the moss- physcomitrella patens : a novel model system for plant development and genomic studies

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

OverviewOverview OverviewOverview

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]

[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)

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]

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

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 ]

[Knight.,2009]

[Michael Prigge et al., 2010]

Physcomitrella is well-placed phylogenetically to provide important comparisons with the flowering plants

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]

Sporophyte (2n)Spore (n)

Protonema (n)

Gametophore (n)

Gametophore Colony (n)

[Sung Hyun Cho.et al.,2007]

DNA barcodingDNA barcoding

Systems biology

Applied studies

Bryotechnology

biopharmaceutical

Abiotic stress tolerance

[Tomoaki Nishiyama et al.,2003]

BryologBryology y

[Anna K. Beike et al., 2010]

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]

Sequence-anchored

genetic linkage map for

the moss, P.patens has

been established

[Yasuko Kamisugi.,2008]

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]

Phytohormones like auxin , cytokinin,ABA and photomorphogenetic pigments are found to be intact in P.patens

[Cove et al., 2009]

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…

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]

[Jipei Yue., 2012]

Horizontal gene transfer

[HK Stenoien., 2005]

[Anna Beike et al ., 2010]

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.

Epigenetic regulation… Epigenetic regulation…

[Lihong Xiao et al .,2012]

[Bestor.,1988]

[Daniel Lang et al., 2008]

Culturing the mossCulturing 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]

Abiotic Stress tolerance in P.patens

[Anna Beike et al ., 2010]

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]

439 genes encoding transcription –associated proteins in response to salt stress and ABA was reported by microarray expression analysis

[Sandra Richard et al., 2010]

Breakthrough technology…

miRNA important regulators of gene expression for both plants and animals

miRNA families are found to be conserved in evolution

Genome-wide expression analyses in Arabidopsis - high specificity of amiRNAs

amiRNAs can be designed to target any gene of interest- functional gene analysis

Genome-wide expression analyses in Arabidopsis - high specificity of amiRNAs

amiRNAs can be designed to target any gene of interest- functional gene analysis

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]

LC-PUFAs important for human diet-C22 PUFAs

Marine fish and algal oils chief source

But…

High production cost,diminishing feed stock limit the supply

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….

[Pichit et al.,2012]

I. a.Osmotic stress treatments

Experimental evidences

[Wolf et al., 2005]

I.b.Dehydration treatment

Overexpression construct

PCR screen

II. Gene silencing by amiRNA

RACE PCR for amiRNA transgenic lines RNA gel blot analysis

[Basel Khraiwesh et al., 2008]

Structure of pMDC43-PsELO5

Primers used for PCR amplification

III. Metabolic engineering

Comparison of ADA and ɷ-3DPA production

ADA-2.3% and DPA -1.1% of total fatty acids

Southern blotting of P.patens

[Pichit et al.,2012]

IMSC

www.moss-stock-center.org

To conclude…

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

Dr.Meena kapoor University school of biotechnology,Guru Gobind Singh Indraprastha University, New Delhi

“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]

Discussion…