Methods and compositions for improving yield characteristics in plants

1 . A corn plant or part thereof comprising at least one mutation in an endogenous Plant AT-rich sequence- and Zinc-binding protein 8 (PLATZ8) gene encoding a PLATZ8 transcription factor, wherein the endogenous PLATZ8 gene:

encodes a polypeptide comprising a sequence having at least 90% sequence identity to the amino acid sequence of SEQ ID NO:71; and

encodes a region having at least 80% sequence identity to one or more of the amino acid sequences of SEQ ID NOs: 81-83 and to one or more of the amino acid sequences of SEQ ID NOS: 84-87,

wherein the at least one mutation is in a region of the endogenous PLATZ8 gene that encodes a zinc-binding domain (B-Box zinc-finger binding domain) of the PLATZ8 transcription factor or in a region of the endogenous PLATZ8 gene that encodes a PLATZ8 domain of the PLATZ8 transcription factor, and

wherein the at least one mutation results in decreased PLATZ8 transcription factor activity.

2 . The corn plant or part thereof of claim 1 , wherein the at least one mutation is in and/or adjacent to the second exon of the PLATZ8 gene.

3 . The corn plant or part thereof of claim 1 , wherein the at least one mutation is in and/or adjacent to the third exon of the PLATZ8 gene.

4 . The corn plant or part thereof of claim 1 , wherein the at least one mutation in the endogenous PLATZ8 gene results in a dominant negative allele, a knock-out allele, a hypomorphic allele, or a loss of function allele.

5 . The corn plant or part thereof of claim 1 , wherein the at least one mutation is a base substitution, a base deletion and/or a base insertion.

6 . The corn plant or part thereof of claim 5 , wherein the base deletion or a base insertion is an out-of-frame deletion, an out-of-frame insertion, an in-frame deletion or an in-frame insertion.

7 . The corn plant or part thereof of claim 6 , wherein the out-of-frame deletion or out-of-frame insertion results in a premature stop codon and the encoded PLATZ8 transcription factor is truncated.

8 . The corn plant or part of claim 1 , wherein the corn plant or part thereof comprising the at least one mutation exhibits an improved yield trait.

9 . The corn plant or part thereof of claim 1 , wherein the at least one mutation results in a mutated PLATZ8 gene that has at least 90% sequence identity to any one of the nucleotide sequences of SEQ ID NOs: 91, 92, 94, 95, 97, 98, 99, 100, 102, 103, 105, 106, 108, 109, 111, or 112 and/or that encodes a mutated PLATZ8 transcription factor having at least 90% sequence identity to any one of the amino acid sequences of SEQ ID NOs: 93, 96, 101, 104, 107, 110, or 113.

10 . A method for producing a corn plant or part thereof comprising at least one cell having a mutation in an endogenous Plant AT-rich sequence- and Zinc-binding protein 8 (PLATZ8) gene, the method comprising contacting a target site within the endogenous PLATZ8 gene in the corn plant or part thereof with a nuclease comprising a cleavage domain and a nucleic acid binding domain, wherein the nucleic acid binding domain of the nuclease binds to a target site within the endogenous PLATZ8 gene, wherein the endogenous PLATZ8 gene:

encodes a polypeptide comprising a sequence having at least 90% sequence identity to the amino acid sequence of SEQ ID NO:71; and

encodes a region having at least 80% sequence identity to one or more of the amino acid sequences of SEQ ID NOs: 81-83 and to one or more of the amino acid sequences of SEQ ID NOs: 84-87, thereby producing the corn plant or part thereof comprising the at least one cell having the mutation in the endogenous PLATZ8 gene,

wherein the mutation is in a region of the endogenous PLATZ8 gene that encodes a zinc-binding domain (B-Box zinc-finger binding domain) of the PLATZ8 transcription factor or in a region of the endogenous PLATZ8 gene that encodes a PLATZ8 domain of the PLATZ8 transcription factor, and

wherein the mutation results in decreased PLATZ8 transcription factor activity.

11 . The method of claim 10 , wherein the nuclease cleaves the endogenous PLATZ8 gene and the mutation is introduced into the zinc-finger binding domain the PLATZ8 transcription factor.

12 . The method of claim 10 , wherein the mutation is a base deletion or base insertion.

13 . The method of claim 12 , wherein the mutation is an out-of-frame deletion or out-of-frame insertion that results in a premature stop codon and the encoded PLATZ8 transcription factor is truncated.

14 . The method of claim 10 , wherein the corn plant that is produced exhibits an improved yield trait as compared to a control corn plant.

15 . The method of claim 10 , wherein the mutation results in a mutated PLATZ8 gene having at least 90% sequence identity to any one of the nucleotide sequences of SEQ ID NOs: 91, 92, 94, 95, 97, 98, 99, 100, 102, 103, 105, 106, 108, 109, 111, or 112 and/or a mutated PLATZ8 transcription factor having at least 90% sequence identity to any one of the amino acid sequences of SEQ ID NOs: 93, 96, 101, 104, 107, 110, or 113.