Dr. Toshiro Shigaki

Dr. Toshiro Shigaki with sago seedling.

I, Toshiro Shigaki, a plant pathologist by training, founded the Pacific Agriculture Alliance (PAA) in 2016. Before assuming the position of Director, PAA, I was Principal Scientist in Biotechnology with Papua New Guinea National Agricultural Research Institute (NARI), where I contributed my knowledge and experience for the capacity development in agriculture in the Pacific. I was the project leader for a number of donor-funded projects that were implemented in several Pacific countries. I would like to describe some of my professional experiences. This my help you envision how best I can serve you.

I have published a number of peer-reviewed papers in plant molecular biology and plant pathology. Occasionally, I develop new methods, tools, and vectors, and make them available to interested people. Some methods, such as the class II-S restriction enzyme based site-directed mutagenesis, are used by many labs in the world. Here is  a brief introduction about me:


B.S. (Physics) The University of Toyama
M.S. (Plant Pathology) The University of Wyoming
Ph.D. (Plant Pathology) The University of Hawaii at Manoa


The Samuel Roberts Noble Foundation (1996-1999)
Baylor College of Medicine (1999-2010)
Indian Institute of Advanced Research (2007)
Papua New Guinea National Agricultural Research Institute (2010-2016)
Pacific Agriculture Alliance (2016-Present)


(45)  2015. G. B. Rauka and T. Shigaki. Occurrence and distribution of aibika (Abelmoschus manihot (L.) Medik.) collar rot and Fusarium rot in Morobe Province, Papua New Guinea. Fiji Agricultural Journal 55:4-10.

(44)  2015. T. Shigaki. Agriculture and biotechnology in Pacific countries. Recent Patents on Food, Nutrition & Agriculture 7: 33-37.

(43) 2012. Q. Wu, T. Shigaki, J.-S. Han, C. K. Kim, K. D. Hirschi, and S. Park. Ectopic expression of a maize calreticulin mitigates calcium deficiency-like disorders in sCAX1-expressing tobacco and tomato. Plant Molecular Biology 80: 609-619.

(42) 2011. M. Manohar*, T. Shigaki*, H. Mei, S. Park, Marshall, J, Aguilar, J., and K. Hirschi. Characterization of Arabidopsis Ca2+/Hexchanger CAX3. Biochemistry 50: 6189-6195. (*co-first authors)

(41) 2011. M. Manohar, T. Shigaki, and K. D. Hirschi. Plant cation/H+ exchangers (CAXs): Biological functions and genetic manipulations. Plant Biology 13: 561-569.

(40)  2011. Q. Wu, T. Shigaki, K. A. Williams, J. -S. Han, C. K. Kim, K. D. Hirschi, and S. Park. Expression of an Arabidopsis Ca2+/H+ antiporter CAX1 variant in petunia enhances cadmium tolerance and accumulation. Journal of Plant Physiology 168:167-173.

(39) 2010. M. Kunta, H. Miao, T. Shigaki, J. L. Perez, and M. Skaria. Ganoderma infecting citrus in Texas is a unique taxon within G. lucidum complex: evidence from the ITS region. Pest Technology. 4:62-64.

(38)  2010. T. Shigaki, H. Mei, J. Marshall, X. Li, M. Manohar, and K. D. Hirschi. The expression of the open reading frame of CAX1, but not its cDNA, confers metal tolerance in yeast. Plant Biology 12:6935-939.

(37)  2010. M. Manohar, H. Mei, A. J. Franklin, E. M. Sweet, T. Shigaki, B. B. Riley, C. W. MacDiarmid, and K. Hirschi. Zebrafish (Danio rerio) endomembrane antiporter similar to a yeast cation/H+ transporter is required for neural crest development. Biochemistry 49:6557-6566.

(36)  2009. J. Zhao, J.M. Connorton, Y. Guo, X. Li, T. Shigaki, K.D. Hirschi, and J.K. Pittman. Functional studies of split Arabidopsis Ca2+/Hexchangers. Journal of Biological Chemistry 284:34075-34083.

(35) 2009. N. Jain, R. Nadgauda, and T. Shigaki. Mining cation (CAX) transporter diversity for nutrition-enhanced crops and phytoremediation. International Journal of Integrative Biology 7:22-25.

(34)  2009.  J. Han, S. Park, T. Shigaki, K. D. Hirschi, and C. K. Kim.  Improved watermelon quality using bottle gourd rootstock expressing a Ca2+/H+ antiporter.  Molecular Breeding 24:201-211.

(33)  2009.  J. Zhao, T. Shigaki, H. Mei, Y. Guo, N. Cheng, and K. D. Hirschi.  Interaction between Arabidopsis Ca2+/H+ exchangers CAX1 and CAX3.  Journal of Biological Chemistry 284:4605-4615.

(32)  2009.  C. Edmond, T. Shigaki, S. Ewert, M. Nelson, J. Connorton, V. Chalova, Z. Noordally, and  J. K. Pittman. Comparative analysis of CAX2-like cation transporters indicates functional and regulatory diversity.  Biochemical Journal 418:145-154.

(31)  2008. H. Mei, T. Shigaki, and K. D. Hirschi. Yeast as a tool for plant Ca2+ transporter research. Current Topics in Plant Biology 9:79-86.

(30)  2006.  T. Shigaki, I. Rees, L. Nakhleh, and K. D. Hirschi.  Identification of three distinct phylogenetic groups of CAX cation/proton antiporters.  Journal of Molecular Evolution 63:815-825.

(29)  2006.  C. K. Kim, J. -S. Han, H. S. Lee, J. Y. Oh, T. Shigaki, S. H. Park, and K. D. Hirschi.  Expression of an Arabidopsis CAX2 variant in potato tubers increases calcium levels with no accumulation of manganese.  Plant Cell Reports 25:1226-1232.

(28)  2006.  T. Shigaki and K. D. Hirschi.  Diverse functions and molecular properties emerging for CAX cation/H+ exchangers in plants.  Plant Biology 8:419-429.

(27)  2006.  F. A. Gray, T. Shigaki, D. W. Koch, R. D. Delaney, F. Hruby, A. M. Gray, M. E. Majerus, D. Cash, R. L. Ditterline, and D. M. Wichman.  Registration of ‘Shoshone’ sainfoin.  Crop Science 46:988.

(26)  2005.  T. Shigaki, M. Kole, J. M. Ward, H. Sze, and K. D. Hirschi.  Cre-loxP recombination vectors for the expression of Riken Arabidopsis full-length cDNAs in plants.  BioTechniques 39:301-304.

(25)  2005.  T. Shigaki, B. J. Barkla, M. C. M. Vergara, J. Zhao, O. Pantoja, and K. D. Hirschi.  Identification of a crucial histidine involved in metal transport activity in the Arabidopsis cation/proton exchanger CAX1.  Journal of Biological Chemistry 280:30136-30142.

(24)  2005.  N. -H. Cheng, J. K. Pittman, T. Shigaki, J. Lachmansingh, S. LeClere, B. Lahner, D. E. Salt, and K. D. Hirschi.  Mutations of multiple CAX transporters alter plant growth, H+-ATPase activity and the ionome.  Plant Physiology 138:2048-2060.

(23)  2005.  T. Shigaki, R. R. Vyzasatya, A. B. Sivitz, J. M. Ward, H. Sze, and K. D. Hirschi.  The Cre-loxP recombination-based reporter system for plant transcriptional expression studies.  Plant Molecular Biology 58:65-73.

(22)  2005.  J. K. Pittman, T. Shigaki, and K. D. Hirschi.  Evidence of differential pH regulation of the Arabidopsis vacuolar Ca2+/H+ antiporters CAX1 and CAX2.  FEBS Letters 579:2648-2656.

(21)  2004.   J. K. Pittman, T. Shigaki, J. L. Marshall, J. L. Morris, N. -H. Cheng, and K. D. Hirschi.  Functionaland regulatory analysis of the Arabidopsis thaliana CAX2 cation transporter.  Plant Molecular Biology 56:959-971.

(20)  2004.  W. -M. Chou*, T. Shigaki*, C. Dammann, Y. -Q. Liu, and M. K. Bhattacharyya.  Inhibition of phosphoinositide-specific phospholipase C results in the induction of pathogenesis-related genes in soybean.  Plant Biology 6:664-672.  (*co-first authors).

(19)  2004.  J. K. Pittman, N. -H. Cheng, T. Shigaki, M. Kunta, and K. D. Hirschi.  Functional dependence on calcineurin by variants of the Saccharomyces cerevisiae vacuolar Ca2+/H+ exchanger Vcx1p.  Molecular Microbiology 54:1104-1116.

(18)  2003.  T. Shigaki, J. K. Pittman, and K. D. Hirschi.  Manganese specificity determinants in the Arabidopsis metal/H+ antiporter CAX2.  Journal of Biological Chemistry 278:6610-6617.

(17)  2003.  N. -H. Cheng, J. K. Pittman, B. J. Barkla, T. Shigaki, and K. D. Hirschi.  The Arabidopsis cax1 mutant exhibits impaired ion homeostasis, development, and hormonal responses, and reveals interplay among vacuolar transporters.  Plant Cell 15:347-364.

(16)  2002.  J. K. Pittman, C. S. Sreevidya, T. Shigaki, H. Ueoka-Nakanishi, and K. D. Hirschi.  Distinct N-terminal regulatory domains of Ca2+/H+ antiporters.  Plant Physiology 130:1054-1062.

(15)  2002.  T. Shigaki, C. Sreevidya, and K. Hirschi.  Analysis of the Ca2+ domain in the Arabidopsis H+/Ca2+ antiporters CAX1 and CAX3.  Plant Molecular Biology 50:475-483.

(14)  2002.  J. K. Pittman, T. Shigaki, N. -H. Cheng, and K. D. Hirschi.  Mechanism of N-terminal autoinhibition in the Arabidopsis Ca2+/H+ antiporter CAX1.  Journal of Biological Chemistry 277:26452-26459.

(13)  2002.  T. Shigaki and K. D. Hirschi.  Chimeric gene construction without reference to restriction sites.  BioTechniques 32:736-740.

(12)  2002.  N. -H. Cheng, J. K. Pittman, T. Shigaki, and K. D. Hirschi.  Characterization of CAX4, an Arabidopsis H+/cation antiporter.  Plant Physiology 128:1245-1254.

(11)  2002.  T. Shigaki and M. K. Bhattacharrya.  Nutrients induce an increase in inositol 1,4,5-trisphosphate in soybean cells: implication for the involvement of phosphoinositide-specific phospholipase C in DNA synthesis.  Plant Biology 4:53-61.

(10)  2001.  T. Shigaki, N. -H. Cheng, J. K. Pittman, and K. Hirschi. Structural determinants of Ca2+ transport in the Arabidopsis H+/Ca2+ antiporter CAX1.  Journal of Biological Chemistry 276:43152-43159.

(9)  2001.  T. Shigaki and K. D. Hirschi.  Use of Class IIS restriction enzymes for site-directed mutagenesis: variations on phoenix mutagenesis.  Analytical Biochemistry 298:118-120.

(8)  2001.  T. Shigaki, D. W. Gabriel, S. S. Patil, D. Borthakur, J. H. Choi, and A. M. Alvarez.  The blight-associated epitope and DNA fragment from Xanthomonas campestris pv. campestris are not required for blight.  Plant Biology 3:106-112.

(7)  2000.  T. Shigaki and K. D. Hirschi.  Characterization of CAX-like genes in plants: implications for functional diversity.  Gene 257:291-298.

(6)  2000.  T. Shigaki, S. C. Nelson, and A. M. Alvarez.  Symptomless spread of blight-inducing strains of Xanthomonas campestris pv. campestris on cabbage seedlings in misted seedbeds.  European Journal of Plant Pathology 106:339-346.

(5)  2000.  T. Shigaki and M. K. Bhattacharyya.  Decreased inositol 1,4,5-trisphosphate content in pathogen-challenged soybean cells.  Molecular Plant-Microbe Interactions 13:563-567.

(4)  2000.  T. Shigaki and M. K. Bhattacharyya.  Phosphate induces rapid H2O2 accumulation in soybean suspension cells.  Plant Biology 2:149-151.

(3)  1999.  T. Shigaki and M. K. Bhattacharyya.  Color coding the cell death status of plant suspension cells.  BioTechniques 26:1060-1062.

(2)  1998.  T. Shigaki, F. A. Gray, R. H. Delaney, and D. W. Koch.  Evaluation of host resistance and intercropping for management of the northern root-knot nematode in common sainfoin, Onobrychis viciifolia.  Journal of Sustainable Agriculture 12:23-39.

(1)  1994.  S. S. Gnanamanickam, T. Shigaki, E. S. Medalla, T. W. Mew, and A. M. Alvarez.  Problems in detection of Xanthomonas oryzae pv. oryzae in rice seed and potential for improvement using monoclonal antibodies.  Plant Disease 78:173-178.

Book Chapters

2016. T. Shigaki. Climate Change and Food Security in the 21st Century: Chapter 25, Application of biotechnologies in the conservation and utilization of plant genetic resources for food security. S. S. Yadav, R. Redden, J. L. Hatfield, A. W. Ebert, and D. Hunter, ed. Wiley-Blackwell International. (in preparation)

2015. T. Shigaki. Encyclopedia of Food and Health: Chapter 124, Cassava-the nature and uses. B. Caballero, P. Finglas, and F. Toldrá, ed. Elsevier.

Popular Articles

2011-2015. Regular contributor for the Papua New Guinean national newspaper The National (List of published articles available on request.).

Symposia And Workshops Organized

2016. Workshop on phytoremediation and sago decline and in Bougainville (Chair of the steering committee), funded by The Christensen Fund, Panguna and Arawa, Autonomous Region of Bougainville, Papua New Guinea, July 23-24, 2016.

2013. Workshop on sago decline in Bougainville (Chair of the steering committee), funded by The Christensen Fund, Arawa, Autonomous Region of Bougainville, Papua New Guinea, November 21, 2013.

2011. National symposium on sago in Papua New Guinea (Chair of the steering committee), funded by Papua New Guinea Sustainable Development Programme, Lae, Morobe Province, Papua New Guinea, July 14-15, 2011.

Invited Talks (recent talks only)

2016, May 17. “Development of LAMP kit for the detection of phytoplasma disease in coconut in Papua New Guinea.” at Lanzhou University, Lanzhou, China.

2014, May 14. “Management and improvement of plant genetic resources in Papua New Guinea and Solomon Islands.” at Riken, Wako, Japan.

2013, October 2. “Molecular breeding initiatives in Papua New Guinea and the Pacific.” at The World Vegetable Center (AVRDC), Shanhua, Tainan, Taiwan.

2013, April 16-17. “Biotechnology and biosafety in Papua New Guinea.” at Asia-Pacific Consortium on Agricultural Biotechnology (APCoAB), a program of the Asia-Pacific Association of Agricultural Research Institutions (APAARI), Bangkok, Thailand.