The New Zealand Institute for Plant & Food Research Limited
Timing in the plant kingdom
Erika Varkonyi-Gasic
The New Zealand Institute for Plant & Food Research Limited
http://www.plantandfood.co.nz/
PFR provides research and innovation to ensure
sustainable growth of plant and marine-based
industries
Plant and Food Research (PFR)
Mt Albert site
The New Zealand Institute for Plant & Food Research Limited
PFR science across portfolios
BREEDING & GENOMICS Building knowledge of key traits at the molecular level to inform the
development of new elite cultivars.
BIOPROTECTION Effective control of pest and disease to protect export market access.
SUSTAINABLE PRODUCTION Systems that increase efficiency and retain quality across the supply chain.
FOOD INNOVATION Identifying intrinsic health benefits in natural produce to develop new foods
and beverages.
SEAFOOD TECHNOLOGIES Optimising the value and quality of seafood and aquaculture.
The New Zealand Institute for Plant & Food Research Limited
Research sectors
Kiwifruit
Potato
Pipfruit
Cropping
Berryfruit
Vegetable
Summerfruit
Food &
beverage
Wine
Seafood
Environmental
Ornamentals
http://ketenewplymouth.peoplesnetworknz.info/image_files/0000/0002/5239/Actinidia_deliciosa__wild_Kiwifruit_-6.JPG
The New Zealand Institute for Plant & Food Research Limited
Fruits of our labor
The New Zealand Institute for Plant & Food Research Limited
The importance of timing
» Plants display a sessile life-style.
» They DO move but can’t escape.
» Need to grow in good conditions and survive adverse conditions.
» Coincidence of flowering with optimal conditions is a prerequisite
to successful sexual reproduction and the yield of seeds, grains
and fruit.
» Plants have evolved mechanisms to integrate environmental and
developmental cues to time their development and ensure
survival.
The New Zealand Institute for Plant & Food Research Limited
Plant life cycle
Seed
Vegetative
growth Death
Flower
• Plants that flower and fruit
only once and then die are
termed monocarpic or
semelparous.
• Annual plants complete their
life cycle within one year.
• Biennial plants take two years.
The New Zealand Institute for Plant & Food Research Limited
Mass flowering bamboos are considered to
be “bad omen“ followed by famine and a
great increase in rat population…
Bamboo flowers once in up to 130 years
The New Zealand Institute for Plant & Food Research Limited
Soft bamboo shoots, stems, and leaves are the major
food source of the giant panda of China, the red panda of
Nepal and the bamboo lemurs of Madagascar…
The New Zealand Institute for Plant & Food Research Limited
Plant juvenility
» Lack of reproduction under favourable environmental conditions
Amorphophallus titanum 'corpse flower‘ first flowering in7 years
The New Zealand Institute for Plant & Food Research Limited
Seed
Dormancy
Vegetative
growth Death
Flower
Perennial plants
• Most perennials are
polycarpic, flowering over
many seasons in their
lifetime.
• Dormant buds = mini
shoots with mini leaves
and flower initials
The New Zealand Institute for Plant & Food Research Limited
Ever-growing peach mutant – no dormancy
Bielenberg lab, Clemson, SC
The New Zealand Institute for Plant & Food Research Limited
Plants can respond to the environment
The New Zealand Institute for Plant & Food Research Limited
Plants can sense and respond to light
Photomorphogenesis
Germination
Shade-avoidance
Phototropism
Stomatal opening
Flavonoid synthesis
Growth and dormancy
The New Zealand Institute for Plant & Food Research Limited
Photoperiodic flowering
Tobacco ‘Maryland mammoth’
is a mutant, needs SD to flower
The New Zealand Institute for Plant & Food Research Limited
Plant photoreceptors absorb light
phototropins cryptochromes phytochromes
The New Zealand Institute for Plant & Food Research Limited
Mutant analysis reveals function of genes
Arabidopsis has 5 PHY and 2 CRY genes
• redundancy
• divergence (new functions)
http://www.yale.edu/dengl
ab/paper/Jigang2011.pdf
The New Zealand Institute for Plant & Food Research Limited
Summary of plant responses to light
Light-regulated transcriptional networks in higher plants Yuling Jiao, On Sun Lau & Xing Wang Deng Nature Reviews Genetics 8, 217-230 (March 2007)
http://www.yale.edu/denglab/paper/Jiao2007.pdf
http://www.nature.com/nrg/journal/v8/n3/full/nrg2049.htmlhttp://www.nature.com/nrg/journal/v8/n3/full/nrg2049.htmlhttp://www.nature.com/nrg/journal/v8/n3/full/nrg2049.html
The New Zealand Institute for Plant & Food Research Limited
trans
cis Pr
Pfr
Phytochrome forms have differential activity
inactive
active
Far-red
Light
Red
Light
Far-red
Light
Red
Light
Cellular response
Da
rkn
ess
fast
slo
w
The New Zealand Institute for Plant & Food Research Limited
Phytochrome activates gene transcription
The New Zealand Institute for Plant & Food Research Limited
Photoperiodic flowering in Arabidopsis
CLOCK
CO
LHA
CCA1
TOC1 GI
Photoperiod pathway
Light
External coincidence model
FT
Clock
regulated
CO
Flowering
inducer
FT
CO protein is
stabilized by light!
The New Zealand Institute for Plant & Food Research Limited
Florigen moves in the phloem
FT = florigen ATC = antiflorigen?
Similar to FT and
competes for the same
interacting partner
The New Zealand Institute for Plant & Food Research Limited
Flowering pathways in Arabidopsis
GA1, GAI,
RGA GA pathway
FCA, FY,
FLD, FVE,
FPA, LD, FLK
Autonomous pathway
CLOCK
CO Light
LHA
CCA1
TOC1 GI
Photoperiod pathway COLD
FLC
FRI, FRL1,
FRL2, VIP3,
VIP4, ART1,
PIE1, ESD4
VIN3
VRN1
VRN2
Vernalization pathway
FT SOC1 LFY
AP1 LFY CAL
Floral meristem identity
Floral pathway integrators
TOE1, TOE2,
SMZ, SNZ,
FLM, SVP,
TFL1, TFL2,
EMF1, EMF2
Ambient
temperature
Nutrient
status
Activators Represors
Floral pathway
integrators
Flowering
Environmental signals
>200 genes are regulating flowering in Arabidopsis.
The New Zealand Institute for Plant & Food Research Limited
SAM
A mutation in the GA pathway causes flowering
» Association of dwarfism and
floral induction with a grape
'green revolution' mutation
» Single nucleotide change in
GAI gene results in
development of
inflorescences instead of
tendrils in grape
Boss and Thomas, Nature 416, 847-850 (25 April 2002)
The New Zealand Institute for Plant & Food Research Limited
Importance of winter
The New Zealand Institute for Plant & Food Research Limited
Winter Wheat Planted Acres by County for Selected States, 2010
Spring Wheat Planted Acres by County for Selected State, 2010
Importance for food production
» Winter wheat represents 70-80 percent of total U.S. production.
» Sown in the fall for summertime harvest.
The New Zealand Institute for Plant & Food Research Limited
Importance for fruit yield
Sufficient winter chilling = synchronised budbreak = more fruit
The New Zealand Institute for Plant & Food Research Limited
- HC + HC
Environmental impact
Dormancy releasing chemicals necessary in NZ conditions.
The New Zealand Institute for Plant & Food Research Limited
Plants can sense and measure temperature
» Seed germination
» Winter dormancy
» Flowering time
… all depend on temperature
Different plants use different types of
genes/proteins as outputs of
vernalization, but the mechanism is
the same: repression of a repressor. A
repressor of FT is de-activated by
cold, resulting in FT florigen activation.
Pin et al, Science 2010
The New Zealand Institute for Plant & Food Research Limited
FLC inactivation in response to cold
FLC represses FT
transcription in the leaf
Very complicated
regulation involving
anti-sense RNA and
modifications in
histones (proteins
packaging DNA)…
The genetic basis of flowering responses to seasonal cues Fernando Andrés & George Coupland Nature Reviews Genetics 13, 627-639 (September 2012)
http://www.nature.com/nrg/journal/v13/n9/full/nrg3291.htmlhttp://www.nature.com/nrg/journal/v13/n9/full/nrg3291.html
The New Zealand Institute for Plant & Food Research Limited
FT can be used to accelerate breeding
Many, many years…
Large plants need space… FT promotes maturity (first flowering)
Transgenic plum
Plum tree
Scorza lab, Kearneysville, WV
The New Zealand Institute for Plant & Food Research Limited
EF 5
>5
Fast breeding (heat resistance example)
Years
MAS (marker-assisted selection)
The New Zealand Institute for Plant & Food Research Limited
FT genes have other roles: tuberization, bulb
formation, fruit yield…
35S:AcFT4
WT
The New Zealand Institute for Plant & Food Research Limited
www.plantandfood.co.nz
The New Zealand Institute for Plant & Food Research Limited
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