Kennen planten ook een puberteit?

Marcel Proveniers, Molecular Plant Physiology, UU

NIBI conferentie Hormonale en Neurale regeling, 15-01-2016

Puberty

http://www.uofmchildrenshospital.org/

“physical changes through which a child's body matures into an adult body capable of sexual reproduction to enable fertilization”

Puberty

Reproductive capability

Morphological changes:• Body size• Body shape• Body composition

Hormonal changes

http://www.uofmchildrenshospital.org/

Do plants go through puberty ?

Reproductive capability – floral competence

Adapted from Matsoukas, 2014

Reproductive capability – phase change

juvenile adult vegetative: vegetative phase change (VPC)

Reproductive capability – floral competence

Reciprocal transfer experiments: inductive non-inductive & v.v.

Reproductive capability – experimental

Reproductive capability – experimental

Juvenile vegetative (JVP)

Adult vegetative (AVP)

Reproductive (RP)

Morphological changes – trichome patterning

Telfer et al., 1997

Morphological changes – abaxial trichomes

Upside up Upside down

Arabidopsis thaliana - zandraket

Morphological changes – leaf size and shape

Hedera sp. - klimop

Syngonium podophyllum

Juvenile

Semi-juvenile (transition)

Adult

Morphological changes – leaf size and shape

Eucalyptus globulus

Juvenile leaves: rounded, symmetrical, opposite phyllotaxy

Adult leaves: elongated, asymmetrical, alternating phyllotaxy

Morphological changes – leaf size and shape

11Morphological changes – leaf size and shape

Acacia heterophylla

Poethig, 2010

Morphological changes – leaf size and shape

Juvenile

Adult

Reproductive

Morphological changes – thorns

Adapted from Peña et al., 2001

Carrizo citrange (Citrus sinensis L. Osbeck × Poncirus trifoliata L. Raf.)

Juv. Adult

Juv. Adult Juv.

Morphological changes – thorns

Ilex aquifolium - Hulst

Morphological changes - Composition

Wollemia nobilis - slangedenfamilie

Juvenile Adult

Juvenile Adult

Zea mays- maïs

Epidermal wax

Morphological changes - Others

Fagus sylvatica - Beuk

Leaf abscission (autumn vs spring)

Adult

Juvenile

Lawson and Poethig, 1995

Morphological changes - Others

Foto Niek Schrier

Quercus sp. - Eik

Leaf abscission (autumn vs spring)

Growing old, but staying young

Gradually growing old, but staying young

Puberty – Hormonal changes

Vegetative phase change – Hormonal changes?

Gibberellins

Evans & Poethig, 1996

Gibberellins promote vegetative phase change

Juvenile Adult

Zea mays- maïs

Gibberellins promote vegetative phase change

After gibberellin treatment:

20 yrs <2 yrs

Gibberellins promote vegetative phase change

Telfer et al., 1997

Upside up Upside down

ga1-3 = gibberellin biosynthesis mutant

… but GA levels do not increase during VPC…

Eriksson et al., 2006

Phase change is specified by miRNAs

Reprinted with permission from Bollman, K.M. Aukerman, M.J., Park, M.-Y., Hunter, C., Berardini, T.Z., and Poethig, R.S. (2003) HASTY, the Arabidopsis ortholog of exportin 5/MSN5, regulates phase change and morphogenesis. Development 130: 1493-1504.

HASTY encodes a protein needed for miRNA export from nucleus to cytoplasm hasty

Wild-type

Juvenile

Adult

Reproductive

Reprinted from Hunter, C., Sun, H., and Poethig, R.S. (2003) The Arabidopsis heterochronic gene ZIPPY is an ARGONAUTE family member. Curr. Biol. 13: 1734–1739, with permission from Elsevier.

ZIPPY (ZIP) encodes an ARGONAUTE protein, part of the RNA Induced Silencing Complex (RISC)

zippy

Wild type

Juvenile

Adult

Reproductive

Phase change is specified by miRNAs

“DNA makes RNA; RNA makes proteins”

Non-coding RNAs - microRNAs

Discover magazine

MIR genes are transcribed into long RNAs that are processed to miRNAs

• miRNAs are encoded by MIR genes

• primary miRNA (pri-miRNA) transcripts fold back into a double-stranded structure, which is processed by DCL1

•The miRNA* strand is degradedDCL

3'5' miRNA

miRNA*

3'5' pri-miRNA

miRNA

MIR gene

mRNA target

Translation inhibition mRNA cleavage

Some MIR gene families are present in all plants or all angiosperms

Cuperus, et al., 2011

These are conserved in all plants

These are conserved in all angiosperms

miR156

The MIR156 gene family is highly conserved

Reinhart et al., 2002

• miR156 is highly conserved

• miR156 is encoded by six or more genes in Arabidopsis

•miR156 targets transcription factors that control developmental phase changes

Vegetative phase change correlates with decrease in miRNA156

Coupland lab, Sara Bergonzi

Wang et al., 2011

Vegetative phase change correlates with decrease in miRNA156

Poethig, 2009

miR156 is necessary and sufficient for the juvenile vegetative phase

Juvenile

Adult

Reproductive

Gandikota et al., 2007

miR156 targets SPL transcription factors

SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) transcription factor proteins

miR156-resistant SPL promotes precocious phase change

Wu and Poethig, 2006

ORF 3’ UTRPromoter

ORFPromoter

ORF 3’ UTRPromoter

SPL3

SPL3Δ

SPL3m

miR156 binding site

Wild-type

miR156-resistant

miR156 SPL

miR156 SPL

Reprinted from Poethig, R.S. (2009) Small RNAs and developmental timing in plants. Curr. Opin. Genet. Devel. 19: 374-378, with permission from Elsevier.

miR156loss-of-function

miR156 OX

miR156 SPL

SPL

Wild-type

miR156 is necessary and sufficient for the juvenile vegetative phase

Juvenile

Adult

Reproductive

Wang et al., 2011

miR156 is necessary and sufficient for the juvenile vegetative phase

VPC involves a temporal cascade of miRNAs and transcription factors

miR156 SPL

miR172 AP2-like

Juvenile Adult Reproductive

MiRNAs Control of Vegetative Phase Change

MiRNA control of Vegetative Phase Change

How is timing of vegetative phase change regulated?

“the node at which vegetative phase change occurs is more closely correlated with the total number of nodes produced up until the transition point than with the height of the shoot or the duration of shoot growth”

Vegetative phase change is controlled by a factor that changes with leaf number

Developmental age versus Chronological age

Vegetative phase change is mediated by a leaf-derived signal

Yang et al., 2011

?

Sugar produced by photosynthesis as an endogenous developmental timing cue?

Yang et al., 2013

Yu et al., 2013

Sugar promotes vegetative phase change

ch1 mutant:low efficiency of photosynthesis

Yang et al., 2013

Yu et al., 2013

Sugar controls miR156 levels

Proveniers, 2013

Sugar is an endogenous cue for VPC

Discoveries.

Sugar May Trigger The Onset Of PubertyApril 30, 1995|By Ron Kotulak and Jon Van, Tribune Staff Writers.

The debate over whether sugar is good or bad for you may take a back seat to new findings by a University of Michigan researcher showing that glucose, the sugar we absorb from food, may trigger the onset of puberty. Scientists have long known that there is a relationship between reproduction and nutrition and it now seems that glucose may tell the brain that the body is well enough fed to begin producing sperm or eggs

University of Wisconsin-Madison study sees dietary tie to early puberty in girls (2012)

Sucrose, not fructose; up to 4 months earlier

Plant versus Human

Is that all?

VPC - Gibberellin revisited

DELLA proteins interfere with GA-dependent transcription factors

GA binding to its receptor and subsequent activation of gene expression

GA binding to its receptor and subsequent activation of gene expression

VPC - Gibberellin revisited

RAV family of transcriptional repressors

TEMPRANILLO 1&2 are regulators of juvenility in plants

Wild type tem1 tem2 mutantMatiás-Hernández et al., 2014

TEMPRANILLO 1&2 are negative regulators of gibberellin biosynthesis

TEM levels normalGibberellin normal

TEM levels increasedGibberellin low (locally)

Matiás-Hernández et al., 2014

Adapted from Spanudakis & Jackson, 2014

“Plant puberty” – interplay of sugar and hormones

Thank you for your attention!

M. Proveniers, UU, H.R. Kruytbuilding room O405; m.proveniers@uu.nl