Profile – Ann M. Hirsch

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Ann M. Hirsch

Job Title:

Professor, Department of MCD Biology, UCLA, Los Angeles, CA

Work Address:

Department of Molecular, Cell and Developmental Biology, 621 Charles Young Drive, South, University of California, Los Angeles, CA 90095-1606


Phone Number:

(310) 206-8673


Google Scholar Profile


Dr. Hirsch’s research focuses on the “hidden half” of the plant, particularly on the beneficial interactions that take place between plant roots and microbes in the rhizosphere microbiome. She previously investigated the importance of phytohormones in Rhizobium-induced nodule development, and the conservation of signal transduction pathways in nodulation and mycorrhization based on common gene expression patterns.  She coordinated the sequencing and annotation of four Burkholderia genomes, including one that nodulates agronomically important legumes growing in arid, acidic soils.   Based on the genomic studies, demonstrated that the symbiotic Burkholderia have had a complex ancestry. The nif and fix genes appear to be derived from a free-living diazotroph, but the nod genes differ in gene number and arrangement between Papilionoid (old world) and Mimosoid (new world) lineages.  Her laboratory determined that the symbiotic species in this genus are unlikely pathogens based on bioinformatics analyses and by using HeLa cell and Caenorhabditis elegans assays.

She and her group currently investigate plant-growth promoting bacteria (PGPB), which are associated with roots, especially from arid environments. Novel drought-adapted, nitrogen-fixing bacteria such as Burkholderia spp. and others may yield genetic traits that increase both nutrient availability and tolerance to salinity and drought, brought about by reduced rainfall, higher soil acidity, and increased temperatures.  In addition, many of the PGPB are effective at inhibiting plant pathogens, either directly by killing the pathogens or indirectly by making plants healthy so they resistant infection.  Moreover, a combination of nitrogen-fixing bacteria and one or more PGPB further enhance plant growth and yield.  To find additional sources of partner PGPBs, Dr. Hirsch and her colleagues investigate the microbiome of nitrogen-fixing nodules.

Research Areas:

Current N-related Projects:


Shimomura S, Arima S, Hayashi M, Maymon M, Hirsch AM, Suzuki A. 2017. Blue light does not inhibit nodulation in Sesbania rostrata.  Plant Signal. Behav.  Jan 2; 12(1): e1268313. Doi: 10.1080/15592324.2016.1268313.


Shimomura A, Naka A, Miyazaki N, Moriuchi S, Arima S, Sato S, Hirakawa H, Tabata S, Hayashi M, Maymon M, Hirsch AM, Suzuki A.  2016.  Blue light perception by both roots and rhizobia inhibits nodule formation in Lotus japonicusMol. Plant-Microbe Interact. 29:786-796.


De Meyer SE, Briscoe L, Martínez-Hidalgo P, Agapakis CM, Estrada de-los Santos P, Seshadri R, Reeve W, Weinstock G, O’Hara G, Howieson J, Hirsch AM.  2016. Symbiotic Burkholderia species show diverse arrangements of nif/fix and nod genes, and lack typical high affinity cytochrome cbb3 oxidase genes. Mol. Plant-Microbe Interact. 29:609-619.


Nagata M, Yamamoto N, Miyamoto T, Shimomura A, Arima S, Hirsch AM, Suzuki A.  2016. Enhanced hyphal growth of arbuscular mycorrhizae by root exudates derived from high R/FR treated Lotus japonicusPlant Signal. Behav. DOI: 10.1080/15592324.2016.1187356.


Sanders ER, Moberg-Parker J, Hirsch AM, Lee PY, Shapiro C, Toma S, Levis-Fitzgerald M.  2016.  Transforming laboratory education in the life sciences.  Microbe 11:69-74.


Estrada-de los Santos P, Rojas-Rojas FU, Tapia-García EY, Vásquez-Murrieta MS, Hirsch AM.  2015.  To split or not to split: an opinion on dividing the genus BurkholderiaAnn. Microbiol.  66:1303–1314.  DOI: 10.1007/s13213-015-1183-1.


Nagata M, Yamamoto N, Shigeyama T, Terasawa Y, Anai T, Sakai T, Inada S, Arima S, Hashiguchi M, Akashi R, Hirsch AM, Suzuki A.  2015.  Red/far red light controls mycorrhizal colonization via jasmonic acid and strigolactone secretion. Plant Cell Physiol. doi: 10.1093/pcp/pcv135.  First published online: September 26, 2015.


Tariq M, Lum MR, Chong AW, Amirapu AB, Hameed S, Hirsch AM.  2015.  A reliable method for the selection and confirmation of transconjugants of plant growth-promoting bacteria especially plant-associated Burkholderia spp.  J. Microbiol. Methods. 117:49-53. Doi: 10.1016/j.mimet.2015.07.008.


Maymon M, Martínez-Hidalgo P, Tran SS, Ice T, Craemer K, Anbarchian T, Sung T, Chou M, Hwang L, Fujishige NA, Ventosa J, Villella W, Sikorski J, Faull KF, Sanders ER. Hirsch AM2015. Mining the phytomicrobiome to understand how bacterial coinoculations enhance plant growth.  Front. Plant Sci. 6:doi: 10.3389/fpls.2015.00784.


Amaya-Gómez, C.V., Hirsch, A.M., and Soto, M.J.  2015.  Biofilm formation assessment in Sinorhizobium meliloti reveals interlinked control with surface motility. BMC Microbiol., 15:58  doi:10.1186/s12866-015-0390-z.


Coutinho Moraes, D.F., Still D., Lum, M.R., Hirsch, A.M.   2015.  DNA-based authentication of botanicals and plant-derived dietary supplements:  where have we been and where are we going?  Planta Med. 81:687-695. DOI: 10.1055/s-0035-1545843.


Nagata, M., Hirsch, A.M., and Suzuki, A.  2015. Lotus japonicas nodulates when it sees red. Chapter 44. In:  Biological Nitrogen Fixation, Volume 2.  F.J. deBrujjn,  (ed.). John Wiley & Sons. pp. 441-445.


Walker, R., Agapakis, C.M., Watkin, E., and Hirsch, A.M.  2015.  Symbiotic nitrogen fixation in legumes: perspectives on the diversity and evolution of nodulation by Rhizobium and Burkholderia species. Chapter 89.  In:  Biological Nitrogen Fixation, Volume 2.  F.J. deBrujjn,  (ed.). John Wiley & Sons. pp. 913-923.


Sanders, E.R., and Hirsch, A.M. 2014.  Immersing undergraduate students into research on the metagenomics of the plant rhizosphere: a pedagogical strategy to engage civic-mindedness and retain undergraduates in STEM.  Front. Plant Sci. Apr 30; 5:157. doi: 10.3389/fpls.2014.00157.


Angus, A.A., Agapakis, C.M., Fong, S., Yerrapragada, S., Estrada-de los Santos, P., Yang, P., Song, N., Kano, S., Caballero-Mellado, J., de Faria, S.M., Dakora, F.D., Weinstock, G., and Hirsch, A.M.  2014. Plant-associated symbiotic Burkholderia species lack hallmark strategies required in mammalian pathogenesis.  PLoS ONE 9(1): e83779. Doi: 10.1371/journal.pone.0083779.


Hirsch, A.M., Alvarado, J., Bruce, D., Chertkov, O., De Hoff, P.L., Detter, J.C., Fujishige, N.A., Goodwin, L.A., Han, J., Han, S., Ivanova, N., Land, M.L., Lum, M.R., Milani-Nejad, N., Nolan, M., Pati, A., Pitluck, S., Tran, S.S., Woyke, T. and Valdés, M.  2013.  Complete genome sequence of Micromonospora strain L5, a potential plant-growth-regulating actinomycete, originally isolated from Casuarina equisetifolia root nodules. Genome Announc. 1(5): e00759-13. Doi: 10.1128/genomeA.00759-13.


Martínez-Aguilar, L. Salazar-Salazar, C., Caballero-Mellado, J., Hirsch, A.M., Vásquez-Murrieta, M.S., and Estrada-de los Santos, P.  2013.  Burkholderia caballeronis sp. nov., a nitrogen fixing species isolated from tomato (Lycopersion esculentum) with the ability to nodulate Phaseolus vulgaris effectivelyA. Van Leeuwenhoek.  6:1063-1071. DOI 10.1007/s10482-013-0028-9.


Schwartz, A.R., Ortiz, I., Maymon, M., Herbold C.W., Fujishige, N.A, Vijanderan J.A., Villella, W., Hanamoto, K., Diener, A., Sanders, E.R., DeMason, D.A., and Hirsch, A.M.  2013. Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with
Rhizobium leguminosarum bv. viciae. Agronomy. 3:595-620; doi: 10.3390/agronomy3040595.
Kaplan D, Maymon M, Agapakis CM, Lee A, Wang A, Prigge BA, Volkogon M, Hirsch AM.   2013. A survey of the microbial community in the rhizosphere of the dominant plant of the Negev Desert, Zygophyllum dumosum Boiss., using cultivation-dependent and –independent methods.  Amer. Jour. Bot.  100: doi: 10.3732/ajb.1200615.


Estrada-de los Santos, P., Vinuesa, P., Martínez-Aguilar, L., Hirsch, A.M., and Caballero-Mellado, J. 2013.  Phylogenetic analysis of Burkholderia species by Multilocus Sequence Analysis. Curr. Microbiol.  67: 51-60.


Angus, A.A., Lee, A.S., Lum, M.R., Shehayeb, M., Hessabi, R., Fujishige, N.A., Yerrapragada S., Kano, S., Song, N., Yang, P., Estrada-de Los Santos, P., de Faria, S.M., Dakora, F.D., Weinstock, G., Hirsch, A.M.  2013.  Nodulation and effective nitrogen fixation of Macroptilium atropurpureum (siratro) by Burkholderia tuberum, a beta-proteobacterium, are influenced by environmental factors.  Plant Soil.   362: 543-562.


Angus, A.A. Hirsch, A.M.  2013.  Biofilm formation in the rhizosphere:  multispecies interactions and implications for plant growth.  InMolecular Microbial Ecology of the Rhizosphere, Volume 2, First Edition, Chapter 66.  F. deBrujjn,  (ed.).  John Wiley & Sons.  Pp. 703-712.


Robledo, M., Rivera, I.P., Jiménez-Zurdo, J.I., Rivas, R., Dazzo, F.B., Velázquez, E., Martínez-Molina, E., Hirsch, A.M., Mateos, P.F.  2012.  Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces.  Microbial Cell Factories.  11:125.  DOI: 10.1186/1475-2859-11-125.


Shigeyama, T., Tominaga, A., Arima, S., Sakai, T., Inada, S., Jikumaru, Y., Kamiya, Y., Uchiumi, T., Abe, M., Hashiguchi, M., Akashi, R., Hirsch, A.M., Suzuki. A.  2012.  Additional cause for reduced JA-Ile in the root of a Lotus japonicus phyB mutant.  Plant Signal. Behav. 7:1-3.


Hirsch, A.M., Fujishige, N.A.  2012.  Molecular signals and receptors:  communication between nitrogen-fixing bacteria and their plant hosts.  In:  Wizany, G. and Baluska, F. (eds.), Biocommunication in Plants.  Springer. Vol. 14, 255-280, DOI: 10.1007/978-3-642-23524-5_1.


Gyaneshwar, P., Hirsch, A.M., Moulin, L., Chen, W.M., Elliott, G.N., Bontemps, C., Estrada-de los Santos, P., Gross, E., Bueno dos Reis Junior, F., Sprent, J.I., Young, J.P.W., James, E.K.  2011.  Legume nodulating β-proteobacteria:  diversity, host range and future prospects.  Mol. Plant-Microbe Inter.  24:1276-1288.


Suzuki, A., Suriyagoda, L, Shigeyama, T., Tominaga, A., Sasaki, M., Hiratsuka, Y., Yoshinaga A., Arima, S., Agarie, S., Sakai, T., Inada, S., Jikumaru, Y, Kamiya, Y., Uchiumi, T., Abe, M., Hashiguchi, M., Akashi, T., Sato, S., Kaneko, T., Tabata, S., Hirsch, A.M2011.  Lotus japonicus nodulation is photomorphogenetically controlled by sensing the R/FR ratio through JA signaling.  Proc. Natl. Acad. Sci.  USA. 108:16837-16842.


Lum, M.R., Hirsch, A.M2011.  Detecting the components of botanical mixtures by single-strand conformation polymorphism analysis.  In: Authentication of Food and Wine, S. E. Ebeler, G. R. Takeoka, P. Winterhalter, eds.  ACS Symposium Series Vol. 1081, pp. 351-362.


Kuo, D., Nie, M., De Hoff, P., Chambers, M., Phillips, Hirsch, A.M., Courey, A.J.  2010. A SUMO-Groucho Q domain fusion proteins:  Characterization and in vivo Ulp1-mediated cleavage.  Prot. Exp. Purif.  76:765-771.


Tominaga, A., Nagata, M., Futsuki, K., Abe, H., Uchiumi, T., Abe, M., Kucho, K., Hashiguchi, M., Akashi, R., Hirsch, A.M., Arima, S., Suzuki, A.  2010.  Effect of abscisic acid on symbiotic nitrogen fixation activity in the root nodules of Lotus japonicus.  Plant Signal. Behav.   5:440-443.


Hirsch, A.M., Lee, A., Deng, W., Tucker, S.C.  2010.  An open-flower mutant of Melilotus alba Desr.:  Potential for  floral-dip transformation of a Papilionoid legume with short life cycle?  Amer. J. Bot.  97: 395-404.


Hirsch, A.M. Valdés, M. 2010. Micromonospora: a versatile microbe not only for biomedicine, but also for biocontrol and the production of biofuels.  Soil Biol. Biochem. 42: 536-542.


Angus, A.A., Hirsch, A.M.  2010.  Perspective: Insights into the history of the legume-betaproteobacterial symbiosis.  Mol. Ecol. 19:28-30.


 Hirsch, A.M.   2010.  How rhizobia survive in the absence of a legume host, a stressful world indeed. In:   J. Seckbach and M. Grube (ed.).  Cellular Origin, Life in Extreme Habitats and Astrobiology.   Vol. 13. Symbiosis and Stress:  Joint Ventures in Biology. Springer Science and Business Media B.V.  Pp.  377-391.


Tominaga, A., Nagata, M., Futsuki, K., Abe, H., Uchiumi, T., Abe, M., Kucho, K., Hashiguchi, M., Akashi, R., Hirsch, A.M., Arima, S., Suzuki, A.  2009.  Enhanced nodulation and nitrogen fixation in the ABA low-sensitive mutant enf1 (enhanced nitrogen fixation) of Lotus japonicusPlant Physiol. 151:1965-1976.


De Hoff, P.L., Brill, L.M., Hirsch, A.M.  2009.  Plant lectins:  the ties that bind in root symbiosis and plant defense.  Mol. Gen. Genom.  282:1-15.  DOI 10.1007/s00438-009-0460-8


Hirsch, A.M., Lum, M.R., Fujishige, N.A.  2009.  Microbial encounters of a symbiotic kind—attaching to roots and other surfaces.  In:  Emons, A.M.C. and T. Ketelaar (eds.). Root Hairs.  Plant Cell Monographs.   Vol. 12.  Springer.  Pp. 295-314.


Nishiguchi, M.K., Hirsch, A.M., DeVinney, R., Vedantam, G., Riley, M.A., Manksy, L.M.  2008.  Mini-review:  Deciphering evolutionary mechanisms between mutualistic and pathogenic symbiosis.  Vie et Milieu (Life and Environment).  58:87-106.


Lee, A., Giordano, W., Hirsch, A.M.  2008.  Cytokinin induces expansin gene expression in Melilotus alba Desr. wild-type and the non-nodulating, non-mycorrhizal (NodMyc) mutant Masym3.  Plant Signal. Behavior  3:218-223.


Fujishige, N.A., Lum, M.R., De Hoff, P.L., Whitelegge, J.P., Faull, K.F., Hirsch, A.M.  2008Rhizobium common nod genes are required for biofilm formation.  Mol. Microbiol.  67:504-515.


Suzuki, A., Hara, H., Kinoue, T., Abe, M., Uchiumi, T., Kucho, K., Higashi, S., Hirsch, A.M., Arima, S.  2008.  Split-root study of autoregulation of nodulation in the model legume Lotus japonicusJ. Plant Res.  121:245-249.


Hirsch, A.M., Fujishige, N.A.  2008.  Commensalism.  In:  Population Dynamics, Vol. 1, Encyclopedia of Ecology, 5 Vols.  Eds. S.E. Jorgensen and B. D. Fath.  Elsevier, Oxford.  pp. 679-683.


Woo, H.-H., Jeong, B.R., Hirsch, A.M., Hawes, M.C.  2007.  Altered expression of closely related UDP-glycosyltransferases from pea and Arabidopsis results in altered root development and function.  Physiol. Plant.  130:250-260.


Woo, H.-H., Jeong, B.R., Hirsch, A.M., Hawes, M.C.   2007.  Characterization of Arabidopsis gene families related to pea UDP-glycosyltransferase and Scutellaria glucuronidase.  Genomics 90:143-153.


Lee, A., Lum, M.R., Hirsch, A.M.  2007.  ENOD40 gene expression and cytokinin responses in the non-nodulating non-mycorrhizal (NodMyc) mutant, Masym3, of Melilotus alba Desr.  Plant Signal. Behav.  2:33-42.


Lum, M.R., Baycher, A., Prigge, B.A., Hardy, M., Heber, D., Hirsch, A.M.   2007.  Identification of green tea (Camellia sinensis L.) and tea oil (Camellia oleifera Abel.) by molecular biological and anatomical methods.  In: Authentication of Food and Wine, S. E. Ebeler, G. R. Takeoka, P. Winterhalter, eds.  Oxford University Press.  pp. 290-304.


Lum, M.R., Hirsch, A.M2007.  Molecular methods for the authentication of botanicals and detection of potential contaminants and adulterants.   In:  IVth International Conference on Quality and Safety Issues Related to Botanicals.  Acta Hort. 720.  Eds.  I.A. Khan, T.J. Smilie, L.E. Craker, Z.E. Gardner.  pp. 59-71.


Lee, A., Hirsch, A.M.  2006.  Signals and responses:  choreographing the complex interaction between legumes and alpha- and beta-rhizobia.  Plant Signal. Behav.  1:161-168.


Rinaudi, L., Fujishige, N.A., Hirsch, A.M., Banchio, E., Zorreguieta, A, Giordano, W.  2006.  Effects of nutritional and environmental conditions on Sinorhizobium meliloti biofilm formation.  Res. Microbiol.  157:867-875.


Fujishige, N.A., Kapadia, N.N., De Hoff, P.L. and Hirsch, A.M.  2006.  Investigations of Rhizobium biofilm formation.  FEMS Microbiol. Ecol.  56:195-205.


Fujishige, N.A., Kapadia, N.N., Hirsch, A.M.  2006.  A feeling for the microorganism: structure on a small scale.  Biofilms on plant roots.  Bot. J. Linn. Soc.  150:79-88.


Luckow, M., Hughes, C., Schrire, B., Pedley, L., Fagg, C., Fortunato, R., Hurter, J., Rico, L., Bruneau, A., Caccavari, M., Crisp, M., Delgado S., A., Doyle, J.J., Harris, S., Herendeen, P.S. Hernández, H.M., Hirsch, A.M., Jobson, R., Klitgaard, B.B., Simpson, B.B., Smith, G.F., Sousa S., M., Timberlake, J., Wills, C.K., Winter, P., Wojciechowski, M.F.  2005Acacia: the case against moving the type to Australia.  Taxon.  54:513-519.


Lum, M., Potter, E., Dang, T., Heber, D., Hardy, M., Hirsch, A.M. 2005. Identification of botanicals and potential contaminants through RFLP and sequencing. Planta Med. 71:841-846.


Valdés, M., Pérez, N.-O., Estrada-de los Santos, P., Caballero-Mellado, J., Peña-Cabriales, J.J.,  Normand, P., Hirsch, A.M.  2005.  Non-Frankia actinomycetes isolated from surface-sterilized roots of Casuarina equisetifolia fix nitrogen.  Appl. Environ. Microbiol.  71: 460-466.


Hirsch, A.M.  2004.  Plant-microbe symbioses:  a continuum from commensalism to parasitism.  Symbiosis.  37:345-363.


Wen, F., Woo, H.H., Hirsch, A.M., Hawes, M.C.  2004.  Lethality of inducible, meristem localized ectopic expression of ß-glucuronidase in plants.  Plant Mol. Biol. Rep.  22:7-14.


Wildman, S.G., Hirsch, A.M., Kirchanski, S.J., Spencer, D.  2004.  Chloroplasts in living cells and the string-of-grana concept of chloroplast structure revisited.  Photosyn. Res.  80:345-352.


Giordano, W., Hirsch, A.M2004.  The expression of MaEXP1, a Melilotus alba expansin gene is up regulated during the sweetclover-Sinorhizobium meliloti interaction. Mol. Plant-Microbe Inter.  17:613–622.


Woo, H.-H., Hirsch, A.M., Hawes, M.C.  2004.  Altered susceptibility to infection by Sinorhizobium meliloti and Nectria haematococca in alfalfa roots with altered cell cycle.  Plant Cell Rep.  12:967-973.


Brill, L.M., Fujishige, N.A., Hackworth, C.A., Hirsch, A.M2004.  Expression of MsLEC1-transgenes in alfalfa plants causes symbiotic abnormalities.  Mol. Plant-Microbe Inter.  17:16-26.


Lum, M.R., Hirsch, A.M2004.  Overcoming fixed nitrogen deficiency by nodulation.  In: Encyclopedia of Crop and Plant Sciences.  Ed., R.M. Goodman.  Marcel Dekker, Inc., New York.  pp. 448-451.


Woo, H.-H., Faull, K.F., Hirsch, A.M., Hawes, M.C.  2003.  Altered life cycle in Arabidopsis thaliana plants expressing PsUGT1, a UDP-glucuronosyltransferase encoding gene from Pisum sativum.  Plant Physiol. 133:538-548.


Lum, M.R, Hirsch, A.M2003.  Roots and their symbiotic microbes: strategies to obtain nitrogen and phosphorous in a nutrient-limiting environment.  J. Plant Growth Regul.  21:368-382.


Karlowski, W.M., Hirsch, A.M2003.  The overexpression of an alfalfa RING-H2 gene induces pleiotropic effects on plant growth and development.  Plant Mol. Biol.  52:121-133.


DeHoff, P., Hirsch, A.M2003.  Nitrogen comes down to earth.  Report from the 5th European Nitrogen Fixation Conference.  Mol. Plant-Microbe Inter.  16:371-375.


Hirsch, A.M., Bauer, W.D., Bird, D.M., Cullimore, J., Tyler, B., Yoder, J.I.  2003.  Molecular signals and receptors—controlling rhizosphere interactions between plants and other organisms.  Ecology. 84: 858–868.


Giordano, W., Lum, M.R., Hirsch, A.M2002.  Effects of a Nod-factor overproducing strain of Sinorhizobium meliloti on the expression of the ENOD40 gene in Melilotus albaCan. J. Bot.  80: 907-915.


Hirsch, A.M., Lum, M.R., Krupp, R.S.N., Yang, W., LaRue T.A.  2002.  Symbiotic and developmental mutants of white sweetclover (Melilotus alba Desr.).  In:  Nitrogen Fixation:  Global Perspectives.  Ed.: T. Finan et al.  CAB International, pp. 323-326.


Leroy, A., Potter, E., Woo, H.-H., Heber, D., Hirsch, A.M.  2002.  PCR-based identification of degraded DNA and monitoring of flavonoids isolated from alfalfa and red clover commercial preparations used as botanicals in dietary supplements.  J. Agr. Food Chem.  50: 5063 –5069.


Hirsch, A.M., Krupp, R.S.N., Lin, Y., Wang, S.S., Yang, W., Tucker, S.C.  2002.  Inflorescence and flower development in wild-type and sid mutant Melilotus alba, white sweetclover.  Can. J. Bot.  80: 732-740.


Lum, M., Li, Y., LaRue, T.A., Schwartz, R.D., Kapulnik, Y., Hirsch, A.M2002.  Investigation of four classes of non-nodulating mutants of white sweetclover (Melilotus alba annua Desr.) mutants and their response to arbuscular-mycorrhizal fungi.  Int. Comp. Biol. 42:  295-303.


Woo, H.-H., Kuleck, G., Hirsch, A.M., Hawes, M.C.  2002.  Flavonoids:  signal molecules in plant development.  Adv. Exp. Med. Biol.  505:51-60.


Hirsch, A.M., Lum, M.R., Downie, JA.  2001.  What makes the rhizobia-legume symbiosis so special?  Plant Physiol.  127:1-9.


van Rhijn, P., Fujishige, N.A., Lim, P.-O., Hirsch, A.M.  2001.  Sugar-binding activity of pea (Pisum sativum) lectin is essential for heterologous infection of transgenic alfalfa (Medicago sativa L.) plants by Rhizobium leguminosarum biovar viciaePlant Physiol.  125:133-144.


Brill, L.M., Evans, C.J., Hirsch, A.M2001.  Expression of MsLEC1– and MsLEC2-antisense genes in alfalfa plant lines causes severe developmental and reproductive abnormalities.  Plant J.  25:453-461.


Gálvez, S., Hirsch, A.M., Wycoff, K.L., Hunt, S., Layzell, D.B., Kondorosi, A., Crespi, M.  2000.  Oxygen regulation of a nodule-located carbonic anhydrase in alfalfa.  Plant Physiol.  124:1059-1068.


Hirsch, A.M. and McFall-Ngai, M.  2000. Fundamental concepts in symbiotic interactions: light and dark; night and day; squids and legumes.  J. Plant Growth Regul. 19:113-130.


Okubara, P.A., Fujishige, N.A., Hirsch, A.M., Berry, A.M.  2000Dg93, a nodule-specific mRNA of Datisca glomerata with homology to a soybean ENODPlant Physiol.  122:1073-1079.


Guinel, F., Hirsch, A.M.   2000.  The involvement of root hairs in mycorrhizal associations.  In:  Cell and Molecular Biology of Plant Root Hairs.  Eds. R.W Ridge and A.M. Emons.  Springer-Verlag, Tokyo, pp. 285-310.


Hirsch, A.M., Lum, M.R., Krupp, R.S.N., Yang, W.. Karlowski, W.M.  2000Melilotus alba Desr., white sweetclover, a mellifluous model legume.  In:  Prokaryotic Nitrogen Fixation: A Model System for the Analysis of a Biological Process.  Ed. E.W. Triplett.  Horizon Scientific Press.  pp. 627-642.


Woo, H.-H., Orbach, M.J., Hirsch, A.M., Hawes, M.C.  1999.  Meristem-localized inducible expression of UDP-glycosyltransferase is essential for growth and development in pea and alfalfa.  Plant Cell.  11:2303-2315.


Brill, L.M., Hirsch, A.M.  1999.  Stable transformation of T1 and T2 transgenic alfalfa with antisense-lectin constructs.  Symbiosis.  27:17-32.


Fang, Y., Hirsch, A.M1999.  The involvement of flavonoids, Nod factors, and phytohormones in nodulation.  In:  Plant Responses to Environmental Stresses:  From Phytohormones to Genome Reorganization.  Ed. H.R. Lerner.  Marcel Dekker, Inc., New York.  pp. 629-658.


Hirsch, A.M1999.  Role of lectins (and rhizobial exopolysaccharides) in legume nodulation.  Curr. Opin. Plant Biol.  2:320-326.


van Rhijn, P., Goldberg, R.B., Hirsch, A.M.  1998Lotus corniculatus nodulation specificity is changed by the presence of a soybean lectin gene.  Plant Cell.  10:1233-1250.


Hirsch, A.M., Kapulnik, Y.  1998.  Signal transduction pathways in mycorrhizal associations:  Comparisons with the Rhizobium-legume symbiosis.  Fungal Genet. Biol.  23:205-212.


Wycoff, K.L., Hunt, S., Gonzales, M.B., VandenBosch, K.A., Layzell, D.B., Hirsch, A.M1998.  Effects of oxygen on nodule physiology and expression of nodulins in alfalfa (Medicago sativa L.).  Plant Physiol.  117:385-395.


Ginzburg, I., David, R., Shaul, O., Atzmon, N., Elad, Y., Wininger, S., Ben-Dor, B., Badani, H., Fang, Y., van Rhijn, P., Li, Y., Hirsch, A.M., and Kapulnik, Y.  1998Glomus intraradices colonization regulates gene expression in alfalfa and tobacco roots.  Symbiosis.  25:145-157.


Fang, Y. and Hirsch, A.M1998.  Studying early nodulin gene ENOD40 expression and induction by Nod factor and cytokinin in transgenic alfalfa.  Plant Physiol.  116:53-68.


Niner, B.M., Hirsch, A.M.  1998.  How many Rhizobium genes, in addition to nod, nif/fix, and exo, are needed for nodule development and function?  Symbiosis.  24:51-102.


McKhann, H.I., Paiva, N.L., Dixon, R.A., Hirsch, A.M.  1998.  Expression of genes for enzymes of the flavonoid biosynthetic pathway in the early stages of the Rhizobium-legume symbiosis.  Adv. Exp. Med. Biol.  439:45-54.


Hirsch, A.M., Fang, Y., Asad, S., Kapulnik, Y.  1997.  The role of phytohormones in plant-microbe symbioses.  Plant Soil.  194:171-184.


van Rhijn, P., Fang, Y., Galili, S., Shaul, O., Atzmon, N., Winiger, S., Eshead, Y., Lum, M., Li, Y., To, V., Fujishige, N., Kapulnik, Y., Hirsch, A.M.  1997.  Expression of early nodulin genes in alfalfa mycorrhizae indicates that signal transduction pathways used in forming arbuscular mycorrhizae and Rhizobium-induced nodules may be conserved.  Proc. Natl. Acad. Sci.  (USA).  94:5467-5472.


Hirsch, A.M., LaRue, T.A.  1997.  Is the legume nodule a modified root or stem or an organ sui generisCrit. Rev. Plant Sci.  16:361-392.


Wycoff, K.L., van Rhijn, P., Hirsch, A.M.  1997.  The ribosomal protein P0 of soybean (Glycine max L. Merr.) has antigenic cross-reactivity to soybean seed lectin.  Plant Mol. Biol.  34:295-306.


McKhann, H.I., Paiva, N.L., Dixon, R.A., Hirsch, A.M1997.  Chalcone synthase transcripts are detected in alfalfa root hairs following inoculation with wild-type Rhizobium melilotiMol. Plant-Microbe Interact.  10:50-58.


Akkermans, A.D.L., Hirsch, A.M1997.  A reconsideration of terminology in Frankia research:  A need for congruence.  Physiol. Plant.  99:574-578.


Niner, B.M., Brandt, J.P., Villegas, M., Marshall, C.R., Hirsch, A.M., Valdés, M.  1996.  Analysis of partial sequences for 16S rRNA of actinomycetes isolated from Casuarina equisetifolia nodules in México.  Appl. Environ. Microbiol.  2:3034-3036.


Hirsch, A.M., Brill, L.M., Lim, P.O., Scambray, J., van Rhijn, P.  1995.  Steps toward defining the role of lectins in nodule development in legumes.  Symbiosis.  19:155-173.


Hirsch, A.M., McKhann, H.I., Reddy, A., Liao, J., Fang, Y., Marshall, C.R.  1995.  Assessing horizontal transfer of nifHDK genes in eubacteria:  nucleotide sequence of nifK from Frankia strain HFPCcI3.  Mol. Biol. Evol.  12:16-27.


Brill, L.M., Konyalian, V.R., Hirsch, A.M.  1995.  A 1.7-kilobase genomic fragment of alfalfa DNA contains the lectin gene Mslec1.  Plant Physiol.  108:1311-1312.


Hirsch, A.M., Kirchanski, S.J.  1995.  Publish and perish: The rules of the game.  Plant Physiol. 109:1131-1132.


Asad, S., Fang, Y., Wycoff, K.L., Hirsch, A.M.  1994.  Isolation and characterization of cDNA and genomic clones of MsENOD40; transcripts are detected in meristematic cells.  Protoplasma. 183:10-23.


Hirsch, A.M., Fang, Y.  1994.  Plant hormones and nodulation:  What’s the connection?  Plant Mol. Biol.  26:5-9.


McKhann, H.I., Hirsch, A.M.  1994.  Does Rhizobium avoid the host response? Curr. Top. Microbiol. Immunol.  192:139-162.


McKhann, H.I., Hirsch, A.M1994.  Isolation of chalcone synthase and chalcone isomerase cDNAs from alfalfa (Medicago sativa L.):  highest transcript levels occur in young roots and root tips.  Plant Mol. Biol.  24:767-777.


Guillén, G., Valdés, M., Liao, J., Hirsch, A.M.  1993.  Identificación de actinobacterias aisladas de nódulos de Casuarina, por tecnicas tradicionales y moleculares.  Revista Lat. Amer. Microbiol.  35:195-200.


Löbler, M., Hirsch, A.M.  1993.  A gene that encodes a proline-rich nodulin with limited homology to PsENOD12 is expressed in the invasion zone of Rhizobium meliloti-induced alfalfa nodules.  Plant Physiol.  103:21-30.


McKhann, H.I., Hirsch, A.M1993In situ localization of specific mRNAs in plant tissues.  In: Methods in Plant Molecular Biology and Biotechnology.  Eds. J.E. Thompson and B.R. Glick. CRC Press, Boca Raton, pp. 173-205.


Scheres, B., McKhann, H.I., Zalensky, A., Löbler, M., Bisseling, T., Hirsch, A.M.  1992.  The PsENOD12 gene is expressed at two different sites in Afghanistan pea pseudonodules induced by auxin transport inhibitors.  Plant Physiol.  100:1649-1655.


Löbler, M., Hirsch, A.M.  1992.  An alfalfa (Medicago sativa L.) cDNA encoding an acidic leghemoglobin (MsLb3).  Plant Mol. Biol.  20:733-736.


Hirsch, A.M.  1992.  Tansley Review No. 40.  Developmental biology of legume nodulation.  New Phytol. 122:211-237.


Hirsch, A.M., McKhann, H.I., Löbler, M.  1992.  Bacterial-induced changes in plant form and function.  Int. J. Plant Sci.  153:S171-S181.


Reddy, A., Bochenek, B., Hirsch, A.M1992.  A new Rhizobium meliloti symbiotic mutant isolated after introducing Frankia DNA sequence into a nodA::Tn5 strain.  Mol. Plant-Microbe Interact.  5: 62-71.


Yang, C. Signer, E.R., Hirsch, A.M. 1992. Nodules initiated by Rhizobium meliloti exopolysaccharide mutants lack a discrete, persistent nodule meristem.  Plant Physiol.  98:143-151.


Simonet, P., Normand, P., Hirsch, A.M., Akkermans, A.D.L.  1990.  The genetics of the Frankia-actinorhizal symbiosis. In: Nitrogen Fixation. Ed: P.M. Gresshoff.  CRC Press, Boca Raton, pp. 77-109.


Kneen, B.E., LaRue, T.A., Hirsch, A.M., Smith, C.A., Weeden, N.F.  1990sym 13—a gene controlling ineffective nodulation in P. sativumPlant Physiol.  94:899-905.


van de Wiel, C., Norris, J.H., Bochenek, B., Dickstein, R., Bisseling, T., Hirsch, A.M.  1990.  Nodulin gene expression and ENOD2 localization in effective nitrogen-fixing and ineffective bacteria-free nodules of alfalfa.  Plant Cell  15:513-516.


Löbler, M., Hirsch, A.M.  1990.  RFLP mapping of the abp1 locus in maize (Zea mays L.). Plant Mol. Biol.  15:513-516.


Hirsch, A.M., Bhuvaneswari, T.V., Torrey, J.G., Bisseling, T.  1989.  Early nodulin genes are induced in alfalfa root outgrowths elicited by auxin transport inhibitors.  Proc. Natl. Acad. Sci. USA.  86:1244-1249