Maeli Melotto


Position Title
Associate Professor

Department of Plant Sciences, College of Agricultural and Environmental Sciences

104 Mann Lab

Profile Introduction

We study infection and contamination of plants (model and crop) with plant and human pathogens.

Research Interests

Plant-Microbe Interactions

Our  work integrates molecular genetics and pathology, genomics and bioinformatics to address two guiding questions:

1) What are the molecular mechanisms underlying stomatal and apoplastic defenses?

2) What are the virulence stratagies employed by bacterial pathogens to overcome/avoid plant defense at the early stages of infection?

Grad Group Affiliations

  • Horticulture and Agronomy Graduate Group
  • Plant Biology
  • Plant Pathology

Specialties / Focus

  • Molecular Biology, Biochemistry and Genomics


  • Melotto Lab at UC Davis

Honors and Awards

  • 2013: Phi Kappa Phi Recognized Professor
  • 2015-2018: Special Visiting Researcher Fellowship, National Council for Scientific and Technology Development of the Ministry of Science, Technology and Innovation (CNPq/MCTI), Brazilian Federal Government.
  • 2017: Faculty Fellowship Summer Institute in Israel (, Jewish National Fund and Media Watch International, New York.

    Professional Societies

    • International Society of Molecular Plant Microbe Interactions (IS-MPMI)
    • American Society of Plant Biologists (ASPB)
    • American Association for the Advancement of Science (AAAS)
    • Bean Improvement Cooperative (BIC)


    • 1999 PhD Plant Breeding and Genetics Michigan State University


    Public Research Profiles


    Research Gate:

    Google Scholar:

    Peer-reviewed Publications

    Panchal S, Melotto M. 2017. Stomate-based defense and environmental cues. Plant Signaling & Behavior 12(9): e1362517.

    Panchal S, Breitbach ZS, Melotto M. 2017. An HPLC-based method to quantify coronatine production by bacteria. Bio-protocol 7(5): e2147.

    Jacob C, Panchal S, Melotto M. 2017. Surface inoculation and quantification of Pseudomonas syringae population in the Arabidopsis leaf apoplast. Bio-protocol 7(5): e2167.

    Melotto M, Zhang F, Oblessuc PR, He SY. 2017. Stomatal defense a decade later. Plant Physiol. 174: 531-571.

    Zhang L, Zhang F, Melotto M, Yao J, He SY. 2017. Jasmonate signaling and manipulation by pathogens and insects. J. Exp. Bot. 68:1371-1385.

    Montano J, Melotto M. 2017. Stomatal bioassay to characterize bacterial-stimulated PTI at the pre-invasion phase of infection. In: Shan L, He P (eds). Methods in Molecular Biology, vol. 1578, Plant Pattern Recognition Receptors, Springer Protocols, Chapter 19: pp. 233-241.

    Panchal S, Chitrakar R, Thompson B, Obulareddy N, Roy D, Hambright WS, Melotto M. 2016. Regulation of stomatal defense by air relative humidity. Plant Physiol. 172:2021-2032.

    Panchal S, Roy D, Chitrakar R, Price L, Breitbach ZS, Armstrong DW, Melotto M. 2016. Coronatine facilitates Pseudomonas syringae infection of Arabidopsis leaves at night. Front. Plant Sci. 7:880.

    Carvalho G, da Silva TGER, Munhoz AT, Monteiro-Vitorello CB, Azevedo RA, Melotto M, Camargo LEA. 2016. Development of a qPCR for Leifsonia xyli subsp. xyli and quantification of the effects of heat treatment of sugarcane cuttings on Lxx. Crop Protection 80:51-55.

    Oblessuc PR, Francisco C, Melotto M. 2015. The Co-4 locus on chromosome Pv08 contains a unique cluster of 18 COK-4 genes and is regulated by immune response in common bean. Theor. Appl. Genet. 128:1193-1208.

    Oblessuc PR, Matiolli CC, Chiorato AF, Camargo LEA, Benchimol-Reis LL, Melotto M. 2015. Common bean reaction to angular leaf spot comprises transcriptional modulation of genes in the ALS10.1 QTL. Front. Plant Sci. 6:152.

    Melotto M, Panchal S, Roy D. 2014. Plant innate immunity against human pathogenic bacteria. Front. Microbiol. 5:411.

    Obulareddy N, Panchal S, Melotto M. 2013. Guard cell purification and RNA isolation suitable for high throughput transcriptional analysis of cell-type responses to biotic stresses. Mol. Plant-Microbe Interact. 26:844-849.

    Melotto M, Kunkel BN. 2013. Virulence strategies of plant pathogenic bacteria. In: Rosenberg E, Stackebrand E, DeLong EF, Thompson F, Lory S (eds). 4th Edition of The Prokaryotes – Prokaryotic Physiology and Biochemistry, Springer-Verlag, Berlin Heidelberg: pp. 61-82. (Invited).

    Roy D, Panchal S, Rosa BA, Melotto M. 2013. Escherichia coli O157:H7 induces stronger plant immunity than Salmonella enterica Typhimurium SL1344. Phytopathology 103:326-332. Focus Issue on Food Safety: Human Pathogens on Plants. (Editor’s Pick).

    Shahid A, Ilyas A, Obulareddy N*, Melotto M, Jin M H-C, Iqbal SM. 2013. Power scavenging and optical absorbance analysis of photosynthetically active protoplasts. J. Energy Resources Tech. 135:012001.1-012001.5. *Melotto Lab PhD student.

    Withers J, Yao J, Mecey C, Howe GA, Melotto M, He SY. 2012. Transcription factor-dependent nuclear import of transcriptional repressors in jasmonate hormone signaling. Proc. Natl. Acad. Sci. USA 109:20148-20153.

    Borges A, Melotto M, Tsai SM, Caldas, DGG. 2012. Changes in spatial and temporal gene expression during incompatible interaction between common bean and anthracnose pathogen. J. Plant Physiol. 15:1216-1220.

    Oblessuc PR, Borges, A, Chowdhury B, Caldas DGG, Tsai SM, Camargo LEA, Melotto M. 2012. Dissecting Phaseolus vulgaris innate immune system against Colletotrichum lindemuthianum infection. PLoS One 7:e43161.

    Baker CM, Chitrakar R, Obulareddy N, Panchal S, Williams P, Melotto M. 2010. Molecular battles between plant and pathogenic bacteria in the phyllosphere. Brazilian J. Med. Biol. Res. 43:698-704. (Invited).

    Chitrakar R, Melotto M. 2010. Assessing stomatal response to live bacterial cells using whole leaf imaging. J. Vis. Exp. 44., doi: 10.3791/2185. (Invited).

    Zeng W, Melotto M, He SY. 2010. Plant stomata: a checkpoint of host immunity and pathogen virulence. Curr. Op. Biotech. 21:599-603. (Invited).

    Triplett L, Melotto M, Sundin GW. 2009. Functional analysis of the N-terminus of the Erwinia amylovora secreted effector DspA/E reveals features required for secretion, translocation, and binding to the chaperone DspB/F. Mol. Plant-Microbe Interact. 22:1282-1292.

    Bray-Speth E, Melotto M, Zhang W, Assmann SM, He SY. 2009. Crosstalk in pathogen and hormonal regulation of guard cell signaling. In: Yoshioka K, Shinozaki K. (eds) Signal Crosstalk in Plant Stress Response, Wiley-Blackwell, John Wiley and Sons, Ltd: pp. 96-112. (Invited).

    Melotto M, Mecey C, Niu Y, Cheng HS, Katsir L, Yao J, Zeng W, Thines B, Staswick P, Browse J, Howe GA, He SY. 2008. A critical role of two positively charged amino acids in the Jas motif of Arabidopsis JAZ proteins in mediating coronatine- and jasmonoyl isoleucine-dependent interactions with the COI1 F-box protein. Plant J. 55:979-988.

    Melotto M, Underwood W, He SY. 2008. Role of stomata in plant innate immunity and foliar bacterial diseases. Annu. Rev. Phytopathol. 46: 101-122. Top 10 most read article of the month (Invited).

    Gepts P, Aragão F, Barros E de, Blair MW, Brondani R, Broughton W, Galasso I, Hernández G, Kami J, Lariguet P, McClean P, Melotto M, Miklas P, Pauls P, Pedrosa-Harand A, Porch T, Sánchez F, Sparvoli F, Yu K. 2008. Genomics of Phaseolus beans, a major source of dietary protein and micronutrient in the Tropics. In: Moore PH, Ming R (eds) Genomics of Tropical Crop Plants, Springer, Berlin: pp. 113-143. (Invited).

    Thines B, Katsir L, Melotto M, Niu Y, Mandaokar A, Liu G, Nomura K, He SY, Howe GA, Browse J. 2007. JAZ repressor proteins are targets of the SCFCOI1 complex during jasmonate signaling. Nature 448:661-665. This article has been highlighted in News and Views in the same Nature issue and rated as the top ten articles of the month. Faculty of 1000 exceptional.

    Hanai LR, Campos T de, Camargo LEA, Benchimol LL, Souza AP de, Melotto M, Carbonell SAM, Chioratto AF, Consoli L, Formighieri EF, Siqueira MVBM, Tsai SM, Vieira MLC. 2007. Development, characterization, and comparative analysis of polymorphism at common bean SSR loci isolated from genic and genomic sources. Genome 50:266-277.

    Underwood W, Melotto M, He SY. 2007. Role of plant stomata in bacterial invasion. Cellular Microbiology 9:1621-1629. (Invited).

    Melotto M, Underwood W, Koczan J, Nomura K, He SY. 2006. Plant stomata function in innate immunity against bacterial invasion. Cell 126:969-980. This article has been highlighted by the editors of Science and Nature among others and rated as the most influential publication in the nitric oxide field for 2006. Faculty of 1000 must read.

    Melotto M*, Monteiro-Vitorello CB, Bruschi AG, Camargo LEA. 2005. Comparative bioinformatic analysis of genes expressed in common bean seedlings. Genome 48:562-570. * Corresponding author.

    Nomura K, Melotto M, He SY. 2005. Suppression of host defense in compatible plant-Pseudomonas syringae interactions. Curr. Op. Plant Biol. 8:361-368. (Invited).

    Chen H, McCaig BC, Melotto M, He SY, Howe GA. 2004. Regulation of plant arginase by wounding, jasmonate, and the phytotoxin coronatine. J. Biol. Chem. 279:45998-46007.

    Melotto M*, Coelho MF, Pedrosa-Harand A, Kelly JD, Camargo LEA. 2004. The anthracnose resistance locus Co-4 of common bean is located on chromosome 3 and contains putative disease resistance-related genes. Theor. Appl. Genet. 109:690-699. * Corresponding author.

    Malvas CC, Melotto M, Truffi D, Camargo LEA. 2003. A homolog of the RPS2 disease resistance gene is constitutively expressed in Brassica oleracea. Genet. Mol. Biology 26:511-516.

    Broughton WJ, Hernandez G, Blair M, Beebe S, Gepts P, Vanderleyden J. 2003. Beans (Phaseolus spp.) – Model Food Legumes. Plant and Soil 252:55-128. Member of the International Consortium for Phaseolus Genomics, Transcriptomics and Proteomics: Phaseomics.

    Melotto M, Kelly JD. 2001. Fine mapping of the Co-4 locus of common bean reveals a resistance gene candidate, COK-4, that encodes for a protein kinase. Theor. Appl. Genet. 103:508-517.

    Melotto M, Kelly JD. 2000. An allelic series at the Co-1 locus conditioning resistance to anthracnose in common bean of Andean origin. Euphytica 116:143-149.

    Melotto M, Balardin RS, Kelly JD. 2000. Host-pathogen interaction and variability of Colletotrichum lindemuthianum. In: “Colletotrichum host specificity, pathology, and host-pathogen interaction”. D. Prusky, S. Freeman, and M.B. Dickman (eds.), pp 346-361. APS Press, St Paul, MN, USA. (Invited).

    Souza AA, Burity HA, Figueiredo MVB, Silva MLRB, Melotto M, Tsai SM. 1999. Symbiotic efficiency of HUP+, HUPHR, HUP- Bradyrhizobium japonicum e Bradyrhizobium elkanii strains in cowpea cultivars. Pesq. Agropec. Brasileira. 34:1925-1031.

    Rodrigues JLM, Melotto M, da Silveira JAG. 1998. Nodulin activies, hydrogenase expression and nitrogen fixation in cowpea inoculated with Hup+ and Hup- symbionts. Brazilian J. Plant Physiol. 10:85-90.

    Rodrigues JLM, Melotto M, Oliveira JTA, da Silveira JAG. 1998. Efficiency of soybean nodules in relation to nodulin activities and hydrogenase expression. Brazilian J. Plant Physiol. 10:173-178.

    Young RA, Melotto M, Nodari RO, Kelly JD. 1998. Marker-assisted dissection of the oligogenic anthracnose resistance in the common bean cultivar, G2333. Theor. Appl. Genet. 96:87-94.

    Melotto M, Afanador L, and Kelly JD. 1996. Development of a SCAR marker linked to the I gene in common bean. Genome 39: 1216-1219.