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Alan M Lloyd

Professor Emeritus
Molecular Biosciences


Postal Address
AUSTIN, TX 78712

The main goal of my lab is to understand developmental mechanisms and pigment pathways in plants. The control of cell fate decisions is a central issue during plant development and pattern formation. One main focus of my lab is to use trichome (epidermal plant hair) initiation as a simple and amenable model to study the control of plant cell fate decision events. Over the years we have identified a combinatorial transcriptional complex that regulates trichome initiation and patterning. We are studying how this complex functions by manipulating the complex members and by investigating many of the complex's transcriptional targets. This complex also has pleiotropic control of the common red/purple anthocyanin pigment pathway in Arabidopsis and most other flowering plants. We have studied how the complex regulates these pigments and recently we have begun work on a red pigment pathway, the betalains, that are narrowly restricted to a single order of flowering plants that include beets, cactus and other taxa. The betalain pathway is much simpler than the anthocyanin pathway and has the potential to be used as a color and fluorescent marker in heterologous systems, fungi, animals and others.


2015 Hatlestad G*, Akhavan N*, Sunnadeniya R, Elam L, Cargile S, Hembd A, Gonzalez A, McGrath M, Lloyd AM,  The beet Y locus encodes an anthocyanin-MYB-like protein that activates the betalain red pigment pathway. *co-first authors. Nature Genetics 47, 92–96. doi:10.1038/ng.3163

2014 Bloomer R, Lloyd A, Symonds V,  The genetic architecture of constitutive and induced trichome density in two new recombinant inbred line populations of Arabidopsis thaliana: phenotypic plasticity, epistasis, and bidirectional leaf damage response. BMC Plant Biology 14, 119-132.

2012 Hatlestad G*, Sunnadeniya R*, Akhavan N, Gonzalez A, Goldman I, McGrath M, Lloyd AM, The beet R locus encodes a new cytochrome P450 required for red betalain production. *co-first authors. Nature Genetics 44, 816-820 doi:10.1038/ng.2297

2011 Hatlestad G, Elam L, Gonzalez A, Lloyd A, Mirabilis jalapa Latent Virus: a new Carlavirus infecting Four O’clocks. Archives of Virology 156(11):2109-11.

2011 Symonds VV, Hatlestad G, Lloyd AM, Natural allelic variation defines a role for ATMYC1: fate determination.  PLoS Genetics Vol. 7, No. 6. (9 June 2011), e1002069. doi:10.1371/journal.pgen.1002069trichome cell

2010 Conte S, Lloyd AM, The MAR1 Transporter is an Opportunistic Entry Point for Antibiotics. Plant Signaling & Behavior 5:49-52.

2009 Conte S, StevensonD, Furner I, Lloyd AM, Mutations in a novel Arabidopsis transporter confer multiple antibiotic resistance. Plant Physiology 151:559-573.

2009 Gonzalez A, Mendenhall J, Huo Y, Lloyd AM, TTG1 complex MYBs, MYB5 and TT2, control outer seed coat differentiation. Developmental Biology 325: 412-421

2008 Zhao M, Morohashi K, Hatlestad G, Grotewold E, Lloyd AM, The TTG1-bHLH-MYB complex controls trichome cell fate and patterning through direct targeting of regulatory loci. Development 135: 1991-1999

2007 Morohashi K, Zhao M, Yang M, Read B, Lloyd AM, Lamb R, Grotewold E, Participation of the Arabidopsis bHLH Factor GL3 in Trichome Initiation Regulatory Events. Plant Physiology 145: 736-746

2005 Symonds VV, Godoy V, Alconanda T, Botto J, Juenger T, Casal J, Lloyd AM, Mapping quantitative trait loci in multiple populations of Arabidopsis thaliana identifies natural allelic variation for trichome density. Genetics 169: 1649-1658

2003 Zhang F, Gonzalez A, Zhao M, Payne CT, Lloyd AM, A network of redundant bHLH proteins functions in all TTG1-dependent pathways of Arabidopsis. Development 130: 4859-4869