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Plant secondary growth derives from the meristematic activity of the vascular cambium. In Arabidopsis thaliana, cell divisions in the cambium are regulated by the transcription factor WOX4, a key target of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR)-RELATED 41 (CLE41) signaling pathway. However, function of the WOX4-like genes in plants that are dependent on a much more prolific secondary growth, such as trees, remains unclear. Here, we investigate the role of WOX4 and CLE41 homologs for stem secondary growth in Populus trees. In Populus, PttWOX4 genes are specifically expressed in the cambial region during vegetative growth, but not after growth cessation and during dormancy, possibly involving a regulation by auxin. In PttWOX4a/b RNAi trees, primary growth was not affected whereas the width of the vascular cambium was severely reduced and secondary growth was greatly diminished. Our data show that in Populus trees, PttWOX4 genes control cell division activity in the vascular cambium, and hence growth in stem girth. This activity involves the positive regulation of PttWOX4a/b through PttCLE41-related genes. Finally, expression profiling suggests that the CLE41 signaling pathway is an evolutionarily conserved program for the regulation of vascular cambium activity between angiosperm and gymnosperm tree species.

• The CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR)-RELATED (CLE) peptide ligands in connection with their receptors are important players in cell-to-cell communications in plants. Here, we investigated the function of the Populus CLV3/ESR-RELATED 47 (PttCLE47) gene during secondary growth and wood formation in hybrid aspen (Populus tremula × tremuloides) using an RNA interference (RNAi) approach. • Expression of PttCLE47 peaks in the vascular cambium. Silencing of the PttCLE47 gene expression affected lateral expansion of stems and decreased apical height growth and leaf size. • In particular, PttCLE47 RNAi trees exhibited a narrower secondary xylem zone with less xylem cells/cell file. The reduced radial growth phenotype also correlated with a reduced number of cambial cell layers. In agreement with these results, expression of several cambial regulator genes was downregulated in the stems of the transgenic trees in comparison with controls. • Altogether, these results suggest that the PttCLE47 gene is a major positive regulator of cambial activity in hybrid aspen, mainly promoting the production of secondary xylem. Furthermore, in contrast to previously characterized CLE genes expressed in the wood-forming zone, PttCLE47 appears to be active at its site of expression.

Plant secondary growth derives from the meristematic activity of the vascular cambium. In Arabidopsis thaliana , cell divisions in the cambium are regulated by the transcription factor WOX 4 , a key target of the CLAVATA 3 ( CLV 3)/ EMBRYO SURROUNDING REGION ( ESR )‐ RELATED 41 ( CLE 41) signaling pathway. However, function of the WOX 4 ‐like genes in plants that are dependent on a much more prolific secondary growth, such as trees, remains unclear. Here, we investigate the role of WOX 4 and CLE 41 homologs for stem secondary growth in Populus trees. In Populus , Ptt WOX 4 genes are specifically expressed in the cambial region during vegetative growth, but not after growth cessation and during dormancy, possibly involving a regulation by auxin. In Ptt WOX 4a/b RNA i trees, primary growth was not affected whereas the width of the vascular cambium was severely reduced and secondary growth was greatly diminished. Our data show that in Populus trees, Ptt WOX 4 genes control cell division activity in the vascular cambium, and hence growth in stem girth. This activity involves the positive regulation of Ptt WOX 4a/b through Ptt CLE 41‐ related genes. Finally, expression profiling suggests that the CLE 41 signaling pathway is an evolutionarily conserved program for the regulation of vascular cambium activity between angiosperm and gymnosperm tree species.

Auxin/indole-3-acetic acid (Aux/IAA) proteins are transcriptional regulators that mediate many aspects of plant responses to auxin. While functions of most Aux/IAAs have been defined mainly by gain-of-function mutant alleles in Arabidopsis thaliana, phenotypes associated with loss-of-function mutations have been scarce and subtle. We report here that the downregulation of IAA9, a tomato (Solanum lycopersicum) gene from a distinct subfamily of Aux/IAA genes, results in a pleiotropic phenotype, consistent with its ubiquitous expression pattern. IAA9-inhibited lines have simple leaves instead of wild-type compound leaves, and fruit development is triggered before fertilization, giving rise to parthenocarpy. This indicates that IAA9 is a key mediator of leaf morphogenesis and fruit set. In addition, antisense plants displayed auxin-related growth alterations, including enhanced hypocotyl/stem elongation, increased leaf vascularization, and reduced apical dominance. Auxin dose-response assays revealed that IAA9 downregulated lines were hypersensitive to auxin, although the only early auxin-responsive gene that was found to be upregulated in the antisense lines was IAA3. The activity of the IAA3 promoter was stimulated in the IAA9 antisense genetic background, indicating that IAA9 acts in planta as a transcriptional repressor of auxin signaling. While no mutation in any member of subfamily IV has been reported to date, the phenotypes associated with the downregulation of IAA9 reveal distinct and novel roles for members of the Aux/IAA gene family.

Whereas the interplay of multiple hormones is essential for most plant developmental processes, the key integrating molecular players remain largely undiscovered or uncharacterized. It is shown here that a member of the tomato auxin/indole-3-acetic acid (Aux/IAA) gene family, Sl-IAA3, intersects the auxin and ethylene signal transduction pathways. Aux/IAA genes encode short-lived transcriptional regulators central to the control of auxin responses. Their functions have been defined primarily by dominant, gain-of-function mutant alleles in Arabidopsis. The Sl-IAA3 gene encodes a nuclear-targeted protein that can repress transcription from auxin-responsive promoters. Sl-IAA3 expression is auxin and ethylene dependent, is regulated on a tight tissue-specific basis, and is associated with tissues undergoing differential growth such as in epinastic petioles and apical hook. Antisense down-regulation of Sl-IAA3 results in auxin and ethylene-related phenotypes, including altered apical dominance, lower auxin sensitivity, exaggerated apical hook curvature in the dark and reduced petiole epinasty in the light. The results provide novel insights into the roles of Aux/IAAs and position the Sl-IAA3 protein at the crossroads of auxin and ethylene signalling in tomato.

The aim of the study was to investigate whether the tumor free distance (TFD), which is the distance in millimeters between the deepest point of invasion and the serosal surface, and absolute depth of invasion (DMI), the distance in millimeters between the endomyometrial junction and the deepest point of myometrial invasion, are useful in surgical staging and in predicting prognosis. The present study retrospectively analyzed 62 cases of endometrial carcinoma with complete surgical staging, carried out over a 4 and half-year period (January 2003 to June 2007). All surgicopathological findings including surgical stages, histological type and grade, myometrial invasion, lymphovascular space invasion, cervical and adnexal involvement, and lymph node metastasis were abstracted from medical records and pathological reports. Univariate and multivariate analyses were performed comparing TFD, DMI and the percentage of mypmetrial invasion (MI) with established prognostic factors. A total of 62 patients were included in the study. A total of 52 (84%) had endometrioid carcinomas and 31 patients (60%) had grade 1 cancer. The deepest MI was <50% in 32 patients (52%). Median DMI was 2.7 mm (range 0-15 mm). Median TFD was 3 mm (range 0-19 mm). There was lymphovascular space invasion (LVSI) in 11 patients (17.5%), cervical involvement in 11 patients (17.5%), extra-uterine extension in 9 cases (14%) and lymph node metastasis in 12 patients (22%). It was demonstrated that 50% MI was significantly associated with prognostic factors (cervical involvement, type 2 carcinomas and LVSI, and was a significant predictor of the 5-year overall survival rate and recurrence-free survival (P=0.05, P=0.01). No significant association was observed between DMI and TFD with clinicopathological parameters and survival rates. The importance of DMI in predicting recurrence of disease was observed to be highest in terms of sensitivity and specificity. The cut-off value with the highest sensitivity and specificity crossing the receive operating characteristic curve was calculated to be 3 mm for DMI and 2.5 mm for TFD. The results indicate that DMI is a superior predictive factor of recurrence of the disease compared with TFD. However, further studies are required in order to prove the prognostic usefulness of these parameters and then to improve management of endometrial cancer.

The plant hormone auxin plays a central role in adventitious rooting and is routinely used with many economically important, vegetatively propagated plant species to promote adventitious root initiation and development on cuttings. Nevertheless the molecular mechanisms through which it acts are only starting to emerge. The Arabidopsis superroot2-1 (sur2-1) mutant overproduces auxin and, as a consequence, develops excessive adventitious roots in the hypocotyl. In order to increase the knowledge of adventitious rooting and of auxin signalling pathways and crosstalk, this study performed a screen for suppressors of superroot2-1 phenotype. These suppressors provide a new resource for discovery of genetic players involved in auxin signalling pathways or at the crosstalk of auxin and other hormones or environmental signals. This study reports the identification and characterization of 26 sur2-1 suppressor mutants, several of which were identified as mutations in candidate genes involved in either auxin biosynthesis or signalling. In addition to confirming the role of auxin as a central regulator of adventitious rooting, superroot2 suppressors indicated possible crosstalk with ethylene signalling in this process.

Whereas the interplay of multiple hormones is essential for most plant developmental processes, the key integrating molecular players remain largely undiscovered or uncharacterized. It is shown here that a member of the tomato auxin/indole-3-acetic acid (Aux/IAA) gene family, SI-IAA3, intersects the auxin and ethylene signal transduction pathways. Aux/IAA genes encode short-lived transcriptional regulators central to the control of auxin responses. Their functions have been defined primarily by dominant, gain-of-function mutant alleles in Arabidopsis. The SI-IAA3 gene encodes a nuclear-targeted protein that can repress transcription from auxin-responsive promoters. SI-IAA3 expression is auxin and ethylene dependent, is regulated on a tight tissue-specific basis, and is associated with tissues undergoing differential growth such as in epinastic petioles and apical hook. Antisense down-regulation of SI-IAA3 results in auxin and ethylene-related phenotypes, including altered apical dominance, lower auxin sensitivity, exaggerated apical hook curvature in the dark and reduced petiole epinasty in the light. The results provide novel insights into the roles of Aux/IAAs and position the SI-IAA3 protein at the crossroads of auxin and ethylene signalling in tomato.

In the first design stage, image reference plays a double role of means of formulation and resolution of problems. In our approach, we consider image reference as a support of creation activity to generate ideas and we propose a tool for navigation in references by image in order to assist daylight ambience design. Within this paper, we present, in a first part, the semantic indexation method to be used for the indexation of our image database. In a second part we propose a synthetic analysis of various modes of referential navigation in order to propose a tool implementing all or a part of these modes.

In Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family interacting with 29 auxin/indole acetic acid repressors (Aux/IAA), themselves forming coreceptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) PROTEINS. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. Considerable efforts have been made to discern the specificity of auxin action. However, owing to a lack of obvious phenotype in single loss-of-function mutants in Aux/IAA genes, most genetic studies have relied on gain-of-function mutants, which are highly pleiotropic. Using loss-of-function mutants, we show that three Aux/IAA proteins interact with ARF6 and/or ARF8, which we have previously shown to be positive regulators of AR formation upstream of jasmonate, and likely repress their activity. We also demonstrate that TIR1 and AFB2 are positive regulators of adventitious root formation and suggest a dual role for TIR1 in the control of JA biosynthesis and conjugation, as revealed by upregulation of several JA biosynthesis genes in the tir1-1 mutant. We propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9 and/or IAA17 that modulate JA homeostasis to control AR initiation. Footnotes * There was a significant mistake in the last version uploaded yesterday April12, 2019