Photoperiodism dynamics during the domestication and improvement of soybean

Soybean(Glycine max) is a facultative short-day plant with a sensitive photoperiod perception and reaction system, which allows it to adjust its physiological state and gene regulatory networks to seasonal and diurnal changes in environmental conditions. In the past few decades, soybean cultivation has spread from East Asia to areas throughout the world. Biologists and breeders must now confront the challenge of understanding the molecular mechanism of soybean photoperiodism and improving agronomic traits to enable this important crop to adapt to geographical and environmental changes. In this review, we summarize the genetic regulatory network underlying photoperiodic responses in soybean. Genomic and genetic studies have revealed that the circadian clock, in conjunction with the light perception pathways, regulates photoperiodic flowering. Here, we provide an annotated list of 844 candidate flowering genes in soybean, with their putative biological functions. Many photoperiod-related genes have been intensively selected during domestication and crop improvement. Finally, we describe recent progress in engineering photoperiod-responsive genes for improving agronomic traits to enhance geographic adaptation in soybean, as well as future prospects for research on soybean photoperiodic responses.

Photoperiod Mediates the Effects of Temperature and Light Intensity on the Proliferation of Ulva prolifera

In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L:D=12:12,14:10 and 10:14),temperature(15℃(LT),25℃(MT)and 30℃(HT))and light intensity(100,200 and 400μmol m^(−2)s^(−1),noted as LL,ML and HL,respectively)conditions.Then the maturation time,spore release number and chlorophyll fluorescence were analyzed.The results suggested that:1)The spore maturation time was accelerated by higher temperature or higher light intensity from 62 h to 36 h,and changes in day length accelerated the spore maturation to a certain extent as compared with 12:12 light/dark cycle;2)Higher light intensity significantly decreased the chlorophyll fluorescence(Fv′/Fm′,NPQ,rETRmax andα)of the mature reproductive segment under 30℃with 12:12 light/dark cycle.But when in the other photoperiods(10:14 and 14:10 conditions),the inhibitory effects of high light intensity were alleviated significantly;3)The optimum condition for the spore maturation and release was 12:12 light/dark cycle,25℃,400μmol m^(−2)s^(−1),with both shorter and longer photoperiod reducing the spore release number;4)Higher light intensity significantly increased the spore release number under 25℃,but these effects were alleviated by 30℃treatment.This study is the first attempt to elucidate the coincidence effects of photoperiod,temperature and light intensity on the reproduction of Ulva,which would help to reveal the mechanism of the rapid proliferation of green tide.

Flowering-time regulation by the circadian clock:From Arabidopsis to crops

Precise timing of flowering in plants is critical for their growth and reproductive processes.One factor controlling flowering time is the cycle of light and darkness within a day,known as the photoperiod.Plants are classified into long-day,short-day,and day-neutral plants based on light requirements for floral initiation.Although the molecular mechanisms that govern this differentiation remain incompletely understood,studies have consistently shown that the circadian clock plays a central role in regulating photoperiod response across diverse plant species.However,there is a scarcity of reviews describing the regulatory network linking the circadian clock with photoperiodic flowering.This review summarizes that regulatory network,focusing on the distinct roles of clock genes in long-day and short-day plants.We also discuss the strategies of clock gene mutations contributing to geographic variation in longday and short-day crops.

Molecular mechanism of flowering time regulation in Brassica rapa:similarities and differences with Arabidopsis

Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable conditions.Brassica rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil crops.Flowering time is one of the most important agricultural traits of B.rapa crops because of its influence on yield and quality.The transition to flowering in B.rapa is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)signaling.These signals are integrated to control the expression of floral integrators BrFTs and BrSOC1s to regulate flowering.In this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in B.rapa and compare this to what is known in Arabidopsis.

Effects of heat stress and long photoperiod on the prostate of rats

Objective:To examine light and heat effects on the morphological,histological,and micrometric structure of the prostate of rats.Methods:Thirty adult male rats were divided into three groups.The control group was kept under 20℃-22℃ and an artificial 12 h/12 h day/night cycle;the temperature group was under normal light and at(42±1)℃ heat for 4 to 5 h daily,and the light group was exposed to 8 h/16 h day/night cycle with 20℃-22℃.Rats were weighed five times(at the beginning of the study and every seven days).Five milliliters(mL)of their peripheral blood were taken.The tissue staining was performed using the hematoxylin-eosin(H&E)stain and periodic acid-Schiff(PAS).In the following,tissue and cellular reactions to the PAS were examined.Results:Folds were located entirely on the surface of the anterior lobe and periphery of the other lobes.The secretory units in the anterior lobe were more than the lateral lobe.A strong reaction of the secretory cells to the PAS was observed.Testosterone serum levels of the light group also significantly increased compared to the control group(P<0.05).The most histometric changes of the lobes were established in the lateral lobes.Heat stress resulted in a significant decrease in testosterone levels and transformed prostate tissue.The epithelium and parenchyma to scaffold ratio in the temperature group decreased.Conclusions:Maximum and minimum changes in the ventral lobe happened under the ascent of temperature and light,respectively.The ventral lobe in the study of prostatic hyperplasia should be more considered.

FLOWERING LOCUS T(FT)in Photosensitive Type Chrysanthemum Accelerates Flowering in Arabidopsis

FLOWERING LOCUS T(FT)is an important factor for integrating flowering signals through the photoperiod pathway,which significantly promotes flowering.Most chrysanthemum varieties are short-day plants,sensitive to the photoperiod,which limits their ornamental and annual production supply.In this study,we aim to analyze the nutrients and flowering-related genes of chrysanthemums with different photoperiod types and to clone and verify the function of the flowering-related gene CmFT.We found that the formation of floral buds requires the accumulation of starch while consuming soluble sugars and the expression patterns of flowering-related genes GIGANTEA(GI),CONSTANS(CO),and FT in C.morifolium‘Zilian’and C.morifolium‘Zihongtuogui’had a certain synchronization during floral buds differentiation according to our quantitative validation,and the expression levels of CmGI,CmCO and CmFT in C.morifolium‘Zihongtuogui’were higher than those in C.morifolium.‘Zilian’in the later stage of differentiation.CmFT was cloned from photosensitive chrysanthemums-C.morifolium‘Zihongtuogui’and polypeptide alignment and phylogenetic analysis showed that CmFT was clustered in FT-like subfamily.In further functional verification,we obtained two Arabidopsis transgenic lines.Our results showed that CmFT transgenic ft mutant lines can significantly accelerate flowering in Arabidopsis.Thus,we can initially confirm that CmFT plays an important role in promoting flowering,which may be the key reason for the photosensitivity of C.morifolium‘Zihongtuogui’.Overall,the results of this study are of great importance in revealing the flowering mechanism of different photoperiod types of chrysanthemums.

Common Organic Amendment (Rice Straw) Can Reduce Salinity Effects on Bean (Phaseolus vulgaris) Growth with or without Photoperiod Manipulation

Soil salinity is a major limiting factor for crop production in coastal areas of Bangladesh. Cheap and sustainable management of soil salinity is hence most sought out topics in agricultural research. Conceptualizing that idea in mind, a pot experiment was conducted in the Department of Soil, Water & Environment, University of Dhaka in order to analyze if common organic amendments (rice straw, saw dust) coupled with reduce photoperiod can mitigate salinity effect on the growth of bean (Phaseolus vulgaris). The experiment was set up following completely randomized design (CRD) with nine treatments and three replications containing Tc (Control), T1 (Ambient photoperiod + 110 mM Salinity treatment + Rice straw), T2 (Reduced photoperiod + 110 mM Salinity treatment + Rice straw), T3 (Ambient photoperiod + 220 mM Salinity treatment + Rice straw), T4 (Reduced photoperiod + 220 mM Salinity treatment + Rice straw), T5 (Ambient photoperiod + 110 mM Salinity treatment + Saw dust), T6 (Reduced photoperiod + 110 mM Salinity treatment + Saw dust), T7 (Ambient photoperiod + 220 mM Salinity treatment + Saw dust) and T8 (Reduced photoperiod + 220 mM Salinity treatment + Saw dust). Organic amendments were used separately at the rate of 12 ton/ha. The highest plant height (98.67 cm), root length (12.5 cm), pod number (10.33), leaf area (13.99 cm2), fresh weight (680 kg/ha), dry weight (316.67 kg/ha) were recorded with the treatment T1 while the second-best treatment was treatment T2 (with highest harvest index 0.040) and these results were statistically significant (p < 0.001). In post-harvest soil, pH, EC, OC, OM;available N, P, K, S;total Ca, Mg, Zn, Mn were increased significantly in treatment T1. The overall results illustrated that the best growth and yield performances were achieved in the treatment T1 and T2.

Effect of Shortening Day Length on Immune Function in Siberian Hamsters

In order to understand the effect of gradual changes in photoperiod on immune function, adult female Siberian hamsters (Phodopus sungorus) were randomly divided into the control group (12L:12D, Con, n = 11) and the shortening day length group (SD, n = 11), in which day length was reduced from 12:12 h to 8:16 h light-dark cycle at the pace of half an hour every week. Meanwhile the winter immunoenhancement hypothesis, which holds that animals’ immune function would be enhanced in winter or winter-like conditions, was tested. Gradual shortening day length had no effect on body mass and body composition including wet carcass mass, the subcutaneous, retroperitoneal, mesenteric and total body fat masses in Siberian hamsters. The masses of liver and small intestine with contents were higher in the SD group than in the Con group, however other organ masses such as brain, heart, kidney and so on did not differ between the two groups. Phytohemagglutinin (PHA) response after 24 h of PHA injection was enhanced by the shortening photoperiod, which supported the winter immunoenhancement hypothesis. The masses of spleen and thymus, white blood cells, bacteria killing capacity indicative of innate immunity were not affected, which did not support this hypothesis. In summary, gradually decrease in day length increased cellular immunity, but had no effect on other immunological parameters in Siberian hamsters.

Regulation of Reproduction in Delayed Gametophyte of Saccharina japonica (Laminariales, Phaeophyceae): Effects of Light Intensity, Quality and Photoperiod

Saccharina japonica gametophytes can survive a long period under unfavorable environmental conditions,while they also delay in growth and/or reproduction.Although the reproduction in delayed gametophyte of S.japonica was known to be strongly influenced by light intensity,light quality,and photoperiod,no previous studies have evaluated their interactive effects on gametogenesis.To evaluate these effects,we used an orthogonal experiment to expose delayed gametophytes of S.japonica to different light intensities,light qualities,and photoperiods for 12 days.The results showed that changes in light intensity rather than light quality and photoperiod significantly affected the relative growth rates of the delayed gametophytes.Blue light had the greatest promotion on reproduction rate.The optimal light conditions in the early vegetative growth phase in gametogenesis induction for the delayed gametophytes were at 60–80μmol photons m^(−2) s^(−1) with daylength of 12 or 16 hours under white or blue light.When the delayed gametophytes were maintained in a constant light condition from delayed state to gametogenesis,the beneficial photoperiods for vegetative growth and reproductive rate were both 16L(16 hours of light):8D(8 hours of dark).However,when the delayed S.japonica gametophytes achieve the optimal growth state during the first 6 days and then they were cultured at different light conditions for the following 6 days,the reproduction rate increased as the daylength decreased and attained a peak value in group of 8L:16D photoperiod,indicating that photoperiod adjustment at the transition period is crucial in the gametogenesis induction process of delayed gametophyte of S.japonica.

LHD3 Encoding a J-Domain Protein Controls Heading Date in Rice

Heading date is one of the most important agronomic traits of rice,which critically affects rice ecogeographical adaptation,yield and quality.In this study,a late heading date 3(lhd3)mutant was screened from the^(60)Co-γirradiation mutant library.The lhd3 delayed heading date in rice under both short day and long day conditions.Map-based cloning combined with Mutmap strategy was adopted to isolate the causal LHD3 gene.The LHD3 gene encodes a DNA_J domain protein,which was ubiquitously expressed in various plant organs,and dominant expressed in stems and leaves.Subcellular localization analysis showed that LHD3 was localized to nucleus,indicating that LHD3 may interact with other elements to regulate the expression of flowering genes.The transcriptions of the heading activators Ehd1,Hd3a and RFT1 significantly decreased in the lhd3 mutant,suggesting that LHD3 may control the heading date through the Ehd1-Hd3a/RFT1 photoperiodic flowering pathway.The variation and haplotype analyses of the genomic region of LHD3 showed that there were 7 haplotypes in the LHD3 region from 4702 accessions.The haplotypes of LHD3 can be divided into two classes:class a and class b,and the heading dates of these two classes were significantly different.Further study showed that two single nucleotide polymorphisms(SNPs),SNP10(G2100C)in Hap II and SNP3(C861T)in Hap VII,may be the functional sites causing early and late heading in accessions.Nucleotide diversity analysis showed LHD3 had been selected in the indica population,rather than in the japonica population.Therefore,the present study sheds light on the regulation of LHD3 on heading date in rice and suggests that LHD3 is a novel promising new target for rice molecular design and breeding improvement.

Regulation of soybean stem growth habit:A ten-year progress report

Stem growth habit dictates plant architecture and influences flowering and podding(seed setting),making it an essential morphological and breeding agronomic trait of soybean(Glycine max).Stem growth habit in soybean is affected by photoperiod and environment and is determined by genetic variation at major genes.Classical genetic analysis identified two critical loci,designated Determinacy 1(Dt1)and Determinacy 2(Dt2).Dt1 is an ortholog of Arabidopsis thaliana TERMINAL FLOWER1(TFL1)and specifies an indeterminate stem growth habit,whereas Dt2 specifies a semi-determinate growth habit.MADS-box proteins,including Dt2,SUPPRESSOR OF OVEREXPRESSION OF CO1(GmSOC1)and MADS-box genes downregulated by E1(GmMDE),repress Dt1 expression.Photoreceptors encoded by the E3 and E4 loci regulate the expression of soybean FLOWERING LOCUS T(GmFT)orthologs via circadian clock genes and E1,and GmFTs compete with Dt1 to regulate stem growth habit.Study of the molecular mechanism underlying the regulation of stem growth habit in soybean has focused on the repression of Dt1 expression.Here we provide an overview of progress made in elucidating the genetic and molecular bases of stem growth habit in soybean,with emphasis on the molecular components responsible for integrating photoperiodic flowering and stem growth habit.

Overexpression of Wheat TaELF3-1BL Delays Flowering in Arabidopsis

EARLY FLOWERING 3(ELF3),a light zeitnehmer(time-taker)gene,regulates circadian rhythm and photoperiodic flowering in Arabidopsis,rice,and barley.The three orthologs of ELF3(TaELF3-1AL,TaELF3-1BL,and TaELF3-1DL)have been identified in wheat too,and one gene,TaELF3-1DL,has been associated with heading date.However,the basic characteristics of these three genes and the roles of the other two genes,TaELF3-1BL and,TaELF3-1AL,remain unknown.Therefore,the present study obtained the coding sequences of the three orthologs(TaELF3-1AL,TaELF3-1BL,and TaELF3-1DL)of ELF3 from bread wheat and characterized them and investigated the role of TaELF3-1BL in Arabidopsis.Protein sequence comparison revealed similarities among the three TaELF3 genes of wheat;however,they were different from the Arabidopsis ELF3.Real-time quantitative PCR revealed TaELF3 expression in all wheat tissues tested,with the highest expression in young spikes;the three genes showed rhythmic expression patterns also.Furthermore,the overexpression of the TaELF3-1BL gene in Arabidopsis delayed flowering,indicating their importance in flowering.Subsequent overexpression of TaELF3-1BL in the Arabidopsis ELF3 nonfunctional mutant(elf3 mutant)eliminated its early flowering phenotype,and slightly delayed flowering.The wild-type Arabidopsis overexpressing TaELF3-1BL demonstrated reduced expression levels of flowering-related genes,such as CONSTANS(AtCO),FLOWERING LOCUS T(AtFT),and GIGANTEA(AtGI).Thus,the study characterized the three TaELF3 genes and associated TaELF3-1BL with flowering in Arabidopsis,suggesting a role in regulating flowering in wheat too.These findings provide a basis for further research on TaELF3 functions in wheat.

A Farmer’s Approach to Detecting Photoperiod Sensitivity in Rice (Oryza sativa ssp. indica) Landraces

Most indigenous rice landraces are sensitive to photoperiod during short day seasons,and this sensitivity is more pronounced in indica than in japonica landraces.Attempts to identify photoperiod sensitive(PPS)cultivars based on the life history stages of the rice plant,and several models and indices based on phenology and day length have not been precise,and in some cases yield counterfactual inferences.Following the empirical method of traditional Asian rice farmers,the author has developed a robust index,based on the sowing and flowering dates of a large number of landraces grown in different seasons from 2020 to 2023,to contradistinguish PPS from photoperiod insensitive cultivars.Unlike other indices and models of photoperiod sensitivity,the index does not require the presumed duration of different life history stages of the rice plant but relies only on the flowering dates and the number of days till flowering of a rice cultivar sown on different dates to consistently identify photoperiod sensitive cultivars.

Immunohistochemical Analysis of IAA in Anthers of the Photoperiod-sensitive Genic Male-sterile Rice

The immunohistochemical localization of IAA and the comparison of their relative levels were carried out for the first time in the anthers of Nongken 58S and its wild type Nongken 58 (Oryza sativa subsp. japonica) after long_day and short_day treatments. The distribution of free_IAA in anthers and its dynamic variation could be reflected by this method. The results showed that the IAA level in the anthers of Nongken 58S after long_day treatment was much lower than that in short_day_treated Nongken 58S and those in wild type Nongken 58 in five stages from pistil and stamen primordia formation to late uninucleate stage. The possible reasons for IAA deficiency in Nongken 58S_LD anthers and its relationship with fertility alteration were also discussed.

Comparative Studies on the Changes of Microtubule Distribution and Reorganization During the Meiotic Stages of Development in Normal (IR36) and a Temperature/photoperiod Sensitive Male Sterile Line (Peiai 64S) of Rice ( Oryza sativa )

Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.

Preliminary Studies on the Effect of Photoperiod and Temperature on Male Fertility of a Cytoplasmic Male Sterile Line in Wheat

[Objective] The study aimed to reveal the effect of photoperiod and temperature on male fertility of cytoplasmic male sterile line Vtai911289a in wheat and discuss the mechanism of male fertility alteration. [ Method ] The sowing-date tests and designed conditions were conducted during 2003 -2005. [ Result] Fertility of Vtai911289a, could alter under specific photoperiod and temperature conditions. Temperature is one of the main factors influencing male fertility of the male sterile lines. Vtai911289a, showed stable sterility under the condition of the mean of daily temperature at fertility sensitive stage lower than 19℃ and presented partial fertility when the mean of daily temperature at fertility sensitive stage lower than 20 - 22℃. Photoperiod to some extent affects the male fertility of Vtai911289a, long-day condition is helpful for the male fertility of the sterile line. [ Conclusion] The application of photoperiod temperature-sensitive cytoplasmic male sterile line in production has a higher safety than that of temperature sensitive sterile line.

Photoperiod Control of Apical Bud and Leaf Senescence in Pumpkin ( Cucurbita pepo ) Strain 185

Short_day (SD) induced the plant senescence in pumpkin ( Cucurbita pepo Linn.) strain 185. Structural assay, gene expression and a series of biochemical analyses were performed to analyze the senescence mechanism in pumpkin strain 185 exposed to SD. Two aspects of important changes initiated in SD exposure contributed to the senescence process. SD functionally led to the initiation of the apical transformation from vegetative to reproductive growth, and then programmed cell death (PCD) in the apical meristem, causing the loss of vigorous growth activity. Moreover, SD treatment resulted in the formation of a great number of dying cells in mesophyll tissue later in the development compared with the phenotype of plants under long_day (LD) conditions. During the senescence process, high expression of nuclease is an important molecular event. These results indicate that the initiation of senescence process in pumpkin stain 185 plants is closely related to the death of cells in apical meristem and mesophyll.

Reproductive polyphenism and its advantages in aphids:Switching between sexual and asexual reproduction

Reproductive polyphenism,which allows one genotype to produce sexual and asexual morphs,is an extreme case of phenotypic plasticity and is commonly observed in aphids.Aphids are typical species that switch these reproductive modes,and the pathway orientation is triggered by the environmental conditions(mainly photoperiod and temperature).The typical arm ual life of aphids in eludes a successi on of parthenogenetic gen erations duri ng the spri ng and summer and a single sexual generation in autumn.In this review,we describe how the environmental cues orientate the reproductive mode of aphids from photoperiodic perception to endocrine regulation,and how juvenile hormones may act on the target cells(oocytes)to initiate the gametogenesis and embryogenesis in sexual and asexual reproduction.We also discuss the paradox of sex,especially the advantages of sexual reproduction in aphids.With the recent development of genomic resources in aphids,many potential genes involved in the reproductive polyphenism will enter the public's awareness.In particular,we describe a novel RNAi method in aphids,which may provide a molecular technique for determining the developmental fate and multiple reproductive strategies.

Advances in Melatonin and Its Functions in Plants

Abstract Melatonin （N-acetyi-5-methoxytryptamine） is a well-known animal hormone, which is synthesized and secreted by pineal gland and takes part in the regulation of circadian rhythm in animals. At present it has been observed that melatonin is widely existed in higher plants while there have no enough studies on functions of melatonin in plants. Researches have already indicated that the possible functions of melatonin in plants include regulating photoperiod, participating in growth regulation, clearing active oxygen, and promoting activity of antioxidase. General reviews upon functions of melatonin in plants are made upon experiments in recent years. We fo-cus on the demonstrated and predicted biological functions of melatonin in plants to bring researchers up to date on this field. The weakness in present studies and the main research directions are also pointed out.

The development of the Rook's(Corvus frugilegus)colony in the face of shifting spring phenology

Many birds species breed in colonies.One of the species in the Corvidae family nesting in groups is the Rook(Corvus frugilegus).The construction of the nest is costly for birds and needs high energy expenditure.Therefore,birds should optimize the time of nest building in relation to environmental,especially weather,conditions.Furthermore,birds should adapt their breeding phenology,including the date of starting the construction of nests for climate change.We observed the dynamics of increasing numbers of nests in a colony of Rooks in relation to air temperature,wind,rainfall,snowfall and day-length(indirect indicator of photoperiodism).Observations were carried out during three breeding seasons(2015-2017)in a large rookery in a big city in north-eastern Poland.The increase in the number of nests was correlated only with day length and no effect of climatic factors on the number of nests in the colony was observed.Number of nests varied significantly between successive years of research.In the case of the Rook(predictable breeders),the photoperiod seems to be the most important factor influencing breeding behavior,especially nest construction.In the last three decades,increasing temperature and time of spring phases have advanced and have influenced changes in the phenology of the availability of food resources.Simultaneously,a rapid decline in the numbers of breeding pairs of the Rook in Poland has been observed,especially in the last three decades.Conservative attachment to the length of the day,which is the main factor responsible for the development of the breeding colony,makes the Rook appear to be a species with low plasticity in the face of rapid climate changes.Thus,we suggest that may indirectly influence the decrease in the breeding population of the Rook.