Transcript ppt - Barley World

PBG430/530
Plant Genetics
The genetic basis and analysis of simply inherited traits:
• Examples including domestication, economic impact, +,+,+
Phenomena particularly important in plants:
• Examples including self-incompatibility, polyploidy , +,+,+
Genetics tools for manipulating plants (and other organisms):
http://www.nwfoodnews.com/2011/02/18/meet-the-sugar-beet/
• Examples
including linkage mapping, genome sequencing,
GMOs, CRISPR-CAS9, epigenetics, +,+,+
Barley domestication traits, the genes, and the mechanisms
Locus/alleles
Phenotype
Mechanism
Btr1,Btr2
Shattering/retention
Loss of function deletions
Vrs1
2-row/6-row
Loss of function deletions
Nud
Hull adherence
Loss of function deletions
Vrn1, Vrn2, Vrn3 Growth habit
Loss of function deletions
Ppd1, Ppd2
Loss of function deletions
Flowering time
Pourkheirandish et al., 2015
Economic impact and GMO:
Hybrid sugarbeet seed production in the Willamette Valley of
Oregon - gene flow with organic table beet
(Greg Loberg West Coast Beet Seed)
Beta vulgaris
2n = 2x = 18
~758 Mb (the haploid (n) genome size, by convention)
(ACH seeds)
(Harris seed )
Sugarbeet seed production in the Willamette Valley – 2017
• ~ 90+% Roundup Ready
• ~ $2,000/acre (gross)
Controlling gene flow to organic table beet
• Spatial separation and pinning
• RR sugarbeet - females only
For more on sugarbeet seed production see CSS450/460
Seed production:
Blue = male
Red = female
Seed production:
Blue = male
Red = female
Genotype: RR
Phenotype: resistant
Genotype: 00
Phenotype: susceptible
http://www.crystalsugar.com
Pair of homologous chromosomes
Each has R gene
Showing only 1 pair of the 9 pairs
of chromosomes (2n = 2x = 18)
Pair of homologous chromosomes
Each missing R gene
Showing only 1 pair of the 9 pairs
of chromosomes (2n = 2x = 18)
R
R
The “R”* locus (same position on
each homologous chromosome)
2 copies of the R gene; each copy is
one allele
0
0
The R locus (same position on each
homologous chromosome)
2 copies of the absence of the R gene;
each copy is one allele
More on the transgene conferring resistance to glyphosate
meiosis
R
Male
R
gamete
meiosis
R
R
0
Female
gamete
0
0
0
R
R
0
R0
R0
0
R0
R0
All F1 progeny plants are R0
Resistant (R is dominant to 0)
R
0
R
RR
R0
0
R0
00
F2 plants
3 Resistant: 1 susceptible
1 RR: 2 R0: 1 00
RR, Rr:
select a resistant type (if you want);
deal with gene flow (if you have to)
Phenomena: Polyploidy
Diploid (2n = 2x) to polyploid (2n = _x) - all in the wheat “family”
1 pair homologous chromosomes
0 sets of homoeologous chromosomes
AA
A A
VAVA
2n = 2x = 14
30,000 genes
Emmer wheat
2 pairs of homologous chromosomes
2 sets of homoeologous chromosomes
AABB
A ABB
3 pairs of homologous chromosomes
3 sets of homoeologous chromosomes
AABBDD
A ABBDD
VAVAVBVB
VAVAVBVBVDVD
2n = 4x = 28
60,000 genes
Durum wheat
2n = 6x = 42
90,000 genes
Bread wheat
2X
8X
Ploidy does not equal horsepower
Genetics tools: CRISPR-CAS9
Clustered Regularly Interspersed Short Palindromic Repeats
Genome editing: delete/add/modify genes
• Target gene sequence and information
• Cas 9 nuclease enzyme
• Guide RNA (gRNA)
• A technical explanation (optional for now):
http://www.sigmaaldrich.com/technical-documents/articles/biology/crispr-cas9-genome-editing.html#what-is
• An overview from an inventor (required):
https://www.youtube.com/watch?v=TdBAHexVYzc
Genetics tools: CRISPR-CAS9
A Naked (Barley) Promise?
Golden Promise barley
With a Nud gene knock-out
Taketa et al., 2008