Insights on Strain-Substrate Interactions and Antioxidant and Anti-Bacterial Properties of the Velvet Foot Medicinal Mushroom Flammulina velutipes (Agaricomycetes).

To study the best substrate for the Indian subcontinent, four different substrates (sawdust + wheat bran, wheat straw + wheat bran + corn cobs, sawdust + corn cobs and wheat straw + wheat bran) were screened for six different Flammulina velutipes strains. The antioxidant and antibacterial properties were studied for these strains. In study it was found that the strain DMRX-767 and DMRX-768 were the most promising for yield and biological efficiency in all substrates and wheat straw + wheat bran being the best with respect to BE. To corroborate the findings, the best strain and best substrate trails were repeated. DMRX-767 and DMRX-768 were the most promising for yield and biological efficiency in all substrates, with wheat straw+wheat bran were again found the best. The methanolic extract of strain DMRX-166 showed highest antibacterial properties as highest inhibition is found for Bacillus subtilis and Pseudomonas syringae. However, DMRO-253 inhibited Ralstonia solanacearum and Xanthomonas campestris. DMRX-768 has the best scavenging ability followed by DMRO-253.

Nanofomulation of zinc oxide and chitosan zinc sustain oxidative stress and alter secondary metabolite profile in tobacco.

Advancement in nanotechnology has improved ways for large-scale production and characterization of nanoparticles of physiologically important metals. The current study explores the impact of Zinc Oxide Nanoparticles (ZnO-NP) and Chitosan-Zinc oxide nano-bioformulation (CH-ZnO) in tissue culture raised callus of Nicotiana benthamiana. Results indicated augmented biomass in CH-ZnO treated callus, while a reduced biomass was observed in ZnO-NP treated callus, at all the concentrations tested. Higher chlorophyll and carotenoid content were recorded in callus treated with 800 ppm CH-ZnO as compared to ZnO-NP treated callus. A higher accumulation of proline was observed in CH-ZnO treated callus when compared to ZnO-NP treatment, which was significantly higher at 50, 200 and 400 ppm CH-ZnO treatment. A maximum reduction in malondialdehyde (MDA) content was recorded at 800 ppm, for both the nano-formulations tested. Likewise, a significant reduction in the H2O2 levels was observed in all the treatments, while the callus treated with 400 ppm ZnO-NP and 800 ppm CH-ZnO recorded the highest reduction. Phenylalanine Ammonia-Lyase (PAL), activity increased significantly in callus treated with 400 ppm concentration for both ZnO-NP and CH-ZnO with respect to control. An increased level of tannin and nicotine were recorded in callus supplemented with 50, 200 and 400 ppm CH-ZnO. Notably, a significant decline of 94 and 52% in tannin content and 25 and 50% in nicotine content was recorded in the callus treated with 800 ppm CH-ZnO and ZnO-NP, respectively. The findings of this study suggest that an optimized dosage of these nano-bioformulations could be utilized to regulate the nicotine content and stress tolerance level.

NPKS uptake, sensing, and signaling and miRNAs in plant nutrient stress.

Sessile nature of higher plants consequently makes it highly adaptable for nutrient absorption and acquisition from soil. Plants require 17 essential elements for their growth and development which include 14 minerals (macronutrients: N, P, K, Mg, Ca, S; micronutrients: Cl, Fe, B, Mn, Zn, Cu, Ni, Mo) and 3 non-mineral (C, H, O) elements. The roots of higher plants must acquire these macronutrients and micronutrients from rhizosphere and further allocate to other plant parts for completing their life cycle. Plants evolved an intricate series of signaling and sensing cascades to maintain nutrient homeostasis and to cope with nutrient stress/availability. The specific receptors for nutrients in root, root system architecture, and internal signaling pathways help to develop plasticity in response to the nutrient starvation. Nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) are essential for various metabolic processes, and their deficiency negatively effects the plant growth and yield. Genes coding for transporters and receptors for nutrients as well as some small non-coding RNAs have been implicated in nutrient uptake and signaling. This review summarizes the N, P, K, and S uptake, sensing and signaling events in nutrient stress condition especially in model plant Arabidopsis thaliana and involvement of microRNAs in nutrient deficiency. This article also provides a framework of uptake, sensing, signaling and to highlight the microRNA as an emerging major players in nutrient stress condition. Nutrient-plant-miRNA cross talk may help plant to cope up nutrient stress, and understanding their precise mechanism(s) will be necessary to develop high yielding smart crop with low nutrient input.