Disclosed herein are viral vectors based on modifications of the Citrus Tristeza virus useful for transfecting citrus trees for beneficial purposes. Included in the disclosure are viral vectors including one or more gene cassettes that encode heterologous polypeptides. The gene cassettes are positioned at desirable locations on the viral genome so as to enable expression while preserving functionality of the virus. Also disclosed are methods of transfecting plants and plants transfected with viral vector embodiments.

The invention relates to the field of genetic engineering tools for gene expression in plants. Specifically, the invention concerns modified Foxtail Mosaic Virus (FoMV) vectors comprising polynucleotide sequences which are capable of driving expression of a gene of interest in a plant host. Accordingly, the invention concerns FoMV-based expression vectors comprising said polynucleotides, compositions comprising modified FoMV vectors, methods of generating gene expression in plants infected with the modified FoMV vectors. The expression vectors, compositions, plants and methods of the present invention find application in many fields of biotechnology, including, for example, gene characterization, protein production and agricultural biotechnology.

The invention provides a method of producing a potexviral vector for expressing a protein of interest in a plant, comprising producing a second heterologous nucleic acid comprising a second ORF encoding said protein and having, in the second ORF, an increased GC-content compared to a first ORF encoding said protein in a first heterologous nucleic acid, and providing said potexviral vector comprising the following segments: (i) a nucleic acid sequence segment encoding a potexviral RNA-dependent RNA polymerase, (ii) a nucleic acid sequence comprising or encoding a potexviral triple-gene block, and (iii) said second heterologous nucleic acid or a portion thereof comprising said second ORF.

The present application discloses an application of OsAO gene for improving rice resistance to rice stripe disease, rice black-streaked dwarf disease or other rice or corn virus diseases caused by homologous virus of rice black-streaked dwarf virus. The present application also provides an application of OsAO gene, the protein encoded by the gene or a recombinant vector containing the gene in regulating plant resistance to rice stripe disease, rice black-streaked dwarf disease or other rice and corn virus diseases caused by homologous virus of rice black-streaked dwarf virus, said protein has the amino acid sequence as shown in Seq 4. The experiment proved that the plant disease resistance is increased in rice overexpressing OsAO gene, indicating that the OsAO protein encoded by this gene plays an important role in rice resistance to rice stripe disease and rice black-streaked dwarf disease.

The present invention relates generally to methods of molecular biology and gene silencing to control pests.

A recombinant vector according to an embodiment is for genome editing without inserting a replicon into the plant genome in a T.sub.0 generation plant. The recombinant vector includes a geminivirus-based replicon between the sequence of LB (left border) and sequence of RB (right border) of Ti plasmid. A method of genome editing without inserting a replicon into the plant genome in a T.sub.0 generation plant according to an embodiment includes transforming a plant cell by inserting a foreign gene to the aforementioned recombinant vector.

A method of producing transformed cell or plant body of maize includes overexpressing, in a cell or plant body of maize, 1) a nucleic acid encoding an amino acid sequence of SEQ ID NO: 2, or a nucleic acid encoding a polypeptide including an amino acid sequence having at least 95% sequence identity with the amino acid sequence of SEQ ID NO: 2, the polypeptide having a function of promoting cell division of maize, or 2) a nucleic acid encoding an amino acid sequence of SEQ ID NO: 15, or a nucleic acid encoding a polypeptide including an amino acid sequence having at least 95% sequence identity with the amino acid sequence of SEQ ID NO: 15, the polypeptide having a function of promoting cell division of maize, the overexpressing being controlled by a promoter including a 35S promoter of Cauliflower mosaic virus.

A combination of virus vectors for genome editing is formed by arranging a polynucleotide encoding a split genome editing enzyme in each of a Tobamovirus vector and a Potexvirus vector and arranging a polynucleotide encoding a guide RNA in one of the vectors. It is found that when these virus vectors are introduced into a plant cell, a complex of a functional Cas9 protein and the guide RNA is formed in the plant cell, and a genome is edited in a target site-specific manner.

Disclosed herein are viral vectors suitable for transfection into woody trees for purposes of delivering and expressing beneficial genes. Specifically exemplified herein are vectors for transfecting citrus trees. The vectors allow for the expression of useful proteins, such as those that can protect the tree from disease. Specifically exemplified herein are methods of transfecting woody trees that allow multiple applications of vectors while avoiding superinfection exclusion.

Methods of providing gene suppression DNA in a eukaryotic organism comprising introducing a first DNA segment and at least one second DNA segment into the genome of the organism. One of the DNA segments contains a promoter and a transcribable DNA. Another DNA segment contains at least part of the transcribable DNA. When inserted in tandem, the DNA segments are assembled in vivo forming a recombinant transcription unit. RNA transcribed from the transcription unit can form double-stranded RNA.