The Moss- Physcomitrella patens : A Novel Model System for Plant Development and Genomic Studies

The moss P.patens has been used as a versatile experimental model organism for the past 80 years and it falls in the division Bryophyta. Being relatively simple in morphology and it generates only few tissues that contain limited number of cell fates (Mark leech et al., 1993), it is extensively being undertaken by plant biologists on both basic and applied strategies covering major areas namely developmental biology, evolution, systems biology, biotechnology ,biodiversity etc., As the organism is predominantly haploid in nature, it is evident that it could allow to develop insights on straight forward investigation/understanding of plant systems and hence, it is amenable for genetic and molecular level studies (Cove., 2009). The availability of complete genome sequence information, genetic and physical map ease the utilization of P.patens in all most all the fields of biology (Yasuko Kamisugi., 2008). It is the only land plant with an efficient system of homologous recombination in its nuclear DNA by which specific gene targeting could be achieved and the strategy of loss of function mutants can be generated by RNAi approach. In this context, the functional genomics of P.patens helps in identifying novel genes which could be employed in metabolic engineering and stress tolerance like drought, salt and osmotic stress thus helps in improving the crop plant performance. Moreover, it serves as a valuable platform for the production of recombinant pharmaceuticals (Anna K. Beike., 2010) Thus, the transfer of novel genes from P.patens has a greater biotechnological impact and may help in better public acceptance. Hence, this presentation aims to confine the advantages of this model plant in plant molecular research by discussing its efficiency in reproduction, range of technologies applied, some interesting characteristic features behind this model and chosen case studies will establish the model behaving as a well-versed medium for wide variety of approaches

2. Introduction
Established models
Emerging model system
Species fact sheet
Timescale of evolution
Life cycle
Comparative studies
Drug production
Epigenetic regulation
Moss culture
Abiotic stress tolerance
Gene silencing
Metabolic engineering
Experimental evidences

Overview
Overview
OverviewOverview

3. Ultimate goal of modern biology-
relationship between biological
systems , presence and activity of
genes
Model systems serve as the
excellent platforms for exploring
the biological relationships and
functions
[Didier Schaefer.,2002]

5. [Cove et al., 1993]
Physcomitrella has been
developed as a model system to
study plant gene function
Versatile model
First established as a laboratory
experimental system in the
1920s by Fritz von Wettstein
(1924)

6. Bryophyta are the simplest
and ancient lineage of land
plants
It includes mosses, liverworts
and hornworts
The mosses and flowering
plants diverged more than 450
million years ago.


[Henrik Toft et al., 2009]

7. Models like Physcomitrella patens serves solving
inquisitive puzzles in plant biological systems

8. Kingdom Plantae
Plants Division Bryophyta
Mosses Subdivision Musci
Class Bryopsida -True mosses
Subclass Bryidae
Order Funariales
Family Funariaceae
Genus Physcomitrella Bruch & Schimp.
Species Physcomitrella patens
(Hedw.) Bruch & Schimp.
[Source:USDA.gov, NRCS ]

9. [Knight.,2009]

10. [Michael Prigge et al., 2010]
Physcomitrella is well-placed phylogenetically to provide important comparisons

with the flowering plants

11. Distinguishing features of Physcomitrella patens
P. patens is a monoecious moss- requires very simple
growth conditions
It is a terrestrial non vascular plant
Relatively simple morphology, with fewer cell fates
than in flowering plants.
[Mark leech et al .,1993]

12. Sporophyte (2n)
Spore (n)
Protonema (n)
Gametophore (n)
Gametophore Colony (n)
[Sung Hyun Cho.et al.,2007]

13. M98cldap srbi DNA barcoding
Systems biology

14. Applied studies
Bryotechnology
biopharmaceutical
Abiotic stress tolerance

15. [Tomoaki Nishiyama et al.,2003]

16. Bryology Bryology
[Anna K. Beike et al., 2010]

17. The assembled P. patens genome (511 Mb) -released by
the Joint Genome Institute
[Ralf Reski.,2005]
Transcriptomic analyses illustrate commonalities
among plant lineages in gene content, structure,
and regulation
[Ralph Quatrano.,2007]

18. Sequence-anchored genetic
linkage map for the moss,
P.patens has been established
[Yasuko Kamisugi.,2008]

19. One-quarter genome contains genes with no known function –key
to identify new and novel gene functions.
[David Cove.,2009]
More than 2,50,000 ESTs are available covering 95 % of moss
transcriptome

[Rensing et al., 2002]

20. Phytohormones like auxin , cytokinin,ABA
and photomorphogenetic pigments are
found to be intact in P.patens
[Cove et al., 2009]

21. A remarkable feature P.patens is its ability to
incorporate transforming DNA at targeted sites
-Homologous recombination
[Yasuko et al.,2006]
Efficient system for reverse genetics
[Strepp et al., 1998]
Versatility…

22. Genome analyses of the moss P.patens has revealed -57 families
of nuclear genes were acquired from prokaryotes, fungi or viruses
[Jipei Yue et al.,2012]

23. [Jipei Yue., 2012]
Horizontal gene transfer

24. [HK Stenoien., 2005]

25. [Anna Beike et al ., 2010]

26. Protoplasts of the moss P.patens easily regenerate into
protonema and therefore provide an ideal system to
explore how differentiated cells can be reprogrammed to
produce stem cells.wnrmoeoirlusom tyirbexu
Epigenetic regulation…
[Lihong Xiao et al .,2012]
[Bestor.,1988]

27. [Daniel Lang et al., 2008]

28. Intrnoducir Eisabb Culturing the moss
Continuous light from fluorescent tubes at an
intensity of between 5 and 20 W/m2
Either on solid and liquid culture
High capacity of regeneration
Axenic growth
Temperatures between 24°C
and 26°C

[Cove.,2005]

29. Abiotic Stress tolerance in P.patens
[Anna Beike et al ., 2010]

30. Tolerates water loss of up to 92% and were able to
recover successfully
Tolerates up to 350mM of NaCl and 500mM of sorbitol
P.patens is highly tolerant against drought, salt
and osmotic stress
[Wolf et al., 2005]

31. 439 genes encoding transcription –associated
proteins in response to salt stress and ABA was
reported by microarray expression analysis
[Sandra Richard et al., 2010]

32. Breakthrough technology…
miRNA important regulators of gene expression
for both plants and animals
miRNA families are found to be conserved in
evolution

33. Genome-wide expression analyses in
Arabidopsis - high specificity of amiRNAs
amiRNAs can be designed to target any gene
of interest- functional gene analysis

34. Tested for amiRNA function in Physcomitrella
Gene PpFtsZ2-1, which is required for chloroplast
division
PpGNT1 gene encoding an N-acetylglucosaminyl
transferase
amiRNA expression in P.patens
[Basel Khraiwesh et al., 2008]

35. LC-PUFAs important for human diet-C
22
PUFAs
Marine fish and algal oils chief source
But…
High production cost,diminishing feed stock limit
the supply

36. Metabolic engineering of an artificial pathway that
activates the production of C22-PUFAs in P.patens
Production of Docosatetraenoic acid (ADA) and n-3
docosapentaenoic acid (DPA)
Pavlova sp. Encodes D5-elongase
Transgenic P.patens with vegetable oil supplementation.
Requires a economic and sustainable source….

37. [Pichit et al.,2012]

38. I. a.Osmotic stress treatments
Experimental evidences

39. [Wolf et al., 2005]
I.b.Dehydration treatment

40. Overexpression construct PCR screen
II. Gene silencing by amiRNA

41. RACE PCR for amiRNA
transgenic lines RNA gel blot analysis

42. [Basel Khraiwesh et al., 2008]

43. Structure of pMDC43-PsELO5
Primers used for PCR amplification
III. Metabolic engineering

44. Comparison of ADA and -3DPA production
ɷ
ADA-2.3% and DPA -1.1% of total fatty acids

45. Southern blotting of P.patens
[Pichit et al.,2012]

46. IMSC
www.moss-stock-center.org

47. To conclude…

48. Moss researcher consortium (left to right): Stefan Rensing, Andy
Cuming, Tomoaki Nishiyama, Ralf Reski, Mitsuyasu Hasebe, Ralph
Quatrano, Brent Mishler, David Cove
Source: http://www.mossgenome.org/members.php

49. Dr.Meena kapoor

University school of biotechnology,
Guru Gobind Singh Indraprastha University,
New Delhi

50. “In the post-genomic era,……………..
to underline the most important contributions brought
to science and, further, to draw attention to
newcomers in the field, that are expected to fill up
the gaps and answer the most specific question we
face in biology,
………………………….is possible by the use of such “Classical
Plant Models”
[Daniel ., 2009]

51. Discussion…