Endophyte-assisted Tolerance of Salinity
Anthony Bird
Introduction: Salinity accumulation in water and soils for
agricultural use is one of the biggest issues faced today. It is estimated
that almost 397 million hectares are salt-affected. In another estimate,
12 million ha of irrigated land may have been lost due to salinity and
rising (FAO, 2008). Total damages to crops so far have totaled over $27
billion as of 2014 (Qadir, et. al., 2014). With the human population
continuing to rise, the necessity to have salt stress resistant crops
becomes more and more critical. Recent, extended droughts have
placed stress on water quality and availability for irrigation, and the
utilization of water with elevated saline content will become a critical
necessity. We are investigating whether or not the endophytes found
in marine plants can confer tolerance to elevated salinity in water to
corn.
Objectives:
Neil Fleck
Doty Lab
University of Washington
Fig.1 Port Susan Bay where sampled plants were
obtained
• Isolating and identifying the properties of endophytes
that may potentially confer salt tolerance to rice and
maize (Zea mays)
• Identifying marine plants with the most effective
endophytic communities.
• Investigate whether Zea mays displays improved
tolerance to a watering regime with elevated salinity.
Results: The maize that were inoculated with MSS2C and
MSR2C showed differences in shoot length between the
saltwater group and the freshwater group. The freshwater
group showed more robust growth in shoot and leaf length
to the saltwater group, though yellowing and stress looked
comparable. With this experiment still in progress as of the
time of this writing, final quantification of the results are
not possible.
Several promising strains of bacteria were plated from
isolations from the extract. Of most interest were the strains
isolated from PSB1, which showed the most variety of
strains matching previous experiments with S. perennis
(strains of which were used to inoculate the maize assay
detailed above). Colonies of PSB1 on MS-Salty showed
similar morphology to previous isolations done in earlier
quarters: small, circular, convex, white colonies that grew in
tight clusters. Two strains from that specimen were selected
for cryo preservation, one from the shoot (PSB1SB – PSB 1,
shoot, strain B), and one from the root, PSB1RA.
Fig. 2 PSB1RA and B which show very promising
growth on MGL medium.
Conclusions: This study shows that there are several strains
Methodology: Seven species of marine plants were
obtained from Port Susan Bay in the north Puget Sound region on the
4th of July weekend. These species were identified, extracts were
made of their roots, leaves, and shoots. These extracts were then
plated onto Murashige-Skooge medium with elevated salinity (MS
Salty) with the most promising colonies, PSB5SB, PSB1RA and PSB1RB,
further isolated on MGL and MS-salty and placed into cold storage for
inoculation testing on Zea mays at a later date.
Concurrently, Zea mays was inoculated with strains MSR2C and
MSS2C, endophytes that were extracted previously from Salicornia
perennis and a control group which was not. After watering with
elevated salinity and a control group which was not watered with
saline water, growth and general health was assessed.
Discussion: Differences in
growth of Zea mays inoculated with
MSR2C and MSS2C were inconclusive.
Two strains of endophytes isolated from
Salicornia Perennis’s roots showed great
promise as well as PSB5SB and PSB5RB
which were extracted from Phyllospadix
scouleri. Further investigation by
inoculation of Zea mays with additional
physiological testing is needed.
of bacterial endophytes in marine plants that show a degree of
halophilia. Further study as to their ability to confer salt tolerance to
inoculated plants requires further research and further investigation
into halophilic terrestrial species.
References:
Qadir, M., Quillérou, E., Nangia, V., Murtaza, G., Singh, M., Thomas, R., . . . Noble, A.
(2014). Economics of salt-induced land degradation and restoration. Natural
Resources Forum Nat Resour Forum, 282-295.
Food and Agriculture Organization of the United Nations, FAO.org. (n.d.). Retrieved
June 12, 2015, from http://www.fao.org/soils-portal/soil-management/managementof-some-problem-soils/salt-affected-soils/more-information-on-salt-affected-soils/en/