1what actively transports auxin?
PIN proteins
2What is TIR1?
major auxin receptor, part of SCF complex
3What are ARFs?
transcription factors that form heterodimers to bind DNA and activate or repress target gene expression
4What is MP?
an ARF protein that mediates embryo axis formation and vascular development.
5What allows MP to activate?
high auxin levels to degrade BDL
6What does TMO7 protein do?
moves to the hypophysis and to vascular cells, contributing to MP-dependent root formation
7MP targets ______
TMOs and PIN1
8when does the apical-basal axis initiate?
zygote to 1 cell division stage
9Radial Axis initiates at the
8 cell to 16 cell division
10TMO5 and LWH activate ______, which starts ________
LOG, cytokinin biosynthesis
11Radial axis establishes
outer versus inner tissue layers and vascular identity
12what are the 2 main functions of SAM?
generate leaves, stems and flowers, and maintain stem cell reservoir
13What is a determinate meristem, and give 1 example
forms a predictable number of organs, floral meristems
14what are indeterminate meristems, and give an example
forms an unspecified number of lateral structures that cannot be predicted, SAM
15what are the meristem zones and what do they do?
CZ: stem cells, PZ: transition region, RZ: maintains stem cells above, contributes to stem formation below
16What is the tunica-corpus concept?
tunica is the outer layer and divides anticlinal (perpendicular), corpus is the inner layer and divides periclinaly (parallel)
17what are chimeras used for?
to analyze which meristem cell layers contribute to which organ tissues
18L1 in arabidopsis produces the
epidermis
19L2 in arabidopsis creates
mesophyll cells and flower reproductive tissues
20L3 in arabidopsis generates
vasculature and interior cells
21How is polyploidy used to prove cell communication between layers?
polyploid cells are twice as big; cells in other layers divide faster to compensate for the larger cell size in another layer
22What is WUS function?
maintain stem cell reservoir
23What is CLV function?
restrict the stem cell reservoir
24what do wus/clv double mutants look like?
same as wus mutant: establish but cannot preserve their stem cell populations
25where is WUS expressed?
organizing center (L3 in RZ); beneath stem cells
26where is CLV3 expressed?
stem cells
27where is CLV1 expressed?
organizing center
28what does over-expressing CLV3 do?
terminates stem cell activity and WUS expression
29ectopic WUS expression in roots activates ____ and induces ____
CLV3 expression, formation of shoot tissues
30how does WUS move from the OC to the stem cells?
through the plasmodesmata
31What are HAM genes?
transcription factors expressed in the PZ and OC that promote SAM activity
32What does HAM activity prevent, and how?
expression of CLV3 in the OC by binding to WUS
33clv mutants have
enlarged IFMs and increase in fruit and seed yield
34what technique enables neo-domestication?
CRISPR-Cas9 editing
35cytokinin is important for _____ formation because it promotes _______
SAM, cell division
36GA promotes ________, so it is antagonistic to ________
cell elongation and differentiation, SAM function
37auxin plays a key role in ____, __________, and ___________
root growth, lateral organ primordia positioning, outgrowth from the SAM
38CKs are involved in
cell division, shoot initiation, and leaf senescence
39CKs are perceived by ________ at the ___ or ______________
AHKs, ER, plasma membrane
40AHKs pass a ___________ to ________, who then pass it to ____________
phosphate group, AHPs, ARRs
41type B ARRs are
transcription factors
42type A ARRs are
inhibitors of CK signaling
43how do type A ARRs interfere with CK signaling?
competing with type B ARRs for phosphyl groups
44What does type B ARR have that type A does not?
DNA binding domain
45ipt quadruple mutants form ______ and make _______ than wild type
smaller SAMs; fewer organs
46LOG genes were first identified in ______ and are highly expressed in __________
rice; SAM stem cells
47log mutants show _________ activity and make ________ than wild type
reduced SAM; fewer organs
48how does CK affect SAM activity?
increases
49WUS directly represses the genes that transcribe ________
type A ARRs
50WUS ______ of cytokinin ____________ is required for proper SAM function
repression; negative regulators
51CK signaling ______ WUS expression
induces
52wild type STM activity is necessary to
establish the SAM during embyro formation
53KNOX class 1 genes are expressed in
shoot and floral meristems
54KNOX class 2 genes are expressed in
lateral organs
55STM is expressed throughout ______- and downregulated in _________
SAM; lateral organs
56how does CK affect KNOX gene expression?
induces expression
57overexpression of STM activates expression of
IPT7
58what is the relationship between STM and WUS?
both maintain the SAM, promote expression of each other, and form a complex to activate CLV3 in the CZ
59why is CLV3 not activated in OC cells?
HAM forms a complex with WUS to prevent it from interacting with STM
60why is CLV3 not activated in PZ cells?
no WUS, just STM
61GA levels must be ____ in the SAM because _______
low; stem cells must stay undifferentiated
62What is the relationship between STM and GA?
mutually exclusive; STM represses GA oxidases
63what is the difference between shoots and leaves?
shoots are indeterminate and maintain stem cell reservoir, leaves are determinant with restricted development
64What does AS1 do, and where is it expressed?
specifies identity of leaf founder cells, distinct from SAM cells; expressed in wild type leaves
65What is the relationship between AS1 and KNOX genes?
KNOX represses AS1 in SAM, AS1 represses KNOX in developing leaves
66what are the 4 steps of leaf formation?
specification of identity, positioning, outgrowth, acquisition of polarity
67Phytomer
a functional unit of a plant that is repeatedly produced to form a shoot
68Plastochron
time interval between production of successive primordia initiation events
69Phyllotaxis
pattern of lateral organ initiation at regular positions around the flanks of the SAM
72what happens if you destroy an incipient leaf primordia?
the placement of the future ones are affected
73NPA
prevents PIN proteins from moving auxin
74growing plants on +NPA
prevents leaf primordium initiation; pin like structure
75what do the results of plants grown on NPA tell us?
auxin transport is critical to leaf initiation
76where are PIN proteins found?
plasma membrane, but only at one end of the cell
77why does auxin transport by PIN1 only move in 1 direction?
polar
78in SAM, where does PIN1 move auxin?
through the L1 cells towards the top of the SAM
79where does leaf initiation take place, and what accumulates there?
flanks of SAM; auxin and PIN proteins
80what does MP do?
orients PIN1 polar localization
81how to young leaf primordia interact with auxin?
they are sinks that suck up auxin
82once in the leaf primordium center, auxin triggers
patterning of the leaf, including vascular strands
83what is ANT and where is it expressed?
induces expression of cell cycle genes ; expressed at sites of leaf initiation
84what is required to position ANT?
PIN1 / auxin
85is ANT is lost, what happens; if it is overexpressed?
lost = smaller leaves; overexpressed = larger leaves
86the adaxial side of the leaf is closest to
SAM (top)
87how is adaxial identity established?
AS1 forms a complex with AS2 and induce HD-ZIP genes
88where are AS1 and AS2 expressed?
AS1 in entire leaf primordia, AS2 only on adaxial
89what genes specify abaxial identity?
KAN genes
90where are KAN genes expressed?
only on abaxial side
91what is the relationship between KAN genes and AS2 + HD-ZIP genes?
repress each other
92KAN upregulates ______ which represses ______
YAB; WUS
93abaxial cells _____ SAM activity
inhibit
94what is the relationship between adaxial cells and SAM?
they promote each other
95what must be down-regulated to to form a normal proximal-distal axis?
KNOX genes
96what do BOP genes do, and how?
promote proximal leaf cell identity by binding to AS2 promoter to induce expression and repress KNOX genes