Arabidopsis JAGGED LATERAL ORGANSIs Expressed in Boundaries and CoordinatesKNOXandPINActivity

Borghi, Loris; Bureau, Marina; Simon, Rüdiger

doi:10.1105/tpc.106.047159

Cited by 140 publications

(146 citation statements)

References 54 publications

Supporting

Mentioning

141

Contrasting

Order By: Relevance

“…However, several loss-of-function mutants of rice and maize LBD genes have been reported to evidence clear phenotypes (Inukai et al, 2005;Liu et al, 2005;Bortiri et al, 2006;Evans, 2007;Taramino et al, 2007). The ectopic expression of several LBD genes, as wild type or as proteins fused to a transcriptional repression domain, yielded morphological phenotypes, provid- ing clues to the biological functions of these LBD genes (Shuai et al, 2002;Chalfun-Junior et al, 2005;Borghi et al, 2007;Okushima et al, 2007). For example, the overexpression of LBD16 or LBD29 induced lateral root formation in the absence of ARF7 and ARF19, and the dominant repression of LBD16 activity inhibited lateral root formation; these findings suggest that these LBDs function downstream of ARF7-and ARF19-dependent auxin signaling in lateral root formation (Okushima et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Although the lbd36 loss-of-function mutants did not show morphological phenotypes, the analysis of lbd36 as2 double mutants showed that these two members act redundantly to control cell fate determination in the petals. Another Arabidopsis gain-of-function mutant, jagged lateral organs-D (jlo-D), generates strongly lobed leaves and the shoot apical meristem prematurely arrests organ initiation, terminating in a pin-like structure (Borghi et al, 2007). During embryogenesis, JLO (=LBD30/ASL19) is necessary for the initiation of cotyledons and development beyond the globular stage.…”

mentioning

confidence: 99%

See 1 more Smart Citation

LBD18/ASL20Regulates Lateral Root Formation in Combination withLBD16/ASL18Downstream ofARF7andARF19in Arabidopsis

et al. 2009

View full text Add to dashboard Cite

The LATERAL ORGAN BOUNDARIES DOMAIN/ASYMMETRIC LEAVES2-LIKE (LBD/ASL) genes encode proteins harboring a conserved amino acid domain, referred to as the LOB (for lateral organ boundaries) domain. While recent studies have revealed developmental functions of some LBD genes in Arabidopsis (Arabidopsis thaliana) and in crop plants, the biological functions of many other LBD genes remain to be determined. In this study, we have demonstrated that the lbd18 mutant evidenced a reduced number of lateral roots and that lbd16 lbd18 double mutants exhibited a dramatic reduction in the number of lateral roots compared with lbd16 or lbd18. Consistent with this observation, significant b-glucuronidase (GUS) expression in Pro LBD18 :GUS seedlings was detected in lateral root primordia as well as in the emerged lateral roots. Whereas the numbers of primordia of lbd16, lbd18, and lbd16 lbd18 mutants were similar to those observed in the wild type, the numbers of emerged lateral roots of lbd16 and lbd18 single mutants were reduced significantly. lbd16 lbd18 double mutants exhibited additively reduced numbers of emerged lateral roots compared with single mutants. This finding indicates that LBD16 and LBD18 may function in the initiation and emergence of lateral root formation via a different pathway. LBD18 was shown to be localized into the nucleus. We determined whether LBD18 functions in the nucleus using a steroid regulator-inducible system in which the nuclear translocation of LBD18 can be regulated by dexamethasone in the wild-type, lbd18, and lbd16 lbd18 backgrounds. Whereas LBD18 overexpression in the wild-type background induced lateral root formation to some degree, other lines manifested the growth-inhibition phenotype. However, LBD18 overexpression rescued lateral root formation in lbd18 and lbd16 lbd18 mutants without inducing any other phenotypes. Furthermore, we demonstrated that LBD18 overexpression can stimulate lateral root formation in auxin response factor7/19 (arf7 arf19) mutants with blocked lateral root formation. Taken together, our results suggest that LBD18 functions in the initiation and emergence of lateral roots, in conjunction with LBD16, downstream of ARF7 and ARF19.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

LBD18/ASL20Regulates Lateral Root Formation in Combination withLBD16/ASL18Downstream ofARF7andARF19in Arabidopsis

et al. 2009

View full text Add to dashboard Cite

show abstract

“…LOB was initially identified from an enhancer trap screen for genes expressed at the adaxial base of initiating lateral organs and other family members identified based on conservation of the so-called N-terminal LOB domain (Shuai et al, 2002). For most LBD family members the function is not known, but for some, roles have been defined in organ development, anthocyanin, and nitrogen metabolism, as well as in responses to phytohormones such as cytokinin, auxin, and gibberellin (Borghi et al, 2007;Bureau et al, 2010;Majer and Hochholdinger, 2011;Feng et al, 2012). To our knowledge, our findings represent the first functional characterization of LBD20 and the first demonstration of a role for any LBD family member in plant-pathogen interactions.…”

Section: Discussionmentioning

confidence: 99%

The Lateral Organ Boundaries Domain Transcription Factor LBD20 Functions in Fusarium Wilt Susceptibility and Jasmonate Signaling in Arabidopsis

et al. 2012

View full text Add to dashboard Cite

The LATERAL ORGAN BOUNDARIES (LOB) DOMAIN (LBD) gene family encodes plant-specific transcriptional regulators functioning in organ development. In a screen of Arabidopsis (Arabidopsis thaliana) sequence-indexed transferred DNA insertion mutants, we found disruption of the LOB DOMAIN-CONTAINING PROTEIN20 (LBD20) gene led to increased resistance to the root-infecting vascular wilt pathogen Fusarium oxysporum. In wild-type plants, LBD20 transcripts were barely detectable in leaves but abundant in roots, where they were further induced after F. oxysporum inoculation or methyl jasmonate treatment. Induction of LBD20 expression in roots was abolished in coronatine insensitive1 (coi1) and myc2 (allelic to jasmonate insensitive1) mutants, suggesting LBD20 may function in jasmonate (JA) signaling. Consistent with this, expression of the JA-regulated THIONIN2.1 (Thi2.1) and VEGETATIVE STORAGE PROTEIN2 (VSP2) genes were up-regulated in shoots of lbd20 following treatment of roots with F. oxysporum or methyl jasmonate. However, PLANT DEFENSIN1.2 expression was unaltered, indicating a repressor role for LBD20 in a branch of the JA-signaling pathway. Plants overexpressing LBD20 (LBD20-OX) had reduced Thi2.1 and VSP2 expression. There was a significant correlation between increased LBD20 expression in the LBD20-OX lines with both Thi2.1 and VSP2 repression, and reduced survival following F. oxysporum infection. Chlorosis resulting from application of F. oxysporum culture filtrate was also reduced in lbd20 leaves relative to the wild type. Taken together, LBD20 is a F. oxysporum susceptibility gene that appears to regulate components of JA signaling downstream of COI1 and MYC2 that are required for full elicitation of F. oxysporum-and JA-dependent responses. To our knowledge, this is the first demonstration of a role for a LBD gene family member in either biotic stress or JA signaling.

show abstract

“…A role for combined regulation of KNOX and auxin activities in boundary delimitation was also suggested by analysis of the boundary-expressed LOB domain gene JAGGED LATERAL ORGANS (JLO), which is sufficient to activate STM and BP expression and repress PIN auxin efflux transporters (Fig. 4) (Borghi et al, 2007).…”

Section: A Cmentioning

confidence: 99%

KNOX genes: versatile regulators of plant development and diversity

2010

View full text Add to dashboard Cite

SummaryKnotted1-like homeobox (KNOX) proteins are homeodomain transcription factors that maintain an important pluripotent cell population called the shoot apical meristem, which generates the entire above-ground body of vascular plants. KNOX proteins regulate target genes that control hormone homeostasis in the meristem and interact with another subclass of homeodomain proteins called the BELL family. Studies in novel genetic systems, both at the base of the land plant phylogeny and in flowering plants, have uncovered novel roles for KNOX proteins in sculpting plant form and its diversity. Here, we discuss how KNOX proteins influence plant growth and development in a versatile context-dependent manner.

show abstract

Arabidopsis JAGGED LATERAL ORGANSIs Expressed in Boundaries and CoordinatesKNOXandPINActivity

Cited by 140 publications

References 54 publications

LBD18/ASL20Regulates Lateral Root Formation in Combination withLBD16/ASL18Downstream ofARF7andARF19in Arabidopsis

LBD18/ASL20Regulates Lateral Root Formation in Combination withLBD16/ASL18Downstream ofARF7andARF19in Arabidopsis

The Lateral Organ Boundaries Domain Transcription Factor LBD20 Functions in Fusarium Wilt Susceptibility and Jasmonate Signaling in Arabidopsis

KNOX genes: versatile regulators of plant development and diversity

Contact Info

Product

Resources

About