Kennen planten ook een puberteit? Marcel Proveniers, Molecular Plant Physiology, UU NIBI conferentie Hormonale en Neurale regeling, 15-01-2016
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/
Adapted from Matsoukas, 2014
Reproductive capability – phase change
juvenile adult vegetative: vegetative phase change (VPC)
Reciprocal transfer experiments: inductive non-inductive & v.v.
Reproductive capability – experimental
Reproductive capability – experimental
Juvenile vegetative (JVP)
Adult vegetative (AVP)
Reproductive (RP)
Telfer et al., 1997
Morphological changes – abaxial trichomes
Upside up Upside down
Arabidopsis thaliana - zandraket
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
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 - 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)
Gibberellins promote vegetative phase change
Telfer et al., 1997
Upside up Upside down
ga1-3 = gibberellin biosynthesis mutant
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
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
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
VPC involves a temporal cascade of miRNAs and transcription factors
miR156 SPL
miR172 AP2-like
Juvenile Adult Reproductive
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
Yang et al., 2013
Yu et al., 2013
Sugar promotes vegetative phase change
ch1 mutant:low efficiency of photosynthesis
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
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