Mikhail E. Nasrallah

From Wikitia
Jump to navigation Jump to search
Mikhail E. Nasrallah
Add a Photo
Alma mater
  • American University of Beirut
  • University of Vermont

Mikhail Elia Nasrallah is Professor Emeritus in the Plant Biology Section of the School of Integrative Plant Science] in the New York State College of Agriculture and Life Sciences at Cornell University.


Nasrallah, a native of Kfarmishki, Lebanon, received a Bachelor of Science degree in Agriculture and a certification in Agronomy [Ingénieur Agricole] from the American University of Beirut in 1960, a Master's degree in Horticulture from the University of Vermont in 1962, and a doctorate degree in Plant Breeding and Genetics from Cornell University in 1965.

Career and Research

Nasrallah carried out postdoctoral research at Cornell University from 1965-1967 and had a faculty position in Genetics at the State University of New York Cortland from 1967 to 1985. He moved to Cornell as a Senior Research Associate in 1985 and joined the faculty at Cornell University in 1992 as a Professor of Plant Biology.

Much of Nasrallah's research has focused on the study of self-incompatibility in plants of the Brassicaceae (crucifer) family. Self-incompatibility (SI) is a post-pollination pre-zygotic genetic barrier widespread among angiosperms which ensures outcrossing by preventing selfing and mating among relatives.[1] In several plant families including crucifers, SI is controlled by one genetic locus, designated the S locus, which exists as multiple variants, each of which encodes a distinct mating (SI) specificity. The highly selective SI barrier is based on the ability of cells of the pistil to discriminate between "self" pollen (i.e. pollen grains that express the same SI specificity as that expressed in the pistil, whether the grains are derived from the same flower, the same plant, or other plants that express the same SI specificity as the pistil) and "nonself" pollen (i.e. pollen that expresses an SI specificity different from that expressed in the pistil). Thus, in pollinations with "nonself" pollen, pollen grains produce tubes that grow through the pistil to the ovary where they fertilize the ovules, leading to seed production. By contrast, "self" pollen is inhibited along the path of pollen tube growth, thus preventing self-fertilization and seed production. In crucifers, the inhibition of "self" pollen occurs at the surface of the stigma, a structure located at the tip of the pistil whose epidermal cells capture pollen, such that pollen grains fail to hydrate and germinate or only produce short tubes that cannot penetrate into the pistil[2]

As a doctoral student at Cornell, Nasrallah used a novel approach to the study of SI. Instead of the pollen-centric focus which at the time had been the norm in research aimed at identifying the molecular components of SI in various plant families,[3] he focused on investigating the contribution of the pistil (specifically the stigma in crucifers) to specificity in the SI response. His immunochemical analysis of the extracts of stigmas derived from self-incompatible Brassica oleracea plants expressing different SI specificities led him to identify the S locus-specific antigen, which was the first molecule encoded by an SI specificity-determining locus to be identified.[4] The success of this work would mark a paradigm shift in the study of SI across various plant families. Indeed, in subsequent years, identification of the pistil determinant of SI specificity preceded identification of the pollen specificity determinant by several years in various species of the Brassicaceae, Solanaceae, and Papaveraceae.

In further research on the Brassicaceae SI system carried out by the Nasrallah team at Cornell, the S locus-specific antigen, subsequently designated the S-locus glycoprotein,[5] was used as a launching pad for a detailed analysis of the Brassica S locus, which determined that the S locus contains, not one gene, but two genes whose protein products determine specificity in the SI response. As a result of this work, S-locus variants, traditionally known as "S alleles", are now known as "S haplotypes". It is now well established that in the Brassicaceae, each S haplotype encodes matched variants of two proteins: the S-locus receptor kinase (SRK), a plasma membrane-spanning protein which is displayed at the surface of stigma epidermal cells[6],[7],[8] and the S-locus cystine-rich protein (SCR), a small protein which is a component of the outer coat of the pollen grain[9],.[10] Further biochemical analysis demonstrated a highly selective S haplotype-specific receptor-ligand relationship between SRK and SCR[11],.[12] Because SCR will only bind the extracellular domain of the SRK encoded in the same S haplotype, it is only in a "self" pollination that SRK is activated and a signaling cascade is triggered which ultimately leads to the rejection of "self" pollen.

While SRK and SCR were first identified in Brassica, functional orthologues of these genes were also identified in Arabidopsis lyrata[13] and subsequently in all self-incompatible crucifer species that have been analyzed to date[14],[15],[16],.[17][18] By contrast, non-functional versions of the SRK and SCR genes were found in several geographical accessions of the self-fertile model plant Arabidopsis thaliana, suggesting that inactivation of these genes likely caused the switch to self-fertility in this species[19],[20],.[21] In a landmark inter-specific transgenic complementation experiment, Nasrallah showed that the transgenic introduction of functional SRK-SCR gene pairs from self-incompatible A. lyrata into A. thaliana was sufficient to revert self-fertile A. thaliana to its ancestral state of SI.[22] This pivotal experiment proved that SRK and SCR are the sole determinants, not only of SI specificity, but also of the out-crossing mode of mating in the Brassicaceae.

Awards and Honors

Nasrallah received the American University of Beirut's highest scholastic honor, the Penrose Award, in 1960[23]; an award in Horticulture from the Burpee Foundation[24] in 1961; and an award from the American Institute of Biological Sciences[25] in 1970 in recognition of an outstanding research contribution related to a vegetable crop used for processing.


  1. Charlesworth, D (2010). "Self-Incompatibility". F1000 Biol Rep. 2: 68. doi:10.3410/B2-68. PMC 2989624. PMID 21173841.
  2. Franklin-Tong, VE (2008). Self-Incompatibility in Flowering Plants: Evolution, Diversity, and Mechanisms. Springer. ISBN 978-3-540-68485-5.
  3. Lewis, D (1952). "Serological reactions of pollen incompatibility substances". Proceedings Fo the Royal Society London Series B Biological Sciences. 140 (898): 127–135. Bibcode:1952RSPSB.140..127L. doi:10.1098/rspb.1952.0049. PMID 13003917.
  4. Nasrallah, ME; Wallace, DH (1967). "Immunochemical detection of antigens in self-incompatibility genotypes of cabbage". Nature. 213 (5077): 700–701. Bibcode:1967Natur.213..700N. doi:10.1038/213700a0.
  5. Nasrallah, JB; Kao, TH; Chen, CH; et al. (1987). "Amino acid sequences of glycoproteins encoded by three alleles at the S locus of Brassica oleracea". Nature. 326 (6113): 617–619. Bibcode:1987Natur.326..617N. doi:10.1038/326617a0.
  6. Stein, JC; Howlett, B; Boyes, DC; et al. (1991). "Molecular cloning of a putative receptor protein kinase gene encoded at the self-incompatibility locus of Brassica oleracea". Proceedings of the National Academy of Sciences USA. 88 (19): 8816–8820. Bibcode:1991PNAS...88.8816S. doi:10.1073/pnas.88.19.8816. PMC 52601. PMID 1681543.
  7. Takasaki, T; Hatakeyama, K; Suzuki, G; et al. (2000). "The S receptor kinase determines self-incompatibility in Brassica stigma". Nature. 403 (6772): 913–916. Bibcode:2000Natur.403..913T. doi:10.1038/35002628. PMID 10706292.
  8. Rea, AC; Nasrallah, JB (2015). "In vivo imaging of the S-locus receptor kinase, the female specificity determinant of self-incompatibility, in transgenic self-incompatible Arabidopsis thaliana". Annals of Botany. 115 (5): 789–805. doi:10.1093/aob/mcv008. PMC 4373290. PMID 25714818.
  9. Schopfer, CR; Nasrallah, ME; nasrallah, JB (1999). "The male determinant of self-incompatibility in Brassica". Science. 286 (5445): 1697–1700. doi:10.1126/science.286.5445.1697. PMID 10576728.
  10. Takayama, S; Shiba, H; Iwano, M; et al. (2000). "The pollen determinant of self-incompatibility in Brassica campestris". Proceedings of the National Academy of Sciences USA. 97 (4): 1920–1925. Bibcode:2000PNAS...97.1920T. doi:10.1073/pnas.040556397. PMC 26537. PMID 10677556.
  11. Kachroo, A; Schopfer, CR; Nasrallah, ME; Nasrallah, JB (2001). "Allele-specific receptor-ligand interactions in Brassica self-incompatibility". Science. 293 (5536): 1824–1826. Bibcode:2001Sci...293.1824K. doi:10.1126/science.1062509. PMID 11546871.
  12. Takayama, S; Shimosato, H; Shiba, H; et al. (2000). "Direct ligand-receptor complex interaction controls Brassica self-incompatibility". Nature. 413 (6855): 534–538. doi:10.1038/35097104. PMID 11586363.
  13. Kusaba, M; Dwyer, K; Hendershot, J; et al. (2001). "Self-incompatibility in the genus Arabidopsis: Characterization of the S locus in the outcrossing A. lyrata and its autogamous relative A. thaliana". Plant Cell. 13 (3): 627–643. doi:10.1105/tpc.13.3.627. PMC 135518. PMID 11251101.
  14. Chantha, SC; Herman, AC; Platts, AE; et al. (2013). "Secondary evolution of a self-incompatibility locus in the Brassicaceae genus Leavenworthia". PLOS Biol. 11 (5): e1001560. doi:10.1371/journal.pbio.1001560. PMC 3653793. PMID 23690750.
  15. Nasrallah, JB; Liu, P; Sherman-Broyles, S; et al. (2007). "Epigenetic Mechanisms for Breakdown of Self-Incompatibility in Interspecific Hybrids". Genetics. 175 (4): 1965–1973. doi:10.1534/genetics.106.069393. PMC 1855105. PMID 17237505.
  16. Neuffer, B; Bechsgaard, J; Paetsch, M; et al. (2023). "S-alleles and mating system in natural populations of Capsella grandiflora (Brassicaceae) and its congeneric relatives". Flora. 299. doi:10.1016/j.flora.2022.152206.
  17. Goubet, PM (2012). "Contrasted patterns of molecular evolution in dominant and recessive self-incompatibility haplotypes in Arabidopsis". PLOS Genetics. 8 (3): e1002495. doi:10.1371/journal.pgen.1002495. PMC 3310759. PMID 22457631.
  18. Zeng, F (2014). "Self-(in)compatibility inheritance and allele-specific marker development in yellow mustard ( Sinapis alba)". Molecular Breeding. 33 (1): 187–196. doi:10.1007/s11032-013-9943-8. PMC 3890562. PMID 24482603.
  19. Sherman-Broyles, S (2007). "S locus genes and the evolution of self-fertility in Arabidopsis thaliana". Plant Cell. 19 (1): 94–106. doi:10.1105/tpc.106.048199. PMC 1820967. PMID 17237349.
  20. Boggs, NA; Nasrallah, ME; Nasrallah, JB (2009). "Independent S-locus mutations caused self-fertility in Arabidopsis thaliana". PLOS Genetics. 5 (3): e1000426. doi:10.1371/journal.pgen.1000426. PMC 2650789. PMID 19300485.
  21. Tsuchimatsu, T (2017). "Patterns of polymorphism at the self-incompatibility locus in 1,083 Arabidopsis thaliana genomes". Molecular Biology and Evolution. 34 (8): 1878–1889. doi:10.1093/molbev/msx122. PMC 5850868. PMID 28379456.
  22. Nasrallah, ME; Liu, P; Nasrallah, JB (2002). "Generation of self-incompatible Arabidopsis thaliana by transfer of two S locus genes from A. lyrata". Science. 297 (5579): 247–249. Bibcode:2002Sci...297..247N. doi:10.1126/science.1072205. PMID 12114625.
  23. "Then and Now" (PDF). No. Summer 2009. American University of Beirut. 2009.
  24. "The Burpee Foundation". The Burpee Foundation.
  25. "AIBS Awards". aibs.org.

External links

Add External links

This article "Mikhail E. Nasrallah" is from Wikipedia. The list of its authors can be seen in its historical. Articles taken from Draft Namespace on Wikipedia could be accessed on Wikipedia's Draft Namespace.