) and zinc (Zn) transporter 8 precursor (ZIP8) and iron (Fe) regulatory transporter1 (IRT1). In silico characterization was performed to determine the sequence similarity of genes of this study in wheat and other crop plants. The results showed an increase in GST, GR and PLDα genes expression under severe stress conditions in both cultivars and the high expression of these genes could be important to protect cells from oxidative stress. Moreover, these genes could detoxify most of the secondary reactive oxygen species which are produced due to Pb stress. However, ZIP8 gene expression was high under mild stress condition while IRT1 gene expression was low in response to severe stress. In conclusion, high expression of GST, GR and PLDα genes could help wheat to survive under Pb stress and one or more of these genes could be used to screen Pb sensitive and resistant cultivars as well as in genetic transformation to develop Pb resistant wheat.