THE ROLE OF <i>KNOX</i> GENES IN PLANT DEVELOPMENT

Hake, Sarah; Smith, Harley M. S.; Holtan, Hans; Magnani, Enrico; Mele, Giovanni; Ramirez, Julio

doi:10.1146/annurev.cellbio.20.031803.093824

Cited by 402 publications

(384 citation statements)

References 132 publications

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“…KNOX homeobox genes are expressed in the shoot meristem where they are required for maintenance of the meristem (reviewed in Hake et al 2004). Ectopic expression of KNOX genes induces speciesspeciWc alterations in leaf shape and morphology, as well as ectopic meristem/shoot production.…”

Section: Discussionmentioning

confidence: 99%

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

Srinivasan

Liu

Heidmann

et al. 2006

Planta

145

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Gain-of-function studies have shown that ectopic expression of the BABY BOOM (BBM) AP2/ ERF domain transcription factor is suYcient to induce spontaneous somatic embryogenesis in Arabidopsis (Arabidopsis thaliana (L.) Heynh) and Brassica napus (B. napus L.) seedlings. Here we examined the eVect of ectopic BBM expression on the development and regenerative capacity of tobacco (Nicotiana tabacum L.) through heterologous expression of Arabidopsis and B. napus BBM genes. 35S::BBM tobacco lines exhibited a number of the phenotypes previously observed in 35S::BBM Arabidopsis and B. napus transgenics, including callus formation, leaf rumpling, and sterility, but they did not undergo spontaneous somatic embryogenesis. 35S::BBM plants with severe ectopic expression phenotypes could not be assessed for enhanced regeneration at the seedling stage due to complete male and female sterility of the primary transformants, therefore fertile BBM ectopic expression lines with strong misexpression phenotypes were generated by expressing a steroid-inducible, posttranslationally controlled BBM fusion protein (BBM:GR) under the control of a 35S promoter. These lines exhibited spontaneous shoot and root formation, while somatic embryogenesis could be induced from in-vitro germinated seedling hypocotyls cultured on media supplemented with cytokinin. Together these results suggest that ectopic BBM expression in transgenic tobacco also activates cell proliferation pathways, but diVerences exist between Arabidopsis/B. napus and N. tabacum with respect to their competence to respond to the BBM signalling molecule.

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Section: Discussionmentioning

confidence: 99%

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

Srinivasan

Liu

Heidmann

et al. 2006

Planta

145

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“…The combined results from all searches revealed a minimum of 129 homeodomain genes in tobacco. The tobacco homeodomain gene family is similar to the plant homeodomain families in other higher plants (Chan et al, 1998;Haecker et al, 2004;Hake et al, 2004;Prigge et al, 2005) and can be divided into nine major subgroups, the knotted class 1, knotted class 2, PHD finger, Bell, glabra, HDZip class 1, HDZip class 2, HDZip class 3, and WOX classes (Supplemental Fig. S2).…”

Section: The Homeodomain Familymentioning

confidence: 99%

Tobacco Transcription Factors: Novel Insights into Transcriptional Regulation in the Solanaceae

Rushton

Bokowiec²,

Han³

et al. 2008

Plant Physiology

240

179

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Tobacco (Nicotiana tabacum) is a member of the Solanaceae, one of the agronomically most important groups of flowering plants. We have performed an in silico analysis of 1.15 million gene-space sequence reads from the tobacco nuclear genome and report the detailed analysis of more than 2,500 tobacco transcription factors (TFs). The tobacco genome contains at least one member of each of the 64 well-characterized TF families identified in sequenced vascular plant genomes, indicating that evolution of the Solanaceae was not associated with the gain or loss of TF families. However, we found notable differences between tobacco and non-Solanaceae species in TF family size and evidence for both tobacco-and Solanaceae-specific subfamily expansions. Compared with TF families from sequenced plant genomes, tobacco has a higher proportion of ERF/AP2, C2H2 zinc finger, homeodomain, GRF, TCP, zinc finger homeodomain, BES, and STERILE APETALA (SAP) genes and novel subfamilies of BES, C2H2 zinc finger, SAP, and NAC genes. The novel NAC subfamily, termed TNACS, appears restricted to the Solanaceae, as they are absent from currently sequenced plant genomes but present in tomato (Solanum lycopersicum), pepper (Capsicum annuum), and potato (Solanum tuberosum). They constitute approximately 25% of NAC genes in tobacco. Based on our phylogenetic studies, we predict that many of the more than 50 tobacco group IX ERF genes are involved in jasmonate responses. Consistent with this, over two-thirds of group IX ERF genes tested showed increased mRNA levels following jasmonate treatment. Our data are a major resource for the Solanaceae and fill a void in studies of TF families across the plant kingdom.

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“…Members of the KNOTTED1-like HO-MEOBOX1 (KNOX1) gene family are known to promote cytokinin biosynthesis in the shoot apical meristem (SAM) (Jasinski et al, 2005), and KNOX1 genes are well established as regulators of indeterminate identity in the SAM throughout angiosperms (Chuck et al, 1996(Chuck et al, , 1998Long et al, 1996;Kerstetter et al, 1997;Hake et al, 2004). Furthermore, KNOX1 expression has been modified repeatedly over evolutionary time to confer prolonged indeterminate identity during organogenic processes within lateral organs (Sinha et al, 1993;Bharathan et al, 2002;Pham and Sinha, 2003;Tsiantis, 2005;Hay and Tsiantis, 2006).…”

Section: Introductionmentioning

confidence: 99%

Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism

et al. 2012

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Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA-mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection.

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THE ROLE OF KNOX GENES IN PLANT DEVELOPMENT

Cited by 402 publications

References 132 publications

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

Tobacco Transcription Factors: Novel Insights into Transcriptional Regulation in the Solanaceae

Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism

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