# US 8,541,649 B2 · Brassinosteroid regulated kinases (BRKs) that mediate brassinosteroid signal transduction and uses thereof

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- Number: US 8,541,649 B2
- Document ID: US8541649B2
- Status: Granted
- Kind: B2
- Application number: 12/506,895
- Filed: 2009-07-21
- Published: 2010-02-18
- Granted: 2013-09-24
- Earliest claimed: 2008-07-21
- Assignees: Carnegie Institution of Washington
- Applicants: Zhi-Yong Wang; Wenqiang Tang
- Inventors: Zhi-Yong Wang; Wenqiang Tang
- Web page: https://patentgrep.com/patent/US8541649B2

## CPC

- C12N 15/8261: {with agronomic (input) traits, e.g. crop yield}
- C12N 9/1205: {Phosphotransferases with an alcohol group as acceptor (2.7.1), e.g. protein kinases}
- Y02A 40/146: Genetically Modified [GMO] plants, e.g. transgenic plants
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

The present invention identifies a novel family of kinases regulated by brassinosteroids, referred to as BRKs (brassinosteroid regulated kinases) or BSKs (brassinosteroid signaling kinases). The present invention provides methods for modulating the response of a plant cell to a brassinosteroid using BRKs.

## Claims

### Claim 1

A fusion protein comprising a brassinosteroid receptor regulated kinase (BRK) polypeptide comprising the amino acid sequence X1X2STNLAX3X4PPEYLR (SEQ ID NO: 25), wherein X1 is either serine, arginine, or isoleucine, X2 and X3 are either tyrosine or phenylalanine, and X4 is either threonine or alanine.

### Claim 2 (depends on 1)

The fusion protein of claim 1, wherein the serine at amino acid position three is phosphorylated.

### Claim 3 (depends on 1)

fusion protein of claim 1, wherein the sequence comprises a serine to alanine mutation at amino acid position three.

### Claim 4 (depends on 1)

The fusion protein of claim 1, wherein the sequence comprises a mutation, wherein the mutation comprises a glutamic acid or aspartic acid at amino acid position three.

### Claim 5 (depends on 1)

An immunogenic composition, comprising the fusion protein of claim 1, together with a pharmaceutically acceptable carrier.

### Claim 6 (depends on 1)

A transgenic plant comprising the fusion protein of claim 1.

### Claim 7 (depends on 1)

The fusion protein of claim 1, wherein the polypeptide comprises an amino acid sequence of at least 95% sequence identity to SEQ ID NO: 2, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20 or SEQ ID NO: 22.

### Claim 8

A polypeptide consisting of SEQ ID NO: 25.

### Claim 9

A brassinosteroid receptor regulated kinase (BRK) polypeptide comprising an amino acid sequence that is at least 95% identical to an amino acid sequence selected from the group consisting of SEQ ID NO: 6, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20 or SEQ ID NO: 22.

### Claim 10 (depends on 9)

A method for modulating a cellular process of a plant cell comprising introducing the brassinosteroid receptor regulated kinase (BRK) polypeptide of claim 9 into the plant cell by transforming the plant cell with a nucleic acid molecule encoding the BRK polypeptide.

### Claim 11 (depends on 10)

The method of claim 10, wherein the cellular process is cell expansion, cell elongation, cell division, cell growth, protection of the cell during exposure to cold, protection of the cell during exposure to heat, protection of the cell during drought, acceleration of senescence of the cell when it is dying, promotion of vascular differentiation, cell wall regeneration, or pollen elongation.

### Claim 12 (depends on 10)

The method of claim 10 wherein the cellular process is inhibited as compared to a control.

### Claim 13 (depends on 10)

The method of claim 10, wherein the cellular process is enhanced as compared to a control.

### Claim 14 (depends on 10)

The method of claim 10, wherein the BRK polypeptide is mutated so that the kinase activity of the BRK polypeptide is inhibited.

### Claim 15 (depends on 10)

The method of claim 10, wherein the kinase activity of the polypeptide BRK is inhibited by mutating a serine residue that is phosphorylated to an alanine residue.

### Claim 16 (depends on 10)

The method of claim 10, further comprising contacting the cell with a brassinosteroid.

### Claim 17 (depends on 9)

The BRK polypeptide of claim 9, wherein the amino acid consists of the amino acid sequence of an amino acid sequence selected from the group consisting of SEQ ID NO: 6, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20 or SEQ ID NO: 22.