No abstract

No abstract

Rust fungi are plant pathogens that secrete an arsenal of effector proteins interfering with plant functions and promoting parasitic infection. Effectors are often species-specific, evolve rapidly, and display low sequence similarities with known proteins. How rust fungal effectors function in host cells remains elusive, and biochemical and structural approaches have been scarcely used to tackle this question. In this study, we produced recombinant proteins of eleven candidate effectors of the leaf rust fungus Melampsora larici-populina in Escherichia coli. We successfully purified and solved the three-dimensional structure of two proteins, MLP124266 and MLP124017, using NMR spectroscopy. Although both MLP124266 and MLP124017 show no sequence similarity with known proteins, they exhibit structural similarities to knottins, which are disulfide-rich small proteins characterized by intricate disulfide bridges, and to nuclear transport factor 2-like proteins, which are molecular containers involved in a wide range of functions, respectively. Interestingly, such structural folds have not been reported so far in pathogen effectors, indicating that MLP124266 and MLP124017 may bear novel functions related to pathogenicity. Our findings show that sequence-unrelated effectors can adopt folds similar to known proteins, and encourage the use of biochemical and structural approaches to functionally characterize effector candidates.

No abstract

The inbreed line of Nicotiana tabacum L. plants harboring a heterologous gene of bovine interferongamma sIFNG under the control of constitutive 35S CaMV promoter was created by Agrobacterium-mediated genetic transformation. The transformation of leaf discs yielded six independent transgenic plants (T 0 generation). All six transformants demonstrated presence of sIFNG insertion and had a normal phenotype. Self-pollination of T 0 plants provided six transgenic families. All families but one inherited sIFNG insertion in T 1 progeny and were used for subsequent selection. Offsprings of selfing were tested for the presence and expression of sIFNG gene and the synthesis of bovine interferon-gamma protein. We identified homozygous sIFNG plant of Inter311.2 family in T 1 generation, which was laid the founder of the inbreed line of transgenic sIFNG tobacco. The line demonstrated stable inheritance and expression of the transgene insertion and presence of a heterologous interferon-gamma protein in the plant tissue up to the fourth generation of transgenic plants tested. Antiviral and immunomodulatory activities of plantproduced interferon-gamma upon bovine cell cultures and laboratory animals (mice) were observed. Created tobacco plants may be used as the bioreactors for production of bovine interferon-gamma for veterinary.