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Raspor M, Mrvaljević M, Savić J, Ćosić T, Kaleri AR, Pokimica N, Cingel A, Ghalawnji N, Motyka V, Ninković S. Cytokinin deficiency confers enhanced tolerance to mild, but decreased tolerance to severe salinity stress in in vitro grown potato. FRONTIERS IN PLANT SCIENCE 2024; 14:1296520. [PMID: 38362121 PMCID: PMC10867153 DOI: 10.3389/fpls.2023.1296520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/29/2023] [Indexed: 02/17/2024]
Abstract
Cytokinin (CK) is a plant hormone that plays crucial roles in regulating plant growth and development. CK-deficient plants are widely used as model systems for investigating the numerous physiological roles of CK. Since it was previously shown that transgenic or mutant CK-deficient Arabidopsis and Centaurium plants show superior tolerance to salinity, we examined the tolerance of three CK-deficient potato lines overexpressing the Arabidopsis thaliana CYTOKININ OXIDASE/DEHYDROGENASE2 (AtCKX2) gene to 50 mM, 100 mM, 150 mM, and 200 mM NaCl applied in vitro. Quantification of visible salinity injury, rooting and acclimatization efficiency, shoot growth, water saturation deficit, and chlorophyll content confirmed that the CK-deficient potato plants were more tolerant to low (50 mM) and moderate (100 mM) NaCl concentrations, but exhibited increased sensitivity to severe salinity stress (150 and 200 mM NaCl) compared to non-transformed control plants. These findings were corroborated by the data distribution patterns according to principal component analysis. Quantification of the activity of superoxide dismutases, peroxidases, and catalases revealed an impaired ability of AtCKX2-transgenic lines to upregulate the activity of antioxidant enzymes in response to salinity, which might contribute to the enhanced sensitivity of these potato lines to severe salt stress. Our results add complexity to the existing knowledge on the regulation of salinity tolerance by CK, as we show for the first time that CK-deficient plants can exhibit reduced rather than increased tolerance to severe salt stress.
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Affiliation(s)
- Martin Raspor
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Miloš Mrvaljević
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Jelena Savić
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Tatjana Ćosić
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Abdul Rasheed Kaleri
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
| | - Nina Pokimica
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Aleksandar Cingel
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Nabil Ghalawnji
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Václav Motyka
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Slavica Ninković
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Cammarata J, Roeder AHK, Scanlon MJ. The ratio of auxin to cytokinin controls leaf development and meristem initiation in Physcomitrium patens. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6541-6550. [PMID: 37498739 DOI: 10.1093/jxb/erad299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/25/2023] [Indexed: 07/29/2023]
Abstract
Crosstalk between auxin and cytokinin contributes to widespread developmental processes, including root and shoot meristem maintenance, phyllotaxy, and vascular patterning. However, our understanding of crosstalk between these hormones is limited primarily to angiosperms. The moss Physcomitrium patens (formerly Physcomitrella patens) is a powerful system for studying plant hormone function. Auxin and cytokinin play similar roles in regulating moss gametophore (shoot) architecture, to those in flowering plant shoots. However, auxin-cytokinin crosstalk is poorly understood in moss. Here we find that the ratio of auxin to cytokinin is an important determinant of development in P. patens, especially during leaf development and branch stem cell initiation. Addition of high levels of auxin to P. patens gametophores blocks leaf outgrowth. However, simultaneous addition of high levels of both auxin and cytokinin partially restores leaf outgrowth, suggesting that the ratio of these hormones is the predominant factor. Likewise, during branch initiation and outgrowth, chemical inhibition of auxin synthesis phenocopies cytokinin application. Finally, cytokinin-insensitive mutants resemble plants with altered auxin signaling and are hypersensitive to auxin. In summary, our results suggest that the ratio between auxin and cytokinin signaling is the basis for developmental decisions in the moss gametophore.
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Affiliation(s)
- Joseph Cammarata
- School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Adrienne H K Roeder
- School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Michael J Scanlon
- School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
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3
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Kotov AA, Kotova LM. Auxin/cytokinin antagonism in shoot development: from moss to seed plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6391-6395. [PMID: 37988175 DOI: 10.1093/jxb/erad417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023]
Abstract
This article comments on:Cammarata J, Roeder AHK, Scanlon MJ. 2023. The ratio of auxin to cytokinin controls leaf development and meristem initiation in Physcomitrium patens. Journal of Experimental Botany 74, 6541–6550.
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Affiliation(s)
- Andrey A Kotov
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
| | - Liudmila M Kotova
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
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4
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Lomin SN, Kolachevskaya OO, Arkhipov DV, Romanov GA. Canonical and Alternative Auxin Signaling Systems in Mono-, Di-, and Tetraploid Potatoes. Int J Mol Sci 2023; 24:11408. [PMID: 37511169 PMCID: PMC10380454 DOI: 10.3390/ijms241411408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
It has long been known that the phytohormone auxin plays a promoting role in tuber formation and stress tolerance in potatoes. Our study aimed to identify and characterize the complete sets of auxin-related genes that presumably constitute the entire auxin signaling system in potato (Solanum tuberosum L.). The corresponding genes were retrieved from sequenced genomes of the doubled monoploid S. tuberosum DM1-3-516-R44 (DM) of the Phureja group, the heterozygous diploid line RH89-039-16 (RH), and the autotetraploid cultivar Otava. Both canonical and noncanonical auxin signaling pathways were considered. Phylogenetic and domain analyses of deduced proteins were supplemented by expression profiling and 3D molecular modeling. The canonical and ABP1-mediated pathways of auxin signaling appeared to be well conserved. The total number of potato genes/proteins presumably involved in canonical auxin signaling is 46 and 108 in monoploid DM and tetraploid Otava, respectively. Among the studied potatoes, spectra of expressed genes obviously associated with auxin signaling were partly cultivar-specific and quite different from analogous spectrum in Arabidopsis. Most of the noncanonical pathways found in Arabidopsis appeared to have low probability in potato. This was equally true for all cultivars used irrespective of their ploidy. Thus, some important features of the (noncanonical) auxin signaling pathways may be variable and species-specific.
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Affiliation(s)
- Sergey N Lomin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
| | - Oksana O Kolachevskaya
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
| | - Dmitry V Arkhipov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
| | - Georgy A Romanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia
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Bai Y, Cai M, Dou Y, Xie Y, Zheng H, Gao J. Phytohormone Crosstalk of Cytokinin Biosynthesis and Signaling Family Genes in Moso Bamboo ( Phyllostachys edulis). Int J Mol Sci 2023; 24:10863. [PMID: 37446040 DOI: 10.3390/ijms241310863] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/21/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
Cytokinin is widely involved in the regulation of plant growth, but its pathway-related genes have not been reported in Moso bamboo. In this study, a total of 129 candidate sequences were identified by bioinformatic methods. These included 15 IPT family genes, 19 LOG family genes, 22 HK family genes, 11 HP family genes and 62 RR family genes. Phylogenetic analysis revealed that the cytokinin pathway was closely related to rice, and evolutionary pattern analysis found that most of the genes have syntenic relationship with rice-related genes. The Moso bamboo cytokinin pathway was evolutionarily conservative and mainly underwent purifying selection, and that gene family expansion was mainly due to whole-gene duplication events. Analysis of transcriptome data revealed a tissue-specific expression pattern of Moso bamboo cytokinin family genes, with auxin and gibberellin response patterns. Analysis of co-expression patterns at the developmental stages of Moso bamboo shoots revealed the existence of a phytohormone co-expression pattern centered on cytokinin signaling genes. The auxin signaling factor PheARF52 was identified by yeast one-hybrid assay as regulating the PheRR3 gene through a P-box element in the PheRR3 promoter region. Auxin and cytokinin signaling crosstalk to regulate Moso bamboo growth. Overall, we systematically identified and analyzed key gene families of the cytokinin pathway in Moso bamboo and obtained key factors for auxin and cytokinin crosstalk, laying the foundation for the study of hormone regulation in Moso bamboo.
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Affiliation(s)
- Yucong Bai
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
| | - Miaomiao Cai
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
| | - Yuping Dou
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
| | - Yali Xie
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
| | - Huifang Zheng
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
| | - Jian Gao
- Key Laboratory of National Forestry and Grassland Administration, Beijing for Bamboo & Rattan Science and Technology, International Center for Bamboo and Rattan, Beijing 100102, China
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6
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Perception, Transduction and Crosstalk of Auxin and Cytokinin Signals. Int J Mol Sci 2022; 23:ijms232113150. [DOI: 10.3390/ijms232113150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 10/27/2022] [Indexed: 11/17/2022] Open
Abstract
Auxins and cytokinins are considered the most important plant hormones, responsible for fundamental traits of the plant organism [...]
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Zheng W, Shi J, Zhu ZY, Jin P, Chen JH, Zhang L, Zhang E, Lin T, Zhu ZJ, Zang YX, Wu JG. Transcriptomic analysis of succulent stem development of Chinese kale ( Brassica oleracea var. alboglabra Bailey) and its synthetic allotetraploid via RNA sequencing. FRONTIERS IN PLANT SCIENCE 2022; 13:1004590. [PMID: 36340371 PMCID: PMC9630916 DOI: 10.3389/fpls.2022.1004590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Chinese kale (Brassica oleracea var. alboglabra Bailey, CC) is a succulent stem vegetable in the Brassica family. Its allotetraploid (AACC) vegetable germplasm, which was synthesized via distant hybridization with the colloquially named 'yellow turnip' (B. rapa L. ssp. rapifera Matzg., AA), has a swelling stem similar to CC. To address the molecular mechanism of stem development for CC and AACC, RNA sequencing (RNA-seq) was used to investigate transcriptional regulation of their stem development at three key stages including 28 days, 42 days and the bolting stage (BS) after sowing. As a result, 32,642, 32,665, 33,816, 32,147, 32,293 and 32,275 genes were identified in six corresponding cDNA libraries. Among them, 25,459 genes were co-expressed, while 7,183, 7,206, 8,357, 6,688, 6,834 and 6,814 genes were specifically expressed. Additionally, a total of 29,222 differentially expressed genes (DEGs) were found for functional enrichment as well as many genes involved in plant hormones including gibberellin (GA), abscisic acid (ABA), cytokinin (CTK) and auxin (AUX). Based on gene expression consistency between CC and AACC, the gene families including DELLA, GID, PYR/PYL, PP2C, A-ARR and AUX/IAA might be related to stem development. Among these, eight genes including Bo00834s040, Bo5g093140, Bo6g086770, Bo9g070200, Bo7g116570, Bo3g054410, Bo7g093470 and Bo5g136600 may play important roles in stem development based on their remarkable expression levels as confirmed by qRT-PCR. These findings provide a new theoretical basis for understanding the molecular mechanism of stem development in Brassica vegetable stem breeding.
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Affiliation(s)
- Wen Zheng
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Jiang Shi
- Institute of Crop Science, Hangzhou Academy of Agricultural Sciences, Hangzhou, China
| | - Zhi-Yu Zhu
- College of Modern Agriculture, Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Ping Jin
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Jia-Hong Chen
- Department of Health and Agriculture, Hangzhou Wanxiang Polytechnic, Hangzhou, China
| | - Liang Zhang
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - E. Zhang
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Tao Lin
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Zhu-Jun Zhu
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Yun-Xiang Zang
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
| | - Jian-Guo Wu
- College of Horticulture Science, Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, Zhejiang A&F University, Hangzhou, China
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Xue Z, Huang F, Liu J, Ke Y, Wei H, Gao P, Qi Y, Yu L. A high trans-zeatin nucleoside concentration in corms may promote the multileaf growth of Amorphophallus muelleri. FRONTIERS IN PLANT SCIENCE 2022; 13:964003. [PMID: 36275554 PMCID: PMC9583388 DOI: 10.3389/fpls.2022.964003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Amorphophallus muelleri has a multileaf growth pattern different from that of other konjacs; however, the hormonal mechanism underlying this phenomenon is not clear. In this study, the levels of hormones closely related to the sprouting of the axillary bud, including five types of cytokinins, indole-3-acetic acid (IAA) and abscisic acid (ABA) were measured. In the second leaf sprouting stage, the content of trans-zeatin riboside (tZR) in corms increased more than 5000-fold over that in the dormancy period. Surprisingly, although the expression of CYP735A1 and CYP735A2, which synthesize the precursors for tZR was elevated at the second leaf sprouting stage, the expression of IPTs, which have key roles in cytokinin biosynthesis, did not change significantly. In addition, most cytokinin contents in leaves during the same period were significantly lower than those in corms. We speculate that the high cytokinin contents in the corms may not biosynthesized de novo in corms. In addition, the IAA content in the corms also considerably increased during the second leaf sprouting stage. Indole-3-acetaldehyde oxidase (AO1) and auxin efflux carrier PIN1A, presented relatively high expression levels in the same period. In contrast, ABA content, and the expression of NCED1, a rate-limiting enzyme in ABA biosynthesis, were suppressed at the second leaf sprouting stage. It is worth mentioning that N6-(Δ2-isopentenyl) adenosine (iP)-type cytokinins have a high content in corms in the dormant period that significantly decreases after the first leaf sprouting stage, which is completely different from the trend of tZR. By treating dormant corms with iP, the percentage of multibud plants increased, and the growth performance in terms of bud and root length was significantly higher than those of the control. This implies that iP-type cytokinins tend to play a role in promoting first seedling sprouting. Furthermore, there was a remarkable increase of the IAA content in both corms and roots under iP treatment but an inhibitory effect in buds. We speculate that the increase in the IAA content induced by iP is tissue specific. These results will assist in the understanding of the role of hormones, especially cytokinins, in the multileaf growth type of konjac.
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Affiliation(s)
| | | | | | | | | | | | - Ying Qi
- *Correspondence: Ying Qi, ; Lei Yu,
| | - Lei Yu
- *Correspondence: Ying Qi, ; Lei Yu,
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Rasskazov D, Chadaeva I, Sharypova E, Zolotareva K, Khandaev B, Ponomarenko P, Podkolodnyy N, Tverdokhleb N, Vishnevsky O, Bogomolov A, Podkolodnaya O, Savinkova L, Zemlyanskaya E, Golubyatnikov V, Kolchanov N, Ponomarenko M. Plant_SNP_TATA_Z-Tester: A Web Service That Unequivocally Estimates the Impact of Proximal Promoter Mutations on Plant Gene Expression. Int J Mol Sci 2022; 23:ijms23158684. [PMID: 35955817 PMCID: PMC9369029 DOI: 10.3390/ijms23158684] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
Synthetic targeted optimization of plant promoters is becoming a part of progress in mainstream postgenomic agriculture along with hybridization of cultivated plants with wild congeners, as well as marker-assisted breeding. Therefore, here, for the first time, we compiled all the experimental data—on mutational effects in plant proximal promoters on gene expression—that we could find in PubMed. Some of these datasets cast doubt on both the existence and the uniqueness of the sought solution, which could unequivocally estimate effects of proximal promoter mutation on gene expression when plants are grown under various environmental conditions during their development. This means that the inverse problem under study is ill-posed. Furthermore, we found experimental data on in vitro interchangeability of plant and human TATA-binding proteins allowing the application of Tikhonov’s regularization, making this problem well-posed. Within these frameworks, we created our Web service Plant_SNP_TATA_Z-tester and then determined the limits of its applicability using those data that cast doubt on both the existence and the uniqueness of the sought solution. We confirmed that the effects (of proximal promoter mutations on gene expression) predicted by Plant_SNP_TATA_Z-tester correlate statistically significantly with all the experimental data under study. Lastly, we exemplified an application of Plant_SNP_TATA_Z-tester to agriculturally valuable mutations in plant promoters.
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Affiliation(s)
| | - Irina Chadaeva
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | | | | | - Bato Khandaev
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | | | - Nikolay Podkolodnyy
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
- Institute of Computational Mathematics and Mathematical Geophysics, 630090 Novosibirsk, Russia
| | | | - Oleg Vishnevsky
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | - Anton Bogomolov
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | | | | | | | | | | | - Mikhail Ponomarenko
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
- Correspondence: ; Tel.: +7-(383)-363-4963 (ext. 1311)
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Kurepa J, Smalle JA. Auxin/Cytokinin Antagonistic Control of the Shoot/Root Growth Ratio and Its Relevance for Adaptation to Drought and Nutrient Deficiency Stresses. Int J Mol Sci 2022; 23:ijms23041933. [PMID: 35216049 PMCID: PMC8879491 DOI: 10.3390/ijms23041933] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 01/19/2023] Open
Abstract
The hormones auxin and cytokinin regulate numerous aspects of plant development and often act as an antagonistic hormone pair. One of the more striking examples of the auxin/cytokinin antagonism involves regulation of the shoot/root growth ratio in which cytokinin promotes shoot and inhibits root growth, whereas auxin does the opposite. Control of the shoot/root growth ratio is essential for the survival of terrestrial plants because it allows growth adaptations to water and mineral nutrient availability in the soil. Because a decrease in shoot growth combined with an increase in root growth leads to survival under drought stress and nutrient limiting conditions, it was not surprising to find that auxin promotes, while cytokinin reduces, drought stress tolerance and nutrient uptake. Recent data show that drought stress and nutrient availability also alter the cytokinin and auxin signaling and biosynthesis pathways and that this stress-induced regulation affects cytokinin and auxin in the opposite manner. These antagonistic effects of cytokinin and auxin suggested that each hormone directly and negatively regulates biosynthesis or signaling of the other. However, a growing body of evidence supports unidirectional regulation, with auxin emerging as the primary regulatory component. This master regulatory role of auxin may not come as a surprise when viewed from an evolutionary perspective.
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11
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Cytokinin Perception in Ancient Plants beyond Angiospermae. Int J Mol Sci 2021; 22:ijms222313077. [PMID: 34884882 PMCID: PMC8657898 DOI: 10.3390/ijms222313077] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022] Open
Abstract
Cytokinins (CKs) control many plant developmental processes and responses to environmental cues. Although the CK signaling is well understood, we are only beginning to decipher its evolution. Here, we investigated the CK perception apparatus in early-divergent plant species such as bryophyte Physcomitrium patens, lycophyte Selaginella moellendorffii, and gymnosperm Picea abies. Of the eight CHASE-domain containing histidine kinases (CHKs) examined, two CHKs, PpCHK3 and PpCHK4, did not bind CKs. All other CHK receptors showed high-affinity CK binding (KD of nM range), with a strong preference for isopentenyladenine over other CK nucleobases in the moss and for trans-zeatin over cis-zeatin in the gymnosperm. The pH dependences of CK binding for these six CHKs showed a wide range, which may indicate different subcellular localization of these receptors at either the plasma- or endoplasmic reticulum membrane. Thus, the properties of the whole CK perception apparatuses in early-divergent lineages were demonstrated. Data show that during land plant evolution there was a diversification of the ligand specificity of various CHKs, in particular, the rise in preference for trans-zeatin over cis-zeatin, which indicates a steadily increasing specialization of receptors to various CKs. Finally, this distinct preference of individual receptors to different CK versions culminated in vascular plants, especially angiosperms.
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