ISOLATION AND ANALYSIS OF GENES THAT FUNCTION IN PLANT MERISTEMS TO REGULATE GROWTH

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
203	1510	1040	100%

Progress 03/31/01 to 03/30/06

Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? The major problem being addressed is the need to feed the growing world population. Generating enough food will take novel crops and growing practices. Towards this end, we are conducting basic research to identify genes that regulate plant growth in maize. The research aims to determine how the plant parts, leaves and inflorescences, are formed. The genetic approach identifies key regulatory molecules that are required for organ initiation and orchestrated cell differentiation. Knowledge concerning how plants grow and differentiate provides an avenue to manipulate plant architecture and plant products. The emphasis is on maize, but because maize and other cereals have a common set of genetic instructions, the information can be transferred to other crops. The work is relevant to yield and crop utilization and is 100% devoted to addressing Component 1 (Functional Utilization of Plant Genomes: Translating Plant Genomics into Crop Improvement) of NP 302, "Plant Biological and Molecular Processes." 2. List by year the currently approved milestones (indicators of research progress) YEAR 1 (FY 2001-02) 1a. Carry out 1-hybrid screen 1b. Binding studies with KN1 and K1P; expression studies 1c. Hybridize RNA to microarray 2a. Transposon; tag MU alleles 2b. Mutagenize pollen 2c. Grow out floral mutants YEAR 2 (FY 2002-03) 1a. Sequence analysis 1b. Map position; obtain insertion alleles 1c. Sequence analysis 2a. Clone genes; screen EMS material 2b. Complementation tests 2c. Isolate tissue 3. YEAR 3 (FY 2003-04) 1a. Expression analysis 1b. Continue introgression 1c. Expression analysis knockouts 2a. Analyze expression; 2nd screen 2b. Complementation tests; cross translocation lines 2c. RNA preps YEAR 4 (FY 2004-05) 1a. Binding studies 1b. Cross mutant to kn1 1c. Binding studies 2a. Analyze expression 2b. Identify linked RFLPs to cross translocation lines 2c. Northerns selected in situs YEAR 5 (FY 2005-06) 1a. Identify maize homologs 1b. Analyze double mutant 1c. Identify maize homologs; functional tests 2a. Identify similar genes in other cereals 2b. Identify position in rice genome; double mutant analysis 2c. Functional tests 4a List the single most significant research accomplishment during FY 2006. Maize inflorescence development This accomplishment addresses NP 302 Component 1, Problem Statement 1A, Advancing from Model Plants to Crop Plants. Maize provides an important model species for other cereals. Genes that regulate the inflorescence directly control the yield of cereal grains. USDA postdoctoral fellow, George Chuck, walked to the tasselseed4 gene. It encodes a microRNA and is the first recessive mutation identified that is a microRNA. Knowledge of the targets of this microRNA will help improve cereal grain yields. 4b List other significant research accomplishment(s), if any. Maize flower development This accomplishment addresses NP 302 Component 1, Problem Statement 1A, Advancing from Model Plants to Crop Plants. Maize provides an important model species for other cereals. Genes that regulate the flower directly control the seed development. USDA funded lab technician with the help of postdoctoral fellow, George Chuck, cloned the bearded ear (be1) mutation in maize. The MADS box gene is expressed exclusively in ears and tassels to regulate flower development. Knowledge of how be1 functions in maize and other cereals will be useful for seed development. 5. Describe the major accomplishments to date and their predicted or actual impact. This research addresses NP 302 Component 1, Problem Statement 1A, Advancing from Model Plants to Crop Plants. Our most significant discovery was the isolation of the KNOTTED1 gene which led to the isolation of related genes in many species. These genes have been powerful tools for plant scientists to determine how organs are formed in plants. The genes are also used as markers for tissue culture and for delaying senescence in horticultural crops. We have now isolated 5 genes that regulate tassel and ear development, ids1, bd1, ts4, be1 and ra2. These genes are unique to the grasses and fundamentally important for grass architecture. Given that the cereals are members of the grass family, the genes we have identified are important for the architecture of the seed-bearing structures. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Many people use our cloned genes. We also contribute stocks to the maize stock center that are then disbursed freely. We have a CRADA with Pioneer to clone the tasselseed4 gene and the Corngrass gene. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). We published the cloning of ramosa2 in The Plant Cell. A feature review was written about our work in the front section of The Plant Cell.

Impacts
(N/A)

Publications

Wilt, F.H., Hake, S.C. 2004. Principles of Developmental Biology. Complete Book. New York, NY. W.W. Norton & Company, Inc. ISBN 0-393-97430-8, 450 p.
Lunde, C., Hake, S.C. 2005. Florets and Rosettes: Meristem Genes in Maize and Arabidopsis. Maydica, 50:451-458.
Bortiri, E., Jackson, D., Hake, S.C. 2006. Advances in maize genomics: the emergence of positional cloning. Current Opinion in Plant Biology, 9(2) :164-171.
Bortiri, E., Chuck, G.S., Vollbrecht, E., Rocheford, T., Martienssen, R., Hake, S.C. 2006. ramosa2 Encodes a LATERAL ORGAN BOUNDARY Domain Protein That Determines the Fate of Stem Cells in Branch Meristems of Maize. The Plant Cell. 18:574-585.
Bart, R., Ronald, P., Hake, S.C. 2006. Fertility versus disease resistance, a hard choice. Genes and Development. 20:1215-1217.

Progress 10/01/04 to 09/30/05

Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The major problem being addressed is the need to feed the growing world population. Generating enough food will take novel crops and growing practices. Towards this end, we are conducting basic research to identify genes that regulate plant growth in maize. The research aims to determine how the plant parts, leaves and inflorescences, are formed. The genetic approach identifies key regulatory molecules that are required for organ initiation and orchestrated cell differentiation. Knowledge concerning how plants grow and differentiate provides an avenue to manipulate plant architecture and plant products. The emphasis is on maize, but because maize and other cereals have a common set of genetic instructions, the information can be transferred to other crops. The work is relevant to yield and crop utilization. 2. List the milestones (indicators of progress) from your Project Plan. Milestones 1. Determine how KNOX genes function to maintain the meristem. 1A. Identify targets of KN1 1B. Characterization of an interacting protein partner 1C. Expression profiling analysis 2. Identify genes that regulate maize inflorescence branching. 2A. Mutant screens. 2B. Genetic analysis and mapping 2C. Gene isolation 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Identify Targets of KN1. Milestone Substantially Met 2. Characterization of an Interacting Protein Partner. Milestone Fully Met 3. Expression Profiling Analysis. Milestone Fully Met 4. Mutant Screens. Milestone Substantially Met 5. Genetic Analysis and Mapping. Milestone Substantially Met 6. Gene Isolation. Milestone Substantially Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? This project expires in FY2006. FY 2006 1. Analysis of KNOX function: regulation of KN1 and determination of downstream KNOX targets. Finish making constructs to test elements of the KN1 gene in transgenic plants. Finish analysis of lignin in KN1 mutants. 2. Identify genes that regulate inflorescence architecture in maize. Finish analysis of tasselseed4, determine expression and potential targets. 3. Identify genes that function in maize leaf development. Map mwp and Wab to smaller region and identify possible candidate genes. FY 2007 1. Analysis of KNOX function: regulation of KN1 and determination of downstream KNOX targets. Determine whether KN1 is regulated by phosphorylation. Determine chromatin environment of KN1. 2. Identify genes that regulate inflorescence architecture in maize. Identify gene for bearded ear mutation by chromosomal position. 3. Identify genes that function in maize leaf development. Test possible candidate genes for mwp and Wab. FY 2008 1. Analysis of KNOX function: regulation of KN1 and determination of downstream KNOX targets. Determine whether GA functions downstream of KN1 in maize. 2. Identify genes that regulate inflorescence architecture in maize. Map Fascicled ear to BAC. 3. Identify genes that function in maize leaf development. Determine gene function for mwp and Wab. 4a What was the single most significant accomplishment this past year? Identification of genes that regulate the maize inflorescence. Maize provides an important model species for other cereals. Genes that regulate the inflorescence directly control the yield of cereal grains. USDA postdoctoral fellow, George Chuck, walked to the tasselseed4 gene. It encodes a microRNA and is the first recessive mutation identified that is a microRNA. 4b List other significant accomplishments, if any. The UC Berkeley postdoctoral fellow in the Hake lab, Esteban Bortiri, analyzed the ramosa2 gene using in situ hybridization techniques. It is expressed very early in ear and tassel development, predicting the position of branch initiation. The sequence and expression pattern for ramosa2 is conserved in sorghum and rice. These data will be useful for others working in different cereals. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Our most significant discovery was the isolation of the KNOTTED1 gene which led to the isolation of related genes in many species. These genes have been powerful tools for plant scientists to determine how organs are formed in plants. The genes are also used as markers for tissue culture and for delaying senescence in horticultural crops. We have now isolated 4 genes that regulate tassel and ear development, ids1, bd1, ts4 and ra2. These genes are unique to the grasses and fundamentally important for grass architecture. Given that the cereals are members of the grass family, the genes we have identified are important for the architecture of the seed-bearing structures. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Many people use our cloned genes. We also contribute stocks to the maize stock center that are then disbursed freely. We have a CRADA with Pioneer to clone the tasselseed 4 gene. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). I am a co-author of a textbook "Principles of Developmental Biology" with Fred Wilt, published by Norton and Norton.

Impacts
(N/A)

Publications

Chuck, G.S., Hake, S.C. 2004. Regulation of developmental transitions. Current Opinion in Plant Biology, 8(1):67-70.
Hake, S.C., Rocheford, T. 2004. Exploiting quantitative trait loci in gene discovery. Genes and Development, 18:597-601.
Hake, S.C., Smith, H.M., Holtan, H., Magnani, E., Mele, G., Ramirez, J. 2004. The Role of KNOX Genes in Plant Development. Annual Reviews of Cell and Developmental Biology, 20:125-151.
Magnani, E., Sjolander, K., Hake, S.C. 2004. From Endonucleases to Transcription Factors: Evolution of the AP2 DNA Binding Domain in Plants. The Plant Cell 16:2265-2277
Bommert, P., Lunde, C., Nardmann, J., Vollbrecht, E., Running, M., Jackson, D., Hake, S.C., Werr, W. 2005. Thick tassel dwarf1 encodes a putative maize ortholog of the Arabidopsis CLAVATAL1 leucine-rich repeat receptor- like kinase. Development, 132:1235-1245.
Foster, T., Hay, A., Hake, S.C. 2004. The establishment of axial patterning in the maize leaf. Development, 131:3921-3929.

Progress 10/01/03 to 09/30/04

Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The major problem being addressed is the need to feed the growing world population. Generating enough food will take novel crops and growing practices. Towards this end, we are conducting basic research to identify genes that regulate plant growth in maize. The research aims to determine how the plant parts, leaves and inflorescences, are formed. The genetic approach identifies key regulatory molecules that are required for organ initiation and orchestrated cell differentiation. Knowledge concerning how plants grow and differentiate provides an avenue to manipulate plant architecture and plant products. The emphasis is on maize, but because maize and other cereals have a common set of genetic instructions, the information can be transferred to other crops. The work is relevant to yield and crop utilization. 2. List the milestones (indicators of progress) from your Project Plan. Milestones 1. Determine how KNOX genes function to maintain the meristem. 1A. Identify targets of KN1 1B. Characterization of an interacting protein partner 1C. Expression profiling analysis 2. Identify genes that regulate maize inflorescence branching. 2A. Mutant screens. 2B. Genetic analysis and mapping 2C. Gene isolation 3. Milestones: A. List the milestones (from the list in Question #2) that were scheduled to be addressed in FY 2004. How many milestones did you fully or substantially meet in FY 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. 1A. Identify Targets of KN1. We have identified some of KN1's targets as genes in the Gibberellin pathway. 1B. Characterization of an Interacting Protein Partner. We identified an interacting partner for KN1 that we call KIP. We also have identified an interacting partner for Arabidopsis KNOX genes, BP and STM. These proteins are required for internode patterning and floral evocation. 1C. Expression Profiling Analysis. We carried out an expression profile and found that KN1 regulates the lignin pathway. 2. Identify Genes that Regulate Maize Inflorescence Branching. We cloned the branched silkless gene in maize and showed it was a protein that carries an AP2 domain. We also cloned the thick tassel dwarf mutation and showed it was a clavata1 ortholog. 2A. Mutant Screens. We have carried out EMS screens for new inflorescence and leaf phenotypes. 2B. Genetic Analysis and Mapping. We mapped polytypic-McClintock to chromosome position and have mapped Wab and Corngrass to small intervals. 2C. Gene Isolation. We isolated the ramosa2 gene by positional cloning. B. List the milestones (from the list in Question #2) that you expect to address over the next 3 years (FY 2005, 2006, & 2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone? FY 2005 1A. Targets of KN1. Chromatin immunoprecipation analysis in maize and rice to identify KN1 targets. 1B. Interacting Partners. Bimolecular fluorescence complementation of KNOX and BELL proteins from Arabidopsis in E. coli. 1C. Expression Analysis. Initiation experiments in rice with inducible Osh1-ER construct. 2A. Mutant Screens. Continue EMS screens to find new mutants. Targeted tagging of polytypic and milkweed pod for transposon induced alleles. 2B. Genetic Analysis. Fine-map Corngrass and Wab 2C. Gene Isolation. Identify the tasselseed4 gene by positional cloning. FY 2006 1A. Targets of KN1. Consolidate results from Chromatin immunoprecipation to find maize coding regions. 1B. Interacting Partners. BiFC of KNOX and BELL proteins in plant cells. 1C. Expression Analysis. Identify genes that were up or down regulated in OSH- ER rice plants. 2B. Genetic Analysis. Map new mutants identified by EMS screens. Determine if new targeted tagged alleles contain insertion. 2C. Gene Iolation. Identify the Wab gene by positional cloning. FY 2007 1B. Interacting Partners. BiFC of KNOX and BELL proteins in transgenic plants with endogenous promoter. 1C. Expression Analysis. Compare expression analysis with chromatin immunoprecipitation experiments to find genes that are in common. 2B. Genetic Analysis: Continue analysis of floral and leaf mutants. Map any new mutants to chromosome position. 2C. Gene Isolation: Identify the milkweed pod gene by positional cloning. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004 (one per Research (OOD) Project): Genes that regulate inflorescence architecture. Maize provides an important model species for other cereals. Genes that regulate the inflorescence directly control the yield of cereal grains. The UC Berkeley postdoctoral fellow in the Hake lab, Esteban Bortiri, carried out a chromosomal walk to the ramosa2 gene, which regulates inflorescence architecture in maize. This is the first report of the isolation of a maize gene based on position in a non-industry setting. The ramosa2 gene will provide an important tool to determine how the inflorescences of maize and other grasses develop. B. Other significant accomplishment(s), if any. Identification of the thick tassel dwarf gene. In a collaboration with UC technician, China Lunde, and Wolfgang Werr of the University of Cologne, the thick tassel dwarf (td1) gene was isolated. TD1 regulate meristem size in both the ear and tassel, increasing spikelet density and row number. TD1 was shown to encode an ortholog of the clavata1 gene from Arabidopsis. The gene provides a useful marker for QTL populations that examine yield in maize. C. Significant activities that support special target populations. NONE D. Progress Report opportunity to submit additional programmatic info to Area Office & NPS. Optional for this project For in-house: NONE 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Our most significant discovery was the isolation of the KNOTTED1 gene which led to the isolation of related genes in many species. These genes have been powerful tools for plant scientists to determine how organs are formed in plants. The genes are also used as markers for tissue culture and for delaying senescence in horticultural crops. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Many people use our cloned genes. We also contribute stocks to the maize stock center that are then disbursed freely. We have a CRADA with Pioneer to clone the tasselseed 4 gene. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. I am a co-author of a textbook "Principles of Developmental Biology" with Fred Wilt, published by Norton and Norton.

Impacts
(N/A)

Publications

MELE, G., ORI, N., SATO, Y., HAKE, S.C. 2003. The knotted1-like homeobox gene BREVIPEDICELLUS regulates cell differentiation by modulating metabolic pathways. 2003. GENES & DEVELOPMENT 17:2088-2093.
Smith, H.M., Hake, S.C. The Interaction of Two Homeobox Genex, BREVIPEDICELLUS and PENNYWISE, Regulates Internode Patterning in the Arabidopsis Inflorescence. The Pant Cell. 2003. 15:1717-27.
HAKE, S.C. MICRORNAS: A ROLE IN PLANT DEVELOPMENT. CURRENT BIOLOGY. 2003. v. 13:21, R851-R852.
Smith, H.M., Campbell, B.C., Hake, S.C. 2004. Competence to respond to floral inductive signals requires the homebox genes pennywise and pound- foolish. Current Biology. v 14, 9:812-817
Holtan, H.E., Hake, S.C. 2003. Quantitative trait locus analysis of leaf dissection in tomato using lycopersicon pennellii segmental introgression lines. Genetics 165:1541-1550.
Kozaki, A., Hake, S.C., Colasanti, J. 2004. The maize ID1 flowering time regulator is a zinc finger protein with novel DNA binding properties. Nucleic Acids Research, 12;32(5):1710-20.
Hay, A., Hake, S.C. 2004. The dominant mutant wavy auricle in blade1 disrupts patterning in a lateral domain of the maize leaf. Plant Physiology, 135:300-308
Hake, S.C. 2003. Frontiers in plant genetics. Genome Biology, 5:302.
Running, M.P., Lavy, M., Sternberg, H., Galichet, A., Gruissem, W., Hake, S., Ori, N., Yalovsky, S. 2004. Enlarged meristems and delayed growth in plp mutants result from lack of caax prenyltransferases. Proceedings of the National Academy of Sciences USA, 101:7815-20.

Progress 10/01/02 to 09/30/03

Outputs
1. What major problem or issue is being resolved and how are you resolving it? The major problem being addressed is the need to feed the growing world population. Generating enough food will take novel crops and growing practices. Towards this end, we are conducting basic research to identify genes that regulate plant growth in maize. In particular, the research aims to determine how the meristem, a group of cells at the growing tip that produces the leaves and flowers, functions. Determining how the meristem functions is relevant to yield and regeneration abilities of different crops. The genes are identified through mutational approaches. 2. How serious is the problem? Why does it matter? Knowledge concerning how plants grow and differentiate provides an avenue to manipulate plant architecture and plant products. The emphasis is on maize, but because maize and other cereals have a common set of genetic instructions, the information can be transferred to other crops. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? NP 302 Plant Biological Molecular Processes (100%). Important genetic traits are identified and the genes are isolated. Seeds carrying these traits are evaluated in genetic experiments. Thus the research relates to the conservation and development of plant germplasm. Analysis and exploration of gene function will lead to improved plant processes. 4. What were the most significant accomplishments this past year? 4A. Single most significant accomplishment during FY03: KNOX genes regulate meristem function and thus are important for growth and evelopment. We identified the targets of the KNOX gene, BREVIPEDICELLUS (BP) using Affymetrix expression profiling. We determined that a number of genes in the lignin pathway are regulated by BP and that lignin levels are increased in mutants that do not make function BP protein and are decreased in plants that overexpress BP. Finding a transcription factor that globally regulates lignin biosynthesis has potential utility for bio-fuels and the use of grasses for ruminants. 4B. Other significant accomplishments: KNOX proteins function as heterodimers to regulate growth and development. We identified a partner protein for BP called PENNYWISE (PNY) that is required for internode development. Plants that lack BP and PNY fail to produce internodes, make additional axillary branches and have altered vascular cells. Knowledge of transcription factors that regulate branching and elongation is required for plant improvement. C. Significant Accomplishments/Activities that Support Target Populations: NONE. D. Progress Report: NONE. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Our most significant discovery was the isolation of the KNOTTED1 gene which led to the isolation of related genes in many species. These genes have been powerful tools for plant scientists to determine how organs are formed in plants. The genes are also used as markers for tissue culture and for delaying senescence in horticultural crops. 6. What do you expect to accomplish, year by year, over the next 3 years? YEAR 1. Aim 1. Identify additional targets of KNOX proteins. Aim 2. Prove that we have cloned thick tassel dwarf. Clone the ramosa2 and tasselseed genes by positional cloning. Aim 3. Analyze genes that regulate leaf size and shape in maize. YEAR 2. Aim 2. Continue analysis of ramosa2 and tasselseed4. Aim 3. Clone the genes that regulate leaf shape in maize. YEAR 3. Aim 2. Identify orthologs of ramosa2 and tasselseed4 in other grasses. Aim 3. Determine how the leaf shape genes function. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Many people use our cloned genes. We also contribute stocks to the maize stock center that are then disbursed freely.

Impacts
(N/A)

Publications

HUBBARD, L., MCSTEEN, P.C., DOEBLEY, J., HAKE, S.C. EXPRESSION PATTERNS AND MUTANT PHENOTYPE OF TEOSINTE BRANCHED1 CORRELATE WITH GROWTH SUPPRESSION IN MAIZE AND TEOSINTE. GENETICS. 2002. 162:1927-1935.
MICOL, J., HAKE, S.C. THE DEVELOPMENT OF PLANT LEAVES. PLANT PHYSIOLOGY. 2003. 131:389-394.
MELE, G., HAKE, S.C. EXPRESSION PROFILING OF PLANT DEVELOPMENT. GENOME BIOLOGY. 2003. 4:215.
HAY, A., DAVID, J., ORI, N., HAKE, S.C. ANALYSIS OF THE COMPETENCE TO RESPOND TO KNOTTED1 ACTIVITY IN ARABIDOPSIS LEAVES USING A STERIOID INDUCTION SYSTEM. PLANT PHYSIOLOGY. 2003. 131:1671-1680.
FLETCHER, J.C., HAKE, S.C. PLANT DEVELOPMENT MAKES STRIDES IN VERMONT. DEVELOPMENTAL CELL 3:479-485, October 2002.
CHUCK, G.S., MUSZYNSKI, M., KELLOGG, E., HAKE, S.C., SCHMIDT, R.J. THE CONTROL OF SPIKELET IDENTITY BY THE BRANCHED SILKLESS1 GENE IN MAIZE. SCIENCE. 2003. 298*5596):1238-41.
HAY, A., KAUR, H., PHILLIPS, A., HEDDEN, P., HAKE, S.C., TSIANTIS, M. THE GIBBERELLIN PATHWAY MEDIATES KNOTTED1-TYPE HOMEOBOX FUNCTION IN PLANTS WITH DIFFERENT BODY PLANS. CURRENT BIOLOGY. 2002. 12:18:1557-1565.

Progress 10/01/01 to 09/30/02

Outputs
1. What major problem or issue is being resolved and how are you resolving it? The major problem being addressed is the need to feed the growing world population. Generating enough food will take novel crops and growing practices. Towards this end, we are conducting basic research to identify genes that regulate plant growth in maize. In particular, the research aims to determine how the meristem, a group of cells at the growing tip that produces the leaves and flowers, functions. Determining how the meristem functions is relevant to yield and regeneration abilities of different crops. The genes are identified through mutational approaches. 2. How serious is the problem? Why does it matter? Knowledge concerning how plants grow and differentiate provides an avenue to manipulate plant architecture and plant products. The emphasis is on maize, but because maize and other cereals have a common set of genetic instructions, the information can be transferred to other crops. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? NP 302 Plant Biological & Molecular Processes (100%). Important genetic traits are identified and the genes are isolated. Seeds carrying these traits are evaluated in genetic experiments. Thus the research relates to the conservation and development of plant germplasm. Analysis and exploration of gene function will lead to improved plant processes. 4. What was your most significant accomplishment this past year? 4A. Single Most Significant Accomplishment during FY02: Branched silkless regulates formation of the spikelet, a condensed branch found in all grasses; and all cereal grains arise in spikelets, thus this structure is very important for agriculture. The work was a collaboration with Dr. Robert Schmidt, UC San Diego. During this reporting period we cloned the branched silkless gene in maize. The knowledge of bd sequence and expression profile could improve grain yields. 4B. Other Significant Accomplishment(s), if any KNOX proteins regulate meristem function and thus are important for growth and development. Binding studies have been carried out at the PGEC. We determined that KNOX proteins interact with another class of proteins to bind at high affinity to specific target sequences. Knowledge of how KNOX proteins regulate other genes has important implications for all plants. C. Significant Accomplishments/Activities that Support Target Populations: NONE. D. Progress Report: 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? Our most significant discovery was the isolation of the KNOTTED1 gene which led to the isolation of related genes in many species. These genes have been powerful tools for plant scientists to determine how organs are formed in plants. The genes are also used as markers for tissue culture and for delaying senescence in horticultural crops. 6. What do you expect to accomplish, year by year, over the next 3 years? YEAR 1. Aim 1: Analysis of KNOX genes in Arabidopsis. Expression profiling to identify targets of KNOX genes in Arabidopsis. Expression profiling in maize to compare developing tassels and ears and the bif2 and bd1 mutants. Clone the ramosa2 gene in maize. YEAR 2. Aim 1: Continue analysis of ramosa2. Initiate analysis on any other transposon tagged genes such as td1. YEAR 3. Aim 2: Begin analysis on target genes on KNOX transcription factors. Carry out mutant screens in maize. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Many people use our cloned genes. We also contribute stocks to the maize stock center that are then disbursed freely.

Impacts
(N/A)

Publications

McSteen, P., Hake, S. 2001. Barren inflorescence2 regulates axillary meristem development in the maize inflorescence. Development, 128:2881- 2891.
Taguchi Shiobara, F., Yuan, Z. Hake, S., Jackson, D. 2001. The fasciated ear2 gene encodes a leucine rich repeat receptor like protein that regulates shoot meristem proliferation in maize. Genes and Development, 15:2755-2766.
Laudencia-Chingcuanco, D., Hake, S. 2002. The indeterminate floral apex1 gene regulates meristem determinacy and identity in the maize inflorescence. Development, 129:2629-2638.
Hake, S., Ori, N. 2002. Plant morphogenesis and KNOX genes. Nature Genetics, 31:121-122.
Smith, H.M., Boschke, I., Hake, S. 2002. Selective interaction of plant homeodomain proteins mediates high DNA-binding affinity. Proc. Natl. Acad. Sci. USA, 99:9579-84.
McSteen, P., Laudencia, D., Colasanti, J. (Sarah Hake's lab, Plant Gene Expression Center). 2000. A floret by any other name: control of meristem identity in maize. Trends in Plant Sci., 5(2):61-66.
Hake, S. 2001. Mobile protein signals cell fate. Nature, 413:261-264.
Kaplinsky, N., Braun, D., Lisch, D., Hay, A., Hake, S.C., Freeling, M. 2002. Biodiversity (Communications arising): Maize transfene results in Mexico are artefacts. Nature, 416:601-602.