Using Genetic Analysis to Understand How Trees Respond to Environmental Stress

Research Issue

Diagram illustrates delicate balance between carbon and nitrogen metabolism.Genetic analysis of organic compounds such as polyamines (which play multiple roles in cell growth, survival and reproduction) and phytochelatin (which defends trees from toxic heavy metals such as cadmium, mercury, lead and arsenic) can provide insights into how trees respond to environmental changes and stressors.

Our Research

Northern Research Station scientists are seeking to understand the biochemical mechanisms that regulate polyamine metabolism under normal and stress conditions. The objectives are to isolate, clone and characterize all polyamine biosynthetic genes that occur in response to chemical and physical stress, first in model plants and then in forest tree species. We will then genetically engineer these species with specific polyamine biosynthetic genes in order to study the roles of cellular polyamines in stress tolerance. In addition, we are evaluating how changes in a single metabolite can disrupt metabolite levels in all directly and indirectly interconnected pathways. This information will help scientists recognize resistant plants and sensitive plants based on their relative amounts of cellular polyamines, amino acids and phytochelatin.
In one study, research on the metabolism of the plant hormone ethylene has provided insights into polyamine metabolism in poplar cells with a breadth and accuracy previously unseen in any plant tissue research. The results have revealed a complex homeostatic (balance-seeking) mechanism at work for polyamine metabolism that involves several parts of the pathway operating in a coordinated manner.

Expected Outcomes

This research will enable scientists to develop more reliable biology-based tools for monitoring forest health, including a toolkit to help predict forest susceptibility to disease and stress.

Research Results

Majumdar, R.; Barchi, B.; Turlapati, S.; Gagne, M.; Minocha, R.; Long, S.; Minocha, S.C. 2016. Glutamate, ornithine, arginine, proline and polyamine metabolic interactions: The pathway is regulated at the post-transcriptional level. Frontiers in plant science 7.

Majumdar, Rajtilak; Minocha, Rakesh; Minocha, Subhash. 2015. Ornithine: at the crossroads of multiple paths to amino acids and polyamines. In: D'Mello, J.P.F., ed. Amino acids in higher plants. Osfordshire, UK: CABI: 156-176. Chapter 9.

Ma, Chuanxin; Chhikara, Sudesh; Minocha, Rakesh; Long, Stephanie; Musante, Craig; White, Jason C.; Xing, Baoshan; Dhankher, Om Parkash. 2015. Reduced Silver Nanoparticle Phytotoxicity in Crambe abyssinica with Enhanced Glutathione Production by Overexpressing Bacterial y-Glutamylcysteine Synthase. Environmental Science & Technology. 49(16): 10117-10126.

Minocha, Rakesh; Majumdar, Rajtilak; Minocha, Subhash C. 2014. Polyamines and abiotic stress in plants: a complex relationship. Frontiers in Plant Science. 5: article 175.

Shao, Lin; Bhatnagar, Pratiksha; Majumdar, Rajtilak; Minocha, Rakesh; Minocha, Subhash C. 2014. Putrescine overproduction does not affect the catabolism of spermidine and spermine in poplar and Arabidopsis. Amino Acids. 46(3): 743-757.

Lasanajak, Yi; Minocha, Rakesh; Minocha, Subhash C.; Goyal, Ravinder; Fatima, Tahira; Handa, Avtar K.; Mattoo, Autar K. 2014. Enhanced flux of substrates into polyamine biosynthesis but not ethylene in tomato fruit engineered with yeast S-adenosylmethionine decarboxylase gene. Amino Acids. 46(3): 729-742.

Majumdar, Rajtilak; Shao, Lin; Minocha, Rakesh; Long, Stephanie; Minocha, Subhash C. 2013. Ornithine: the overlooked molecule in the regulation of polyamine metabolism. Plant & Cell Physiology. 54(6): 990-1004.[with supplementary document].

Page, Andrew F.; Minocha, Rakesh; Minocha, Subhash C. 2012. Living with high putrescine: expression of ornithine and arginine biosynthetic pathway genes in high and low putrescine producing poplar cells. Amino Acids. 42(1): 295-308.

Puckett, Emily E.; Serpiglia, Michelle J.; DeLeon, Alyssa M.; Long, Stephanie; Minocha, Rakesh; Smart, Lawrence B. 2012. Differential expression of genes encoding phosphate transporters contributes to arsenic accumulation in shrub willow (Salix spp.). Environmental and Experimental Botany. 75: 248-257.

Mattoo, Autar K.; Minocha, Subhash C.; Minocha, Rakesh; Handa, Avtar K. 2010. Polyamines and cellular metabolism in plants: transgenic approaches reveal different responses to diamine putrescine versus higher polyamines spermidine and spermine. Amino Acids. 38:405-413.

Mohapatra, Sridev; Cherry, Smita; Minocha, Rakesh; Majumdar, Rajtilak; Thangavel, Palaniswamy; Long, Stephanie; Minocha, Subhash C. 2010. The response of high and low polyamine producing cell lines to aluminum and calcium stress. Plant Physiology and Biochemistry. 48:612-620.

Mohapatra, Sridev; Minocha, Rakesh; Long, Stephanie. 2009. Putrescine overproduction negatively impacts the oxidative state of poplar cells in culture. Plant Physiology and Biochemistry 47, 262-271.

Page, Andrew F.; Mohapatra, Sridev; Minocha, Rakesh; Minocha, Subhash C. 2007. The effects of genetic manipulation of putrescine biosynthesis on transcription and activities of the other polyamine biosynthetic enzymes. Physiologia Plantarum. 129: 707-724.

Research Participants

Principal Investigator

  • Rakesh Minocha, US Forest Service Northern Research Station, Senior Supervisory Plant Physiologist

Research Partner

  • Subhash C. Minocha, University of New Hampshire, Biological Sciences Department
  • Stephanie Long, US Forest Service Northern Research Station, Biological Sciences Technician and Lab Manager
  • Jeffrey W. Cary, USDA/ARS, Southern Regional Research Center Food and Feed Safety Research Unit
  • Rajtilak Majumdar, USDA/ARS, Southern Regional Research Center Food and Feed Safety Research Unit
  • Autar K. Mattoo, USDA-ARS, Sustainable Agricultural Systems Laboratory
  • Om Parkash (Dhanker), University of Massachusetts, Department of Plant Biology
  • Last modified: September 11, 2018