ERECTA is required for protection against heat-stress in the AS1 / AS2 pathway to regulate adaxial?abaxial leaf polarity in Arabidopsis

Qi, Yiping; Sun, Yue; Xu, Lin; Xu, Yuquan; Huang, Hai

doi:10.1007/s00425-004-1248-z

Cited by 57 publications

(48 citation statements)

References 29 publications

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“…In all single CRF mutant alleles identified, small notches appear in the cotyledons and occasionally the first true leaves, suggesting localized areas of restricted cell expansion or division. The penetrance of the phenotype increased when seedlings were grown at elevated temperatures (data not shown), as has been observed in the asymmetric leaves (as1 and as2) and cup-shaped cotyledons (cuc1 and cuc2) mutants (26,27). In multiple crf mutants, the penetrance of the phenotype increases, reaching up to Ϸ50% in the crf1,2,5 triple mutant.…”

Section: Crf Protein Relocalization Defines a Branch Point In The Cytsupporting

confidence: 68%

A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway

Rashotte

Mason

Hutchison³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

348

380

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The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial twocomponent phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of unknown function are transcriptionally up-regulated by cytokinin through this pathway, and we have designated these AP2 genes CYTOKININ RESPONSE FACTORS (CRFs). In addition to their transcriptional regulation by cytokinin, the CRF proteins rapidly accumulate in the nucleus in response to cytokinin, and this relocalization depends on the histidine kinases and the downstream histidine-containing phosphotransfer proteins, but is independent of the ARRs. Analysis of loss-of-function mutations reveals that the CRFs function redundantly to regulate the development of embryos, cotyledons, and leaves. Furthermore, the CRFs mediate a large fraction of the transcriptional response to cytokinin, affecting a set of cytokinin-responsive genes that largely overlaps with type-B ARR targets. These results indicate that the CRF proteins function in tandem with the type-B ARRs to mediate the initial cytokinin response. Thus, the evolutionarily ancient two-component system that is used by cytokinin branches to incorporate a unique family of plant-specific transcription factors.cell signaling ͉ plant hormones

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Section: Crf Protein Relocalization Defines a Branch Point In The Cytsupporting

confidence: 68%

A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway

Rashotte

Mason

Hutchison³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

348

380

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“…This structure is believed to be caused by a partial loss of the leaf adaxial identities (Xu et al, 2003). In some extreme cases, the as2-101 plants even produced some abaxialized needle-like structures, though the frequency was very low (Xu et al, 2003;Qi et al, 2004). In the course of completing a mutagenesis screen for as2-101 enhancers, we identified one plant exhibiting apparently increased numbers of needle and lotus leaves ( Figure 1C).…”

Section: Resultsmentioning

confidence: 99%

The Proteolytic Function of theArabidopsis26S Proteasome Is Required for Specifying Leaf Adaxial Identity

Huang

Liang

et al. 2006

The Plant Cell

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Polarity formation is central to leaf morphogenesis, and several key genes that function in adaxial-abaxial polarity establishment have been identified and characterized extensively. We previously reported that Arabidopsis thaliana ASYMMERTIC LEAVES1 (AS1) and AS2 are important in promoting leaf adaxial fates. We obtained an as2 enhancer mutant, asymmetric leaves enhancer3 (ae3), which demonstrated pleiotropic plant phenotypes, including a defective adaxial identity in some leaves. The ae3 as2 double mutant displayed severely abaxialized leaves, which were accompanied by elevated levels of leaf abaxial promoting genes FILAMENTOUS FLOWER, YABBY3, KANADI1 (KAN1), and KAN2 and a reduced level of the adaxial promoting gene REVOLUTA. We identified AE3, which encodes a putative 26S proteasome subunit RPN8a. Furthermore, double mutant combinations of as2 with other 26S subunit mutations, including rpt2a, rpt4a, rpt5a, rpn1a, rpn9a, pad1, and pbe1, all displayed comparable phenotypes with those of ae3 as2, albeit with varying phenotypic severity. Since these mutated genes encode subunits that are located in different parts of the 26S proteasome, it is possible that the proteolytic function of the 26S holoenzyme is involved in leaf polarity formation. Together, our findings reveal that posttranslational regulation is essential in proper leaf patterning.

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“…Poethig (Wu et al, 2008), Y. Eshed (Eshed et al, 2004), Y. Zhao (Zhao et al, 2001;Cheng et al, 2006), and T.J. Guilfoyle (Ulmasov et al, 1997), respectively. Plant growth in soil and on media was according to our previous conditions (Chen et al, 2000;Qi et al, 2004).…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

YUCCAGenes Are Expressed in Response to Leaf Adaxial-Abaxial Juxtaposition and Are Required for Leaf Margin Development

Wang

et al. 2011

Plant Physiology

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During leaf development, the formation of leaf adaxial-abaxial polarity at the primordium stage is crucial for subsequent leaf expansion. However, little is known about the genetic control from polarity establishment to blade outgrowth. The leaf margin, comprising elongated margin cells and hydathodes, is thought to affect leaf expansion. Here, we show that mutants with defective leaf polarity or with loss of function in the multiple auxin-biosynthetic YUCCA (YUC) genes exhibited a similar abnormal leaf margin and less-expanded leaves. Leaf margins of these mutants contained fewer hydathodes and an increased number of cell patches in which the patterns of epidermal cells resembled those of hydathodes. The previously characterized leafabaxialized asymmetric leaves2 (as2) revoluta (rev) and leaf-adaxialized kanadi1 (kan1) kan2 double mutants both produce fingershaped, hydathode-like protrusions on adaxial and abaxial leaf surfaces, respectively. YUCs are required for formation of the protrusions, as those produced by as2 rev and kan1 kan2 were absent in the yuc1 yuc2 yuc4 triple mutant background. Expressions of YUC1, YUC2, and YUC4 were spatially regulated in the leaf, being associated with hydathodes in wild-type leaves and protrusions on as2 rev and kan1 kan2 leaves. In addition, inhibition of auxin transport by treatment of seedlings with N-(1-naphtyl) phtalamic acid or disruption of the auxin gradient by transforming plants with the 35S:YUC1 construct also blocked leaf margin development. Collectively, our data show that expressions of YUCs in the leaf respond to the adaxial-abaxial juxtaposition, and that the activities of auxin mediate leaf margin development, which subsequently promotes blade outgrowth.

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ERECTA is required for protection against heat-stress in the AS1 / AS2 pathway to regulate adaxial?abaxial leaf polarity in Arabidopsis

Cited by 57 publications

References 29 publications

A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway

A subset of Arabidopsis AP2 transcription factors mediates cytokinin responses in concert with a two-component pathway

The Proteolytic Function of theArabidopsis26S Proteasome Is Required for Specifying Leaf Adaxial Identity

YUCCAGenes Are Expressed in Response to Leaf Adaxial-Abaxial Juxtaposition and Are Required for Leaf Margin Development

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