National Wetlands Newsletter, vol. 31, no. 1. Copyright © 2009 Environmental Law Institute.® Washington D.C., USA. Reprinted by permission of the National Wetlands Newsletter. To subscribe, call 800-433-5120, write [email protected], or visit http://www.eli.org.

Improving Wetland Plants: A Good, Bad, or an “It Depends” Idea? By Jack Gallagher Wetlands provide a number of benefits to the environment and to society generally. Should we try to enhance those benefits through the genetic modification of wetland plants? Below, the author looks at scenarios that give rise to the need for improved wetland plants and the techniques for doing so.

istorically, wetlands have at times been held in high There are several situations where we may need genetic strains esteem and in others decried as sources of evil and different from those that have historically dominated a particular illness. We are now in one of the golden ages of wetland. Likewise, there are several techniques that can be used to wetlands. They are protected by laws at the national develop new lines of plants that may satisfy these needs. The partic- Hand state levels and declared to be treasures of the planet at the ular techniques used will depend on the plant species and the char- international level. Real estate agents brag of their beauty and acteristics needed. The environmental issues and risks will depend marsh-front lots bring a premium price. On the whole, members on the methods, the genes involved, and the environmental setting. of our society are very aware of wetlands’ contribution to the well being of the biosphere and they support efforts to maintain and Situations restore their functionality. Restoration Plants of course play a keystone role in the ecology of these The restoration of wetland functions in degraded sites, where ecosystems (Seliskar et al. 2002) in determining the flow of en- there are disturbances (natural or human-caused) that cannot be ergy, the cycling of elements, and the structure of the habitat fully rectified even with a high expenditure of money, is one situ- for other organisms. The gene combinations that various plants ation in which gene manipulation may be warranted. Damage re- have evolved define a suite of organisms that interact with oth- sulting from burial with fill, water deprivation brought about by ers (bacteria, fungi, invertebrates, and vertebrates) in ecological blocked creek flow, and injury produced by chemical pollution are dances that produce a diversity of wetland ecosystems valued by challenges that happen on the scale of living memory. On a lon- human societies. The unique anatomy and physiology associated ger time scale, drying or drowning eliminates coastal wetlands as with each plant species and their underlying variations influences sea level adjusts, as do inland wetlands as rainfall and evaporation the functioning of the ecosystem and the degree to which society patterns shift. Ice burdens from glacier evolution instigate geo- places value on the wetland. Is the wetland a breeding or nursery logic responses that alter hydrologic conditions in soils through ground for living marine resources such as crabs, fish, or shrimp? elevation adjustment. On an even longer term, historical climate Is it functioning as a foraging area for adults and as a buffer to change and changes in sea level have resulted in wide swings in the absorb runoff from uplands, as well as to absorb wave energy from quantity and types of wetlands. Now, with evidence that changes the open water? will occur more rapidly in the future, significant restructuring of Given our present appreciation of wetlands and the plants the coast will be evident within the living memory of our current that reside there, should we improve wetland plants, for example, population. In cases where we can make a difference, we need through genetic engineering? What is wrong with them the way to consider wetland plant genotypes that will thrive under sub- they are? Why would someone want to develop wetland plants optimal conditions and even improve the conditions to the point with characteristics different from the wild ones that we have come where the local wild types can grow once again. to appreciate? After all, they have evolved very efficient structur- al, physiological, and biochemical features for coping effectively Wastewater Treatment with the stresses. Their upland counterparts are not adapted to A second reason to develop wetland plants with characteristics compete in these stressful environments of soft, anaerobic, and in different from the wild types in a given location is to take ad- many cases saline soils they call home. vantage of the plants’ native qualities, such as flooding and sa- linity tolerance, while enhancing other traits to help solve some of societies’ problems not related to the functioning of natural Dr. John (Jack) Gallagher is a Professor of Marine Biosciences at the wetlands. These uses may be far-away from the natural wetlands. University of Delaware College of Marine and Earth Studies. He is on For example, common reed (Phragmites australis) is used for dry- the Scientific and Technical Advisory Committee of the Partnership for ing biosolids from wastewater treatment plants, but modification the Delaware Estuary and Co-Director of the Halophyte Biotechnol- of some of its features would enhance its performance and expand ogy Center. the geographic range of its use. Cattails (Typha spp.) are used for

10 national wetlands newsletter wastewater and acid mine waste treatment and also might be func- need to be improved. Plants with the desired characteristics may tionally improved and altered to decrease invasive potential. be obtained by following one or more of several protocols.

Saline Agriculture Selection Thirdly, some grasses, especially those having both flood and salt Variants with the desired traits may be found by searching nearby tolerance, have potential as pasture, hay, and turf grasses in many wild populations of the same species for naturally occurring muta- unproductive saline uplands and locations where only saline water tions. Ecologically, this is the least controversial source since the is available for irrigation (Gallagher 1985). Some dicots (a type genotype is already present in local ecosystems. If the desired char- of flowering plant) have potential for use as vegetables, such as acteristics are not present locally, more distant populations may Atriplex triangularis, which is spinach-like (Gallagher and Seliskar be examined. In the case of a restoration project, the argument 1993). Another dicot of interest is seashore mallow (Kosteletzkya against bringing in genotypes of the same species from a distant virginica) that produces an oil seed with both biofuel and feed location is that the introduction of a new genotype into the re- potential (Ruan et.al. 1008). Thus, saline agriculture development stored wetland may shift original zonation patterns or food web prompted by the shortage of freshwater for irrigation presents a functioning and spread into adjacent wetlands that are function- third situation where there is a reason to genetically modify salt- ing normally. Accordingly, there should be good ecological reasons tolerant wetland plants to have better crop characteristics, such for proposing to bring in such plants based on the local conditions. as more seeds, larger leaves, or different chemical composition. The fundamental understanding of the interactions of the plants These conditions occur along coasts, in naturally occurring saline with the abiotic and biotic components of the ecosystem is criti- land areas with brackish aquifers, and in former agricultural fields cal in making the decision about if and what is to be introduced. where improper irrigation led to salinization. One positive example is the use of variants that have a higher root to shoot ratio to initiate the restoration of a site where the soil is Phytoremediation very low in organic matter (Seliskar and Gallagher, 2000). These Fourth, there are situations where wetland soils have become con- plants will quickly add organic sources for the edaphic food web taminated. One “restoration” approach could be to cap the site with and alter the physical and chemical properties of the soil, thereby clean soil to prevent the spread of the contaminant; however, this enhancing greater structural and functional complexity. Such sys- will alter the hydrology such that the wetland will be lost and an tems have greater resiliency to environmental stress than wetlands upland community produced instead. Another approach is to dig that are deficient in microbial, algal, and animal components. out the contaminated material and rebuild the wetland from the Where needed, selection of plant varieties to drive the devel- soil up. This approach totally destroys the marsh for a protracted oping marsh toward higher function has great potential, but some time and is very expensive. In light of these problems, the idea of detractors are concerned that the loss of heterogeneity from using using the extensive root system of the plants to forage for the con- a narrower gene pool found in a selected line might endanger the taminants in the soil, take them up into the roots, and transport wetland in the long term if environmental factors change. Never- the toxic material to the above-ground parts of the plant where it theless, if future conditions change and become unfavorable for can be harvested and removed from the scene is an attractive one, the planted line, the wetland will have had a period with high in- both ecologically and economically (Raskin 1996). Another option put to the soil and the marsh soil ecosystem will have experienced is to have the plant sequester the material out of circulation in the rapid development. Nearby wetlands can then provide numerous root system. The plant chosen for gene manipulation will depend unselected propagule sources to replace the faltering plants of the on the remediation option chosen, due to differences in physiol- selected type. In severely damaged wetlands the choice may be to ogy. For example, P. australis sequesters more metals belowground use very special selections or declare the area a loss. For example, than Spartina alterniflora, while the latter releases more from the if climate change and the consequent sea level rise rate are faster leaves via salt excretion (Weis and Weis 2004). than the local plant genotypes and sediment sources can compen- sate for, a plant line with a high root-to-shoot ratio may be the Techniques only way to maintain the area as a wetland (Seliskar 1998). The methods that wetlands biologists rely on to develop improved wetland plants with special features all have their roots in the Breeding methods developed for agricultural crops. In instances where it would be advantageous for characteristics The first step is to understand how wetland plants function found in two different individuals to be combined, a breeding within themselves and within the ecosystem. That knowledge can program may make it possible to combine them in a new line then be applied to the four situations where there are compelling if the two are sexually compatible. It may be that the particular reasons to seek plants with different genetic characteristics: difficult combination hasn’t happened naturally because the distribution restoration conditions where local genotypes won’t thrive; waste- is discontinuous or because they are too far apart. For example, S. water treatment and biosolids-drying applications where function alterniflora plants in Maine and Georgia have different character- and invasiveness need to be addressed; saltwater agricultural enter- istics that may be useful to try to combine, such as stem density prises where crop characteristics need to be enhanced; and contam- and stem height. Even if grown in a common garden they will not inated soil remediation efforts where plant uptake and transport naturally cross (breed) because they do not flower at the same time

January-February 2009 11 (Somers and Grant 1981) due to different responses to day length. which a genetic change occurs could be the beginning of the next It would be necessary to manipulate these to achieve synchrony. whole plant. Thus, nothing unnatural is produced, only the likeli- If the needed characteristics aren’t found in the wild or the hood of it being captured and expressed is enhanced. This process within-species crosses are not compatible, more technical ap- is not directed toward any particular change and, thus, finding a proaches will need to be taken and the arena moves from the field desired change in a regenerated plant requires the examination of to the laboratory. many regenerated plants. A green and white striped form of P. australis, which is useful Tissue Culture in drying sludge, is an example of a somalclonal variant of value. The protocols for culturing wetland plants may be straightforward Because of its markings, this variant can be identified if it escapes or very complex and time consuming (Wang et al. 2007). But from the treatment plant and the wastewater agency held respon- once a protocol is established for a species it can be useful for sible for its eradication; likewise, if the species shows up in green several purposes. For example, the diversity of genotypes of each form in a place previously free of P. australis, the treatment plant wetland plant species can be preserved for use in restoration. Tis- will not be responsible (Seliskar 2007). sue culture can be very helpful in this endeavor because hundreds The need for large numbers of plants can be greatly reduced of lines of a particular species can be held in vitro in a single refrig- when looking for certain characteristics, such as resistance to sa- erator and then brought out and multiplied for use at a later date. linity or other chemical or physical conditions, by transferring Unlike selection, breeding, and tissue culture procedures, where the changes only involve alterations in the genome of the species of the plant being manipulated, changes initiated by genetic transformation may include genetic material from several other organisms.

Another example is where an embryo host plant is incompatible the cell culture into a media with high levels of the factor. Only with the hybrid embryo. In this case, the embryo is excised from those cells that have genetically changed will grow on the media. the host parent and grown to a plantlet on artificial media before However, this does not always result in whole plants being more being transferred to soil. This procedure is no different from usual tolerant, since many characteristics are the result of integrating breeding except that the crosses can bypass barriers of incompat- processes in organs and/or between organs (Li et al. 2006). As ibility that block the cross in the wild. with any “improved” plant one must be careful about what is re- In cases where the desired characteristic is not found in the leased into the wetland; it may thrive too well and become an wild, tissue culture can be used to capture somaclonal variance invasive pest. generated in plant cell cultures. This procedure involves inducing callus tissue (undifferentiated cell growth) from vegetative or re- Genetic Transformation productive tissue and growing it on sterile artificial media. After Unlike selection, breeding, and tissue culture procedures, where a period of callus growth, the media composition is changed to the changes only involve alterations in the genome of the spe- induce the regeneration of whole plants. These induction media cies of the plant being manipulated, changes initiated by genetic and protocols are modifications of those developed for agricultural transformation may include genetic material from several other plants. Few wetland plants have agricultural relatives from which to organisms. In these cases, foreign genes are introduced using one draw the protocols and those that do are seldom directly transfer- of several techniques. Particle guns (Li and Gallagher 1996) or able from agriculture. bacterial vectors_+_, such as Agrobacterium tumefacisens (Rao et Some people are concerned that the resulting plants are un- al.1997, Nandakumar et al. 2007) are typically used to introduce natural since the phenotype was not found in the wild. However, specific genes from other species. The introduced material may its absence is not due to it being a change that could only have involve combinations of viral, bacterial, animal, or plant genetic occurred in tissue culture, but because the chances of it being ex- material; hence, a genetically engineered plant is one that nature pressed in the next generation are rare. Should the genetic change could not have produced. The capability to make new combina- occur anywhere in the whole plant in the field other than in the tions by this method plus the ability to make changes specific in reproductive tissue, it would not be incorporated into the seed form or function give genetic transformation technology unique and passed on. In the case of the callus culture, any of the cells in power in the development of plant lines for specific uses. Yet with

12 national wetlands newsletter these opportunities come more risks, as discussed below. Conclusion Organic and toxic element pollution offers an opportunity In most situations there is no need to “improve” wetland plants in a for phytoremediation whereby genetic engineering is used to de- given location. However, climate change and an increasing human velop plants that more efficiently clean up the environment (Mea- population are placing more pressure on the existing wetlands, gher 2000). Depending on the plant, element, and environment, and demands for use of the genetic features of wetland plants to the strategy is to hold the toxin in the belowground tissue or move solve intensifying social problems are on the rise. Difficult restora- it to the shoots and perhaps out into the atmosphere as a volatile tion cases and the threat of extensive loss of wetlands due to sea compound (Pilon-Smits and Pilon 2002). An uptake and volatil- level rise often call for enhanced wetland plant varieties. Waste- ization remediation strategy is used for selenium runoff diverted water treatment, phytoremediation, and halophyte agriculture to constructed wetlands from farmlands. There, bacteria in the for food, feed, and biofuel production often require features not rhizosphere of the extensive root system of the wetland plants use common in the wild types of wetland plants. These varietal needs root compounds for energy sources and volatilize the selenium can be met by selection, breeding, tissue culture, and genetic engi- into non-toxic dimethyl selenide that is carried away in the atmo- neering. Environmental concerns about the first three techniques, sphere. Currently, created wetland systems are most active during which are the most familiar, are primarily about invasiveness and the warmer months. Researchers are considering how genetically require testing, judicial handling, and built-in safeguards when engineered plants might enhance volitization rates throughout the possible. Diversity concerns must also be considered in restoration year (Yang 2003). uses. Genetic engineering, however, is the area where we have the Explosives-contaminated groundwater and soils are other least experience. A thorough knowledge of wetland function and situations where phytoremediation is useful for decontaminating reproductive biology of the plants involved will enable wetlands military sites. A group of wetland and aquatic plants was screened biologists to foresee the consequences of using transgenic plants by Best et al. (1998) for their ability to remove TNT from ground- near or in wetlands. water. Carex vulpinoidea (fox sedge) was one of the plants evalu- ated. At some point a plant like fox sedge might be the subject for References transformation to improve its degradation ability. Best, E.P.H., M.E. Zappi, H.L. Fredrickson, S.L. Sprecher, S.L. Larson, and M. As is done in traditional crops, it may be desirable to stack Ochman. 1997. Screening of aquatic and wetland plant species for phytore- several transgenes in halophytic crops derived from wetland mediation of explosives-contaminated groundwater from the Iowa Army plants. It is important to consider possible risks, however. Say, for ammunition plant. In: Bioremediation of Surface and Subsurface Contami- nation, Book Series: Annals of the New York Academy of Sciences 829: 179- example, transgenic plants with an insecticide for Lepodopterians 194. (i.e., butterflies, moths) and resistance to several herbicides were Eastham, K. and J. Sweet. 2002. Genetically modified organisms (GMOs): The grown near natural wetlands. There would be a good chance that significance of gene flow through pollen transfer. Environmental issue report No. 28, European Environment Agency. the transgenic plants would escape into the natural wetlands. The Gallagher, J.L. 1985. Halophytic crops for cultivation at seawater salinity. Plant herbicide resistance would have little impact on ecosystem func- and Soil 89: 323‑336. tions in the natural wetlands. However, the naturally occurring, Gallagher, J.L. 1995. Biotechnology approaches for improving halophytic crops: somaclonal variation and genetic transformation. In: Biology of Salt-Toler- insect killing BT gene from a bacterium might increase the fit- ant Plants, M.A. Khan and I.A. Ungar (Eds.), pp. 397-406. Department of ness of the plant if susceptible insects were a factor in growth and Botany, University of Karachi, Karachi, Pakistan. reproduction of the plant. Aside from the fear that the transgenic Gallagher, J.L. and D.M. Seliskar. 1993. Selecting halophytes for agronomic value: Lessons from whole plants and tissue culture. In: Strategies for Utilizing Salt- plant might be an aggressive type, there is concern that an added Affected Lands, L. Moncharoen (Ed.). Funny Publishing Limited Partner- gene might escape to wild individuals of the same species or close ship, Bangkok, Thailand. pp. 414-425. relatives of the altered plants. This has been a concern with crop Li, X. and J.L. Gallagher. 1996. Expression of foreign genes, GUS and hygromy- cin resistance, in the halophyte Kosteletzkya virginica in response to bom- plants and their wild relatives. For example, if the BT gene from bardment with the Particle Inflow Gun. Journal of Experimental Botany 47: bacteria is inserted into a crop plant, it could possibly end up in 1437-1447. a close wild relative via out-crossing. Thus, the wild plant would Li, X., D.M. Seliskar, and J.L. Gallagher. 2006. Cellular responses to salinity of two coastal halophytes with different whole plant tolerance: Kosteletzkya vir- be producing its own insecticide for Lepodopterians, thus possibly ginica (L.) Presl. and Sporobolus virginicus (L.) Kunth. In: Ecophysiology of upsetting the natural ecosystem. If an herbicide-resistant gene is High Salinity Tolerant Plants, M.A. Khan and D.J. Weber (Eds.), pp. 187- placed in the plant, it could outcross and produce an herbicide- 200. Springer Publishers, the Netherlands. Meagher, R.B. Phytoremediation of toxic elemental and organic pollutants. 2000. resistant weed. This is not so much of an issue where the plant is Current Opinion in Plant Biology 3: 153-162. a sophisticated crop plant (corn and soybeans) since they usually Nandakumar. R., L. Chen, and S.M.D. Rogers. 2007. A stable and reproducible don’t have close wild relatives nearby and are so specialized that transformation system for the wetland monocot Juncus accuminatus (bul- rush) mediated by Agrobacterium tumefaciens. In Vitro Cellular and Develop- they only survive where we pamper them. However, with rape- mental Biology—Plant 43: 187-194. seed (canola), there is a high risk of crop to wild relative crosses Pilon-Smits, E. and M. Pilon. 2002. Phytoremediation of metals using transgenic since there may be cross-compatible wild relatives growing nearby plants. Critical Reviews in Plant Sciences 21: 439-456. flowering in synchrony (Eastham and Sweet 2002). In the case of a wetland species with transgenes planted near the same wild type species in a wetland, the opportunity for gene flow to the wild Continued on page 22 type could be high.

January-February 2009 13 Gallagher, continued from page 13 Medley & Scozzafava, continued from page 9

Rao, J.D., D.M. Seliskar, and J.L. Gallagher. 1997. Shoot regeneration and Agro- Rothrock, P.E. 2004. Floristic Quality Assessment in Indiana, the Concept, Use, and bacterium-mediated genetic transformation of seashore mallow. 1997 Con- Development of Coefficients of Conservatism. Taylor University, Upland, IN. gress on In Vitro Biology, Washington, D.C., June. In Vitro 33 (3), Part II, Scozzafava, M. E., T. E. Dahl, C. Faulkner, and M. Price. 2007. Assessing status, p. 56A. trends, and condition of wetlands in the United States. National Wetlands Raskin, I. 1996. Plant genetic engineering may help with environmental cleanup. Newsletter 29:24-28. Proceedings of the National Academy of Science 93: 3164-3166. Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region, 4th Edition. Ruan, C.J., H. Li, Y.Q. Guo, P. Qin, J.L. Gallagher, D.M. Seliskar, S. Lutts, and Indiana Academy of Science, Lisle, IL. G. Mahy. 2008. Kosteletzkya virginica, an agroecoengineering halophytic spe- Swink, F., and Wilhelm, G. (1979). Plants of the Chicago region. Morton Arbore- cies for alternative agricultural production in China’s east coast: Ecological tum, Lisle, IL. adaptation and benefits, seed yield, oil content, fatty acid and biodiesel pro- Taft, J.B., G.S. Wilhelm, D.M. Ladd, and L.A. Masters. 1997. Floristic Quality perties. Ecological Engineering 32: 320-328. Assessment for Vegetation in Illinois: A Method for Assessing Vegetation Seliskar, D.M. 1998. Natural and tissue culture-generated variation in the salt Integrity. Erigenia, 15:3-95. marsh grass Sporobolus virginicus: Potential selections for marsh creation and Vadnais, Jeannine. Personal communication, August 26, 2008. restoration. Hort Science 33: 622-625. Vance, Linda. Personal communication, August 11, 2008. Seliskar, D.M. 2007. Phragmites australis: A Closer Look at a Marsh Invader. A Del- White, Deborah. Personal communication, August 11, 2008 aware Sea Grant Bulletin, University of Delaware Sea Grant College Program. Seliskar, D.M. and J.L. Gallagher. 2000. Exploiting wild population diversity and somaclonal variation in the salt marsh grass Distichlis spicata (Poaceae) for marsh creation and restoration. American Journal of Botany 87: 141-146. Euliss et al., continued from page 5 Seliskar, D.M., J.L. Gallagher, D.M. Burdick, and L.M. Mutz. 2002. The regula- tion of ecosystem functions by ecotypic variation in the dominant plant: A References Spartina alterniflora salt marsh study. Journal of Ecology 90: 1-11. Somers, G.F. and D. Grant. 1981. Influence of seed source upon phenology of Euliss, N. H., Jr., L. M. Smith, D. A. Wilcox, and B. A. Browne. 2008. Linking flowering of Spartina alterniflora Loisel. and the likelihood of cross pollina- ecological processes with wetland management goals: charting a course for a tion. American Journal of Botany 68: 6-9. sustainable future. Wetlands 28: 553-562. Von der Lippe, M. and I. Kowarik. 2007. Crop seed spillage along roads: a factor National Research Council. 2002. Riparian Areas: Functions and Strategies for of uncertainty in the containment of GMO. Ecography 30: 483-490. Management. Wang, J., D.M. Seliskar, and J.L. Gallagher. 2003. Tissue culture and plant regen- National Research Council. 1995. Wetlands: Characteristics and Boundaries. eration of Spartina alterniflora: Implications for wetland restoration. Wet- National Resources Conservation Service (NRCS). CEAP National Assessment: lands 23: 386-393. Wetlands, at http://www.nrcs.usda.gov/TECHNICAL/NRI/ceap/wetlands. Weis, J.S. and P. Weis. 2004. Metal uptake, transport and release by wetland html (last visited Dec. 10, 2008). plants: implications for phytoremediation and restoration. Environment In- Smith, L.M., N. H. Euliss, Jr., D. A. Wilcox, and M. M. Brinson. 2008. Applica- ternational 30: 685-700. tion of a geomorphic and temporal perspective to wetland management in Yang, S. 2003. Wetlands clean selenium from agricultural runoff. Berkeleyan. North America. Wetlands 28: 563-577. http://berkeley.edu/news/berkeleyan/2003/01/22_selen.html. Wilcox, D.A. 2008. Education and training of future wetland scientists and manag- ers. Wetlands 28: 578-584.

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