FFGA1 Protein Is Essential for Regulating Vegetative Growth, Cell Wall Integrity, and Protection against Stress in Flammunina filiformis.

Flammulina filiformis is a popular mushroom which has been regarded as a potential model fungus for mycelium growth, fruiting body development, and stress response studies. Based on a genome-wide search, four genes encoding heterotrimeric G protein α subunits were identified in F. filiformis. The data of conserved domain analysis showed that these genes contain only one subgroup I of Gα subunit (Gαi), similar to many other fungi. To explore the function of Gαi, FfGa1 over-expression (OE) and RNA interference (RNAi) strains were generated using the Agrobacterium tumefaciens-mediated transformation (ATMT) approach. RNAi transformant strains showed remarkably reduced growth on PDA medium and added sensitivity to cell wall-enforcing agents with maximum growth inhibition, but showed better growth in response to hypertonic stress-causing agents, while OE strains exhibited more resistance to thermal stress and mycoparasite Trichoderma as compared to the wild-type and RNAi strains. Taken together, our results indicated that FfGa1 positively regulates hyphal extension, and is crucial for the maintenance of cell wall integrity and protection against biotic and abiotic (hypertonic and thermal) stress.

Fluorescent sensor based on triphenylamine for Zn2+ with high selectivity and imaging in living cells.

It is of great importance to design a fluorescent sensor with high selectivity, sensitivity and large Stokes shift to zinc detection for environmental water sample and in vivo. Herein, A novel Zn2+ fluorescent sensor with larger Stokes shift (110 nm) 1-((5-(4-(diphenylamino)phenyl)pyridine-2-imino)methyl)naphthalene-2-ol (abbr. TPA-PN) was designed and synthesized. In DMF-H2O (V: V = 1: 1, pH = 7.0) solution, it could achieve high selectivity and sensitivity to Zn2+, there was a linear responsive range of 0-20 µM of concentration of Zn2+ ions for the sensor, the detection limit was as low as 19.134 nM and the binding constant was calculated to be 3.24 × 104 M-1. The species of TPA-PN and zinc were clarified at different pH. Besides, the interaction properties and fluorescence mechanism were demonstrated by the species theory, density functional theory (DFT) calculation, 1H NMR titration, FT-IR and MS. Most importantly, it provided a new real-time, on-site method and showed excellent potential in-vivo imaging ability.