Reproductive Growth Research Articles

The parasitic copepod, Sarcotretes scopeli Jungersen, 1911 castrate its mesopelagic fish host Benthosema glaciale

AbstractThe mesopelagic fish Benthosema glaciale [Actinopterygii: Myctophiformes: Myctophidae], abundant in open ocean and deep fjords, is targeted for future exploitation despite existing knowledge gaps on population vital rates. Among these gaps, the vulnerability to pathogens is poorly understood. Parasites rely on the metabolic energy of their host and infections might compromise host physiology and behaviour, which in turn, may affect growth and survival. Parasitic infections by the copepod Sarcotretes scopeli [Crustacea: Copepoda: Pennellidae] have frequently been recorded from the North Atlantic, including west Norwegian fjords. In this paper we present data on how S. scopeli infection affect reproductive investment, energetic status, and growth of its host, the mesopelagic fish B. glaciale. Our results indicate that (i) S. scopeli reduce reproductive investment (measured as gonadosomatic index GSI) of both female and male B. glaciale; (ii) that the energy storage (hepatosomatic index HSI) appeared unaffected in female B. glaciale, while infected male hosts have higher HSI than uninfected, and (iii) that infected fish are in poorer condition than uninfected. These findings may indicate that S. scopeli could have a significant regulatory impact on B. glaciale populations.

Identification and Gene Fine Mapping of the Bisexual Sterility Mutant Meiosis Abnormal Bisexual Sterility 1 in Rice

Exploring the genes regulating rice fertility is of great value for studying the molecular mechanisms of rice reproductive development and production practices. In this study, we identified a sterile mutant from the mutant library induced by ethyl methanesulfonate (EMS), designated as meiosis abnormal bisexual sterility 1 (mabs1). The mabs1 mutant exhibits no phenotypic differences from the wild-type during the vegetative growth phase but shows complete sterility during the reproductive growth phase. Phenotypic observations revealed that both pollen and embryo sac fertility are lost in mabs1. Notably, in mabs1, the development of the anther inner and outer walls, tapetum degeneration, and callose synthesis and degradation all proceed normally, yet meiosis fails to form normal tetrads. Genetic analysis indicated that this mutant trait is controlled by a single recessive nuclear gene. By constructing a genetic segregation population, we successfully mapped the MABS1 gene to a 49 kb region between primer markers Y7 and Y9 on chromosome 1. Resequencing revealed a single-nucleotide substitution in the exon of the LOC_Os01g66170 gene, which resulted in a change from Valine to Isoleucine. Subsequent sequencing of this locus in both wild-type and mabs1 mutants confirmed this mutation. Therefore, we have identified the gene at LOC_Os01g66170 as a candidate for MABS1, a previously unreported novel gene involved in rice meiosis. Through RT-qPCR, we found that the expression levels of multiple meiosis-related genes were significantly changed in the mabs1 mutant. Therefore, we believe that MABS1 is also involved in the process of rice meiosis. This study lays the groundwork for a functional study of MABS1.

Microbiome and nutrient dynamics of organic manures for precision NPK management in sunflower (Helianthus annuus L.)

AbstractOrganic manure plays an important role in soil fertility, microbial communities and sustainable agricultural strategies. In organic cultivation of crops, manures are mostly used without any calculation of the nutrients added to soil through their application. The quantities of nutrients supplied by the organic manures to the crop have to equalize the quantity of nutrients supplied by inorganic chemical fertilizers, in order to replace chemical fertilizers in organic farming. Since the organic manures release nutrients slowly into the soil over a period of time, the availability of nutrients to the standing crop requires precise estimation. In the present study, the amount of nutrients available in the soil as well as in all the manures was calculated. Moreover, the study included metagenomic analysis of different organic manures used by farmers and gives an insight to the role the microbiome plays in plant growth. Using a formula of STCR‐IPNS (soil test crop response integrated plant nutrition system), the quantities of different combinations of organic manures required to supply nitrogen, phosphorus and potassium (NPK) to sunflower plants were calculated. Organic manure combinations using animal bone meal, neem cake, farmyard manure and vermicompost recorded better growth and yield responses in sunflower plants compared to inorganic chemical fertilizers. Based on the estimation of NPK in the individual manures and in the soil, pot experiments were carried out to understand the effect of organic manures as well as inorganic fertilizers in the vegetative and reproductive growth of sunflower.

Phosphorus-Mediated Transition from Vegetative to Reproductive Growth in Dwarf Coconut (Cocos nucifera L.)

Reducing the time before the flowering stage in coconut (Cocos nucifera L.) trees greatly influences yield, yet the mechanisms driving the switch from vegetative to reproductive growth are not well understood, especially the role of phosphorus in this transition. In this study, dwarf coconut plants of the same cultivation age were selected and categorized into the vegetative phase (VP) or the reproductive phase (RP). By examining the phenotypic traits, nutrient variations in the roots and soil, and the transcriptional expression of relevant genes in the roots across both phases, we investigated the potential mechanisms driving the transition from the VP to the RP in coconuts. The shoots of coconuts in the RP were significantly taller compared to those in the VP. Moreover, the phosphorus concentration in the roots of coconuts during the RP was 1.31 times higher than in the VP, which may be linked to the significant upregulation of the PT1 genes AZ11G0219160 and AZ02G0034860 in the roots of coconuts in the RP. In addition, all phosphorus-containing metabolites in the roots during the RP showed a significant increase, particularly those related to long-chain fatty acids and ribonucleotide metabolites. This suggests that coconut roots may facilitate the progression from vegetative to reproductive growth by enhancing phosphorus uptake via PT1s and promoting the synthesis and accumulation of phosphorus-containing metabolites.

Dwarfism mechanism in Malus clonal rootstocks.

The dwarfing mechanism in apple clonal rootstocks is driven by complex interactions between anatomical, hormonal, genetic, and phenolic factors, offering potential for advanced genetic manipulation to optimize tree size and enhance orchard productivity. The widespread adoption of dwarfing rootstocks is pivotal to modern commercial apple (Malus × domestica Borkh) orchards due to their ability to control tree size, shorten the juvenile period, and enhance reproductive growth and overall productivity. The underlying mechanisms of rootstock-induced dwarfism are multifaceted and involve interactions between phenotypic, anatomical, genetic, and phytohormonal factors. This review consolidates current understanding, highlighting the importance of auxin (IAA), cytokinins (CKs), gibberellins (GAs), and abscisic acid (ABA) in mediating growth suppression through impaired transport and hormone signaling. The phenotypic impacts, including reduced root growth, shorter sylleptic shoots, and higher floral bud densities, are discussed alongside genetic loci such as Dw1, Dw2, and Dw3, and the influence of key genes/TFs like MdWRKY9, RGL, and PIN. Anatomically, dwarf rootstocks exhibit a higher bark-to-wood ratio and restricted hydraulic conductivity, which contribute to reduced scion vigour. Furthermore, the accumulation of phenolic compounds in the graft union of dwarfing rootstocks further modulates the growth inhibition. These insights lay the groundwork for advanced molecular breeding strategies, incorporating gene-editing technologies to improve dwarf rootstock development, providing avenues for enhanced orchard management and apple productivity.

Integrated Analysis of microRNAs and Transcription Factor Targets in Floral Transition of Pleioblastus pygmaeus.

Bamboo plants have erratic flowering habits with a long vegetative growth and an uncertain flowering cycle. The process of floral transition has always been one of the hot and intriguing topics in bamboo developmental biology. As master modulators of gene expression at the post-transcriptional level, miRNAs play a crucial role in regulating reproductive growth, especially in floral transition of flowering plants. Pleioblastus pygmaeus is a kind of excellent ground cover ornamental bamboo species. In this study, we performed miRNA expression profiling of the shoot buds and flower buds from the bamboo species, to investigate flowering-related miRNAs in bamboo plants. A total of 179 mature miRNAs were identified from P. pygmaeus, including 120 known miRNAs and 59 novel miRNAs, of which 96 (61 known miRNAs and 35 novel miRNAs) were differentially expressed in the shoots at different growth stages. Based on target gene (TG) prediction, a total of 2099 transcription factors (TFs) were annotated to be TGs of the 96 differentially expressed miRNAs (DEMs), corresponding to 839 recordings of DEM-TF pairs. In addition, we identified 23 known DEMs involved in flowering and six known miRNAs related to floral organ development based on previous reports. Among these, there were 11 significantly differentially expressed miRNAs, with 124 TF targets corresponding to 132 DEM-TF pairs in P. pygmaeus. In particular, we focused on the identification of miR156a-SPL (SQUAMOSA Promoter-Binding protein-Like) modules in the age pathway, which are well-known to regulate the vegetative-to-reproductive phase transition in flowering plants. A total of 36 TF targets of miR156a were identified, among which there were 11 SPLs. The Dual-Luciferase transient expression assay indicated miR156a mediated the repression of the PpSPL targets in P. pygmaeus. The integrated analysis of miRNAs and TGs at genome scale in this study provides insight into the essential roles of individual miRNAs in modulating flowering transition through regulating TF targets in bamboo plants.

More than flowering: CONSTANS plays multifaceted roles in plant development and stress responses.

Plants have evolved a remarkable ability to sense and respond to changes in photoperiod, allowing adjustments to their growth and development based on seasonal and environmental cues. The floral transition is a pivotal stage in plant growth and development, signifying a shift from vegetative to reproductive growth. CONSTANS (CO), a central photoperiodic response factor conserved in various plants, mediates day-length signals to control the floral transition, although its mechanisms of action vary among plants with different day-length requirements. In addition, recent studies have uncovered roles for CO in organ development and stress responses. These pleiotropic roles in model plants and crops make CO a potentially fruitful target for molecular breeding aimed at modifying crop agronomic traits. This review systematically traces research on CO, from its discovery and functional studies to the exploration of its regulatory mechanisms and newly discovered functions, providing important insight into the roles of CO and laying a foundation for future research.

Leaf nutrient basis for the differentiation of photosynthetic traits between subtropical evergreen and deciduous trees.

Compared to evergreens, deciduous tree species usually have higher photosynthetic efficiency to complete vegetative and reproductive growth in a shorter growing season. However, the nutrient basis for the differentiation of photosynthesis functional traits between evergreen and deciduous tree species has not yet been clarified. Thirty evergreen and twenty deciduous angiosperm tree species from a subtropical common garden were compared in terms of photosynthetic traits and leaf nutrients. Generally, their differences in area-based photosynthetic capacity were uncorrelated with area-based leaf nutrient content but were caused by the fraction of nitrogen allocated to photosynthetic components. By comparison, the differences in mass-based photosynthetic capacity were more correlated with leaf nitrogen content than leaf phosphorus and potassium content. Convergence in phosphorus and potassium constraints to photosynthesis occurred in deciduous tree species but not in evergreen tree species. Furthermore, leaf C/N ratio played a more significant role than leaf mass per area in determining the differentiation of photosynthetic traits between evergreen and deciduous groups. Our findings provide insight into the nutrient basis for photosynthetic carbon gain and functional strategies across trees species.

First report of ergot caused by Claviceps clavispora in switchgrass (Panicum virgatum L.) in Georgia, USA.

Switchgrass (Panicum virgatum L.) is a North American grass species with biofuel potential. Claviceps spp. is known to infect the florets of various grass species, initially characterized by a sticky honeydew exudate and later as sclerotium replacing the seed in the infected ovary (Tanaka et al 2023). Since 2019, from July to October, switchgrass panicles in Georgia have been observed with honeydew and black sclerotia. The disease was first noted on some of the 285 accessions of the genome-wide association study (GWAS) panels at the University of Georgia's Iron Horse Farm in Watkinsville and Gibbs Farm in Tifton, GA. In Watkinsville, GA, ergot incidence was 5%, 6%, 65% and 54% in 2019, 2020, 2021 and 2022, respectively. Symptomatic panicles with honeydew and sclerotia were collected in 2021 (sample Scl) and 2023 (samples Cla_M and ATH20cl) from Watkinsville, GA. Under microcopy, panicles with honeydew symptoms had mycelium and conidia (9 μm long [range of 5-13 μm] and 4 μm wide [3-5 μm]) consistent with Claviceps spp. (Tooley et al. 2001). Sclerotia were 1.5 mm long (range 1-3 mm). Sclerotia were surface sterilized for 3 minutes in 5% NaOCl, followed by 70% ethanol then rinsed three times in distilled water. Sterilized sclerotia were plated on potato dextrose agar and placed on bench top with a 12-hour day/night cycle at room temperature (22°C) (Singh 1976). After 2 months, the sclerotia produced sterile apothecia. For molecular identification, genomic DNA was extracted from three honeydew samples following the protocol of Doyle and Doyle (1987). The internal transcribed spacer (ITS) region and RNA polymerase second largest subunit (RPB2) gene were amplified using ITS4/ITS5 (White et al. 1990) and 5F2/7CR (Liu et al. 1999) primer sets. The ITS region of ATH20cl, Cla_M, and Scl (GenBank nos. PP546317- PP546319) showed 92.83-97.48% identity to C. clavispora (NR_163506.1). The RPB2 region of ATH20cl, Cla_M, and Scl (GenBank nos. PP573916- PP573918) showed 97.46-97.72% identity to C. clavispora (LT216566.1). The maximum likelihood tree constructed in MEGA-X (Kumar et al. 2018) using concatenated ITS (539 bp) and RPB2 (792 bp) gene sequences from this study and eleven reference sequences from Tanaka et al. (2023), revealed close relatedness of ATH20cl, Cla_M, and Scl to C. clavispora under section Pusillae. The pathogenicity test for samples ATH20cl and Cla_M was conducted in the greenhouse on switchgrass cultivar 'Alamo' grown in injection molded pots containing Sungro professional growing mix. Three replicates plants at reproductive (R3) growth stage were inoculated by immersing panicles in 105 spores/ml suspension for 5 minutes and bagged for 3 days (Tooley et al. 2001). Control plants were immersed in distilled water. Honeydew symptoms and sclerotia appeared within 7- and 90-days post-inoculation, respectively, whereas control plants remained symptom-free. The honeydew collected from the infected Alamo panicles were reconfirmed to produce similar spores to those collected from the field. This is the first report of ergot caused by C. clavispora in switchgrass. Ergot was also observed since 2019 on some accessions from the same GWAS panel planted at the University of Tennessee Plant Sciences Farm in Knoxville, TN. This information will be beneficial to determine the effect of ergot on biomass production and seed quality of switchgrass in the southeastern U.S.

Combined toxic effects of yessotoxin and polystyrene on the survival, reproduction, and population growth of rotifer Brachionus plicatilis at different temperatures.

Yessotoxin (YTX) is a disulfated toxin produced by harmful dinoflagellates and causes risks to aquatic animals. Polystyrene (PS) microplastics could absorb toxins in seawaters but pose threats to organism growth. In this study, the combined toxic effects of YTX (0, 20, 50, and 100 µg L-1) and PS (0, 5, and 10 µg mL-1) on the survival, reproduction, and population growth of marine rotifer Brachionus plicatilis at 20 °C, 25 °C, and 30 °C were evaluated. Results indicated that the survival time (S), time to first batch of eggs (Ft), total offspring per rotifer (Ot), generational time (T0), net reproduction rate (R0), intrinsic growth rate (rm), and population growth rate (r) of rotifers were inhibited by YTX and PS at 25 °C and 30 °C. Low temperature (20 °C) improved the life-table parameters T0, R0, and rm at YTX concentrations less than 100 µg L-1. Temperature, YTX, and PS had interactive effects on rotifers' S, Ft, Ot, T0, R0, rm, and r. The combined negative effects of YTX and PS on rotifers' survival, reproduction, and population growth were significantly enhanced at 30 °C. These findings emphasized the importance of environmental temperature in studying the interactive effects of microplastics and toxins on the population growth of zooplankton in eutrophic seawaters.

The Response of Inorganic and Organic Fertilizers on Growth, Yield and Quality of Cluster Bean [Cyamopsis tetragonoloba (L.) Taub.] in the Village Chikkenahalli of Challakere Taluk, Chitraduraga District

Cluster bean is one of the significant yet underutilized leguminous vegetables belonging to family fabaceae. It is known by various names across the country such as gaur, chavli kaayi, gori kaayi, khutt, govar, and kothavare. A field experiment on cluster bean was carried out during the summer season of the year 2024 at the farm of P. L. Dodda Rangegowda in Chikkenahalli of Challakere taluk, Chitradurga district, Karnataka. The primary objectives of the study are to examine the effects of organic and inorganic fertilizers on the productivity and growth characteristics of cluster bean; to identify the advantages and disadvantages of these fertilizers in relation to productivity, soil fertility, and environment and further to review the effects of mixed organic and inorganic fertilizers on yield and soil fertility. The experiment was laid out in a randomized block design with four replications and five treatments which comprised of 100 percent organic (FYM and chicken manure), 100 percent inorganic (NPK), 50 percent organic + 50 percent inorganic, 100 percent organic + jeevamruta and control. The results revealed that, treatment T3 outperformed the others, showing the highest values for plant height, number of branches per plant, days to first flowering, days to first vegetable harvest, pod length, pod width, yield per plant, yield per plot, and yield per hectare, while the control recorded the lowest values. Soil properties such as pH, EC, SOC and NPK levels improved when combination of organic and inorganic fertilizers were applied together. Based on these results, it can be concluded that, the application of organic manures, along with chemical fertilizers, positively enhanced the vegetative growth, reproductive growth, yield, quality of cluster bean and soil parameters.

Elevated CO2 Concentration Extends Reproductive Growth Period and Enhances Carbon Metabolism in Wheat Exposed to Increased Temperature.

Both elevated atmospheric CO2 concentration ([CO2]) and increased temperature exert notable influences on wheat (Triticum aestivum L.) growth and productivity when examined individually. Nevertheless, limited research comprehensively investigates the combined effects of both factors. Winter wheat was grown in environment-controlled chambers under two concentrations of CO2 (ambient CO2 concentration and ambient CO2 concentration plus 200 µmol mol-1) and two levels of temperature (ambient temperature and ambient temperature plus 2°C). The phenology, photosynthesis, carbohydrate and nitrogen metabolism, yield and quality responses of wheat were investigated. Elevated [CO2] did not counteract warming-induced shortening of wheat phenological period but prolonged grain filling. Even though photosynthetic adaptation occurred during the reproductive growth period, elevated [CO2] still significantly enhanced carbohydrate accumulation under warming, particularly at the grain filling stage, thereby increasing yield by 20.1% compared with the ambient control. However, elevated [CO2] inhibited nitrogen assimilation at the grain filling stage under increased temperature by downregulating the expression levels of TaNR, TaNIR, TaGS1 and TaGOGAT and reducing glutamine synthetase activity, which directly led to a significant decrease of 19.4% in grain protein content relative to the ambient control. These findings suggest that elevated [CO2] will likely increase yield but decrease grain nutritional quality for wheat under future global warming scenarios.

Impact of flooding at the early reproductive growth stage on soybean yield and seed composition

AbstractFlooding stress is a growing threat to global soybean [Glycine max (L.) Merr.] production as the frequency and intensity of extreme precipitations are increasing due to climate change. Soybean is highly sensitive to flooding and substantial yield losses are observed due to a cascade of negative physiological responses induced by hypoxia. Hence, there is a pressing need for the development of flood‐tolerant genotypes. This study evaluated the grain yield and seed protein and oil content of 31 soybean genotypes over 2 years under both non‐flooding and flooding conditions, where flooding entailed a 4‐day partial water submergence during the early reproductive growth stages R1/R2. Mixed‐effects linear models were utilized to assess the impact of flood damage scores (FDSs, 1–4 scale) on observed phenotypes, as well as differences in observed phenotypes between tolerant, moderate, and susceptible genotypes across flooding and non‐flooding treatments. No significant impact of FDS was observed for seed protein and oil content. In addition, no significant differences in these phenotypes were observed between flooding and non‐flooding treatments across the various genotype categories. On average, for each unit increase in FDS, grain yield decreased by 432.7 kg ha−1 (17.4%). Tolerant genotypes experienced roughly 33% yield losses between flooding and non‐flooding treatments, while moderate and susceptible genotypes experienced 44% and 51% yield losses, respectively. The advancements in genomics and phenomics are promising for the identification and incorporation of novel flood‐tolerant alleles through plant breeding, potentially mitigating flooding‐induced yield losses across diverse environmental conditions.

Rapid screening for resistance to Sitobion avenae (F.) and Rhopalosiphum padi (L.) in winter wheat seedlings and selection of efficient assessment methods.

Sitobion avenae (F.) and Rhopalosiphum padi (L.) are harmful pests of wheat [Triticum aestivum (L.)]. No genetic resistance against the aphids has been identified in commercial wheat varieties and resistance phenotyping can be time-consuming and laborious. Here, we tested a high-throughput phenotyping method to screen 29 commercial winter wheat varieties for alate antixenosis and antibiosis. We validated this method using comprehensive behavioural analyses, including alate attraction to volatile organic compounds (VOCs) and a feeding bioassay using an electrical penetration graph (EPG), subsequently highlighting possible sources of resistance. We observed differences in alate behaviour upon assessing alate settlement on wheat seedlings and attraction towards VOCs, revealing the importance of visual and early post-alighting cues for alate host selection. Aphid settlement was four times higher on the most preferred variety than on the least preferred variety. Using an EPG bioassay, we identified phloem feeding and stylet derailment parameters linked to resistance. We found antibiosis assessment on detached leaves to be an inadequate screen because it produced results inconsistent with intact leaves assessment. Alate and nymph mortality were identified as key traits signifying antibiosis, showing significant positive relationships with alate reproduction and nymph mean relative growth rate. Overall, antixenosis and antibiosis varietal responses were consistent for both aphid species. Alate settlement on wheat seedlings was a more efficient antixenosis screen than an olfactometer assay using VOCs. In addition to assessing alate and nymph survival for antibiosis, this allows for more rapid phenotyping of large numbers of genotypes to identify novel aphid resistance genes for varietal improvement. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Biomolecular condensation programs floral transition to orchestrate flowering time and inflorescence architecture.

Biomolecular condensation involves the concentration of biomolecules (DNA, RNA, proteins) into compartments to form membraneless organelles or condensates with unique properties and functions. This ubiquitous phenomenon has garnered considerable attention in recent years owing to its multifaceted roles in developmental processes and responses to environmental cues in living systems. Recent studies have revealed that biomolecular condensation plays essential roles in regulating the transition of plants from vegetative to reproductive growth, a programmed process known as floral transition that determines flowering time and inflorescence architecture in flowering plants. In this Tansley insight, we review advances in how biomolecular condensation integrates developmental and environmental signals to program and reprogram the floral transition thus diversifies flowering time and inflorescence architecture.

Effects of nutritional stress on soil fertility and antioxidant enzymes of rice in different growth periods.

Stress in plants denotes the detrimental impact of alterations in external environmental conditions on regular plant growth and development. Plants employ diverse mechanisms to mitigate or evade nutritional stress-induced damage. In order to investigate the physiological response mechanism of plants to nutritional stress and assess its impact on soil nutrient content and antioxidant enzyme activity in rice, a field experiment was conducted applying five treatments: control, nitrogen (N) deficiency, phosphorus (P) deficiency, potassium (K) deficiency, and full fertilization. Rice leaf and soil samples were concurrently gathered during both the vegetative and reproductive growth stages of rice. Analysis was conducted on soil N, P, and K levels, as well as leaf antioxidant enzyme activities, to investigate the impact of nutrient stress on rice antioxidant enzymes and soil fertility. The research findings indicate that full fertilization treatment enhanced the agronomic properties of the soil compared to the control treatment. In the N-deficiency treatment, reactive oxygen species (ROS) levels increased by 16.53-33.89% during the reproductive growth period compared to the vegetative growth period. The peroxidase (POD) activity decreased by 41.39% and superoxide dismutase (SOD) activity increased by 36.22% under K-deficiency treatment during the reproductive growth period compared to the vegetative growth period. Consequently, applying N and P fertilizer during the vegetative growth period can decrease membrane lipid peroxidation levels by 7.34-72.53%. The full fertilization treatment markedly enhanced rice yield compared to other treatments and increased the Nitrogen activation coefficient (NAC) and Phosphorus activation coefficient (PAC) in the soil, while decreasing the PAC. Elevating NAC levels can stimulate the activity or content of PRO, MDA, and RPS during the vegetative growth stage, whereas in the reproductive growth stage, it will decrease the content of ROS, PRO, and MDA. This data offers valuable insights and theoretical support for nutritional stress research.

AINTEGUMENTA-LIKE genes regulate reproductive growth and bud dormancy in Platanus acerifolia.

Platanus acerifolia AIL genes PaAIL5a/b and PaAIL6b participate in FT-AP1/FUL-AIL pathways to regulate bud dormancy. In addition, PaAIL6a/b can promote flowering, and PaAIL5b and PaAIL6b affect floral development. Bud dormancy and floral induction are essential processes for perennial plants, they are both regulated by photoperiod, temperature, and hormones, indicating the existence of common regulators for both processes. AINTEGUMENTA-LIKE (AIL) genes regulate reproductive growth of annual plants, including floral induction and flower development, and their homologs in poplar and grape act downstream of the florigen gene FT and the floral meristem identity genes AP1/FUL and function to maintain growth and thus inhibit dormancy induction. However, it is not known whether AIL homologs participate in the reproduction processes in perennials and whether the Platanus acerifolia AIL genes are involved in dormancy. P. acerifolia is a perennial woody plant whose reproductive growth is strongly associated with dormancy. Here, we isolated four AIL homologs from P. acerifolia, PaAIL5a, PaAIL5b, PaAIL6a, and PaAIL6b, and systematically investigated their functions by ectopic-overexpression in tobacco. The findings demonstrate that PaAIL5a/b and PaAIL6b respond to short day, low temperature, and hormone signals and act as the components of the FT-AP1/FUL-AIL pathway to regulate the bud dormancy in P. acerifolia. Notably, PaAIL5a/b and PaAIL6b function downstream of PaFTL-PaFUL1/2/3 to inhibit the dormancy induction and downstream of PaFT-PaFUL2/3 to promote the dormancy release. In addition, PaAIL6a/b were found to accelerate flowering in transgenic tobacco, whereas PaAIL5b and PaAIL6b affected the flower development. Together, our results suggest that PaAIL genes may act downstream of different PaFT/PaFTL and PaFUL proteins to fulfill conservative and diverse roles in floral initiation, floral development, and dormancy regulation in P. acerifolia.

Advantages of compost tea: Promotion of nitrogen influx into the fruit and improvement of fruit nitrogen metabolism in tomato

The use of compost tea is important to improve food safety. However, the effect of compost tea on N uptake and partitioning in tomato is unclear. In this study, we measured temporal and spatial changes in nitrogen content, enzyme activities, and expression levels of nitrogen transporters genes in different organs of tomato treated with five nutrient solutions. The results showed that the expression levels of ammonium transporter protein genes (AMT1s) increased and that of a nitrogen transporters gene (NRT2.1) decreased under treatment with compost tea, which promoted NH4+ transport to the fruit and reduced nutrient wastage compared with the response to chemical fertilizers. In addition, the lowermost leaves on the stem showed reduced nitrate content, faster metabolism, and decreased chlorophyll a content, but fruit yield was not increased, in compost tea-treated plants. These changes were dependent on the expression level of the glutamine synthetase gene (GS1.1), which was increased in leaves and decreased in fruit. Compost tea influenced the expression of critical genes in the fruits and leaves, and improved the competitiveness of sexual reproductive growth as a sink for nitrogen. However, the benefits of compost tea were reduced when it was mixed chemical fertilizers. This research establishes a theoretical framework for optimization of organic vegetable cultivation and promoting the widespread production of organic crops.

Hydroxamate Siderophores Intensify the Co-Deposition of Cadmium and Silicon as Phytolith-Like Particulates in Rice Stem Nodes: A Natural Strategy to Mitigate Grain Cadmium Accumulation.

Sequestration of cadmium (Cd) in rice phytolith can effectively restrict its migration to the grains, but how hydroxamate siderophore (HDS) affects phytolith formation within rice plants especially the fate of Cd and silicon (Si) remains poorly understood. Here, we found that the addition of HDS increased the content of dissolved Si and Cd in soil pore water as well as its absorption by the rice roots during the reproductive growth stage. HDS effectively trapped orthosilicic acid and Cd ions at the third stem nodes of rice plants via hydrogen bonds and chelation interactions, which then rapidly deposited on the xylem cell wall through hydrophobic interactions. Ultimately, Cd was immobilized as phytolith-like particulates in the form of CdSiO3. Field experiments verified that Cd accumulation was significantly reduced by 46.4% in rice grains but increased by 41.2% in rice stems after HDS addition. Overall, this study advances our understanding of microbial metabolites enhancing the instinctive physiological barriers within rice plants.

TaNAR2.1 and TaNAR2.2 differ in influencing nitrogen uptake and growth of wheat (Triticum aestivum L.)

NAR2 (Nitrate assimilation related protein) is a protein chaperone involved in transporting nitrate across membranes. However, the expression pattern and function of NAR2 genes in wheat are still largely unknown. Here, we cloned two TaNAR2 genes (TaNAR2.1 and TaNAR2.2). To assess and compare the functional differences of TaNAR2.1 and TaNAR2.2, we analyzed the subcellular localization and expression pattern of the two genes in wheat under low nitrogen (LN) and high nitrogen (HN) conditions, as well as the nitrate influx and root system architecture of TaNAR2.1 and TaNAR2.2 overexpression wheat under LN and HN. Additionally, we investigated the effects of TaNAR2.1 and TaNAR2.2 overexpression on the growth phenotype, nitrogen uptake and yield of wheat throughout the growth period. There are significant differences in the expression patterns and functions of TaNAR2.1 and TaNAR2.2. TaNAR2.1 is located in the cytoplasm, nucleus and the plasma membrane, whereas TaNAR2.2 is a cytoplasm-specific protein. TaNAR2.1 appears to exhibit larger changes in expression levels and a higher capacity for nitrate influx than TaNAR2.2 under external nitrate supply. Overexpression of TaNAR2.1 significantly improves grain nitrogen use efficiency and increases grain yield, whereas overexpression of TaNAR2.2 enhances vegetative and reproductive growth of wheat roots. These findings indicate that TaNAR2.1 plays a crucial role in wheat nitrogen accumulation and yield, while TaNAR2.2 is pivotal for wheat root growth.