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The role of NBCL genes in floral patterning and symmetry
Typical eudicot flowers are composed of four concentric whorls of organ types: the protective sepals, the showy petals, the male stamens, and the female carpels (Alvarez-Buylla et al., 2010). Floral-meristem identity factors LFY and AP1 provide A-class activity by promoting sepal and petal identities and by antagonizing C-class function in the outer whorls. Similar A-class activity for BOP1/2 was revealed by triple mutant analyses with lfy and ap1 (Causier et al., 2010). The arrangement of floral organs in most eudicot flowers is tetramerous or pentamerous. The option for dorsal-ventral (adaxial-abaxial) asymmetry is superimposed on this pattern (Smyth, 2005). Loss-of-function bop mutations in Arabidopsis, pea, and M. truncatula all increase the number of floral organs and perturb dorsal-ventral growth patterns, altering flower symmetry (Yaxley et al., 2001; Hepworth et al., 2005; Couzigou et al., 2012). Flower symmetry is also affected, with the formation of additional organs (Ha et al., 2003; Norberg et al., 2005; Xu et al., 2010). During reproductive development, BOP1 transcripts are detected in young floral buds, and at the base of the sepals and petals. bop1 bop2 mutant flowers are frequently subtended by bract-like organs developing ectopically on the inflorescence. The mutant flowers have an open structure with two petaloid, in which the abaxial sepals are missing, irrespective of whether the flowers are subtended by bracts or not (Norberg et al., 2005; Hepworth et al., 2005; McKim et al., 2008). Typical pea coch flowers are dorsalized with enlarged floral bracts and supernumerary organs in all whorls (Yaxley et al., 2001; Kumar et al., 2011; Couzigou et al., 2012; Sharma et al., 2012). The patterning changes in bop1 bop2 and coch mutants seem to be concentrated on the abaxial (ventral) side of the floral meristem. Dorsalization of coch flowers suggests that COCH might inhibit ventral expression of CYCLOIDIA-TCP genes to maintain asymmetry. BOP1 and BOP2 act redundantly during reproductive development to control bract suppression, floral patterning, and floral organ number. In addition, the defect in gynoecium formation was observed, with half of the bop1-4 bop2-11 gynoecia contained only a single, fertile carpel (Ha et al., 2007).
PsCOCH1 was shown to be required for the P. sativum inflorescence development and flower organ identity acquisition (Yaxley et al., 2001; Couzigou et al., 2012; Sharma et al., 2012). The Pscoch1 mutant displays a range of phenotypes from normal flowers to open ones, which lead to quick drying of the pollen that largely reduced self-fertility, and show supernumerary organs at each whorl with abnormal organ fusion and aberrant organ mosaic (Yaxley et al., 2001; Couzigou et al., 2012). The number and the development of stamens are also affected and more or less ten abnormally fused anthers are present. In addition, up to 4 occasionally fused carpels may be present in Pscoch1 mutant (Yaxley et al., 2001) and more complex bracts are present in mutant flowers (Couzigou et al., 2012). In Medicago noot1 mutant, the flower modification is subtle and all the noot alleles possess additional organs (petals and stamens) in flowers (Couzigou et al., 2012). In the lotus Ljnbcl1:LORE1 mutants the first striking phenotype is their defective flower development leading to almost complete sterility (Magne et al., 2018b).
PsCOCH2 mutation increased the PsCOCH1 aerial vegetative mutant phenotypes
The PsCOCH1 gene is known to confer stipule identity but a role in leaf development was not reported. Here studied the role of PsCOCH2 in vegetative organs development such as stipules and leaves using the Pscoch1, Pscoch2 single mutants, and the Pscoch1coch2 double mutant. Leaves from the first nodes of the Pscoch mutants were looking for most of them like the wild-type Caméor with two proximal leaflets and distal tendrils (Fig. 3a). In Pscoch1, we found few leaves that showed minor defects in leaf patterning, often limited to an additional proximal leaflet and also a small leaflet appearing with distal tendrils (Fig. 3b). Pscoch2 presented no particular leaf phenotypes (Fig. 3c). In Pscoch1coch2 most of the leaves did not present patterning defect, however, some leaves (about 16%) presented an increased leaf complexity. Modified Pscoch1coch2 leaves presented more than two proximal leaflets and besides the distal parts of the leaf were often reiterating compound leaves or leaflets (Fig. 3d). On later nodes, once leaves become compound, all the leaves in the different Pscoch mutants showed a wild-type phenotype with at least two pairs of proximal leaflets and a terminal tendril (Fig. 6e, f, g). Occasionally, the Pscoch1coch2 mutant showed leaf patterning defects such as the fusion of more than five leaflets (Fig. 3h) or dichotomy in leaves along the proximal-distal axis (data not shown).
Analysis of the stipule morphology revealed that Caméor and PsCOCH2 have wild-type peltate stipules (Fig. 3i, k). PsCOCH1 stipules morphology is drastically affected as previously described in the literature and shows a range of stipule phenotypes, such as the absence of stipules, thread-like stipules, leaflet-like stipules or compound leaf-like stipules (Fig. 3j). Similar modifications were observed in the Pscoch1coch2 double mutant (Fig. 3i). The stipule modifications and the penetrance of this phenotype are already particularly strong in Pscoch1 and it was difficult to assess if this phenotype is increased in the Pscoch1coch2 double mutant. To investigate if the Pscoch2 mutation increased the stipule phenotype of Pscoch1, the stipules morphology was checked node by node form 1 to 13 in Caméor, Pscoch1, Pscoch2, and Pscoch1coch2. This analysis revealed that Caméor and Pscoch2 present only a wild-type peltate stipule (Fig. 3i, k; supplemental Table S4). Pscoch1 presented mainly an absence of a stipule from nodes 1 to 5, thread-like stipules from nodes 6 to 7, and leaflet-like stipules from nodes 8 to 13 (Fig. 3j; supplemental Table S4). Pscoch1coch2 presented mainly an absence of a stipule from nodes 1 to 9, thread-like stipules at node 10, and leaflet-like stipules from nodes 11 to 13 (Fig. 3l; supplemental Table S4). These results show that the absence of stipules is prolonged along with the nodes of the double mutant and thus suggests that the stipules alteration is increased in Pscoch1coch2 double mutant compared to Pscoch1 (supplemental table S4) revealing the role of Pscoch2 in stipule development.
NBCL genes are important for plant architecture
A vegetative shoot consists of a series of reiterative modules known as phytomers to generate the aerial parts of the plant. Each phytomer comprises a node to which a leaf is attached, a subtending internode, and a bud at the base of the internode (Sussex, 1989). Internode patterning is a key determinant of inflorescence architecture, with variations in the length and pattern of internode elongation contributing to diversity in inflorescence height and organization of secondary branches and flowers on the primary stem (Sussex, 1989). In Arabidopsis, ectopic expression BOP1 or BOP2 results in either short plants with floral pedicels pointing downward (Ha et al., 2007) or short bushy plants with irregular internodes (Norberg et al., 2005).
In this study, we found that M. truncatula NBCL genes also play a role in internode elongation. The loss-of-function mutants Mtnoot1 and Mtnoot2 play no major roles in internode elongation. Mtnoot2 displays a bit longer internodes compared with the wild type but Mtnoot1 has wild type plant height or is a bit shorter (Fig. 4a, b). However, the Mtnoot1mtnoot2 double mutant plants are taller, with longer internodes and continuous growth of the shoots because of infertility (Fig. 4a, b). The average length of internodes was increased 1.5 times compared to wild type (Fig. 4b). In addition, we also found that the average length of the floral pedicels was doubled in the double mutant when compared to wild type and Mtnoot1 and Mtnoot2 single mutants (Fig. 4c-d). These results suggest that MtNOOT1 and MtNOOT2 work together to repress internodes and floral pedicels elongation to maintain the plant architecture.
MtNOOT1 and MtNOOT2 are required for flower development
In wild-type M. truncatula, the flowers have pentamerous organs in the outermost four whorls (sepals, petals, and outer and inner stamens) and a central carpel (Benlloch et al., 2003; Wang et al., 2008). At the early stage, the non-open flowers have a pea-like closed structure (Fig. 5a) and subsequently show a corolla with three smaller petals (Fig. 5b). In addition, the central carpel is enclosed by a stamen tube (Fig. 5d) made off 10 anthers (Fig. 5e). Sepals have five teeth at the base of the flower (Fig. 5f). The M. truncatula noot1 mutant also has a pea-like closed structure (Fig. 5g) and flower modifications are subtle with additional organs, such as petals and stamens (Fig. 5h-i; Couzigou et al., 2012). Histological analysis of juvenile flowers also show the fused petal (sup. 5b) compare to wild type (sup. 5a), but the floral organs such as central carpels and sepals were not modified (Fig. 5j-l). The noot2 mutants displayed the WT flower phenotype (Fig. 5m-r, sup. 5b). In Mtnoot1 and Mtnoot2, however, all mutants flowers were precociously opened (Fig. 5s) and resulted in premature anther senescence. The histological analysis of these juvenile flowers also highlighted the premature stamens senescence (sup. 5d). Furthermore, the petal number was increased in double mutants due to frequent floral organ fusion (Fig. 5t-u), although this increase was variable among flowers. In wild-type plants and single mutants, the central carpel is enclosed by a stamen tube, however, it was frequently separated and not able to enclose the carpel in the Mtnoot1noot2 double mutant (Fig. 5v, sup. 5d). Moreover, the stamens were abnormal, the anthers were dried resulting in sterility and the central carpel developed to a pod-like structure (Fig. 5w, sup. 5e). Furthermore, circular sepal had an increased number of teeth (Fig. 5x). Taken together, these phenotypes indicated that the Mtnoot1noot2 double mutant is defective in floral organ identity, showing that MtNOOT1 and MtNOOT2 are redundantly required for Medicago flower development.
Pscoch1coch2 present accentuated floral patterning
Previous studies showed that the coch1 mutation alters various aspects of flower development (Yaxley et al., 2001; Couzigou et al., 2012). Pscoch1 displayed a large range of floral alterations and a mis-organization of floral organs that impact the symmetry and the whole structure of the flower (close to open) leading to self-fertility alteration (sup. 6a-d). Pscoch1 display regularly an incorrect number of floral organs at each whorl, aberrant fusions between organs and mosaics of different floral organs reflecting organ identity alterations (sup. 6a-l). Here, using the double mutant Pscoch1coch2, we tested the role of the PsCOCH2 gene in flower formation.
Global observations revealed that Pscoch1 flowers share a similar open flower phenotype but a small wing appeared (Fig. 6a-b, sup. 6f, h) and the Pscoch2 flowers show a WT phenotype. The Pscoch1coch2 mutant also showed a plethora of strong floral organization defects (data not shown) difficult to discriminate from the Pscoch1 single mutant. However, in the Pscoch1coch2 double mutant originating from four independent crosses, we observed a striking additive phenotype which generally consists of the fusion between two flowers, or resulting in impressive complex floral phenotypes (Fig. 6d). Wild-type Caméor pea flowers are composed of two fused keel petals, two wing petals, and a standard petal (Fig. 6e), while the coch1 has additional wing petals (Fig. 6f, sup. 6f, h). In contrast, the coch2 mutant has WT flowers. In the Pscoch1coch2 double mutants, the bases of two flowers are frequently fused resulting in a single calyx showing supernumerary sepals (Fig. 6h). In the third whorl, petals of the two flowers co-exist resulting in a complex corolla showing supernumerary petals. Roughly at the center of these kinds of flowers, two petals that look-like two wings were fused along their adaxial side indicating the site of fusion between the two flower corollas (Fig. 6d, h). In contrast to WT Caméor and the coch2 mutant having ten anthers and a single central carpel (Fig. 6i and 6k), in coch1 we observed an increase of the anther number and rarely two central carpels (Fig. 6j). In contrast, the Pscoch1coch2 double mutant displayed striking alteration of the anther number and most of the flowers had two (occasionally three or four) central carpels (Fig. 6l). Furthermore, six or more sepals were found in coch1 (Fig. 6n, sup. 6j, l) and coch1coch2 mutants (Fig. 6p) when WT and coch2 plants have five sepals (Fig. 6m, o). These phenotypes were to our knowledge not reported in the literature concerning Pscoch1 single mutant. Such strong alterations of the floral patterning in the Pscoch1coch2 double mutant suggests that the Pscoch2 mutant increased the Pscoch1 mutant phenotype and reveals that both genes are involved in the flower development in pea.
PsCOCH2 participates to the symbiotic organ development and functioning (this part from Kevin Magne PhD thesis)
In M. truncatula, the Mtnoot2 single mutant has no symbiotic phenotype (Magne et al., 2018a). By contrast, the double mutant Mtnoot1noot2 has exacerbate Mtnoot1 nodule to root phenotype leading to a complete loss of nodule identity and the loss of the nitrogen fixation ability (Couzigou et al., 2012; Magne et al., 2018a). To study the role of the PsCOCH2 gene in the symbiotic process, the mutant line Pscoch2 Ps1178 was used. Pscoch2 Ps1178 homozygous mutants were nodulated using R. leguminosarum P221 and nodule phenotypes were compared to Caméor. Twenty-seven days after inoculation with rhizobia, the Pscoch2 mutant nodules presented a typical wild-type indeterminate nodule shape and were not different from wild-type Caméor (Fig. 9a, b).
Pscoch1 single mutant is known to already present a very strong nodule to root phenotype (Couzigou et al., 2015) which does not impair the symbiotic performance of pea (Ferguson & Reid, 2005). In order to know if the Pscoch2 mutation increases the Pscoch1 nodule to root phenotype and if it affects the nodulation process, we generated the double mutant Pscoch1coch2. Nodulation experiments on Caméor, Pscoch1, Pscoch2, and Pscoch1coch2 mutants showed that 90 % of the Pscoch1 nodules are pink hybrid nodule-root structures as described in Fergusson and Reid, 2005 and (Fig. 9c,e). Pscoch1coch2 also develops hybrid nodule-root structures in a similar proportion than PsCOCH1 (≈90 %, Fig. 9d,e) but these hybrid nodule-root structures remain clearly smaller (three times) with faint pink to white coloration indicating a defect in development and nitrogen fixation efficiency (Fig. 9d). Furthermore big pink converted or not nodules as shown in Fig. 9a, b, c, were not observed in Pscoch1coch2. The nodule number formed in the different Pscoch mutants indicates that Caméor, Pscoch1, and Pscoch2 formed in average hundred nodules per plant that are mostly converted in Pscoch1 (Fig. 9f). Surprisingly, while Caméor and Pscoch2 produced on average forty nodule primordia per plant, very few nodule primordia were observed in Pscoch1 (Fig. 9f). In contrast, Pscoch1coch2 double mutants present supernumerary nodules and nodule primordia, one hundred of each, that is twice as much as Caméor, Pscoch1, and Pscoch2 (Fig. 9f). The symbiotic performance was assessed in the mutants using the ARA test and normalized by the plant. This revealed that all the mutants were fix+, however once normalized per nodule, the experiment showed that the Pscoch1coch2 nitrogen fixation is significantly reduced relative to wild-type (Fig. 9g, h). These results suggest that the nodule to root conversion takes place earlier in the double mutant and results in non-functional nodules. They also show that PsCOCH2 participates in the symbiotic process.
NBCL2 participate to leaves and stipules development and determinacy
Gene expression analysis revealed a strong transcriptional overlap between MtNOOT1 and MtNOOT2 in M. truncatula and between PsCOCH1 and PsCOCH2 in P. sativum. The two homologous genes are co-expressed in many aerial organs, especially in leaves and flowers in the two plants suggesting a common role in the regulation of aerial organ development and possible functional redundancy. The Pscoch2 and Mtnoot2 single mutants did not present particular aerial patterning defects in pea and M. truncatula, respectively, suggesting that the PsCOCH1 or MtNOOT1 genes may be sufficient for the development of the different aerial organs and/or that the PsCOCH2 or MtNOOT2 genes can be dispensable. This may also reflect functional redundancy between NBCL1 and NBCL2 genes in the two plants.
To better evaluate the role of the PsCOCH2 and MtNOOT2 genes, we used the double mutants Pscoch1coch2 and Mtnoot1noot2. Our approach relies on the phenotypic comparison between the Pscoch1 (Mtnoot1) and Pscoch2 (Mtnoot1) single and the Pscoch1coch2 or (Mtnoot1noot2I) double mutants. The Pscoch1 mutant has already been described for stipules and flower developmental alterations. The penetrance of the Pscoch1 mutation in pea, is strong for the aerial and symbiotic mutant phenotypes (Yaxley et al., 2001; Ferguson & Reid, 2005; Couzigou et al., 2012, 2015). In Mtnoot1, defects in the aerial organ, however, were mild, with reduced stipule and occasionally increased petal number. This indicates that PsCOCH1 plays a more important role in pea than MtNOOT1 in Medicago for development. Another difficulty we were facing in this study is the variability of the aerial Pscoch1 single mutant phenotypes. Taken together, the strong penetrance and the variability of the aerial Pscoch1 phenotypes make the phenotypic characterization and comparison between the Pscoch1 single and the Pscoch1coch2 double mutants particularly difficult. Despite these difficulties, we tried to understand if the Pscoch2 mutation accentuates or not some Pscoch1 mutant phenotypes.
Our observation showed that the Pscoch1coch2 double mutant phenotype is similar to the Pscoch1 one for stipules and flower modifications. However, in Pscoch1coch2 we observed occasionally strong leaf morphology alterations characterized by an increase in leaf complexity. At the early stages of development, most of the plants had fused leaves, indicating a defect in the control of leaf development and determinacy. Such leaf alterations were not previously reported for Pscoch1. Previous studies described the Pscoch1 mutant as strictly impacted in the stipule identity and flower morphology. The leaf morphology alterations observed in the double Pscoch1coch2 mutant suggests that the PsCOCH2 genes must also play a role in the regulatory network of leaf development and determinacy. In the double Mtnoot1noot2 Medicago mutant, some additional leaf defects were also observed, including modified leaflets from transformed stipules and enlarged leaf size. These leaf defects were not observed in Mtnoot1 and/ or Mtnoot2 single mutants, indicating that MtNOOT1 and MtNOOT2 act together in leaf identity. In Arabidopsis, the NBCLs (BOP1/2) genes play important roles in regulating leaf morphogenesis and patterning (Ha et al., 2003, 2007). The most dramatic developmental effect is on leaf development, with the bop1-1 dominant-negative and bop1bop2 null mutant leaves displaying extensive lobe formation and forming ectopic outgrowths of blade tissue along petioles of cotyledons and leaves (Ha et al., 2003, 2007; Norberg et al., 2005; Hepworth et al., 2005). In tomato, three BOPs genes (SlBOP1/2/3) were involved in the diversity of leaf complexity through repression of the leaflet formation (Izhaki et al., 2018). This suggests that the NBCL genes function redundantly to control leaf development in different species.
Table of contents :
INTRODUCTION
1. Legume crops in sustainable agriculture and ecology
2. Symbiotic association engaging plants and nitrogen-fixing bacteria
3. Nodule shapes and evolution in the Rosid I clade
4. Indeterminate versus determinate legume nodules
5. Nod factors signaling-dependent activation of nodule organogenesis
6. Symbiotic organ identity regulation
7. Gene networks controlling biogenesis of shoot apical meristem (SAM), axillary meristems (AMs), and floral meristems (FMs)
8. The NBCL genes in lateral organ boundary regulation
9. The role of NBCLs in leaf formation and patterning
10. The NBCL genes control flowering-time, inflorescence architecture and internode patterning
11. The role of NBCL genes in floral patterning and symmetry
12. The NBCL genes involved in shoots and inflorescence branching
13. The role of BOP in fruit architecture and lignin biosynthesis
14. NBCLs are essential for differentiation and separation of abscission in dicot
15. BOPs interact with other factors to mainten development
16. The other roles of BOPs
CHAPTER I. Legume NBCLs genes are redundantly required for aerial organ development and root nodule identity
Abstract
INTRODUCTION
RESULTS
MtNOOT1 and MtNOOT2 genes expression in M. truncatula aerial organs
PsCOCH1 and PsCOCH2 are co-expressed in aerial organ and are induced in indeterminate nodules of P. sativum
MtNOOT1 and MtNOOT2 redundantly control stipule development
PsCOCH2 mutation increased the PsCOCH1 aerial vegetative mutant phenotypes
NBCL genes are important for plant architecture
MtNOOT1 and MtNOOT2 are required for flower development
Pscoch1coch2 present accentuated floral patterning
Legume NBCLs control pod number and seed size
PsCOCH2 participates to the symbiotic organ development and functioning (this part from Kevin Magne PhD thesis)
NBCL2 participates to the regulation of the floral patterning in M. truncatula and pea
The NBCL clade shares conserved function governing fruit architecture
PsCOCH2 is involved in nodule development and identity
MATERIALS AND METHODS
Plant material
Coch2 mutant isolation
Plant growth conditions
Plant genotyping
Material fixation and X-gluc staining
RNA preparation and reverse transcription
qRT-PCR gene expression analysis
Acetylene reduction assay
CHAPTER II. The COCHLEATA1 gene controls branching and flowering time in pea
Abstract
INTRODUCTION
RESULTS
Mutations in the pea COCH1 gene increase shoot branching
In Medicago Mtnoot1 and Mtnoot2 play opposite roles in lateral branching
The COCH1 gene is necessary for long-distance signaling
PsCOCH1 is deficient in the SL signaling pathway
PsCOCH1 expression is downregulated by CK and responds to exogenous CK application independently of SL
IAA stimulates PsCOCH1 expression
The legume NBCLs participate in flowering time determination
DISCUSSION
A novel role for NBCL genes in plant development
PsCOCH1 is necessary for long-distance signaling and deficient in the SL signaling pathway .
PsCOCH1 participates in hormone cross talk to control plant architecture
NBCL genes are involved in flowering-time regulation
Extending the concept of strigolactone in floral transition and nodule identity
MATERIAL AND METHODS
Plant material, growth conditions and scoring methods
Grafting studies
Strigolactone application
Exogenous auxin studies
RNA extraction and cDNA synthesis
CHAPTER III. The Brachypodium distachyon BLADE-ON-PETIOLE-Like proteins UNICULME4 and LAXATUM-A are redundantly required for plant development
Summary
INTRODUCTION
RESULTS
Generation of Bdlaxa Crispr-Cas9 null alleles and of Bdcul4laxa double mutants
BdlaxaCR and BdlaxaTI, and Bdcul4Q127*BdlaxaCR and Bdcul4W203*BdlaxaT381I mutants present similar phenotypes
The loss-of-function of BdCUL4 and BdLAXA affects internode cells elongation
BdCUL4 is required for ligule and represses BdLAXA in auricle formation
BdCUL4 and BdLAXA present antagonistic roles in leaf positioning
BdCUL4 and BdLAXA are required for spikelet architecture and determinacy
BdLAXA is inhibited by BdCUL4 in the control of floral organ number and identity
BdLAXA is required to maintain seed size and roots growth
BdCUL4 and BdLAXA are not necessary for seed abscission
BdCUL4 and BdLAXA regulate secondary cell wall lignification and composition
BdCUL4 and BdLAXA regulate cellulose and lignin associated gene expression
DISCUSSION
MATERIALS AND METHODS
Plant material
Growth conditions
Plasmid construction and transformation of Agrobacterium strains
Callus culture
Transformation of B. distachyon
Genotyping of the transgenic plants and Bdcul4Bdlaxa mutants
qRT-PCR gene expression analysis
Imaging, light microscopy and sample preparation
CHAPTER IV Characterization of potential MtNODULEROOT1 and MtNODULEROOT2 interacting partners participating in nodule and aerial organ development
Abstract
INTRODUCTION
RESULTS
Identification of the M. truncatula ALOG gene
Isolation and characterization of M. truncatula Mtalog1 Tnt1 insertional mutants
Construction and preliminary characterization of the Mtnoot1alog1 and Mtnoot2alog1 double mutants in nodule
Characterization of the Mtalog1 and Mtnoot1alog1 double mutants in aerial development
The MtNOOT1 gene regulate class II MtKNOX gene expression in nodules
DISCUSSION
MATERIALS AND METHODS
Plant material and growth conditions
Transformation of Medicago truncatula
Crossing between noot and Mtalog1 and noot mutant lines and proMtKNOX3::GUS
M. truncatula DNA extraction and Tnt1 insertional mutant genotyping
Construction of the overexpression, MtALOG-GFP and promoter: GUS plasmids
Inoculations of Medicago
Light microscopy and sample preparation
RT-qPCR gene expression analysis
Phylogeny of M. truncatula ALOG genes
GENERAL DISCUSSION
The nbcl1nbcl2 double mutants highlight the role of the NBCL2 genes in the patterning of aerial organs
NBCL genes redundantly control plant architecture
NBCL1 genes regulate shoot branching and control strigolactones production
NBCL genes are involved in flowering-time regulation
NBCL functions in aerial vegetative and reproductive organs patterning are conserved in grasses .
NBCL1-dependent abscission process are not conserved in grass
Investigation of potential interacting partners and downstream targets of NOOT proteins
CONCLUSIONS
REFERENCES