Dissection of molecular mechanisms of leaf expansion and

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Dissection of molecular mechanisms of leaf
expansion and plant growth for improvement of
agricultural and bioenergy crops
Developmental biology for improvement of
agricultural and bioenergy crops Molecular and
genetic resources for genetic studies of
agronomical traits and Identification of
candidate genes associated with the desired traits
Rujin Chen (Samuel Roberts Noble Foundation) Jia
Li (University of Oklahoma) Ming Yang (Oklahoma
State University) Elison Blancaflor (Samuel
Roberts Noble Foundation) Richard Dixon (Samuel
Roberts Noble Foundation)
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• Important issues related to bioenergy and
  agricultural crop production
• Yield quantity economy
• Foliar area volume transportation, processing
  and digestibility
• Cell wall composition quality digestibility
  and processing

Rationale 1. Understanding how plant organ
size/growth is regulated may lead to improved
yield 2. Understanding how leaf expansion is
regulated may lead to desired foliar area 3.
Understanding how leaf/stem ratio and cell wall
components are regulated may lead to
improved quality

• Goals and Deliverables
• Screen and isolate Medicago truncatula mutant
  lines with desired growth and
• cell wall composition
• 2. In-depth physiological and biochemical
  analysis of isolated mutants
• In-depth analysis of gene expression between wild
  type and isolated mutants during
• vegetative and reproductive growth to identify
  candidate genes associated with
• desired traits
• Initiate and complete genetic mapping and cloning
  of selected mutants
• integrate identified candidate genes into marker
  assisted breeding programs
• to identify markers associated with
  agronomically important traits
• Disseminate results into public domains and into
  established outreach programs

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Expertise and resources
Rujin Chen - Auxin signaling leaf development
generated a large collection of Medicago
truncatula mutants
Ming Yang (OSU) - Cell cycle and transcription
factor regulation of plant growth
Control
35SCYCLIN
Jia Li (OU) Brassinosteroid signaling and
plant growth
Elison Blancaflor cell biology cytoskeleton
and cell wall enzymes
Richard Dixon Metabolic engineering for
improvement of alfalfa
bri1-5 bak1-1D
bri1-5
Control
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• A large collection of Medicago truncatula (a
  close relative of alfalfa) mutants have been
  generated
• at the Noble Foundation in the past several
  years. We propose to utilize this resources to
  isolate
• mutant lines with desired agronomical traits
  such as increased growth and reduced cell wall
• indigestible components for improvement of
  agricultural and bioenergy crops

Medicago truncatula mutant lines grown In a Noble
Foundation greenhouse
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Examples of mutants with desired agronomical
traits
M.t. cv Jemalong A17
big leaf mutant
narrow leaf mutant
Loss-of-function mutations in Big Leaf locus
resulted in increased dry weight (biomass) and
leaf areas and delayed senescence. Loss-of-fun
ction mutants in Narrow Leaf locus resulted in
greatly reduced leaf areas and biomass.
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Goals and deliverables (continued)

• In-depth analysis of isolated mutants in the
  following areas auxin-mediated growth
• processes cell cycle regulation
  brassinosteroid signaling cytoskeleton
  organization
• cell wall and secondary metabolite composition
• In-depth analysis of gene expression between wild
  type and isolated mutants during vegetative and
  reproductive growth to identify genes associated
  with the desired traits using Affymetrix Medicago
  Genome Array
• Initiate and complete genetic mapping and cloning
  of selected mutants
• integrate identified candidate genes into marker
  assisted breeding programs
• to develop markers associated with agronomically
  important traits in alfalfa
• Disseminate results into public domains and into
  the established outreach
• programs

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Participants (requests) Samuel Roberts Noble
Foundation (two postdoctoral fellows and one
technician) Rujin Chen (auxin signaling, leaf
development and genetics) Elison Blancaflor
(cell biology and cytoskeleton) Richard Dixon
(biochemistry and natural product engineering)
Malay Saha (marker development and marker
assisted breeding program) Yuhong Tang (manager
of microarray analysis facility) Jiangqi Wen
(manager of molecular and genetic resources
facility) University of Oklahoma (one Ph.D.
student) Jia Li (brassinosteroid signaling and
cell growth) Oklahoma State University (one
Ph.D. student) Ming Yang (cell cycle
regulation)