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Washington State University Molecular Plant Sciences

Director, Molecular Plant Sciences Graduate Program
Professor of Crop Biotechnology, Department of Crop and Soil Sciences
Ph.D. 1995, Department of Botany, University of Washington. Dr. Neff’s Research


One project in my lab focuses on the role that a pair of Arabidopsis cytochrome P450 enzymes, BAS1/CYP72B1/CYP734A1 and SOB7/CYP72C1, have on the inactivation of a family of growth-promoting hormones, the brassinosteroids. We have shown that hormone inactivation plays a role in both light- and brassinosteroid-mediated development in plants. We have shown that BAS1 and SOB7 interact synergistically and redundantly to negatively regulate seedling hypocotyl and cotyledon expansion in response to light, as well as the size of adult plants and fruits. Our future focus will be on understanding the similarities and differences between the biochemistries of BAS1 and SOB7, exploring which pathways regulate these P450s and characterizing interactions with other brassinosteroid-inactivation pathways.

A second project in my lab focuses on the role that a Dof-class transcription factor, SOB1/OBP3, has on modulating seedling and adult plant stature in various tissues and light conditions. We have shown that SOB1 negatively regulates seedling hypocotyl and cotyledon expansion in response to light, acting through different photoreceptors in each tissue. SOB1 also represses the growth of adult plants. Our future focus will be to examine whether SOB1 is involved in hormone signaling, to address the possibility that related proteins are functional homologues of SOB1, and to identify which genes regulate and are regulated by this transcription factor.

A third project in my lab focuses on characterizing a pair of AT-hook-domain containing DNA-binding proteins, SOB3 and ESC, and the role that they have in modulating seedling responsiveness to light. We have shown that these two proteins act redundantly in light-mediated inhibition of hypocotyl elongation. We have also shown that the over-expression of SOB3 delays senescence and increases leaf biomass, stem thickness and flower size. Our future focus will be to uncover the mechanisms by which these and other AT-hook-domain containing proteins regulate plant development.

A fourth project in my lab focuses on characterizing a small family of plant-specific proteins related to SOB5 and the role that they have in modulating levels of the plant hormones, cytokinins. The SOB5-like (SOFL) family of proteins has not been previously characterized and has no homology to proteins or domains of known function. We have shown that the overexpression of SOB5, SOFL1 and SOFL2 confers an increase in the levels of specific cytokinins while delaying leaf senescence. Our future focus will be to uncover the biochemical action of this family of proteins and how they link cytokinin- and light-mediated plant development.

Selected Publications

(Senior/Corresponding Author indicated by an “*”)

Zhao J, Favero D, Peng H and Neff MM* (in press for the Proceedings of the National Academy of Sciences USA) The Arabidopsis thaliana AHL family modulates hypocotyl growth redundantly by interacting with each other via the PPC/DUF296 domain

Sandhu KS and Neff MM* (in press for Plant Signaling and Behavior) The Arabidopsis gene ATST4a is not a typical brassinosteroids inactivating gene

Sandhu KS, Koirala PS and Neff MM* (2013) The ben1-1 brassinosteroid-catabolism mutation is unstable due to epigenetic modifications of the intronic T-DNA insertion G3: Genes, Genomes, Genetics 3 1587-1595

Bell EM, Lin W-C, Husbands A, Yu L, Jaganatha V, Jablonska B, Mangeon M, Neff MM, Girke T, and Springer PS* (2012) Arabidopsis LATERAL ORGAN BOUNDARIES negatively regulates brassinosteroid accumulation to limit growth in organ boundaries. Proceedings of the National Academy of Sciences USA 109 21146-21151 doi:10.1073/pnas.1210789109.

Sandhu KS, Hagely K, and Neff MM* (2012) Genetic interactions between brassinosteroid-inactivating P450s and photomorphogenic photoreceptors in Arabidopsis thaliana. G3: Genes, Genomes, Genetics 2 1585-1593.

Thornton LE*, Peng H and Neff MM (2011) Rice CYP734A cytochrome P450s inactivate brassinosteroids in Arabidopsis Planta 234 (6) 1151-1162.

Thornton LE*, Rupasinghe SG, Peng H, Schuler MA and Neff MM (2010) Arabidopsis CYP72C1 is an atypical cytochrome P450 that inactivates brassinosteroids Plant Molecular Biology 74 (1-2) 167-181.

Zhang J, Vankova R, Malbeck J, Dobrev PI, Xu Y, Chong K and Neff MM* (2009) AtSOFL1 and AtSOFL2 act redundantly as positive modulators of the endogenous content of specific cytokinins in Arabidopsis. PLoS ONE 4 (12) e8236 11 pages.

Neff MM*, Sanderson L and Tedor D (2009) Light-mediated germination in lettuce seeds: Resurrection of a classic plant physiology lab exercise. The American Biology Teacher 71 367-370.

Borevitz J and Neff MM (2008) Phenotypic analysis of Arabidopsis mutants: Hypocotyl Length. Cold Spring Harbor Protocols 3 (3) doi:10.1101/pdb.prot4962.

Chen H, Zhang J, Neff MM, Hong S-W, Deng XW and Xiong L* (2008) Integration of light and abscisic acid signaling during seed germination and early seedling development. Proceedings of the National Academy of Sciences USA 105 4495-4500.

Street IH, Shah PK, SmithAM, Avery N, and Neff MM* (2008) The AT-Hook Containing Proteins SOB3/AHL29 and ESC/AHL27 are Negative Modulators of Hypocotyl Growth in Arabidopsis. Plant Journal 54 1-14.

Nemri A, Neff MM, Burrell M, Jones JDG and Studholme DJ* (2007) Marker development for the genetic study of natural variation in Arabidopsis thaliana. Bioinformatics 23 3108-3109.

Zhang J, Wrage EL, Vankova R, Malbeck J, and Neff MM* (2006) Overexpression of SOB5 suggests the involvement of a novel plant protein in cytokinin-mediated development. Plant Journal 46 834-848.

Ward JM, SmithAM, Shah PK, GallantiSE, YiH, DemianskiAJ, van der GraaffE, KellerB and Neff MM* (2006) A New Role for the AP2 Transcription Factor, LEP, in Gibberellin-Induced Germination is Revealed by the Mis-Expression of a Homologous Gene, SOB2/DRN-like. Plant Cell 18 29-39.

Turk EM, Fujioka S, Seto H, Shimada Y, Takatsuto S, Yoshida S, Wang H, Torres QI, Ward JM, Murthy G, Zhang J, Walker JC and Neff MM* (2005) BAS1 and SOB7 Act Redundantly to Modulate Arabidopsis Photomorphogenesis via Unique Brassinosteroid Inactivation Mechanisms. Plant Journal 42 23-34.

Ward JM, Cufr CA, Denzel MA and Neff MM* (2005) The Dof transcription factor, OBP3, modulates phytochrome and cryptochrome signaling in Arabidopsis. Plant Cell 17 475-485.

Turk EM, Fujioka S, Seto H, Shimada Y, Takatsuto S, Yoshida S, Denzel MA, Torres QI and Neff MM* (2003) CYP72B1 Inactivates Brassinosteroid Hormones: An Intersection Between Photomorphogenesis and Plant Steroid Signal Transduction. Plant Physiology, 133 1643-1653.

Neff MM*, Turk E and Kalishman M (2002) Web-based Primer Design for Single Nucleotide Polymorphism Analysis. Trends in Genetics, 18 613-615.

Weigel D*, Ahn JH, Blázquez MA, Borevitz J, Christensen SK, Fankhauser C, Ferrándiz C, Kardailsky I, Malancharuvil EJ, Neff MM, Nguyen JT, Sato S, Wang Z, Xia Y, Dixon RA, Harrison MJ, Lamb CJ, Yanofsky MF and Chory J (2000) Activation tagging in Arabidopsis. Plant Physiology, 122 1003-1013.

Neff MM, Fankhauser C and Chory J* (2000) Light: An indicator of time and place. Genes and Development, 14 257-271.

Neff MM, Nguyen SM, Malancharuvil EJ, Fujioka S, Noguchi T, Seto H, Tsubuki M, Honda T, Takatsuto S, Yoshida S and Chory J* (1999) BAS1: A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis. Proceedings of the National Academy of Sciences USA 96 15316-15323.

Neff MM and Chory J* (1998) Genetic interactions between phytochrome A, phytochrome B and cryptochrome 1 during Arabidopsis development.  Plant Physiology, 118 27-36.

Neff MM*, Neff JD, Chory J and Pepper AE  (1998) dCAPS, a simple technique for the genetic analysis of single nucleotide polymorphisms: experimental applications in Arabidopsis thaliana genetics.  Plant Journal, 14 387-392.

Chory J*, Chatterjee M, Cook RK, Elich T, Fankhauser C, Li J, Nagpal P, Neff MM, Pepper A, Poole D, Reed J and Vitart V (1996) From seed germination to flowering, light controls plant development via the pigment phytochrome. Proceedings of the National Academy of Sciences USA 93 12066-12071.

Blum DE, Neff MM and Van Volkenburgh E* (1994) Light-stimulated cotyledon expansion in the blu3 and hy4 mutants of Arabidopsis thaliana.  Plant Physiology 105: 1433-1436.

Neff MM and Van Volkenburgh E* (1994) Light-stimulated cotyledon expansion in Arabidopsis seedlings: The role of phytochrome B.  Plant Physiology 104: 1027-1032.

Geiser JR, van Tuinen D, Brockerhoff SE, Neff MM and Davis TN* (1991) Can calmodulin function without binding calcium? Cell 65: 949-959.



#6,534,313 “Genetically modified plants having modulated brassinosteroid signaling” Inventors: Michael M. Neff and Joanne Chory. Owner: The Salk Institute for Biological Studies. Awarded: 3/18/03.

#7,265,264 “The gene for a Dof transcription factor capable of altering the size and stature of a plant” Inventor: Michael M. Neff. Owner: Washington University. Awarded: 9/4/07