Flowering Time Research Articles

Transcriptome Profiling Reveals Key Regulatory Networks for Age-Dependent Vernalization in Welsh Onion (Allium fistulosum L.).

Plants exhibit diverse pathways to regulate the timing of flowering. Some plant species require a vegetative phase before being able to perceive cold stimuli for the acceleration of flowering through vernalization. This research confirms the correlation between the vernalization process and seedling age in Welsh onions. Findings from two vernalization experiments conducted at different time intervals demonstrate that seedlings must reach a vegetative phase of at least 8 weeks to consistently respond to vernalization. Notably, 8-week-old seedlings subjected to 6 weeks of vernalization displayed the shortest time to bolting, with an average duration of 138.1 days. Transcriptome analysis led to the identification of genes homologous to those in Arabidopsis thaliana that regulate flowering. Specifically, AfisC7G05578 (CO), AfisC2G05881 (AP1), AfisC1G07745 (FT), AfisC1G06473 (RAP2.7), and AfisC2G01843 (VIM1) were identified and suggested to have potential significance in age-dependent vernalization in Welsh onions. This study not only presents a rapid vernalization method for Welsh onions but also provides a molecular foundation for understanding the interplay between seedling age and vernalization.

Early flowering enhances performance among conspecifics.

Timing plays a crucial role in plant survival as it determines the environmental conditions during which each phenophase develops. In Mediterranean regions, with high temperatures and low precipitation during summer, the timing of flowering may impact plant performance. Different species avoid harsh abiotic conditions by flowering weeks or months earlier than others. On a shorter time scale, conspecifics that flower just a few days earlier may also gain biotic advantages, such as reduced competition for nutrients or pollinators. We propose that earlier flowering, whether by days for conspecifics or by weeks to months for different species, allows plants to avoid biotic and abiotic stress, respectively, leading to increased reproductive success and growth. We hypothesize that: (i) earlier-flowering species will have higher growth and reproductive success than other species co-occurring in the community, and (ii) earlier-flowering conspecifics will show higher growth and reproductive success than the average of their co-occurring conspecifics. A field study was conducted in SE Spain using 98 co-occurring individuals of four species. We monitored phenology, water loss, and growth over a growing season and estimated relative individual reproduction. Early-flowering species did not show higher relative reproduction than late, co-occurring flowering species, although they differed in water loss. However, early-flowering conspecifics had higher growth and relative reproduction than later-flowering conspecifics, but did not differ in water loss. Our results suggest that early flowering might reduce intraspecific competition among conspecifics, rather than enhance performance of those species that avoid harsh summer conditions (high temperatures and low precipitations).

Chromatin loops gather targets of upstream regulators together for efficient gene transcription regulation during vernalization in wheat

BackgroundPlants respond to environmental stimuli by altering gene transcription that is highly related with chromatin status, including histone modification, chromatin accessibility, and three-dimensional chromatin interaction. Vernalization is essential for the transition to reproductive growth for winter wheat. How wheat reshapes its chromatin features, especially chromatin interaction during vernalization, remains unknown.ResultsCombinatory analysis of gene transcription and histone modifications in winter wheat under different vernalization conditions identifies 17,669 differential expressed genes and thousands of differentially enriched peaks of H3K4me3, H3K27me3, and H3K9ac. We find dynamic gene expression across the vernalization process is highly associated with H3K4me3. More importantly, the dynamic H3K4me3- and H3K9ac-associated chromatin-chromatin interactions demonstrate that vernalization leads to increased chromatin interactions and gene activation. Remarkably, spatially distant targets of master regulators like VRN1 and VRT2 are gathered together by chromatin loops to achieve efficient transcription regulation, which is designated as a “shepherd” model. Furthermore, by integrating gene regulatory network for vernalization and natural variation of flowering time, TaZNF10 is identified as a negative regulator for vernalization-related flowering time in wheat.ConclusionsWe reveal dynamic gene transcription network during vernalization and find that the spatially distant genes can be recruited together via chromatin loops associated with active histone mark thus to be more efficiently found and bound by upstream regulator. It provides new insights into understanding vernalization and response to environmental stimuli in wheat and other plants.

Increasing the Nighttime Lighting Duration Can Hasten Flowering of Long-day Plants

Low-intensity (≈2 μmol·m−2·s−1) photoperiodic lighting is often delivered at night to promote flowering of long-day greenhouse ornamentals when natural daylengths are short. An intermediate far-red (FR) fraction [percentage of FR light in red (R) + FR light] is necessary for the most rapid flowering in some crops, including snapdragon (Antirrhinum majus) and petunia (Petunia ×hybrida), compared with a low FR fraction. Specialty light-emitting diodes (LEDs) that include R+FR light with an intermediate FR fraction are effective at floral promotion but cost-prohibitive, whereas common warm-white (WW) LEDs with a low FR fraction can delay flowering. Because the duration to saturate flowering is longer than currently used (e.g., 4 to 8 hours) for some long-day plants, we conducted a replicated greenhouse experiment to determine how the WW or R+FR LED lighting duration influenced flowering. We grew snapdragon ‘Liberty Classic Yellow’, petunia ‘Easy Wave Burgundy Star’, and petunia ‘Wave Purple Improved’ under truncated 8-h natural short days with or without WW or R+FR (1:1) LEDs operating for 0, 4, 8, 12, or 16 hours in the middle of each night throughout the experiment. Snapdragon flowered 13 to 16 days earlier (21% to 28% earlier) under R+FR LEDs than under WW LEDs regardless of the lighting duration. Increasing the lighting duration from 0 to 16 hours decreased flowering time by up to 16 days and decreased plant height and leaf number at flowering under R+FR LEDs but not under WW LEDs. For petunia ‘Easy Wave Burgundy Star’, although WW LEDs delayed flowering by 6 to 13 days but promoted lateral branching compared with R+FR LEDs, the gap in flowering time narrowed as the lighting duration increased from 4 to 16 hours. Increasing the lighting duration improved the efficacy of WW LEDs but not R+FR LEDs. Flowering of petunia ‘Wave Purple Improved’ was unaffected as the lighting duration increased from 4 to 16 hours regardless of the lamp type and was delayed by 6 to 10 days under WW LEDs than under R+FR LEDs. For both petunia cultivars, flowering time was similar under 16-hour WW LEDs and 4-hour R+FR LEDs. In conclusion, increasing the nighttime lighting duration increased the efficacy of WW LEDs at promoting flowering of petunia and increased the efficacy of R+FR LED lamps at promoting flowering of snapdragon. Delivering WW LEDs all night long can minimize flowering delay in petunia compared with R+FR LEDs. In contrast, an intermediate FR fraction was indispensable to promote flowering of snapdragon, for which WW LEDs were ineffective.

Functional characterization of CaSOC1 at low temperatures and its role in low-temperature escape

Environmental factors such as light and temperature tightly regulate plant flowering time. Under stressful conditions, plants inhibit vegetative growth and accelerate flowering as an emergency response. This adaptive mechanism benefits the survival of species and enhances their reproductive success. This phenomenon is often referred to as stress escape. However, the signaling pathways between low-temperature signals and flowering time are poorly understood. In this study, the MIKC transcription factor, CaSOC1, was isolated from pepper (Capsicum annuum), which showed suppressed expression under low-temperature conditions. Silencing the expression of CaSOC1 in pepper plants resulted in reduced photosynthetic capacity, inhibited vegetative growth, and increased sensitivity to low temperatures. In contrast, overexpression of CaSOC1 increased the biomass of tomato plants under normal growth conditions but suppressed their antioxidant enzyme activity at low temperatures, which negatively regulated their cold tolerance. Furthermore, intermittent low-temperature treatment with CaSOC1 overexpression promoted early flowering in tomato plants. Our findings demonstrate that CaSOC1 reduced the cold tolerance of pepper plants under short term low-temperature conditions, whereas intermittent low-temperature treatment enhanced flower bud differentiation, enabling stress escape and adaptation to long low-temperature environments.

IIIVmrMLM.QEI: An effective tool for indirect detection of QTN-by-environment interactions in genome-wide association studies

Although 3VmrMLM-MEJA and several indirect indicators have been employed to identify QTN-by-environment interactions (QEIs) in genome-wide association studies (GWAS), there is no convenient, flexible, and accurate method to comprehensively identify QEIs. To address this issue, 3VmrMLM-random was first extended to 3VmrMLM-fixed. Next, the two single-environment QTN detection methods were integrated with trait differences and regression parameters to indirectly detect QEIs. Finally, these indirect indicators were extended to include environmental factors (EFs, such as temperature) and four environmental variation indicators. As a result, both 3VmrMLM-random and 3VmrMLM-fixed, alongside all the indirect indicators, were incorporated into a new tool, IIIVmrMLM.QEI, designed for effective QEI identification. Simulation studies demonstrated that 3VmrMLM-fixed showed significantly higher powers than existing fixed-SNP-effect methods (MLM and EMMAX) because it takes into account all the possible effects and controls for all the possible polygenic backgrounds. 3VmrMLM-random and 3VmrMLM-fixed exhibited superior combination power to 3VmrMLM-MEJA. In the re-analysis of Arabidopsis flowering time across three temperatures, 3VmrMLM-fixed (12) detected more known gene-by-environment interactions (GEIs) than both MLM (1) and EMMAX (1). Additionally, IIIVmrMLM.QEI (18) detected more known GEIs than 3VmrMLM-MEJA (6), when all indirect indicators were analyzed. All 18 GEIs were confirmed by haplotype analysis and associated with temperature variation in previous studies. Two and five GEIs were identified only by 3VmrMLM-fixed and 3VmrMLM-random, respectively, and 12 GEIs were identified only by indirect indicators, indicating the need to expand models and indirect indicators. This study provides a novel tool (https://github.com/YuanmingZhang65/IIIVmrMLM.QEI) for more comprehensive QEI detection.

Mangifera spp. in the Ethnoclimatology Study of Tatangar Banjar Tradition in Kalimantan

The biodiversity of Mangifera spp. not only supports the local economy and preserve food security but also safeguards cultural heritage through their role in ethnoclimatology studies within the Tatangar tradition of the Banjar community in Kalimantan. The Banjar community demonstrates a unique connection with nature by utilizing specific Mangifera species as crucial indicators of seasonal transitions, deeply ingrained in their cultural identity. The aim of this study is to reveal the prevalence of various Mangifera species, including endangered ones, in diverse landscapes, promoting a sustainable agroforestry system and conservation efforts. Qualitative and quantitative research methods were employed to explore and analyze Tatangar knowledge within the Banjar community in Mandiangin Barat Village, particularly its connections to climate and weather. The Banjar community further traditionally classifies Mangifera species, or known as “asam-asaman”, based on morphological traits, aiding in their interpretation of Tatangar signs. These signs, rooted in the flowering time of Mangifera trees, serve as essential climate indicators, guiding agricultural practices and influencing decisions on planting and harvesting. This local knowledge enhances agricultural resilience, enriches their cultural heritage, and underscores the intrinsic relationship between culture, nature, and sustainability in Kalimantan, making it a valuable subject for ethnoclimatological exploration

Functional Diversity of A-Type RING Ligases (ATL) Genes: Insights into the Crucial Roles of E3 Ubiquitin Ligases in Plant Biology

AbstractE3 ubiquitin ligases are vital components of the ubiquitin–proteasome system (UPS), responsible for maintaining protein balance and controlling cellular functions. E3 ligases target specific proteins for degradation or modify their activities through ubiquitin attachment. One prominent E3 ligase family is the ATL family, which comprises 100 members in Arabidopsis thaliana and has significantly expanded in plant genomes. All ATLs share a common domain architecture, featuring a transmembrane domain at the amino-terminal region, a distinct RING-H2 finger domain, and the GLD motif. The RING domain facilitates interactions between E3 ligases, E2-conjugating enzymes, and target proteins, enabling the transfer of ubiquitin molecules. The amino-terminal and carboxy-terminal regions introduce sequence diversity and potentially mediate interactions with other components that assist in UPS function or target recognition. ATLs had been classified within groups, each group encompasses specific ATLs with defined roles in various biological processes. For example, group C-ATLs are implicated in drought tolerance, flower development, phosphate homeostasis, and immune signaling. G-ATLs are associated with carbon/nitrogen stress, immune signaling, salt stress, ABA responses, cadmium tolerance, and sugar-mediated plant growth. A-ATLs participate in early elicitor-response, salt and drought responses, and flowering time regulation. Lastly, D-ATLs are involved in the regulation of programmed cell death. This review let perceive ATLs as a cohesive group of E3 ligases, shedding light on their functional diversifity and redundancy, specifically examining their participation in diverse biological processes, explore their evolutionary history shaped by gene duplication events, and appraise their interactions with key proteins and targets of ubiquitination. This comprehensive overview aims to offer insights into the role of ATLs in plant adaptation, defense mechanisms, and stress tolerance, while also underlying molecular and evolutionary mechanisms and regulatory networks that govern these processes.

An eight-founder wheat MAGIC population allows fine-mapping of flowering time loci and provides novel insights into the genetic control of flowering time

Flowering time synchronizes reproductive development with favorable environmental conditions to optimize yield. Improved understanding of the genetic control of flowering will help optimize varietal adaptation to future agricultural systems under climate change. Here, we investigate the genetic basis of flowering time in winter wheat (Triticum aestivum L.) using an eight-founder multi-parent advanced generation intercross (MAGIC) population. Flowering time data was collected from field trials across six growing seasons in the United Kingdom, followed by genetic analysis using a combination of linear modelling, simple interval mapping and composite interval mapping, using either single markers or founder haplotype probabilities. We detected 57 quantitative trait loci (QTL) across three growth stages linked to flowering time, of which 17 QTL were identified only when the major photoperiod response locus Ppd-D1 was included as a covariate. Of the 57 loci, ten were identified using all genetic mapping approaches and classified as ‘major’ QTL, including homoeologous loci on chromosomes 1B and 1D, and 4A and 4B. Additional Earliness per se flowering time QTL were identified, along with growth stage- and year-specific effects. Furthermore, six of the main-effect QTL were found to interact epistatically with Ppd-D1. Finally, we exploited residual heterozygosity in the MAGIC recombinant inbred lines to Mendelize the Earliness per se QTL QFt.niab-5A.03, which was confirmed to modulate flowering time by at least four days. This work provides detailed understanding of the genetic control of phenological variation within varieties relevant to the north-western European wheat genepool, aiding informed manipulation of flowering time in wheat breeding.

Molecular mechanisms of flowering time differentiation revealed by transcriptomic sequencing and de novo analysis in Chinese invasive populations of Ambrosia artemisiifolia

BackgroundAmbrosia artemisiifolia is a highly invasive herb with deleterious effects on public health and agricultural systems. Flowering time in this species has been reported to vary along a latitudinal gradient, which may contribute to local adaptation and invasion success in China. However, the molecular basis for the flowering time differentiation remains unclear.ResultsA common garden experiment confirmed a latitudinal gradient in flowering time among seven Chinese populations. Differentially expressed genes (DEGs) across sampling times and flowering time groups were identified through transcriptome sequencing and analyses of DGE and WGCNA, and were partially annotated to circadian rhythm, light response and hormone response through GO enrichment. By annotating to Flowering Interactive Database (FLOR-ID) and protein-protein interaction (PPI) databases, 53 candidate genes for flowering time differentiation were identified, with 23 of these genes linked to the photoperiod pathway. Additionally, 43 of 53 candidate genes exhibited expression correlated with latitude. Six genes, including FKF1, FT, FUL, MAF2, WNK4 and WNK5, were inferred to promote flowering, while 5 genes, FBH3, FLK, NCL(1), POL2A, and ZHD4, likely repress flowering, based on their expression patterns in relation to latitude and sampling times. Notably, NCL(1), FBH3, MAF2, and FLK may function differently in A. artemisiifolia compared to Arabidopsis thaliana.ConclusionsThis study identified key candidate genes related to the differentiation of flowering time in Chinese ragweed populations, providing valuable insights into molecular mechanisms of phenological adaptation and invasive success of ragweed.

Histone modification H3K27me3 is essential during chilling-induced flowering in Litchi chinensis.

Litchi (Litchi chinensis), a prominent fruit tree in the Sapindaceae, initiates flowering in response to low autumn and winter temperatures. This study investigates the epigenetic regulation of this process, focusing on the marks histone H3 lysine 27 trimethylation (H3K27me3) and its deposition genes during the chilling-induced floral induction and initiation stages. Our genomic analysis delineated the H3K27me3 deposition landscape across the pre-floral induction (PFId), floral induction (FId), and floral initiation (FIn) stages. We identified 5,635 differentially H3K27me3-modified genes (DHGs) in buds and 4,801 DHGs in leaves. Integration of the RNA-seq and ChIP-seq datasets identified 1,001 differentially regulated genes (DRGs) in buds and 675 DRGs in leaves, offering insights into the genes potentially targeted by H3K27me3. To probe the functional role of H3K27me3, we employed GSK343, a histone H3 lysine methyltransferase inhibitor. Treatment with GSK343 during the chilling-induced flowering process led to reduced H3K27me3 deposition at the TREHALOSE-6-PHOSPHATE SYNTHASE 1 (LcTPS1) and FRIGIDA (LcFRI) loci, resulting in increased gene expression. This manipulation delayed flowering and reduced flowering rates, confirming the pivotal role of H3K27me3 in chilling-induced flowering in litchi. Gene co-expression network analysis identified SHORT VEGETATIVE PHASE 10 (LcSVP10) as a crucial regulator in litchi flowering. Overexpression of LcSVP10 in Arabidopsis thaliana delayed flowering, indicating a conserved function in flowering time control. Our results elucidate the molecular and epigenetic mechanisms that govern floral induction in litchi and highlight the potential of epigenetic modifications to regulate flowering time in horticultural plants.

Morpho-Phenological, Chemical, and Genetic Characterization of Italian Maize Landraces from the Lazio Region.

In the framework of a Collaboration Agreement between CREA and ARSIAL, a morpho-phenological, chemical, and genetic characterization of maize populations native to the Lazio region was carried out. During 2022 and 2023, a set of 50 accessions, belonging both to ARSIAL and CREA maize collections, were multiplied in Bergamo. Morpho-phenological descriptors were recorded in the field: plant height, ear height, and male and female flowering time. The grain chemical composition in terms of protein, lipid, starch, ash and fiber was evaluated by near-infrared spectroscopy (NIRS). A double-digest restriction-site-associated DNA sequencing (ddRADseq) strategy was used to genotype the landraces. The two collections were not significantly different in terms of grain chemical composition. On the other hand, the ARSIAL and CREA germplasm showed a different distribution in the three cluster-based population structure obtained by ddRADseq, which largely corresponded to the distribution map of their collection sites. The materials from the Lazio region maintained by ARSIAL and CREA were revealed to be different. The comparison between the two groups of landraces showed the importance of characterizing germplasm collections to promote the recovery and valorization of local biodiversity.

Identification of Genetic Loci Associated with Bolting Time in Radish (Raphanus sativus L.) by QTL Mapping and GWAS

Bolting time is a critical trait that affects crop yield, adaptability, and overall productivity, making its regulation vital for agricultural success. In this study, we explored the genetic mechanisms controlling flowering time in radish (Raphanus sativus) via a combination of quantitative trait locus (QTL) analysis and genome-wide association study (GWAS). By developing an F2 population from a cross between the relatively late-bolting variety ‘L432’ and the early-bolting variety ‘L285’, we identified 12 QTLs associated with bolting time. Furthermore, a GWAS performed on 60 East Asian radish accessions revealed 14 candidate genes potentially involved in flowering and bolting regulation. FLOWERING LOCUS C (FLC2) was the major candidate gene explaining the early and late bolting types. One locus was commonly detected from QTL and GWAS on chromosome 4, where CONSTANS-like (COL4) is located. To validate these findings, SNP markers were designed and applied to F2 populations, revealing a correlation between marker presence and bolting phenotypes. These results offer valuable insights into the molecular control of bolting time in radish and identify candidate genes for use in marker-assisted breeding. These findings could enhance breeding efforts for optimizing bolting time in various radish markets.

Carbon and nitrogen signaling regulate FLOWERING LOCUS C and impact flowering time in Arabidopsis.

The timing of flowering in plants is modulated by both carbon (C) and nitrogen (N) signaling pathways. In a previous study, we established a pivotal role of the sucrose-signaling trehalose 6-phosphate pathway in regulating flowering under N-limited short-day conditions. In this work, we show that both wild-type Arabidopsis (Arabidopsis thaliana) plants grown under N-limited conditions and knock-down plants of TREHALOSE PHOSPHATE SYNTHASE 1 induce FLOWERING LOCUS C (FLC) expression, a well-known floral repressor associated with vernalization. When exposed to an extended period of cold, a flc mutant fails to respond to N availability and flowers at the same time under N-limited and full-nutrition conditions. Our data suggest that SUCROSE NON-FERMENTING 1 RELATED KINASE 1-dependent trehalose 6-phosphate-mediated C signaling and a mechanism downstream of N signaling (likely involving NIN-LIKE PROTEIN 7) impact the expression of FLC. Collectively, our data underscore the existence of a multi-factor regulatory system in which the C and N signaling pathways jointly govern the regulation of flowering in plants.

Association of GhGeBP genes with fiber quality and early maturity related traits in upland cotton

Transcription Factors (TFs) are key regulators of how plants grow and develop. Among the diverse TF families, the Glabrous-enhancer binding protein (GeBP) family plays a key role in trichome initiation and leaf development. The specific roles of GeBP TFs in plants remain largely unexplored, although GeBP transcription factors play important roles in plants. This study identified 16 GhGeBP genes in Gossypium hirsutum, ranging from 534 bp (GhGeBP14) to 1560 bp (GhGeBP2). Phylogenetic analysis grouped 16 GhGeBP genes clustered into three subgroups, unevenly distributed across 14 chromosomes. Analysis of the cis-acting elements revealed 408 motifs in the 2 kb upstream regions of the promoters, including stress-responsive, phytohormone-responsive, and light-responsive elements. Tissue-specific expression analysis showed 8 GhGeBP genes were highly expressed across all tissues, while GhGeBP4 and GhGeBP12 were down-regulated under conditions of drought, salt, cold, and heat stress. A genome-wide association study (GWAS) identified GhGeBP4 was associated with fiber micronaire (FM) and fiber strength (FS), while GhGeBP9 was linked to the node of the first fruiting branch (NFFB) and flowering time (FT). Haplotype analysis revealed that GhGeBP4-HAP2 exhibited higher fiber quality traits, while GhGeBP9-HAP2 was associated with early maturity. The results of this study offer significant insights that are worthy of further investigation into the role of the GhGeBP gene family in G. hirsutum and promising targets for marker-assisted selection strategies in cotton breeding programs, particularly for improving fiber quality and early maturity traits.

Local haplotyping reveals insights into the genetic control of flowering time variation in wild and domesticated soybean.

The timing of flowering in soybean [Glycine max(L.) Merr.], a key legume crop, is influenced by many factors, including daylight length or photoperiodic sensitivity, that affect crop yield, productivity, and geographical adaptation. Despite its importance, a comprehensive understanding of the local linkage landscape and allelic diversity within regions of the genome influencing flowering and contributing to phenotypic variation in subpopulations has been limited. This study addresses these gaps by conducting an in-depth trait association and linkage analysis coupled with local haplotyping using advanced bioinformatics tools, including crosshap, to characterize genomic variation using a pangenome dataset representing 915 domesticated and wild-type individuals. The association analysis identified eight significant loci on seven chromosomes. Moving beyond traditional association analysis, local haplotyping of targeted regions on chromosomes 6 and 20 identified distinct haplotype structures, variation patterns, and genomic candidates influencing flowering in subpopulations. These results suggest the action of a network of genomic candidates influencing flowering time and an untapped reservoir of genomic variation for this trait in wild germplasm. Notably, GlymaLee.20G147200 on chromosome 20 was identified as a candidate gene that may cause delayed flowering in soybean, potentially through histone modifications of floral repressor loci as seen in Arabidopsis thaliana (L.) Heynh. These findings support future functional validation of haplotype-based alleles for marker-assisted breeding and genomic selection to enhance latitude adaptability of soybean without compromising yield.

Artificial selection of two antagonistic E3 ubiquitin ligases finetunes soybean photoperiod adaptation and grain yield

The precise control of flowering time is of utmost importance for crop adaptation to varying environmental conditions and consequently determines grain yield and plant fitness. Soybean E2, the homolog of Arabidopsis GIGANTEA, is a major locus contributing to high-latitude adaptation and is involved in photoperiod sensitivity. However, due to major effects of E2, additional genetic loci controlling soybean flowering and adaptation have historically been masked and difficult to identify. Here, by eliminating the effect of E2, we identified a Tof9 locus controlling flowering in which ZEITLUPE 2 (ZTL2) is the causal gene. ZTL2 encodes an F-box E3 ubiquitin ligase with homology to Arabidopsis ZEITLUPE and is shown to play a key role in the soybean photoperiodic flowering pathway. ZTL2 physically interacts with E2 to mediate its degradation. Intriguingly, ZTL2 and FKF1, both belong to the F-box-type E3 ubiquitin-ligase family, exhibit opposite roles in regulating soybean flowering. ZTL2 degrades E2, leading to early flowering, while FKF1 stabilizes E2, resulting in delayed flowering. The balance between ZTL2-mediated degradation and FKF1-mediated stabilization enables soybeans to finetune flowering time and maximize grain yield. Field-grown ztl2 mutants are taller, flower late, and have increased yield parameters. ZTL2 and FKF1b bear contrasting artificial-selection patterns to adapt to different latitudes. This antagonistic regulation is crucial for soybean adaptation to diverse ecological settings and allows plants to fine-tune their flowering time in response to photoperiod and latitudinal changes.

GmHSP40.1, a nuclear-localized soybean J domain protein, participates in regulation of flowering time through interacting with EMF1 and JMJ14

Heat shock protein 40s (HSP40s) are a group of J domain proteins (JDPs), which serve as co-chaperones for heat shock protein 70s. We previously reported that over-expression of a soybean class C JDP, GmHSP40.1, in Arabidopsis activated defense responses. Surprisingly, a significantly delayed flowering phenotype was also observed for the GmHSP40.1-overexpressing (OE) lines. We provided evidence that the late-flowering phenotype observed in the GmHSP40.1-OE lines was not due to impaired pri-miRNA processing and pre-mRNA splicing. Instead, we found that GmHSP40.1 interacted and co-localized with both EMF1 and JMJ14, two major components in the EMF1 complex (EMF1c), which plays a key role in depositing and maintaining the H3K27me3 modification in the FT locus. Consistent with these interactions, the H3K27me3 modification at FT chromatin was significantly increased, whereas the H3K27me3 modification at FLC locus was significantly decreased in the GmHSP40.1-OE line compared with the wde-type Col-0. Interestingly, the H3K4me3 modification was just opposite to H3K27me3 modification at FT and FLC loci, suggesting an antagonistic relationship between these two modifications. Accordingly, the expression of FT and FLC was significantly reduced and increased, respectively, in the GmHSP40.1-OE line compared with that of Col-0. Lastly, we showed that both EMF1 and JMJ14 are genetically epistatic to GmHSP40.1-overexpression. Together, our results revealed that GmHSP40.1 negatively regulates flowering time through promoting the function of EMF1c via interacting with both EMF1 and JMJ14.

Characterization of an olive population relevant for genome-wide association studies on flowering time

Characterization of an olive population relevant for genome-wide association studies on flowering time

Effect of watering interval on growth and production of 2 maize (Zea mays L.) varieties in drought stressed media treated with chitosan

Abstract Maize is an important food source after rice, but its production is often hampered by drought stress. This study aimed to assess the effect of watering intervals on two maize varieties by applying chitosan from black soldier fly (Hermetia illucens) cocoon shell waste. The study used a Randomized Block Design (RBD) with two treatment factors. The first factor was watering interval consisting of five levels: daily watering, no watering for 4, 8, 12, and 16 days. The second factor was maize variety, Bonanza F1 and Bisi-18. The results showed that the watering interval had a significant effect on plant height, number of leaves, stem diameter at 7 weeks of age, cob weight, 100 seed weight, root volume and length, and time of female flower emergence. The treatment of Bonanza F1 and Bisi-18 varieties also had a significant effect on plant height at 7 weeks of planting, stem diameter at 6-7 weeks of planting, root volume, root length, female flowering time, cob weight and length. In addition, the interaction between watering interval and maize varieties significantly affected plant height, 100 seed weight, cob length, root volume, root length, and time to female flower emergence.