Characterization, anti-microbial, anti-oxidant and growth promoting effects of biogenically synthesized silver nanoparticles derived from Dicliptera bupleuroides Nees.

One of the most important areas of nanotechnology is the use of nanoparticles (NPs) for a variety of environmental and biological applications, with silver nanoparticles (Ag-NPs) gaining a lot attention due to their distinct properties. The current study deals with the synthesis of Ag-NPs from Dicliptera bupleuroides Nees leaf extract and to determine their antioxidant, antimicrobial potential and effects on wheat seed germination and growth. UV-Visible spectrum revealed a prominent absorption peak at 442 nm, elucidating the conformation of the Ag-NPs synthesis. Scanning electron microscopy (SEM) showed distinctive triangular, pyramidal, and irregular shape. X-ray diffraction (XRD) demonstrated their crystalline nature, with average crystallite size of the Ag-NPs measured at 20.52 nm. Fourier-transform infrared spectroscopy (FT-IR) further confirmed the presence of functional groups such as Phenols (O-H stretch), transition metal carbonyls N-H, ≡C-H, C ≡ N, C ≡ C, C-Cl, C-Br and O-H bonds on the surface Ag-NPs. The antibacterial activity of the Ag-NPs was most pronounced against Bacillus subtilis, with a zone of inhibition (ZOI) measuring 11 mm ± 0.57 at a concentration of 1000 µg/mL (45% inhibition). Likewise, Ag-NPs exhibited highest antioxidant potential (73.2%) at 100 µg/mL compared with standard (ascorbic acid) which showed (76%) at the same concentration. Furthermore, the effect of D. bupleuroides mediated Ag-NPs on wheat seeds growth and germination was recorded maximum at high concentrations (200-300 ppm). In conclusion, D. bupleuroides mediated Ag-NPs showed safe, cost effective and environmentally friendly synthesis which can be used as an antibacterial and antioxidant agent as well as for enhancing the growth and seed germination of crop seeds globally. RESEARCH HIGHLIGHTS: Nanotechnology is the study of nanoparticles for biological and environmental applications. Ag-NPs among other NPs have received broad attention because of their unique properties. D. bupleuroides Ag-NPs: 45% antibacterial, 73.2% antioxidant, enhance wheat germination. D. bupleuroides-mediated Ag-NPs are both cost-effective and environmentally beneficial.

RNAseq of diverse spring wheat cultivars released during last 110 years.

Here, we performed RNA-seq based expression analysis of root and leaf tissues of a set of 24 historical spring wheat cultivars representing 110 years of temporal genetic variations. This huge 130 tissues RNAseq dataset was initially used to study expression pattern of 97 genes regulating root growth and development in wheat. Root system architecture (RSA) is an important target for breeding stress-resilient and high-yielding wheat cultivars under climatic fluctuations. However, root transcriptome analysis is usually obscured due to challenges in root research due to their below ground presence. We also validated the dataset by performing correlation analysis between expression of RSA related genes in roots and leaves with 25 root traits analyzed under varying moisture conditions and 10 yield-related traits. The Pearson's correlation coefficients between root phenotypes and expression of root-specific genes varied from -0.72 to 0.78, and strong correlations with genes such as DRO1, TaMOR, ARF4, PIN1 was observed. The presented datasets have multiple uses such as a) studying the change in expression pattern of genes during time, b) differential expression of genes in two very important tissues of wheat i.e., leaf and roots, and c) studying customized expression of genes associated with important phenotypes in diverse wheat cultivars. The initial findings presented here provided key insights into understanding the transcriptomic basis of phenotypic variability of RSA in wheat cultivars.

Biochemical and phenological characterization of diverse wheats and their association with drought tolerance genes.

Drought is one of the most important wheat production limiting factor, and can lead to severe yield losses. This study was designed to examine the effect of drought stress on wheat physiology and morphology under three different field capacities (FC) viz. 80% (control), 50% (moderate) and 30% (severe drought stress) in a diverse collection of wheat germplasm including cultivars, landraces, synthetic hexaploid and their derivatives. Traits like grain weight, thousand grain weight and biomass were reduced by 38.23%, 18.91% and 26.47% respectively at 30% FC, whereas the reduction rate for these traits at 50% FC were 19.57%, 8.88% and 18.68%. In principal component analysis (PCA), the first two components PC1 and PC2 accounted for 58.63% of the total variation and separated the cultivars and landraces from synthetic-based germplasm. Landraces showed wide range of phenotypic variations at 30% FC compared to synthetic-based germplasm and improved cultivars. However, least reduction in grain weight was observed in improved cultivars which indicated the progress in developing drought resilient cultivars. Allelic variations of the drought-related genes including TaSnRK2.9-5A, TaLTPs-11, TaLTPs-12, TaSAP-7B-, TaPPH-13, Dreb-B1 and 1fehw3 were significantly associated with the phenological traits under drought stress in all 91 wheats including 40 landraces, 9 varieties, 34 synthetic hexaploids and 8 synthetic derivatives. The favorable haplotypes of 1fehw3, Dreb-B1, TaLTPs-11 and TaLTPs-12 increased grain weight, and biomass. Our results iterated the fact that landraces could be promising source to deploy drought adaptability in wheat breeding. The study further identified drought tolerant wheat genetic resources across various backgrounds and identified favourable haplotypes of water-saving genes which should be considered to develop drought tolerant varieties.

Genetic Variability and Aggressiveness of Tilletia indica Isolates Causing Karnal Bunt in Wheat.

Karnal bunt caused by Tilletia indica is a quarantine disease of wheat causing huge economic losses due to the ban on the import of bunted grains. This study was designed to characterize pathogenicity, aggressiveness and genetic diversity of 68 Tilletia indica isolates collected from different geographic regions of Pakistan. Forty-six isolates were tested for their pathogenicity on eight wheat varieties, out of which three were non-aggressive. The coefficient of infection (CI) ranged from 15.73% (PB-25) to 10% (PB-68, PB-60, and PB-43). The isolates collected from central Punjab showed higher infestation compared to other isolates. Among the wheat varieties used for the aggressiveness study, WL-711 showed susceptible reaction with 10.88% CI, while NIFA-Barsat, HD-29, Janbaz, Bakhtawar-92, Tatara, and AARI 2011 showed resistance to the highly resistant response. These isolates were amplified using 31 random amplified polymorphic DNA (RAPD) markers and 32 inter-simple sequence repeat (ISSR) markers for diversity analysis. The principal component analysis (PCA) and analysis of molecular variance (AMOVA) showed greater divergence among isolates collected from Punjab and Khyber Pakhtunkhwa (KPK), with a moderate level of admixture. The isolates from Faisalabad (Punjab) were more aggressive compared to isolates from KPK and were clearly separated based on PCA, indicating the significant genetic distance in the populations. Our findings will assist breeders and pathologists in better understanding the pathogenic variability in Tilletia indica and in subsequent disease management.

Genome-Wide Association and Genomic Prediction for Stripe Rust Resistance in Synthetic-Derived Wheats.

Stripe rust caused by Puccnina striiformis (Pst) is an economically important disease attacking wheat all over the world. Identifying and deploying new genes for Pst resistance is an economical and long-term strategy for controlling Pst. A genome-wide association study (GWAS) using single nucleotide polymorphisms (SNPs) and functional haplotypes were used to identify loci associated with stripe rust resistance in synthetic-derived (SYN-DER) wheats in four environments. In total, 92 quantitative trait nucleotides (QTNs) distributed over 65 different loci were associated with resistance to Pst at seedling and adult plant stages. Nine additional loci were discovered by the linkage disequilibrium-based haplotype-GWAS approach. The durable rust-resistant gene Lr34/Yr18 provided resistance in all four environments, and against all the five Pst races used in this study. The analysis identified several SYN-DER accessions that carried major genes: either Yr24/Yr26 or Yr32. New loci were also identified on chr2B, chr5B, and chr7D, and 14 QTNs and three haplotypes identified on the D-genome possibly carry new alleles of the known genes contributed by the Ae. tauschii founders. We also evaluated eleven different models for genomic prediction of Pst resistance, and a prediction accuracy up to 0.85 was achieved for an adult plant resistance, however, genomic prediction for seedling resistance remained very low. A meta-analysis based on a large number of existing GWAS would enhance the identification of new genes and loci for stripe rust resistance in wheat. The genetic framework elucidated here for stripe rust resistance in SYN-DER identified the novel loci for resistance to Pst assembled in adapted genetic backgrounds.