The tomato OST1-VOZ1 module regulates drought-mediated flowering.

Flowering is a critical agricultural trait that substantially affects tomato fruit yield. Although drought stress influences flowering time, the molecular mechanism underlying drought-regulated flowering in tomato remains elusive. In this study, we demonstrated that loss of function of tomato OPEN STOMATA 1 (SlOST1), a protein kinase essential for abscisic acid (ABA) signaling and abiotic stress responses, lowers the tolerance of tomato plants to drought stress. slost1 mutants also exhibited a late flowering phenotype under both normal and drought stress conditions. We also established that SlOST1 directly interacts with and phosphorylates the NAC (NAM, ATAF and CUC)-type transcription factor VASCULAR PLANT ONE-ZINC FINGER 1 (SlVOZ1), at residue serine 67, thereby enhancing its stability and nuclear translocation in an ABA-dependent manner. Moreover, we uncovered several SlVOZ1 binding motifs from DNA affinity purification sequencing analyses and revealed that SlVOZ1 can directly bind to the promoter of the major flowering-integrator gene SINGLE FLOWER TRUSS to promote tomato flowering transition in response to drought. Collectively, our data uncover the essential role of the SlOST1-SlVOZ1 module in regulating flowering in response to drought stress in tomato and offer insights into a novel strategy to balance drought stress response and flowering.

ZmELF6-ZmPRR37 module regulates maize flowering and salt response.

The control of flowering time in maize is crucial for reproductive success and yield, and it can be influenced by environmental stresses. Using the approaches of Ac/Ds transposon and transposable element amplicon sequencing techniques, we identified a Ds insertion mutant in the ZmPRR37 gene. The Ds insertion showed a significant correlation with days to anthesis. Further research indicated that ZmPRR37-CR knockout mutants exhibited early flowering, whereas ZmPRR37-overexpression lines displayed delayed flowering compared to WT under long-day (LD) conditions. We demonstrated that ZmPRR37 repressed the expression of ZmNF-YC2 and ZmNF-YA3 to delay flowering. Association analysis revealed a significant correlation between flowering time and a SNP2071-C/T located upstream of ZmPRR37. The SNP2071-C/T impacted the binding capacity of ZmELF6 to the promoter of ZmPRR37. ZmELF6 also acted as a flowering suppressor in maize under LD conditions. Notably, our study unveiled that ZmPRR37 can enhance salt stress tolerance in maize by directly regulating the expression of ABA-responsive gene ZmDhn1. ZmDhn1 negatively regulated maize salt stress resistance. In summary, our findings proposed a novel pathway for regulating photoperiodic flowering and responding to salt stress based on ZmPRR37 in maize, providing novel insights into the integration of abiotic stress signals into floral pathways.

ZmABF4-ZmVIL2/ZmFIP37 module enhances drought tolerance in maize seedlings.

Drought, as a primary environmental factor, imposes significant constraints on developmental processes and productivity of plants. PHDs were identified as stress-responsive genes in a wide range of eukaryotes. However, the regulatory mechanisms governing PHD genes in maize under abiotic stress conditions are still largely unknown and require further investigation. Here, we identified a mutant, zmvil2, in the EMS mutant library with a C to T mutation in the exon of the Zm00001d053875 (VIN3-like protein 2, ZmVIL2), resulting in premature termination of protein coding. ZmVIL2 belongs to PHD protein family. Compared to WT, zmvil2 mutant exhibited increased sensitivity to drought stress. Consistently, overexpression of ZmVIL2 enhances drought resistance in maize. Y2H, BiFC, and Co-IP experiments revealed that ZmVIL2 directly interacts with ZmFIP37 (FKBP12-interacting protein of 37). zmfip37 knockout mutants also exhibit decreased drought tolerance. Interestingly, we demonstrated that ZmABF4 directly binds to the ZmVIL2 promoter to enhance its activity in yeast one hybrid (Y1H), electrophoretic mobility shift assay (EMSA) and dual luciferase reporter assays. Therefore, we uncovered a novel model ZmABF4-ZmVIL2/ZmFIP37 that promotes drought tolerance in maize. Overall, these findings have enriched the knowledge of the functions of PHD genes in maize and provides genetic resources for breeding stress-tolerant maize varieties.

ZmC2H2-149 negatively regulates drought tolerance by repressing ZmHSD1 in maize.

Drought is a major abiotic stress that limits maize production worldwide. Therefore, it is of great importance to improve drought tolerance in crop plants for sustainable agriculture. In this study, we examined the roles of Cys2 /His2 zinc-finger-proteins (C2H2-ZFPs) in maize's drought tolerance as C2H2-ZFPs have been implicated for plant stress tolerance. By subjecting 150 Ac/Ds mutant lines to drought stress, we successfully identified a Ds-insertion mutant, zmc2h2-149, which shows increased tolerance to drought stress. Overexpression of ZmC2H2-149 in maize led to a decrease in both drought tolerance and crop yield. DAP-Seq, RNA-Seq, Y1H and LUC assays additionally showed that ZmC2H2-149 directly suppresses the expression of a positive drought tolerance regulator, ZmHSD1 (hydroxysteroid dehydrogenase 1). Consistently, the zmhsd1 mutants exhibited decreased drought tolerance and grain yield under water deficit conditions compared to their respective wild-type plants. Our findings thus demonstrated that ZmC2H2-149 can regulate ZmHSD1 for drought stress tolerance in maize, offering valuable theoretical and genetic resources for maize breeding programmes that aim for improving drought tolerance.

Single-cell RNA sequencing profiles reveal cell type-specific transcriptional regulation networks conditioning fungal invasion in maize roots.

Stalk rot caused by Fusarium verticillioides (Fv) is one of the most destructive diseases in maize production. The defence response of root system to Fv invasion is important for plant growth and development. Dissection of root cell type-specific response to Fv infection and its underlying transcription regulatory networks will aid in understanding the defence mechanism of maize roots to Fv invasion. Here, we reported the transcriptomes of 29 217 single cells derived from root tips of two maize inbred lines inoculated with Fv and mock condition, and identified seven major cell types with 21 transcriptionally distinct cell clusters. Through the weighted gene co-expression network analysis, we identified 12 Fv-responsive regulatory modules from 4049 differentially expressed genes (DEGs) that were activated or repressed by Fv infection in these seven cell types. Using a machining-learning approach, we constructed six cell type-specific immune regulatory networks by integrating Fv-induced DEGs from the cell type-specific transcriptomes, 16 known maize disease-resistant genes, five experimentally validated genes (ZmWOX5b, ZmPIN1a, ZmPAL6, ZmCCoAOMT2, and ZmCOMT), and 42 QTL or QTN predicted genes that are associated with Fv resistance. Taken together, this study provides not only a global view of maize cell fate determination during root development but also insights into the immune regulatory networks in major cell types of maize root tips at single-cell resolution, thus laying the foundation for dissecting molecular mechanisms underlying disease resistance in maize.

ZmERF21 directly regulates hormone signaling and stress-responsive gene expression to influence drought tolerance in maize seedlings.

Drought stress adversely impacts crop development and yield. Maize frequently encounters drought stress during its life cycle. Improvement of drought tolerance is a priority of maize breeding programs. Here, we identified a novel transcription factor encoding gene, APETALA2 (AP2)/Ethylene response factor (ERF), which is tightly associated with drought tolerance in maize seedlings. ZmERF21 is mainly expressed in the root and leaf and it can be highly induced by polyethylene glycol treatment. Genetic analysis showed that the zmerf21 mutant plants displayed a reduced drought tolerance phenotype, accompanied by phenotypical and physiological changes that are commonly observed in drought conditions. Overexpression of ZmERF21 in maize significantly increased the chlorophyll content and activities of antioxidant enzymes under drought conditions. RNA-Seq and DNA affinity purification sequencing analysis further revealed that ZmERF21 may directly regulate the expression of genes related to hormone (ethylene, abscisic acid) and Ca signaling as well as other stress-response genes through binding to the promoters of potential target genes. Our results thereby provided molecular evidence of ZmERF21 is involved in the drought stress response of maize.

Genome-wide identification of HD-ZIP transcription factors in maize and their regulatory roles in promoting drought tolerance.

Drought is the main limiting factor of maize productivity, therefore improving drought tolerance in maize has potential practical importance. Cloning and functional verification of drought-tolerant genes is of great importance to understand molecular mechanisms under drought stress. Here, we employed a bioinformatic pipeline to identify 42 ZmHDZ drought responsive genes using previously reported maize transcriptomic datasets. The coding sequences, exon-intron structure and domain organization of all the 42 genes were identified. Phylogenetic analysis revealed evolutionary conservation of members of the ZmHDZ genes in maize. Several regulatory elements associated with drought tolerance were identified in the promoter regions of ZmHDZ genes, indicating the implication of these genes in plant response to drought stress. 42 ZmHDZ genes were distributed unevenly on 10 chromosomes, and 24 pairs of gene duplications were the segmental duplication. The expression of several ZmHDZ genes was upregulated under drought stress, and ZmHDZ9 overexpressing transgenic plants exhibited higher SOD and POD activities and higher accumulation of soluble proteins under drought stress which resulted in enhanced developed phenotype and improved resistance. The present study provides evidence for the evolutionary conservation of HD-ZIP transcription factors homologs in maize. The results further provide a comprehensive insight into the roles of ZmHDZ genes in regulating drought stress tolerance in maize.

ZmCCT regulates photoperiod-dependent flowering and response to stresses in maize.

BACKGROUND: Appropriate flowering time is very important to the success of modern agriculture. Maize (Zea mays L.) is a major cereal crop, originated in tropical areas, with photoperiod sensitivity. Which is an important obstacle to the utilization of tropical/subtropical germplasm resources in temperate regions. However, the study on the regulation mechanism of photoperiod sensitivity of maize is still in the early stage. Although it has been previously reported that ZmCCT is involved in the photoperiod response and delays maize flowering time under long-day conditions, the underlying mechanism remains unclear. RESULTS: Here, we showed that ZmCCT overexpression delays flowering time and confers maize drought tolerance under LD conditions. Implementing the Gal4-LexA/UAS system identified that ZmCCT has a transcriptional inhibitory activity, while the yeast system showed that ZmCCT has a transcriptional activation activity. DAP-Seq analysis and EMSA indicated that ZmCCT mainly binds to promoters containing the novel motifs CAAAAATC and AAATGGTC. DAP-Seq and RNA-Seq analysis showed that ZmCCT could directly repress the expression of ZmPRR5 and ZmCOL9, and promote the expression of ZmRVE6 to delay flowering under long-day conditions. Moreover, we also demonstrated that ZmCCT directly binds to the promoters of ZmHY5, ZmMPK3, ZmVOZ1 and ZmARR16 and promotes the expression of ZmHY5 and ZmMPK3, but represses ZmVOZ1 and ZmARR16 to enhance stress resistance. Additionally, ZmCCT regulates a set of genes associated with plant development. CONCLUSIONS: ZmCCT has dual functions in regulating maize flowering time and stress response under LD conditions. ZmCCT negatively regulates flowering time and enhances maize drought tolerance under LD conditions. ZmCCT represses most flowering time genes to delay flowering while promotes most stress response genes to enhance stress tolerance. Our data contribute to a comprehensive understanding of the regulatory mechanism of ZmCCT in controlling maize flowering time and stress response.

Large-scale reconstruction of chromatin structures of maize temperate and tropical inbred lines.

Maize is a model plant species often used for genetics and genomics research because of its genetic diversity. There are prominent morphological, genetic, and epigenetic variations between tropical and temperate maize lines. However, the genome-wide chromatin conformations of these two maize types remain unexplored. We applied a Hi-C approach to compare the genome-wide chromatin interactions between temperate inbred line D132 and tropical line CML288. A reconstructed maize three-dimensional genome model revealed the spatial segregation of the global A and B compartments. The A compartments contain enriched genes and active epigenome marks, whereas the B compartments are gene-poor, transcriptionally silent chromatin regions. Whole-genome analyses indicated that the global A compartment content of CML288 was 3.12% lower than that of D132. Additionally, global and A/B sub-compartments were associated with differential gene expression and epigenetic changes between two inbred lines. About 25.3% of topologically associating domains (TADs) were determined to be associated with complex domain-level modifications that induced transcriptional changes, indicative of a large-scale reorganization of chromatin structures between the inbred maize lines. Furthermore, differences in chromatin interactions between the two lines correlated with epigenetic changes. These findings provide a solid foundation for the wider plant community to further investigate the genome-wide chromatin structures in other plant species.

Identification of ZmNF-YC2 and its regulatory network for maize flowering time.

Flowering time is an important agronomic trait that determines the distribution and adaptation of plants. The accurate prediction of flowering time in elite germplasm is critical for maize breeding. However, the molecular mechanisms underlying the photoperiod response remain elusive in maize. Here we cloned the flowering time-controlling gene, ZmNF-YC2, by map-based cloning and confirmed that ZmNF-YC2 is the nuclear transcription factor Y subunit C-2 protein and a positive regulator of flowering time in maize under long-day conditions. Our results show that ZmNF-YC2 promotes the expression of ZmNF-YA3. ZmNF-YA3 negatively regulates the transcription of ZmAP2. ZmAP2 suppresses the expression of ZMM4 to delay flowering time. We then developed a gene regulatory model of flowering time in maize using ZmNF-YC2, ZmNF-YA3, ZmAP2, ZMM4, and other key genes. The cascading regulation by ZmNF-YC2 of maize flowering time has not been reported in other species.

CLA4 regulates leaf angle through multiple hormone signaling pathways in maize.

Leaf angle is an important agronomic trait in cereals and shares a close relationship with crop architecture and grain yield. Although it has been previously reported that ZmCLA4 can influence leaf angle, the underlying mechanism remains unclear. In this study, we used the Gal4-LexA/UAS system and transactivation analysis to demonstrate in maize (Zea mays) that ZmCLA4 is a transcriptional repressor that regulates leaf angle. DNA affinity purification sequencing (DAP-Seq) analysis revealed that ZmCLA4 mainly binds to promoters containing the EAR motif (CACCGGAC) as well as to two other motifs (CCGARGS and CDTCNTC) to inhibit the expression of its target genes. Further analysis of ZmCLA4 target genes indicated that ZmCLA4 functions as a hub of multiple plant hormone signaling pathways: ZmCLA4 was found to directly bind to the promoters of multiple genes including ZmARF22 and ZmIAA26 in the auxin transport pathway, ZmBZR3 in the brassinosteroid signaling pathway, two ZmWRKY genes involved in abscisic acid metabolism, ZmCYP genes (ZmCYP75B1, ZmCYP93D1) related to jasmonic acid metabolism, and ZmABI3 involved in the ethylene response pathway. Overall, our work provides deep insights into the ZmCLA4 regulatory network in controlling leaf angle in maize.

MicroRNA transcriptomic analysis of the sixth leaf of maize (Zea mays L.) revealed a regulatory mechanism of jointing stage heterosis.

BACKGROUND: Zhengdan 958 (Zheng 58 × Chang 7-2), a commercial hybrid that is produced in a large area in China, is the result of the successful use of the heterotic pattern of Reid × Tang-SPT. The jointing stage of maize is the key period from vegetative to reproductive growth, which determines development at later stages and heterosis to a certain degree. MicroRNAs (miRNAs) play vital roles in the regulation of plant development, but how they function in the sixth leaf at the six-leaf (V6) stage to influence jointing stage heterosis is still unclear. RESULT: Our objective was to study miRNAs in four hybrid combinations developed in accordance with the Reid × Tang-SPT pattern, Zhengdan 958, Anyu 5 (Ye 478 × Chang 7-2), Ye 478 × Huangzaosi, Zheng 58 × Huangzaosi, and their parental inbred lines to explore the mechanism related to heterosis. A total of 234 miRNAs were identified in the sixth leaf at the V6 stage, and 85 miRNAs were differentially expressed between the hybrid combinations and their parental inbred lines. Most of the differentially expressed miRNAs were non-additively expressed, which indicates that miRNAs may participate in heterosis at the jointing stage. miR164, miR1432 and miR528 families were repressed in the four hybrid combinations, and some miRNAs, such as miR156, miR399, and miR395 families, exhibited different expression trends in different hybrid combinations, which may result in varying effects on the heterosis regulatory mechanism. CONCLUSIONS: The potential targets of the identified miRNAs are related to photosynthesis, the response to plant hormones, and nutrient use. Different hybrid combinations employ different mature miRNAs of the same miRNA family and exhibit different expression trends that may result in enhanced or repressed gene expression to regulate heterosis. Taken together, our results reveal a miRNA-mediated network that plays a key role in jointing stage heterosis via posttranscriptional regulation.

Functions and regulatory framework of ZmNST3 in maize under lodging and drought stress.

The growth and development of maize are negatively affected by various abiotic stresses including drought, high salinity, extreme temperature, and strong wind. Therefore, it is important to understand the molecular mechanisms underlying abiotic stress resistance in maize. In the present work, we identified that a novel NAC transcriptional factor, ZmNST3, enhances maize lodging resistance and drought stress tolerance. ChIP-Seq and expression of target genes analysis showed that ZmNST3 could directly regulate the expression of genes related to cell wall biosynthesis which could subsequently enhance lodging resistance. Furthermore, we also demonstrated that ZmNST3 affected the expression of genes related to the synthesis of antioxidant enzyme secondary metabolites that could enhance drought resistance. More importantly, we are the first to report that ZmNST3 directly binds to the promoters of CESA5 and Dynamin-Related Proteins2A (DRP2A) and activates the expression of genes related to secondary cell wall cellulose biosynthesis. Additionally, we revealed that ZmNST3 directly binds to the promoters of GST/GlnRS and activates genes which could enhance the production of antioxidant enzymes in vivo. Overall, our work contributes to a comprehensive understanding of the regulatory network of ZmNST3 in regulating maize lodging and drought stress resistance.

ZmIBH1-1 regulates plant architecture in maize.

Leaf angle (LA) is a critical agronomic trait in maize, with more upright leaves allowing higher planting density, leading to more efficient light capture and higher yields. A few genes responsible for variation in LA have been identified by map-based cloning. In this study, we cloned maize ZmIBH1-1, which encodes a bHLH transcription factor with both a basic binding region and a helix-loop-helix domain, and the results of qRT-PCR showed that it is a negative regulator of LA. Histological analysis indicated that changes in LA were mainly caused by differential cell wall lignification and cell elongation in the ligular region. To determine the regulatory framework of ZmIBH1-1, we conducted RNA-seq and DNA affinity purification (DAP)-seq analyses. The combined results revealed 59 ZmIBH1-1-modulated target genes with annotations, and they were mainly related to the cell wall, cell development, and hormones. Based on the data, we propose a regulatory model for the control of plant architecture by ZmIBH1-1 in maize.

MicroRNA 399 as a potential integrator of photo-response, phosphate homeostasis, and sucrose signaling under long day condition.

BACKGROUND: Photoperiod-sensitivity is a critical endogenous regulatory mechanism for plant growth and development under specific environmental conditions, while phosphate and sucrose signaling processes play key roles in cell growth and organ initiation. MicroRNA399 is phosphate-responsive, but, whether it has roles in other metabolic processes remains unknown. RESULTS: MicroRNA399 was determined to be sucrose-responsive through a microRNA array assay. High levels of sucrose inhibited the accumulation of microRNA399 family under phosphate starvation conditions in Arabidopsis thaliana. Similarly, exogenous sucrose supplementation also reduced microRNA399 expression in maize at developmental transition stages. RNA sequencing of a near-isogenic line(photoperiod-sensitive) line and its recurrent parent Huangzao4, a photoperiod-insensitive line, was conducted at various developmental stages. Members of microRNA399 family were down-regulated under long-day conditions in the photoperiod-sensitive near-isogenic line that accumulated more sucrose in vivo compared with the control line Huangzao4. CONCLUSION: MicroRNA399s may play central roles in the integration of sucrose sensing and photoperiodic responses under long day conditions in maize.

Dual functions of ZmNF-YA3 in photoperiod-dependent flowering and abiotic stress responses in maize.

Nuclear factor-Y (NF-Y) transcription factors are important regulators of several essential biological processes, including embryogenesis, drought resistance, meristem maintenance, and photoperiod-dependent flowering in Arabidopsis. However, the regulatory mechanisms of NF-Ys in maize (Zea mays) are not well understood yet. In this study, we identified an NF-Y transcription factor, ZmNF-YA3. Genome-wide analysis showed that ZmNF-YA3 bound to >6000 sites in the maize genome, 2259 of which are associated with genic sequences. ZmNF-YA3 was found to interact with CONSTANS-like (CO-like) and flowering promoting factor1 (FPF1) through yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays. Quantitative real-time reverse transcription-PCR (qRT-PCR) combined with yeast one-hybrid assay and EMSA suggested that NF-YA3 could promote early flowering by binding to the FLOWERING LOCUS T-like12 (FT-like12) promoter in maize. Morerover, we also showed that ZmNF-YA3 could improve drought and high-temperature tolerance through binding to the promoter regions of bHLH92, FAMA, and the jasmonic acid activator MYC4, respectively. These results contribute to a comprehensive understanding of the molecular mechanisms and regulatory networks of NF-Y transcription factors in regulating maize flowering time and stress response in maize.

Dual functions of the ZmCCT-associated quantitative trait locus in flowering and stress responses under long-day conditions.

BACKGROUND: Photoperiodism refers to the ability of plants to measure day length to determine the season. This ability enables plants to coordinate internal biological activities with external changes to ensure normal growth. However, the influence of the photoperiod on maize flowering and stress responses under long-day (LD) conditions has not been analyzed by comparative transcriptome sequencing. The ZmCCT gene was previously identified as a homolog of the rice photoperiod response regulator Ghd7, and associated with the major quantitative trait locus (QTL) responsible for Gibberella stalk rot resistance in maize. However, its regulatory mechanism has not been characterized. RESULTS: We mapped the ZmCCT-associated QTL (ZmCCT-AQ), which is approximately 130 kb long and regulates photoperiod responses and resistance to Gibberella stalk rot and drought in maize. To investigate the effects of ZmCCT-AQ under LD conditions, the transcriptomes of the photoperiod-insensitive inbred line Huangzao4 (HZ4) and its near-isogenic line (HZ4-NIL) containing ZmCCT-AQ were sequenced. A set of genes identified by RNA-seq exhibited higher basal expression levels in HZ4-NIL than in HZ4. These genes were associated with responses to circadian rhythm changes and biotic and abiotic stresses. The differentially expressed genes in the introgressed regions of HZ4-NIL conferred higher drought and heat tolerance, and stronger disease resistance relative to HZ4. Co-expression analysis and the diurnal expression rhythms of genes related to stress responses suggested that ZmCCT and one of the circadian clock core genes, ZmCCA1, are important nodes linking the photoperiod to stress tolerance responses under LD conditions. CONCLUSION: Our study revealed that the photoperiod influences flowering and stress responses under LD conditions. Additionally, ZmCCT and ZmCCA1 are important functional links between the circadian clock and stress tolerance. The establishment of this particular molecular link has uncovered a new relationship between plant photoperiodism and stress responses.

CACTA-like transposable element in ZmCCT attenuated photoperiod sensitivity and accelerated the postdomestication spread of maize.

The postdomestication adaptation of maize to longer days required reduced photoperiod sensitivity to optimize flowering time. We performed a genome-wide association study and confirmed that ZmCCT, encoding a CCT domain-containing protein, is associated with the photoperiod response. In early-flowering maize we detected a CACTA-like transposable element (TE) within the ZmCCT promoter that dramatically reduced flowering time. TE insertion likely occurred after domestication and was selected as maize adapted to temperate zones. This process resulted in a strong selective sweep within the TE-related block of linkage disequilibrium. Functional validations indicated that the TE represses ZmCCT expression to reduce photoperiod sensitivity, thus accelerating maize spread to long-day environments.

Dissection of the genetic architecture underlying the plant density response by mapping plant height-related traits in maize (Zea mays L.).

Plant height is one of the most heritable traits in maize (Zea mays L.). Understanding the genetic control of plant height is important for elucidating the molecular mechanisms that regulate maize development. To investigate the genetic basis of the plant height response to density in maize, we evaluated the effects of two different plant densities (60,000 and 120,000 plant/hm(2)) on three plant height-related traits (plant height, ear height, and ear height-to-plant height ratio) using four sets of recombinant inbred line populations. The phenotypes observed under the two-plant density treatments indicated that high plant density increased the phenotypic performance values of the three measured traits. Twenty-three quantitative trait loci (QTLs) were detected under the two-plant density treatments, and five QTL clusters were located. Nine QTLs were detected under the low plant density treatment, and seven QTLs were detected under the high plant density treatment. Our results suggested that plant height may be controlled mainly by a common set of genes that could be influenced by additional genetic mechanisms when the plants were grown under high plant density. Fine mapping for genetic regions of the stable QTLs across different plant density environments may provide additional information about their different responses to density. The results presented here provide useful information for further research and will help to reveal the molecular mechanisms related to plant height in response to density.