Method for regulating gene expression

1. A method for regulating expression of a target protein in a plant cell, wherein the 5′ untranslated region (5′-UTR) of the encoding gene of said target protein comprises an upstream open reading frame (uORF), wherein the method comprises introducing into the plant cell a genome editing system that targets the uORF, thereby increasing or decreasing or eliminating inhibition of target protein expression by the uORF,

wherein the introduction of the genome editing system that targets the uORF results in mutation of one or more nucleotides in the uORF, and

wherein

(i) the mutation of one or more nucleotides results in a weak translation initiation codon in the uORF being mutated into a strong translation initiation codon, whereby inhibition of target protein expression by the uORF is enhanced and target protein expression level is reduced, or

(ii) the mutation of one or more nucleotides results in a strong translation initiation codon in the uORF being mutated into a weak translation initiation codon, or the mutation results in the uORF not being translated, whereby inhibition of target protein expression by the uORF is reduced and target protein expression level is increased, and

wherein the strong translation initiation codon is ATG, and the weak translation initiation codon is selected from the group consisting of GTG, ATC, ACG, TTG or AAG.

2. The method of claim 1 , wherein the genome editing system is selected from the group consisting of a precise base editing (PBE) system, a CRISPR-Cas9 system, a CRISPR-Cpf1 system, a CRISPRi system, a zinc finger nuclease system, and TALEN system.

3. The method of claim 1 , wherein the plant cell is a cell of plants including monocots and dicots, such as a cell of rice, corn, wheat, sorghum, barley, soybean, peanut, Arabidopsis thaliana, Lactuca sativa.

4. A plant cell engineered by the method of claim 1 , wherein the expression level of the target protein in the plant cell is altered relative to an unmodified plant cell.

5. A method of producing a genetically modified plant, comprising the step of regenerating an intact plant from the cell of claim 4 , wherein the expression level of the target protein in the genetically modified plant is altered relative to a plant that has not been genetically modified.