1
|
Cui Y, He M, Liu J, Wang S, Zhang J, Xie S, Hu Z, Guo S, Yan D. Maize LOST SUBSIDIARY CELL encoding a large subunit of ribonucleotide reductase is required for subsidiary cell development and plant growth. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4449-4460. [PMID: 37103989 PMCID: PMC10433938 DOI: 10.1093/jxb/erad153] [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: 12/13/2022] [Accepted: 04/26/2023] [Indexed: 06/19/2023]
Abstract
The four-celled stomatal complex consists of a pair of guard cells (GCs) and two subsidiary cells (SCs) in grasses, which supports a fast adjustment of stomatal aperture. The formation and development of SCs are thus important for stomatal functionality. Here, we report a maize lost subsidiary cells (lsc) mutant, with many stomata lacking one or two SCs. The loss of SCs is supposed to have resulted from impeded subsidiary mother cell (SMC) polarization and asymmetrical division. Besides the defect in SCs, the lsc mutant also displays a dwarf morphology and pale and striped newly-grown leaves. LSC encodes a large subunit of ribonucleotide reductase (RNR), an enzyme involved in deoxyribonucleotides (dNTPs) synthesis. Consistently, the concentration of dNTPs and expression of genes involved in DNA replication, cell cycle progression, and SC development were significantly reduced in the lsc mutant compared with the wild-type B73 inbred line. Conversely, overexpression of maize LSC increased dNTP synthesis and promoted plant growth in both maize and Arabidopsis. Our data indicate that LSC regulates dNTP production and is required for SMC polarization, SC differentiation, and growth of maize.
Collapse
Affiliation(s)
- Yongqi Cui
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Meiqing He
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Jie Liu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Shuang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Junli Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Shiyi Xie
- Maize Engineering and Technology Research Center of Hunan Province, College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Zhubing Hu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Siyi Guo
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| | - Dawei Yan
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng 475004, China
| |
Collapse
|
2
|
Shen W, Sun J, Xiao Z, Feng P, Zhang T, He G, Sang X. Narrow and Stripe Leaf 2 Regulates Leaf Width by Modulating Cell Cycle Progression in Rice. RICE (NEW YORK, N.Y.) 2023; 16:20. [PMID: 37071312 PMCID: PMC10113404 DOI: 10.1186/s12284-023-00634-3] [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: 09/23/2022] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Leaf morphology is an important component of the idea plant architecture that extensively influences photosynthesis, transpiration, and ultimately grain yield in crops. However, the genetic and molecular mechanisms regulating this morphology remain largely unclear. RESULTS In this study, a mutant showing a narrow and stripe leaf phonotype, designated nsl2, was obtained. Histological analysis revealed defects in the vascular system and reduced epidermal cell number in the nsl2, while the cell size remained unchanged. Map-based cloning and genetic complementation experiments revealed that NSL2, which encodes a small subunit of ribonucleotide reductases (RNRs), is a null allelic with ST1 and SDL. The NSL2 was expressed in variety of tissues, with the highest levels detected in leaves, and its protein was localized in the nucleus and cytoplasm. The dNTPs level was altered in the nsl2 mutant, and thereby affecting the dNTPs pool balance. In addition, flow cytometric analysis and the altered transcript level of genes related to cell cycle indicated that NSL2 affects cell cycle progression. CONCLUSIONS Our findings here suggest that NSL2 function in the synthesis of dNTP, the deficient of which leads to DNA synthesis block and in turn affects cell cycle progression, and ultimately decreased cell number and narrow leaf in the nsl2 plant.
Collapse
Affiliation(s)
- Wenqiang Shen
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Jiajie Sun
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Zan Xiao
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Ping Feng
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Ting Zhang
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Guanghua He
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| | - Xianchun Sang
- Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China
| |
Collapse
|
3
|
Liang H, He Q, Zhang H, Zhi H, Tang S, Wang H, Meng Q, Jia G, Chang J, Diao X. Identification and haplotype analysis of SiCHLI: a gene for yellow-green seedling as morphological marker to accelerate foxtail millet (Setaria italica) hybrid breeding. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:24. [PMID: 36739566 DOI: 10.1007/s00122-023-04309-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
We cloned and developed functional markers for the SiCHLI gene, which is responsible for the yellow-green color of leaves in foxtail millet, a frequently used marker trait in the hybrid breeding of foxtail millet by using bulked segregant analysis sequencing and haplotype analysis on the F2 and core-collected nature populations. The color of leaves has been widely used as a marker for the hybrid breeding of foxtail millet; however, few related gene have been cloned to date. Here, we used two F2 populations generated from crosses between the highly male-sterile material 125A with yellow-green leaves, and CG58 and S410, which have green leaves, to identify the genes underlying the yellow-green color of the leaves of foxtail millet. The leaves of 125A seedlings were yellow-green, but they became green at the heading stage. The content of chlorophyll a and chlorophyll b was lower, the number of thylakoid lamellae and grana was reduced, and the chloroplasts was more rounded in 125A than in S410 at the yellow-green leaf stage; however, no differences were observed between 125A and S410 in these traits and photosynthetic at the heading stage. Bulked segregant analysis and map-based cloning revealed that the SiCHLI gene is responsible for the leaf colors of 125A. A nonsynonymous mutation (C/T) in exon 3 causes yellow-green leaves in 125A at the seedling stage. Haplotype analysis of the SiCHLI gene in 596 core collected accessions revealed a new haplotype associated with high photosynthetic metabolic potential at the heading and mature stages, which could be used to enhance sterile lines with yellow-green leaves. We developed a functional marker that will facilitate the identification of foxtail millet accessions with the different types of yellow-green leaves. Generally, our study provides new genetic resources to guide the future marker-assisted or target-base editing in foxtail millet hybrid breeding.
Collapse
Affiliation(s)
- Hongkai Liang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Qiang He
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Hui Zhang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Hui Zhi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Sha Tang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Hailong Wang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Qiang Meng
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Guanqing Jia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China
| | - Jinhua Chang
- College of Agronomy, Agricultural University of Hebei, Baoding, 071001, China
| | - Xianmin Diao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, Haidian, China.
| |
Collapse
|
4
|
Gu M, Lu Q, Liu Y, Cui M, Si Y, Wu H, Chai T, Ling HQ. Requirement and functional redundancy of two large ribonucleotide reductase subunit genes for cell cycle, chloroplast biogenesis and photosynthesis in tomato. ANNALS OF BOTANY 2022; 130:173-187. [PMID: 35700127 PMCID: PMC9445600 DOI: 10.1093/aob/mcac078] [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: 02/23/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Ribonucleotide reductase (RNR), functioning in the de novo synthesis of deoxyribonucleoside triphosphates (dNTPs), is crucial for DNA replication and cell cycle progression. In most plants, the large subunits of RNR have more than one homologous gene. However, the different functions of these homologous genes in plant development remain unknown. In this study, we obtained the mutants of two large subunits of RNR in tomato and studied their functions. METHODS The mutant ylc1 was obtained by ethyl methyl sulfonate (EMS) treatment. Through map-based cloning, complementation and knock-out experiments, it was confirmed that YLC1 encodes a large subunit of RNR (SlRNRL1). The expression level of the genes related to cell cycle progression, chloroplast biogenesis and photosynthesis was assessed by RNA-sequencing. In addition, we knocked out SlRNRL2 (a SlRNRL1 homologue) using CRISPR-Cas9 technology in the tomato genome, and we down-regulated SlRNRL2 expression in the genetic background of slrnrl1-1 using a tobacco rattle virus-induced gene silencing (VIGS) system. KEY RESULTS The mutant slrnrl1 exhibited dwarf stature, chlorotic young leaves and smaller fruits. Physiological and transcriptomic analyses indicated that SlRNRL1 plays a crucial role in the regulation of cell cycle progression, chloroplast biogenesis and photosynthesis in tomato. The slrnrl2 mutant did not exhibit any visible phenotype. SlRNRL2 has a redundant function with SlRNRL1, and the double mutant slrnrl1slrnrl2 is lethal. CONCLUSIONS SlRNRL1 is essential for cell cycle progression, chloroplast biogenesis and photosynthesis. In addition, SlRNRL1 and SlRNRL2 possess redundant functions and at least one of these RNRLs is required for tomato survival, growth and development.
Collapse
Affiliation(s)
| | | | - Yi Liu
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, Jiangxi, China
| | - Man Cui
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yaoqi Si
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | | | - Tuanyao Chai
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | | |
Collapse
|
5
|
Aggarwal PR, Pramitha L, Choudhary P, Singh RK, Shukla P, Prasad M, Muthamilarasan M. Multi-omics intervention in Setaria to dissect climate-resilient traits: Progress and prospects. FRONTIERS IN PLANT SCIENCE 2022; 13:892736. [PMID: 36119586 PMCID: PMC9470963 DOI: 10.3389/fpls.2022.892736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Millets constitute a significant proportion of underutilized grasses and are well known for their climate resilience as well as excellent nutritional profiles. Among millets, foxtail millet (Setaria italica) and its wild relative green foxtail (S. viridis) are collectively regarded as models for studying broad-spectrum traits, including abiotic stress tolerance, C4 photosynthesis, biofuel, and nutritional traits. Since the genome sequence release, the crop has seen an exponential increase in omics studies to dissect agronomic, nutritional, biofuel, and climate-resilience traits. These studies have provided first-hand information on the structure, organization, evolution, and expression of several genes; however, knowledge of the precise roles of such genes and their products remains elusive. Several open-access databases have also been instituted to enable advanced scientific research on these important crops. In this context, the current review enumerates the contemporary trend of research on understanding the climate resilience and other essential traits in Setaria, the knowledge gap, and how the information could be translated for the crop improvement of related millets, biofuel crops, and cereals. Also, the review provides a roadmap for studying other underutilized crop species using Setaria as a model.
Collapse
Affiliation(s)
- Pooja Rani Aggarwal
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Lydia Pramitha
- School of Agriculture and Biosciences, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
| | - Pooja Choudhary
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | | | - Pooja Shukla
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Manoj Prasad
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Mehanathan Muthamilarasan
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| |
Collapse
|
6
|
Li H, Li L, Wu W, Wang F, Zhou F, Lin Y. SvSTL1 in the large subunit family of ribonucleotide reductases plays a major role in chloroplast development of Setaria viridis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:625-641. [PMID: 35608125 DOI: 10.1111/tpj.15842] [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: 11/03/2021] [Revised: 05/04/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Ribonucleotide reductases (RNRs) are essential enzymes in DNA synthesis. However, little is known about the RNRs in plants. Here, we identified a svstl1 mutant from the self-created ethyl methanesulfonate (EMS) mutant library of Setaria viridis. The mutant leaves exhibited a bleaching phenotype at the heading stage. Paraffin section analysis showed the destruction of the C4 Kranz anatomy. Transmission electron microscopy results further demonstrated the severely disturbed development of some chloroplasts. MutMap analysis revealed that the SvSTL1 gene is the primary candidate, encoding a large subunit of RNRs. Complementation experiments confirmed that SvSTL1 is responsible for the phenotype of svstl1. There are two additional RNR large subunit homologs in S. viridis, SvSTL2 and SvSTL3. To further understand the functions of these three RNR large subunit genes, a series of mutants were generated via CRISPR/Cas9 technology. In striking contrast to the finding that all three SvSTLs interact with the RNR small subunit, the phenotype varied along with the copies of chloroplast genome among different svstl single mutants: the svstl1 mutant exhibited pronounced chloroplast development and significantly fewer copies of the chloroplast genome than the svstl2 or svstl3 single mutants. These results suggested that SvSTL1 plays a major role in the optimal function of RNRs and is essential for chloroplast development. Furthermore, through the analysis of double and triple mutants, the study provides new insights into the finely tuned coordination among SvSTLs to maintain normal chloroplast development in the emerging C4 model plant S. viridis.
Collapse
Affiliation(s)
- Huanying Li
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Lin Li
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Weichen Wu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Fei Wang
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Fei Zhou
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| |
Collapse
|
7
|
Zhang H, Tang S, Schnable JC, He Q, Gao Y, Luo M, Jia G, Feng B, Zhi H, Diao X. Genome-Wide DNA Polymorphism Analysis and Molecular Marker Development for the Setaria italica Variety "SSR41" and Positional Cloning of the Setaria White Leaf Sheath Gene SiWLS1. FRONTIERS IN PLANT SCIENCE 2021; 12:743782. [PMID: 34858451 PMCID: PMC8632227 DOI: 10.3389/fpls.2021.743782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/13/2021] [Indexed: 05/03/2023]
Abstract
Genome-wide DNA polymorphism analysis and molecular marker development are important for forward genetics research and DNA marker-assisted breeding. As an ideal model system for Panicoideae grasses and an important minor crop in East Asia, foxtail millet (Setaria italica) has a high-quality reference genome as well as large mutant libraries based on the "Yugu1" variety. However, there is still a lack of genetic and mutation mapping tools available for forward genetics research on S. italica. Here, we screened another S. italica genotype, "SSR41", which is morphologically similar to, and readily cross-pollinates with, "Yugu1". High-throughput resequencing of "SSR41" identified 1,102,064 reliable single nucleotide polymorphisms (SNPs) and 196,782 insertions/deletions (InDels) between the two genotypes, indicating that these two genotypes have high genetic diversity. Of the 8,361 high-quality InDels longer than 20 bp that were developed as molecular markers, 180 were validated with 91.5% accuracy. We used "SSR41" and these developed molecular markers to map the white leaf sheath gene SiWLS1. Further analyses showed that SiWLS1 encodes a chloroplast-localized protein that is involved in the regulation of chloroplast development in bundle sheath cells in the leaf sheath in S. italica and is related to sensitivity to heavy metals. Our study provides the methodology and an important resource for forward genetics research on Setaria.
Collapse
Affiliation(s)
- Hui Zhang
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, China
| | - Sha Tang
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - James C. Schnable
- Department of Agronomy and Horticulture, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Qiang He
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuanzhu Gao
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mingzhao Luo
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Guanqing Jia
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Baili Feng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, China
| | - Hui Zhi
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xianmin Diao
- Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Xianmin Diao,
| |
Collapse
|
8
|
Xie S, Luo H, Huang Y, Wang Y, Ru W, Shi Y, Huang W, Wang H, Dong Z, Jin W. A Missense Mutation in a Large Subunit of Ribonucleotide Reductase Confers Temperature-Gated Tassel Formation. PLANT PHYSIOLOGY 2020; 184:1979-1997. [PMID: 33020253 PMCID: PMC7723098 DOI: 10.1104/pp.20.00219] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/15/2020] [Indexed: 05/15/2023]
Abstract
Temperature is a major factor regulating plant growth. To reproduce at extreme temperatures, plants must develop normal reproductive organs when exposed to temperature changes. However, little is known about the underlying molecular mechanisms. Here, we identified the maize (Zea mays) mutant thermosensitive vanishing tassel1-R (tvt1-R), which lacks tassels at high (restrictive) temperatures due to shoot apical meristem (SAM) arrest, but forms normal tassels at moderate (permissive) temperatures. The critical stage for phenotypic conversion in tvt1-R mutants is V2 to V6 (Vn, where "n" is the number of leaves with collars visible). Positional cloning and allelism and complementation tests revealed that a G-to-A mutation causing a Arg277-to-His277 substitution in ZmRNRL1, a ribonucleotide reductase (RNR) large subunit (RNRL), confers the tvt1-R mutant phenotype. RNR regulates the rate of deoxyribonucleoside triphosphate (dNTP) production for DNA replication and damage repair. By expression, yeast two-hybrid, RNA sequencing, and flow cytometric analyses, we found that ZmRNRL1-tvt1-R failed to interact with all three RNR small subunits at 34°C due to the Arg277-to-His277 substitution, which could impede RNR holoenzyme (α2β2) formation, thereby decreasing the dNTP supply for DNA replication. Decreased dNTP supply may be especially severe for the SAM that requires a continuous, sufficient dNTP supply for rapid division, as demonstrated by the SAM arrest and tassel absence in tvt1-R mutants at restrictive temperatures. Our study reveals a novel mechanism of temperature-gated tassel formation in maize and provides insight into the role of RNRL in SAM maintenance.
Collapse
Affiliation(s)
- Shiyi Xie
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Hongbing Luo
- Maize Engineering and Technology Research Center of Hunan Province, Hunan Agricultural University, Changsha 410128, China
| | - Yumin Huang
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Yaxin Wang
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Wei Ru
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Yunlu Shi
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Wei Huang
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Hai Wang
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Zhaobin Dong
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Weiwei Jin
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China
| |
Collapse
|