About

John L. Celenza is an Associate Professor of Biology at Boston University and serves as the Director of the Program in Biochemistry & Molecular Biology. He is also the Co-Chair of the Biology Anti-Racism Committee. His research focuses on the plant kingdom, particularly on the amino acid tryptophan, which functions in protein synthesis and as a precursor for natural products involved in growth, development, and plant defense. Using Arabidopsis thaliana as a model system, he combines genetic, molecular biological, and biochemical methods to study how tryptophan is converted into the growth hormone auxin, glucosinolates for antiherbivory, and the antifungal compound camalexin. His work aims to define the genes and enzymes involved in tryptophan biosynthesis and metabolism, understand regulatory mechanisms, and determine the effects of genetic perturbations on plant growth and development.

Research topics

• Ecology
• Biology
• Genetics
• Microbiology
• Botany

Selected publications

• Arbuscular Mycorrhizal Fungi Boost Development of an Invasive <i>Brassicaceae</i>

  Plant Cell & Environment · 2025-03-25 · 5 citations

  articleOpen access

  Invasive plant growth is affected by interactions with arbuscular mycorrhizal fungi (AMF). AMF are mutualists of most land plants but suppress the growth of many plants within the Brassicaceae, a large plant family including many invasive species. Alliaria petiolata (garlic mustard) is a nonnative, nonmycorrhizal Brassicaceae distributed throughout North America in forest understories where native species rely on AMF. If AMF suppress growth of garlic mustard, it may be possible to inoculate AMF to manage invasions. Here, we show that in contrast to expectation, garlic mustard growth nearly doubled in response to AMF inoculation under both laboratory and field conditions. This effect was negatively linked to investments in glucosinolates, a class of defensive compounds. In contrast to typical symbiosis, AMF did not produce arbuscules where nutrient exchange occurs in roots, but AMF inoculation increased plant and soil nitrogen availability. Our findings reveal an adjacent pathway by which AMF promote invasive plant growth without classic symbiotic exchanges. Prior assumptions that garlic mustard suppresses AMF are inadequate to explain invasion success since it benefits from interactions with AMF. This study is the first to demonstrate extensive growth promotion following AMF inoculation in mustard plants, with important implications for invasion biology and agriculture.

  PublisherOA PDFDOI

• Indolic glucosinolate pathway provides resistance to mycorrhizal fungal colonization in a non‐host Brassicaceae

  Ecosphere · 2020 · 27 citations

  • Biology
  • Botany
  • Microbiology

  Abstract Most terrestrial plants form mycorrhizas, but a number of agricultural plants, including the Brassicaceae, are non‐mycorrhizal. Brassicaceae can still be colonized by arbuscular mycorrhizal fungi (AMF), but species like Arabidopsis thaliana experience growth reductions following AMF colonization at similar magnitude to that of fungal pathogen infections and lack key genes necessary for nutrient exchange. Arabidopsis also produces specific secondary compounds via the modification of tryptophan, including indolic glucosinolates (IGs), which have anti‐fungal properties and may therefore be involved in reducing AMF colonization. This study therefore addressed whether the ability to produce IGs facilitates resistance to AMF colonization and growth suppression. We challenged with AMF inoculation transgenic Arabidopsis lines which produce no or enhanced IGs levels in comparison with the wild‐type. Arbuscular mycorrhizal fungal inoculation suppressed the development of IG‐removed plants, activated their pathogen‐response defenses, and enhanced AMF vesicle colonization of their root systems. Arbuscular mycorrhizal fungi had no detrimental effects on wild‐type or IG‐enhanced plants. Using BLAST to identify IG orthologs across 29 Brassicales, we also show that non‐mycorrhizal species possess orthologous proteins for IG biosynthesis to Arabidopsis which AMF‐associated Brassicales lack. In conclusion, the IG production pathway appears to serve an important and previously unknown role in reducing AMF colonization in Arabidopsis and may serve similar functions in non‐host Brassicales more broadly.

  PublisherOA PDFDOI

• Identification of an Arabidopsis Aminotransferase that Facilitates Tryptophan and Auxin Homeostasis

  bioRxiv (Cold Spring Harbor Laboratory) · 2015-01-16

  preprintOpen accessSenior authorCorresponding

  Abstract IAA plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 ( I ndole S evere S ensitive ) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1 , but not WT, uses primarily Trp-I IAA synthesis when grown on indolesupplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant’s increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways.

  PublisherOA PDFDOI

• Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in <i>Arabidopsis</i>

  Genetics · 2015-07-10 · 32 citations

  articleOpen accessSenior authorCorresponding

  Indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 ( I: ndole S: evere S: ensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indole-supplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant's increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways.

  PublisherOA PDFDOI

• Comment pertaining to "Observation of the dynamical Casimir effect in a superconducting circuit", Nature 10:1038 v 479

  viXra · 2012-01-01

  preprintSenior author

  The recent measurements of the Casimir effect by Wilson, et al1 established the existence of a pervasive background of charged particles in what has been perceived as an empty Universe. As a result, photons moving through what we have hitherto taken as a vacuum will be slowed5, while neutrino speed will be unaffected. All our measurements of the propagation of light and its wavelength have not been been corrected for this slowing.

  Publisher

• Redirection of tryptophan metabolism in tobacco by ectopic expression of an Arabidopsis indolic glucosinolate biosynthetic gene

  Phytochemistry · 2010-11-25 · 31 citations

  article
  PublisherDOI

• Indolic glucosinolates at the crossroads of tryptophan metabolism

  Phytochemistry Reviews · 2008-10-24 · 55 citations

  articleSenior author
  PublisherDOI

• Auxin acts as a local morphogenetic trigger to specify lateral root founder cells

  Proceedings of the National Academy of Sciences · 2008-06-16 · 630 citations

  articleOpen access

  Plants exhibit an exceptional adaptability to different environmental conditions. To a large extent, this adaptability depends on their ability to initiate and form new organs throughout their entire postembryonic life. Plant shoot and root systems unceasingly branch and form axillary shoots or lateral roots, respectively. The first event in the formation of a new organ is specification of founder cells. Several plant hormones, prominent among them auxin, have been implicated in the acquisition of founder cell identity by differentiated cells, but the mechanisms underlying this process are largely elusive. Here, we show that auxin and its local accumulation in root pericycle cells is a necessary and sufficient signal to respecify these cells into lateral root founder cells. Analysis of the alf4-1 mutant suggests that specification of founder cells and the subsequent activation of cell division leading to primordium formation represent two genetically separable events. Time-lapse experiments show that the activation of an auxin response is the earliest detectable event in founder cell specification. Accordingly, local activation of auxin response correlates absolutely with the acquisition of founder cell identity and precedes the actual formation of a lateral root primordium through patterned cell division. Local production and subsequent accumulation of auxin in single pericycle cells induced by Cre-Lox-based activation of auxin synthesis converts them into founder cells. Thus, auxin is the local instructive signal that is sufficient for acquisition of founder cell identity and can be considered a morphogenetic trigger in postembryonic plant organogenesis.

  PublisherOA PDFDOI

• Sites and Regulation of Auxin Biosynthesis in Arabidopsis Roots

  The Plant Cell · 2005-03-16 · 555 citations

  articleOpen access

  Auxin has been shown to be important for many aspects of root development, including initiation and emergence of lateral roots, patterning of the root apical meristem, gravitropism, and root elongation. Auxin biosynthesis occurs in both aerial portions of the plant and in roots; thus, the auxin required for root development could come from either source, or both. To monitor putative internal sites of auxin synthesis in the root, a method for measuring indole-3-acetic acid (IAA) biosynthesis with tissue resolution was developed. We monitored IAA synthesis in 0.5- to 2-mm sections of Arabidopsis thaliana roots and were able to identify an important auxin source in the meristematic region of the primary root tip as well as in the tips of emerged lateral roots. Lower but significant synthesis capacity was observed in tissues upward from the tip, showing that the root contains multiple auxin sources. Root-localized IAA synthesis was diminished in a cyp79B2 cyp79B3 double knockout, suggesting an important role for Trp-dependent IAA synthesis pathways in the root. We present a model for how the primary root is supplied with auxin during early seedling development.

  PublisherOA PDFDOI

• <i>Arabidopsis ALF4</i> encodes a nuclear‐localized protein required for lateral root formation

  The Plant Journal · 2004-01-09 · 143 citations

  articleOpen accessSenior authorCorresponding

  Lateral root formation, the primary way plants increase their root mass, displays developmental plasticity in response to environmental changes. The aberrant lateral root formation (alf)4-1 mutation blocks the initiation of lateral roots, thus greatly altering root system architecture. We have positionally cloned the ALF4 gene and have further characterized its phenotype. The encoded ALF4 protein is conserved among plants and has no similarities to proteins from other kingdoms. The gene is present in a single copy in Arabidopsis. Using translational reporters for ALF4 gene expression, we have determined that the ALF4 protein is nuclear localized and that the gene is expressed in most plant tissues; however, ALF4 expression and ALF4's subcellular location are not regulated by auxin. These findings taken together with further genetic and phenotypic characterization of the alf4-1 mutant suggest that ALF4 functions independent from auxin signaling and instead functions in maintaining the pericycle in the mitotically competent state needed for lateral root formation. Our results provide genetic evidence that the pericycle shares properties with meristems and that this tissue plays a central role in creating the developmental plasticity needed for root system development.

  PublisherOA PDFDOI

Frequent coauthors

• Jennifer Normanly

  University of Massachusetts Amherst

  29 shared

• Anna K. Hull

  23 shared

• Marian Carlson

  Columbia University

  18 shared

• Yunde Zhao

  University of California, San Diego

  16 shared

• José M. Alonso

  North Carolina State University

  16 shared

• Kendrick A. Goss

  Bluebird Bio (United States)

  16 shared

• Neeru R. Gupta

  Kaiser Permanente

  16 shared

• Joseph R. Ecker

  Salk Institute for Biological Studies

  16 shared