Type-B ARRs Control Carpel Regeneration Through Mediating AGAMOUS Expression in Arabidopsis

Rong, Xiao; Sang, Ya Lin; Wang, Liang; Meng, Wen Jing; Zou, Chun Hao; Dong, Yu; Bie, Xiao Min; Cheng, Zhi Juan; Zhang, Xian Sheng

doi:10.1093/pcp/pcx187

Cited by 21 publications

(15 citation statements)

References 48 publications

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“…In Arabidopsis, disruption of this pathway at multiple stages has resulted in modified reproductive development, with cytokinin typically being implicated in enhancing development of female floral parts [46]. For example, it has recently been shown that the Type B response regulators ARR1 and ARR10 bind to the promoter region of the floral homeotic gene AGAMOUS , and down-regulation of these genes inhibits carpel regeneration in an in vitro assay [49]. Similarly, triple mutants of ARR1 , ARR10 , and ARR12 have severely compromised gynoecial development [50].…”

Section: Discussionmentioning

confidence: 99%

A Willow Sex Chromosome Reveals Convergent Evolution of Complex Palindromic Repeats

Zhou

Macaya‐Sanz

Carlson

et al. 2019

Preprint

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1 Background 2 Sex chromosomes in a wide variety of species share common characteristics, including the 3 presence of suppressed recombination surrounding sex determination loci. They have arisen 4 independently in numerous lineages, providing a conclusive example of convergent evolution. 5Mammalian sex chromosomes contain multiple palindromic repeats across the non-recombining 6 region that facilitate sequence conservation through gene conversion, and contain genes that are 7 crucial for sexual reproduction. Plant sex chromosomes are less well understood, and in 8 particular it is not clear how coding sequence conservation is maintained in the absence of 9 homologous recombination. 10 Results 11 Here we present the first evidence of large palindromic structures in a plant sex chromosome, 12 based on a highly contiguous assembly of the W chromosome of the dioecious shrub Salix 13 purpurea. Two consecutive palindromes span over a region of 200 kb, with conspicuous 20 kb 14 stretches of highly conserved sequences among the four arms. The closely-related species S. 15 suchowensis also has two copies of a portion of the palindrome arm and provides strong 16 evidence for gene conversion. Four genes in the palindrome are homologous to genes in the SDR 17 of the closely-related genus Populus, which is located on a different chromosome. These genes 18 show distinct, floral-biased expression patterns compared to paralogous copies on autosomes.19 Conclusion 20The presence of palindromic structures in sex chromosomes of mammals and plants highlights 21 the intrinsic importance of these features in adaptive evolution in the absence of recombination. 22Convergent evolution is driving both the independent establishment of sex chromosomes as well 23 as their fine-scale sequence structure. 24 26 103 297 kb in length lacked mapped markers and could not be placed unambiguously. 104Location of the SDR 105 We repeated sex association analysis with our new assembly with Chr15Z removed. 106Among 54,959 tested SNPs, all 105 significantly sex-associated SNPs were present only on 107 Chr15W (Fig. 1a; Additional File 2: Figure S2a-c), and markers from PARs and other scaffolds 108 in the main genome did not show any sex association (Additional File 2: Figure S2a). The eight 109 top-ranking sex-associated markers were distributed from 7.66 Mb to 8.66 Mb. Sex-associated 110 markers were primarily heterozygous in females and homozygous in males, confirming our 111 previously-reported observation of ZW sex determination in S. purpurea [18].

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Section: Discussionmentioning

confidence: 99%

A Willow Sex Chromosome Reveals Convergent Evolution of Complex Palindromic Repeats

Zhou

Macaya‐Sanz

Carlson

et al. 2019

Preprint

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“…Finally, carpel regeneration was impaired in AG amiRNA lines, confirming the requirement of this gene during carpel formation. Although these experiments were performed in a carpel-inducing system, they suggest that the cytokinin-dependent control of AG expression, through ARR1 and ARR10, might also be functional during normal carpel development [27].…”

Section: Flower Developmentmentioning

confidence: 99%

“…For example, in loss-of-function lines of ARR1 and ARR10, carpel (see Glossary) regeneration from callus was impaired [27]. These B-type ARRs were shown to bind the AGAMOUS (AG) promoter region and induce expression of this carpel identity defining gene.…”

Section: Flower Developmentmentioning

confidence: 99%

“…Although great advances have been made, the real challenge will be to understand how cytokinins regulate these developmental processes at a molecular level. For example, regulation of WUS and AG expression levels through specific B-type ARRs explains how cytokinins can promote shoot formation [19][20][21][22][23]27]. However, examples of these direct links to key developmental regulators are still very scarce.…”

Section: Concluding Remarks and Future Perspectivesmentioning

confidence: 99%

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Cytokinin – A Developing Story

Wybouw

Rybel

2019

Trends in Plant Science

176

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In the past decade, tremendous advance has been made in understanding the biosynthesis, perception and signaling pathways of the plant hormone cytokinin. It also became clear that interfering with any of these steps greatly impacts all stages of growth and development. This has spurted renewed effort recently to understand how cytokinin signaling affects developmental processes. As a result, new insights on the role of cytokinin signaling and the downstream targets during e.g. shoot apical meristem, flower, female gametophyte, stomata and vascular development are being unraveled. In this review, we aim to give a comprehensive overview of recent findings on how cytokinin influences growth and development in plants and highlight areas for future research. 2 Cytokinins: from signaling to development Cytokinins, a class of phytohormones with diverse molecular structures [1], were first discovered in the late 1950's while looking for the molecule responsible for the growthpromoting activity of autoclaved herring sperm DNA [2]. Since then, the signaling pathway of cytokinins has been intensely studied. In our current understanding, cytokinins are synthesized by the ISOPENTENYL TRANSFERASE (IPT) and LONELY GUY (LOG) enzymes, whereas cytokinin conjugation act mainly through CYTOKININ OXIDASE (CKX) enzymes.Cytokinins are next perceived by the ARABIDOPSIS HISTIDINE KINASE2-4 (AHK2-4) receptors which initiates a phosphorylation signaling cascade. This phospho-relay starts with auto-phosphorylation of the receptors and will ultimately lead to phosphorylation and activation of B-type ARABIDOPSIS REPSONSE REGULATORS (ARRs) through the ARABIDOPSIS HISTIDINE PROTEINS (AHPs). The active ARRs will then induce cytokinin responsive genes, such as those encoding the cytokinin signaling repressors A-type ARRs or CYTOKININ RESPONSE FACTORS (CRFs). For detailed information on the biosynthesis, transport, perception and signaling cascades of cytokinins, we refer to several excellent recent reviews [1,[3][4][5]. With the now well studied aspect of cytokinin signaling, the next step is to understand how these processes impinge on plant growth and development. Over the past few years, an increasing number of studies highlight the importance of cytokinins during many developmental processes. In this review, we discuss how these insights aid in understanding how cytokinins controls development at a molecular level. Shoot developmentAlready in the early years of cytokinin research, it was clear that these molecules have a big influence on plant growth, especially together with auxin [6,7]. Plants grown on high levels of auxin and cytokinin massively proliferate and dedifferentiate leading to callus (see Glossary).Growing callus on high cytokinin levels induces shoot regeneration [6]. Based on these classical experiments, cytokinins are considered the main class of hormones involved in shoot development. Cytokinin controls shoot cell fateCytokinin signaling was shown to be vital in the context of shoot apical meristem (SAM; see Glossary) develo...

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“…Thus, the flower number can be controlled by modulating the cytokinin levels.At the early flower developmental stage of a meristem-organizing center to be formed, cytokinins establish the meristematic competence of the floral meristem [23]. During pistil establishment, the cytokinin signaling B-type regulators ARABIDOPSIS RESPONSE REGULATOR (ARR)1 and ARR10 bind to the promoter of AGAMOUS (AG) and thereby induce expression of this carpel identity gene [24]. In addition, the pistils were absent in rice log mutant, in which active cytokinin levels were reduced [11], and absence of the SHOOT MERISTEMLESS (STM) gene, an activator of cytokinin biosynthesis, in Arabidopsis also results in the production of flowers without pistils.…”

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confidence: 99%

Flower-Specific Overproduction of Cytokinins Altered Flower Development and Sex Expression in the Perennial Woody Plant Jatropha curcas L.

Xin

Tao

et al. 2020

IJMS

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Jatropha curcas L. is monoecious with a low female-to-male ratio, which is one of the factors restricting its seed yield. Because the phytohormone cytokinins play an essential role in flower development, particularly pistil development, in this study, we elevated the cytokinin levels in J. curcas flowers through transgenic expression of a cytokinin biosynthetic gene (AtIPT4) from Arabidopsis under the control of a J. curcas orthologue of TOMATO MADS BOX GENE 6 (JcTM6) promoter that is predominantly active in flowers. As expected, the levels of six cytokinin species in the inflorescences were elevated, and flower development was modified without any alterations in vegetative growth. In the transgenic J. curcas plants, the flower number per inflorescence was significantly increased, and most flowers were pistil-predominantly bisexual, i.e., the flowers had a huge pistil surrounded with small stamens. Unfortunately, both the male and the bisexual flowers of transgenic J. curcas were infertile, which might have resulted from the continuously high expression of the transgene during flower development. However, the number and position of floral organs in the transgenic flowers were well defined, which suggested that the determinacy of the floral meristem was not affected. These results suggest that fine-tuning the endogenous cytokinins can increase the flower number and the female-to-male ratio in J. curcas.

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Type-B ARRs Control Carpel Regeneration Through Mediating AGAMOUS Expression in Arabidopsis

Cited by 21 publications

References 48 publications

A Willow Sex Chromosome Reveals Convergent Evolution of Complex Palindromic Repeats

A Willow Sex Chromosome Reveals Convergent Evolution of Complex Palindromic Repeats

Cytokinin – A Developing Story

Flower-Specific Overproduction of Cytokinins Altered Flower Development and Sex Expression in the Perennial Woody Plant Jatropha curcas L.

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