Angus Murphy Professor Ph.D. Area of Interest: Auxin-related growth, Herbicide metabolism, Metal tolerance and accumulation E-mail: CV

Teaching Responsibilities

• HORT 551, Biophysical Plant Physiology
• HORT 590, Plant Membrane Transport
• HORT 601, Planning and Presenting Horticultural Research

PULSe - Interdisciplinary Life Science Training Group

Auxin-related growth
Herbicide metabolism
Human Helath

Teaching 

• HORT 551 Biophysical Plant Physiology
• HORT 553 Plant Growth & Development
• HORT 590 Plant Membrane Transport

Research Homepage

• Murphy/Peer Lab
• Onocological Sciences Center
• Purdue Summer Research Opportunity Program

Graduate studentships are available.

Undergraduate independent study and senior thesis projects are available.

 

Current Research Interests

The cellular basis of auxin transport

Plant form is dependent on the establishment of polarity: growth takes place in apical regions of roots and shoots in response to basic developmental programming which is then modulated by environmental cues. Plants can also undergo tropic growth in order to adapt to changes in light, orientation, or surface contact. However, even when tropic responses alter the direction of growth, the overall polarity of the plant remains intact.

Biochemical and physiological evidence suggests that the polarity of plant growth is regulated at the cellular level and involves components of the cytoskeleton, plasma membrane, and cell wall. Plant cells must therefore possess mechanisms to asymmetrically direct proteins to specific cell surfaces. These mechanisms appear to be regulated by developmental and environmental cues.

Auxin, or indole acetic acid (IAA), is an essential, multifunctional plant hormone that influences virtually every aspect of plant growth and development. Although auxin-dependent growth is evident in all plant tissues, it is synthesized primarily in apical regions of the shoot and is then transported in a polar fashion to other sites. When auxin reaches the root apex, it is redistributed away from the root tip through cortical and epidermal tissues. In tropic growth, auxin is diverted laterally to one side of the plant stem or root. As a result, the cells in that portion of the stem or root below the point of redistribution elongate. The result is bending toward light, gravitational pull, or a potential point of attachment.

Auxin is taken up into cells by diffusion augmented by a proton co-transporter, but can only exit from cells via basally-localized efflux carriers. Mutants deficient in auxin transport generally display aberrant morphology. Auxin is thus thought to maintain cellular polarity and, as a result, its own asymmetric transport mechanism.

The directionality of efflux is established primarily by efflux complexes characterized by the PIN family of facilitator proteins. Biochemical evidence suggests that the PIN proteins may mediate basal levels of auxin efflux, but also modulate the acitivity of ATP-dependent p-glycoprotein auxin transport proteins.

Chemiosmotic Model of Polar Auxin Transport

John Raven (1975) and Mary Helen Goldsmith (1976) proposed the currently accepted chemiosmotic model of auxin transport. IAA is protonated (IAAH) in the acidic extracellular space & enters the cell via diffusion or an H+ sympoter (AUX1). In the neutral pH of the cytosol, IAA is anionic & can only exit the cell via basally localized auxin efflux complex (characterized by PIN1), creating & maintaining an auxin gradient.

Testing the Chemiosmotic Model

avp1 null plants have fewer H+ ATPases on the plasma membrane (PM). The extracellular pH is less acidic, therefore IAAH amounts are less, & IAA transport is reduced. AVP1 overexpressors have more H+ ATPases on the PM, more acidic pH, more IAAH & enhanced IAA transport. (Li et al., 2005)

Diffusion effects in small cells vs. larger cells

In meristematic tissue, cells are small & re-diffusion of exported IAA into these cells is greater than in large cells. In small cells, IAA transporters have non-polar localization, & IAA export is greater than the rate of diffusion into the cell. In larger cells (e.g. vascular tissue), IAA transporters have polar localization where IAA re-diffusion is less of a factor. (Blakeslee, Peer & Murphy, 2005a,b)

PGPs (p-glycoproteins) and auxin transport

PGPs are PM anion transporters characterized by 12 membrane-spanning helices, 2 ATP-binding sites, a phosphorylation site, and a C-terminal protein-protein interaction domain. The 21 expressed PGPs in Arabidopsis each have tissue-specific expression & localization. PGPs were initially associated with sauxin transport when they were purified by affinity chromatography with NPA, an auxin efflux inhibitor.

pgp mutants examined thus far have reduced shoot basipetal IAA transport and are dwarfs. pgp1 mutants have slightly altered hypocotyl and root gravitropic bending. pgp19 mutants have hypertropic bending. pgp4 mutants exhibit altered root bending in response to gravity. (Murphy and Taiz, 1999a,b; Murphy et al., 2000; Noh et al., 2001; Murphy et al., 2002; Geisler et al., 2003; Geisler & Blakeslee et al., 2005; Teresaka et al., 2005)

PGP1 and PGP19 mediate IAA efflux while PGP4 mediates IAA influx. PGP4 has a unique N-terminal region. Domain swapping experiments, specifically with transmembrane (TM) and nucleotide binding domains (NBD), are underway to resolve which regions of the proteins determine the direction of IAA transport. Analysis of the promoter regions will also indicate if the direction of IAA transport is due to tissue-specific interactions with other proteins of the auxin transport complex (Titapiwatanakun & Murphy).

PGPs in Monocots

PGP mutations have been identified in maize (br2), sorghum (dw3) and rice. They are also dwarfs with reduced IAA transport at the nodes. However, they have normal seeds and yields. (Multani et al., 2003; Knoeller & Murphy)

PGPs and Human Health

Multiple Drug-Resistance/P-glycoproteins (MDR/PGPs) function in pumping chemotherapeutic drugs out of cells in human cancer patients. Flavonoids inhibit the activity of MDR/PGPs, so more of the drug stays in the cancer cells, decreasing the effective dose of chemotherapy drug given to a patient, thereby reducing the adverse effects of the drug on the patient. Co-therapies with flavonoids are being used. For example, cancer patients undergoing chemotherapy may be instructed to drink grapefruit juice (hesperidin is the active flavonoid) prior to their treatment. The flavonoid EGCG (epigallocatechin gallate) from green tea modulates MDR/PGP activity, reverses MDR/PGP drug resistance, and reduces MDR/PGP gene expression.

 

APM (aminopeptidase M) and cellular trafficking

APM, an M1 metallopeptidase, is a bifunctional protein with trafficking & catalytic domains. It has one transmembrane domain and occurs in processed & unprocessed forms. We are investigating potential activities of the processed form and whether APM is autocatalytic. APM, a single-copy gene, was identified by NPA-affinity chromatography. APM is most similar to human insulin-responsive aminopeptidase/oxytocinase (IRAP) and APN (CD13). APM is localized in microsomal membranes and on the plasma membrane and is associated with sterol-rich membranes, as is IRAP. Other components of IRAP/GLUT4 system have homologs in Arabidopsis implicated in auxin transport and/or cellular targeting. (Murphy and Taiz, 1999a,b; Murphy et al., 2000, 2002; Muday & Murphy, 2002; Muday, Murphy & Peer, 2003).

APM is strongly expressed in developing seeds and 3-5d seedlings and at regions of differentiation: root & shoot apices, root-shoot junction. Analysis with inducible promoter and RNAi constructs as well as embryonic marker lines are underway to determine the critical spatio-temporal expression necessary for proper development. (Murphy et al., 2002; Bandyopadhyay & Murphy, Hosein & Murphy)

The adaptor complexes and endocytosis are not well-characterized in plants, and this critical component of cellular trafficking is being investigated. (Park & Murphy)

The role of aminopeptidases, particularly aminopeptidase P (APP), in wounding responses are also under investigation. (Makam & Murphy)

APM and Human Health

Loss of traditional diets rich in flavonoids and other nutrients among Americans has contributed to the rise of type II diabetes and obesity. APM/IRAP is involved in intracellular trafficking of proteins related to type II diabetes, and they are also involved in sterol uptake into intestinal cells. Flavonoids have been shown to inhibit both the activity of the M1 proteinases and to modulate intracellular trafficking. Therefore, flavonoid-based therapies and a return to traditional diets can help reduce the incidence of type II diabetes and obesity. The use of herbicides on our food has been linked to cancer. APM activity in food crops reduces the toxicity of the herbicide to the plants, but can increase the carcinogenicity of the herbicides to humans.

Amide herbicide metabolism

A byproduct of the auxin transport research in our lab has been the dissection of amidase activities in plant tissues that hydrolyze amide herbicides like Alanap. We are exploring the metabolism of amide herbicides in planta to determine 1) the extent to which their carcinogenic breakdown products are retained in horticultural crops and 2) whether these compounds enhance susceptibility to plant pathogens. Additionally, we are exploring use of plant and microbe combinations to remediate soils contaminated with either amide herbicides or their polycyclic aromatic hydrocarbon breakdown products.

Flavonoid Signaling

Flavonoids are poylyphenolic compounds that are important flavor and color c onstituents of plant-based foods. Flavonoids are signaling molecules within the plant, between the plant and other organisms (nod gene induction in rhizobacteria), and within other organisms. For example, flavonoids are phytoestrogens and act as mild estrogens in humans.

Flavonoid accumulation in the plant is tissue-specific. Aglycone flavonols are associated with the PM and endomembranes. They act as autocrine effectors within the cells they are synthesized, but may also act as paracrine effectors in adjacent cells, as flavonols appear to be at plasmadesmata. (Murphy et al., 2000; Peer & Murphy, 2005)

Targets

Flavonoids are antioxidants antioxidants and scavenge reactive oxygen species (ROS) thereby potentially regulating the pathways induced by ROS. Flavonoids are also kinase and phosphatase inhibitors. As such, they can modulate signal transduction within the cell. Likely targets are PTEN, PID, RCN1 (PP2a), and PGPs. A major target of ROS is PTEN, a tumor suppressor implicated in breast cancer. Flavonoids (like xanthohumol from hop) can reduce stimulate PTEN and reduce tumor proliferation.

Flavonoids and IAA

IAA treatment induces ROS in Arabidopsis roots. In the absence of flavonoids (tt4), more ROS fluorescence is observed but decreased ROS fluorescence if excess flavonols are present (tt3), due to flavonoid anti-oxidant activity. Flavonol accumulation also occurs after IAA treatment; IAA catabolism induces ROS. A modest increase in flavonols is observed after a modest increase in IAA, but after NPA treatment, which increases the amount of IAA in cells, flavonol accumulation is significantly increased. Flavonols also modulate auxin transport (Peer et al., 2004; Peer & Murphy, 2005)

 

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Selected Publications

Titapiwatanakun B, Blakeslee JJ, Bandyopadhyay A, Yang H, Mravec J, Sauer M, Cheng Y, Adamec J, Nagashima A, Geisler M, Sakai T, Friml J, Peer WA, Murphy AS. 2008. ABCB19/PGP19 stabilises PIN1 in membrane microdomains in Arabidopsis. Plant J. 2008 Sep 4.

Peer WA, Murphy AS. 2007. Flavonoids and auxin transport: modulators or regulators? Trends Plant Sci. 12(12):556-63.

Rojas-Pierce M, Titapiwatanakun B, Sohn EJ, Fang F, Larive CK, Blakeslee J, Cheng Y, Cutler SR, Peer WA, Murphy AS, Raikhel NV. 2007. Arabidopsis P-glycoprotein19 participates in the inhibition of gravitropism by gravacin. Chem Biol. 14(12):1366-76. Erratum in: Chem Biol. 2008 Jan;15(1):87.

Kim JI, Sharkhuu A, Jin JB, Li P, Jeong JC, Baek D, Lee SY, Blakeslee JJ, Murphy AS, Bohnert HJ, Hasegawa PM, Yun DJ, Bressan RA. 2007. yucca6, a dominant mutation in Arabidopsis, affects auxin accumulation and auxin-related phenotypes. Plant Physiol. 145(3):722-35.

Green RJ, Murphy AS, Schulz B, Watkins BA, Ferruzzi MG. 2007. Common tea formulations modulate in vitro digestive recovery of green tea catechins. Mol Nutr Food Res. Sep;51(9):1152-62.

Shin R, Burch AY, Huppert KA, Tiwari SB, Murphy AS, Guilfoyle TJ, Schachtman DP. 2007. The Arabidopsis transcription factor MYB77 modulates auxin signal transduction. Plant Cell. 19(8):2440-53.

Jain A, Poling MD, Karthikeyan AS, Blakeslee JJ, Peer WA, Titapiwatanakun B, Murphy AS, Raghothama KG. 2007. Differential effects of sucrose and auxin on localized phosphate deficiency-induced modulation of different traits of root system architecture in Arabidopsis. Plant Physiol. 144(1):232-47.

Blakeslee JJ, Bandyopadhyay A, Lee OR, Mravec J, Sauer M, Titapiwatanakun B, Makam SN, Cheng Y, Bouchard R, Adamec J, Geisler M, Nagashima A, Sakai T, Martinoia E, Friml J, Peer WA, Murphy AS (2007) Interactions among PIN and PGP auxin transporters in Arabidopsis Plant Cell. 2007 Jan 19; [Epub ahead of print] PDF Suppl. data

Bandyopadhyay A, Blakeslee JJ, Lee OR, Mravec J, Sauer M, Titapiwatanakun B, Makam SN, Bouchard R, Geisler M, Martinoia E, Friml J, Peer WA, Murphy AS (2007) Interactions of PIN and PGP auxin transport mechanisms. Intercellular Signalling in Plants. Biochemical Society Transactions 35: 137-141. PDF

Orlova I, Marshall-Colon A, Schnepp J, Wood B, Varbanova M, Fridman E, Blakeslee JJ, Peer WA, Murphy AS, Rhodes D, Pichersky E, Dudareva N. (2006) Reduction of Benzenoid Synthesis in Petunia Flowers Reveals Multiple Pathways to Benzoic Acid and Enhancement in Auxin Transport. Plant Cell. 2006 Dec 28; [Epub ahead of print] PDF

Peer WA, Mahmoudian M, Freeman JL, Lahner B, Richards EL, Reeves RD, Murphy AS, Salt DE. (2006) Assessment of plants from the Brassicaceae family as genetic models for the study of nickel and zinc hyperaccumulation. New Phytol. 172: 248-260. PDF

Bouchard R, Bailly A, Blakeslee JJ, Oehring SC, Vincenzetti V, Lee OR, Paponov I, Palme K, Mancuso S, Murphy AS, Schulz B, Geisler M. (2006) Immunophilin-like TWISTED DWARF1 modulates auxin efflux activities of Arabidopsis P-glycoproteins. J Biol Chem. 281: 30603-30612. PDF Suppl. data

Petrasek J, Mravec J, Bouchard R, Blakeslee JJ, Abas M, Seifertova D, Wisniewska J, Tadele Z, Kubes M, Covanova M, Dhonukshe P, Skupa P, Benkova E, Perry L, Krecek P, Lee OR, Fink GR, Geisler M, Murphy AS, Luschnig C, Zazimalova E, Friml J (2006) PIN proteins perform a rate-limiting function in cellular auxin efflux. Science 312: 914-918. PDF Suppl. data

Geisler M, Murphy AS (2006) The ABCs of Plant p-glycoprotein transporters. FEBS Letts 580: 1094-1102. PDF

Blakeslee JJ, Bandyopadhyay A, Lee OR, Sauer M, Mravec J, Titapiwatanakun B, Makam S, Bouchard R, Adamec J, Geisler M, Martinoia E, Friml J, Peer WA, Murphy AS (2006) Interactions between PGP, PIN, and AUX/LAX auxin transport proteins from Arabidopsis. Plant Growth Regulation Society of America PDF

Baluska F, Barlow P, Baskin T, Chen R, Feldman L, Forde B, Geisler M, Jernstedt J, Menzel D, Muday G, Murphy A, Samaj J, Volkmann D (2005) What is apical and what is basal in plant root development.Trends in Plant Science 10: 409-411. PDF

Geisler M, Blakeslee JJ, Bouchard R, Lee OR, Vincenzetti V, Bandyopadhyay A, Titapiwantanakun B, Peer WA, Bailly A, Richards EL, Ejendal KFK, Smith AP, Baroux C, Grossniklaus U, Muller A, Hrycyna CA, Dudler R, Murphy AS, Martinoia E (2005) Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PGP transporter AtPGP1. The Plant Journal 44: 179-194. PDF

Terasaka K, Blakeslee JJ, Titapiwatanakun B, Peer WA, Bandyopadhyay A, Makam SN, Lee OR, Richards EL, Murphy AS, Sato F, Yazaki K (2005) PGP4, an ATP-binding cassette P-glycoprotein, catalyzes auxin transport in Arabidopsis thaliana roots. Plant Cell 17: 2922-2939. PDF Suppl. data

Li J, Yang H, Peer WA, Richter G, Blakeslee JJ, Bandyopadhyay A, Titapiwatanakun B, Undurraga S, Khodakovskaya M, Richards EL, Krizek B, Murphy AS, Gilroy S, Gaxiola R. 2005. Arabidopsis H+-PPase AVP1 regulates auxin mediated organ development. Science 310: 121-125. PDF Suppl. data

Murphy AS, Bandyopadhyay A, Holstein SE, Peer WA (2005) Endocytotic cycling in PM proteins. Annual Review of Plant Biology 56: 221-251. PDF

Blakeslee JJ, Peer WA, Murphy AS (2005a) Auxin transport. Current Opinion in Plant Biology 8: 494-500. PDF

Blakeslee JJ, Peer WA, Murphy AS (2005b) MDR/PGP auxin transport proteins and endocytotic cycling. Plant Cell Monographs: Plant Endocytosis Springer, Berlin, pp. 159-176. PDF

Peer WA, Murphy AS (2005) Flavonoids as signal molecules; Tagets of flavonoid action. In The Science of Flavonoids, E. Grotewold, ed. Springer, Berlin, pp. 239-268. PDF

Choi G, Kim JI, Hong SW, Shin B, Choi G, Blakeslee JJ, Murphy AS, Seo Y, Kim K, Koh EJ, Song PS, Lee H (2005) A Possible Role of NDPK2 in the Regulation of Auxin Mediated Responses for Plant Growth and Development. Plant Cell Physiol 48: 1246-1254. PDF

Makam SN, Peer WA, Blakeslee JJ, Murphy AS (2005) Cultural conditions contributing to vine decline syndrome in watermelon. HortScience 40: 597-601. PDF

Baxter IR, Young JC, Armstrong G, Foster N, Bogenschutz N, Cordova T, Peer WA, Hazen SP, Murphy AS, Harper JF (2005) A plasma membrane H+-ATPase is required for the formation of proanthocyanidins in the seed coat endothelium of Arabidopsis thaliana. PNAS 102: 2649-2654. PDF

Peer WA, Baxter IR, Richards EL, Freeman JL, Murphy AS (2005) Phytoremediation and hyperaccumulator plants. In Molecular Biology of Metal Homeostasis and Detoxification. Topics in Current Genetics Vol 14 Tamas M and Martinoia E, eds. Springer, Berlin, pp. 299-340. PDF

Blakeslee JJ, Bandyopadhyay A, Peer WA, Makam SN, Murphy AS (2004) PIN1 auxin efflux facilitator plays a role in phototropism. Plant Physiology 134: 28-31. PDF

Peer WA, Bandyopadhyay A, Blakeslee JJ, Srinivas MN, Chen RJ, Masson PH, Murphy AS (2004) Variation in PIN gene expression and protein localization in flavonoid mutants with altered auxin transport. Plant Cell 16: 1898-1911. PDF Supplementary Figure

Multani DS, Briggs S, Chamberlin MA, Blakeslee JJ, Murphy AS, Johal G (2003) Control of plant height in maize by an ABC transporter of the multidrug resistance class. Science 302: 81-84. PDF

Surpin M, Zheng H, Morita MT, Saito C, Avila-Teeguarden E, Blakeslee JJ, Bandyopadhyay A, Kovaleva V, Carter D, Murphy AS, Tasaka M, Raikhel N (2003) The VTI family of SNARE proteins is necessary for plant viability and mediates different protein transport pathways. Plant Cell 15: 2885-2899. PDF

Muday GK, Peer WA, Murphy AS (2003) Vesicular cycling mechanisms that control auxin transport polarity. Trends Plant Sci. 8: 301-304. PDF

Smith AP, Nourizadeh S, Peer WA, Xu J, Bandyopadhyay A, Murphy AS, Goldsbrough PB (2003) Arabidopsis AtGSTF2 is regulated by ethylene and auxin, and encodes a glutathione S-transferase that interacts with flavonoids. Plant Journal 36: 433-442. PDF

Noh B, Bandyopadhyay A, Peer WA, Spalding EP, Murphy AS (2003) Enhanced gravi- and phototropism in plant mdr mutants mislocalizing the auxin efflux protein PIN1. Nature 423: 999-1002. PDF

Geisler M, Kolukisaoglu HU, Billion K, Berger J, Saal B, Bouchard R, Frangne N, Koncz-Kalman Z, Koncz C, Dudler R, Blakeslee J, Murphy AS, Martinoia E, and Schulz B (2003) TWISTED DWARF1, a unique plasma membrane-anchored immunophilin-like protein, interacts with Arabidopsis multidrug resistance-like transporters AtPGP1 and AtPGP19. Mol Biol Cell 14: 4238-4249. PDF

Peer WA, Mamoudian M, Lahner B, Reeves RD, Murphy AS, Salt DE (2003) Identifying model metal hyperaccumlating plants: germplasm analysis of 20 Brassicaceae accessions from a wide geographic area. New Phytologist 159: 421-430. PDF

Peer WA, Murphy AS (2003) Floral scent of Arabidopsis lyrata (Brassicaceae). Biochemical Systematics and Ecology 31: 1193-1195. PDF

Murphy AS (2002) Auxin: the Growth Hormone, In Plant Physiology, Taiz L, Zeiger E, eds. Sinauer Associates, Sunderland MA.

Murphy AS (2002) Exploring the cellular basis of auxin transport, In Plant Physiology, Taiz L, Zeiger E, eds. Sinauer Associates, Sunderland MA.

Muday GK, Murphy AS (2002) An emerging model of auxin transport regulation. Plant Cell 14: 293-299. PDF

Murphy AS, Hoogner K, Peer WA, Taiz L (2002) Identification, purification, and molecular cloning of N-1-naphthylphthalmic acid -binding plasma membrane-associated aminopeptidases from Arabidopsis. Plant Physiology 128: 935-950. PDF

Noh B, Murphy AS, Spalding EP (2001) Multidrug Resistance-like genes of Arabidopsis required for auxin transport and auxin-mediated development. Plant Cell 13: 2441-2454. PDF

Brown DE, Rashotte A, Murphy AS, Normanly J, Tague BW, Peer WA, Taiz L, Muday GK (2001) Flavonoids Act as Negative Regulators of Auxin Transport in Vivo in Arabidopsis. Plant Physiol 126: 524-535. PDF

Peer WA, Brown DE, Tague BW, Muday GK, Taiz L, Murphy AS (2001) Flavonoid Accumulation Patterns of Transparent Testa Mutants of Arabidopsis. Plant Physiol 126: 536-548. PDF

Murphy AS, Peer WA, Taiz L (2000) Regulation of Auxin Transport by Aminopeptidases and Endogenous Flavonoids. Planta 211: 315-324. PDF

Murphy A, Taiz L (1999) Naphthylphthalamic acid is enzymatically hydrolyzed at the hypocotyl-root transition zone and other tissues of Arabidopsis seedlings. Plant Physiol. Biochem 37: 413-430. PDF

Murphy A, Taiz L (1999) Localization and characterization of soluble and plasma membrane aminopeptidase activities in Arabidopsis seedlings. Plant Physiol. Biochem 37: 431-443. PDF

Murphy A, Eisinger W, Schaff J, Kochian L, Taiz L (1999) Early copper-induced leakage of K+ from Arabidopsis seedlings is mediated by ion channels and coupled to citrate efflux. Plant Physiol. 121: 1375-1382. PDF

Murphy A, Taiz L (1999) Copper responses in the model plant Arabidopsis thaliana. Wenzel WW, Ed. Int. Soc. For Trace Element Res. Vienna Austria.

Garcia-Hernandez M, Murphy A, Taiz L (1998) Metallothioneins 1 and 2 have distinct but overlapping expression patterns in Arabidopsis thaliana. Plant Physiol. 118: 387-397. PDF

Murphy A, Taiz L (1997) Correlation between potassium efflux and copper sensitivity in 10 Arabidopsis ecotypes. New Phytol 136: 211-222. PDF

Murphy A, Zhou J, Goldsbrough P, Taiz L (1997) Purification and immunological identification of metallothioneins 1 and 2 from Arabidopsis thaliana. Plant Physiol. 113: 1293-1301. PDF

Murphy A, Taiz L (1995) Comparison of metallothionein gene expression and nonprotein thiols in ten Arabidopsis ecotypes. Correlation with copper tolerance. Plant Physiol. 109: 945-954.PDF

Murphy A, Taiz L (1995) A new vertical mesh transfer technique for metal-tolerance studies in Arabidopsis-ecotypic variation and copper-sensitive mutants. Plant Physiol 108: 29-38. PDF

 

Errata in papers from the Murphy Lab

Brown, et al. (2001) and Murphy et al., (2000). Materials and Methods, seedling auxin transport assays should read (0.2 μL) of 1.0 mM [¹⁴C] IAA in ethanol (5.0 nCi μL^-1).

 

Noh et al. (2000). Material and Methods, auxin transport assays should read 0.1 μL of 50-500 μM [¹⁴C]-IAA.