Search

Practical Application Coconut endosperm residue is an abundant and low‐cost resource of dietary fiber, but the low soluble fiber content limits its functional properties and applications in the food industry. To improve the hypolipidemic and hypoglycemic properties, coconut endosperm residue fiber (CERF) was modified by superfine‐grinding and mix enzymatic hydrolysis alone, or combined with acetylation or hydroxypropylation. The effects of these modifications on the structure and functional properties were studied using scanning electron microscopy, Fourier‐transformed infrared spectroscopy, and in vitro tests. After these modifications, the microstructure of CERF became more porous, and its soluble fiber content, surface area, water adsorption, and expansion capacities were all improved (p < 0.05). Moreover, superfine‐grinding and mix enzymolysis combined with acetylation treated CERF showed the highest surface hydrophobicity (48.96) and cholesterol and cholate adsorption abilities (33.72 and 42.04 mg∙g‒1). Superfine‐grinding‐, mix enzymolysis‐, and hydroxypropylation‐treated CERF exhibited the highest viscosity (17.84 cP), glucose adsorption capacity (29.61 µmol∙g‒1), and glucose diffusion inhibition activity (73.96%), and water‐expansion ability (8.60 mL∙g‒1). Additionally, superfine‐grinding and mix enzymatic hydrolyzed CERF had the highest α‐amylase inhibiting activity (42.76%). Therefore, superfine‐grinding and mix enzymolysis alone or combined with hydroxypropylation were better choices to improve hypoglycemic properties of CERF; meanwhile, superfine‐grinding and mix enzymolysis combined with acetylation can effectively improve its hypolipidemic properties.This study offered three composite modification methods to improve the soluble fiber content and in vitro hypolipidemic and hypoglycemic properties of coconut endosperm residue fiber. These modification methods were practicable and low‐cost. Moreover, it provides good choices to improve the functional properties and applications of other dietary fibers in the food industry. [ABSTRACT FROM AUTHOR]

The yield potential of large-panicle rice is often limited by grain-filling barriers caused by the development of inferior spikelets (IS). Photoassimilates, which are the main source of rice grain filling, mainly enter the caryopsis through the dorsal vascular bundle. The distribution of assimilates between superior spikelets (SS) and IS is influenced by auxin-mediated apical dominance; however, the mechanism involved is still unclear. In this study, the effect of auxin signaling on the grain filling of SS and IS was investigated in two large-panicle japonica rice varieties, W1844 and CJ03. Compared to SS, IS displayed delayed initiation of filling and a significantly lower grain weight. Furthermore, the endosperm development in IS remained stagnant at the coenocytic stage. The development of the dorsal vascular bundle in the IS was also slow, and poor sucrose-unloading was observed during the initial grain filling stage. However, the endosperm development in IS immediately started after the improvement of dorsal vascular bundle development. GUS activity staining further revealed that indole-3-acetic (IAA) was localized in the dorsal vascular bundle and surrounding areas, suggesting that the low IAA content observed in the IS during the initial grain filling stage may have delayed the development of the dorsal vascular bundle. Therefore, these results demonstrate that IAA may control sugar transport and unloading by regulating dorsal vascular bundle development, consequently affecting endosperm development in IS. [ABSTRACT FROM AUTHOR]

The glycolyt ic enzyme cytoplasmic glyceraldehyde-3-phosphate dehydrogenase (GAPC3) is involved in multiple biological processes in plants, including transcriptional regulation, and material metabolism. However, the relationship between OsGAPC3 and the quality traits of rice is poorly understood. Here we identify OsGAPC3 mutations that enhance the protein content and grain nutritional quality of rice by regulating the OsAAP6 gene expression. The number and volume of type-II protein bodies in the endosperm of the OsGAPC3 mutants, and GPC increase significantly. We report significant increases in chalkiness area and degree, and decreases for starch content, gel consistency, and taste value. Results of proteomic detection and analysis reveal that OsGAPC3 affects the major storage substances (proteins and starch) metabolism in rice, and the accumulation of proteins and starch in the endosperm. Additionally, the OsGAPC3 mutation significantly decreases the rice-seedling salt tolerance. Therefore, OsGAPC3 affects multiple quality traits of rice, participates in regulating rice-seedling salt-stress response. These data can be used to design better-quality and stronger salt-resistant rice varieties. [ABSTRACT FROM AUTHOR]

The article published in the New Phytologist on October 15, 2024, explores the impact of OsPHO1;2 rice mutants on grain-filling defects. The study reveals that OsPHO1;2 plays a crucial role in transferring phosphate from maternal to filial tissues in developing seeds, affecting grain quality and yield. The research suggests that the grain-filling defects in Ospho1;2 mutants are primarily due to impaired phosphate unloading from maternal tissues, challenging previous models proposed by other studies. Reciprocal crosses between Ospho1;2 mutants and wild-type rice further confirm the maternal effect contributing to the observed grain defects. [Extracted from the article]

Rice (Oryza sativa L.) endosperm is essential to provide nutrients for seed germination and determine grain yield. RNA editing, a post-transcriptional modification essential for plant development, unfortunately, is not fully characterized during rice endosperm development. Here, we perform systematic analyses to characterize RNA editome during rice endosperm development. We find that most editing sites are C-to-U CDS-recoding in mitochondria, leading to increased hydrophobic amino acids and changed structures of mitochondrial proteins. Comparative analysis of RNA editome reveals that CDS-recoding sites present higher editing frequencies with lower variabilities and their resultant recoded amino acids tend to exhibit stronger evolutionary conservation across many land plants. Furthermore, we classify mitochondrial genes into three groups, presenting distinct patterns in terms of CDS-recoding events. Besides, we conduct genome-wide screening to detect pentatricopeptide repeat (PPR) proteins and construct PPR-RNA binding profiles, yielding candidate PPR editing factors related to rice endosperm development. Taken together, our findings provide valuable insights for deciphering fundamental mechanisms of rice endosperm development underlying RNA editing machinery. A systematic study of the RNA editome during rice endosperm development suggests that predominant C-to-U CDS-recoding editing events produce conserved hydrophobic amino acids, and affect structures and functions of mitochondrial proteins. [ABSTRACT FROM AUTHOR]

SUMMARY Starch synthesis in maize endosperm adheres to the basipetal sequence from the apex downwards. However, the mechanism underlying nonuniformity among regions of the endosperm in starch accumulation and its significance is poorly understood. Here, we examined the spatiotemporal transcriptomes and starch accumulation dynamics in apical (AE), middle (ME), and basal (BE) regions of endosperm throughout the filling stage. Results demonstrated that the BE had lower levels of gene transcripts and enzymes facilitating starch synthesis, corresponding to incomplete starch storage at maturity, compared with AE and ME. Contrarily, the BE showed abundant gene expression for genetic processing and slow progress in physiological development (quantified by an index calculated from the expression values of development progress marker genes), revealing a sustained cell vitality of the BE. Further analysis demonstrated a significant parabolic correlation between starch synthesis and physiological development. An in‐depth examination showed that the BE had more active signaling pathways of IAA and ABA than the AE throughout the filling stage, while ethylene showed the opposite pattern. Besides, SNF1‐related protein kinase1 (SnRK1) activity, a regulator for starch synthesis modulated by trehalose‐6‐phosphate (T6P) signaling, was kept at a lower level in the BE than the AE and ME, corresponding to the distinct gene expression in the T6P pathway in starch synthesis regulation. Collectively, the findings support an improved understanding of the timing of starch synthesis and cell vitality in regions of the endosperm during development, and potential regulation from hormone signaling and T6P/SnRK1 signaling. [ABSTRACT FROM AUTHOR]

Genomic imprinting is observed in endosperm, a placenta-like seed tissue, where transposable elements (TEs) and repeat-derived small RNAs (sRNAs) mediate epigenetic changes in plants. In imprinting, uniparental gene expression arises due to parent-specific epigenetic marks on one allele but not on the other. The importance of sRNAs and their regulation in endosperm development or in imprinting is poorly understood in crops. Here we show that a previously uncharacterized CLASSY (CLSY)-family chromatin remodeler named OsCLSY3 is essential for rice endosperm development and imprinting, acting as an upstream player in the sRNA pathway. Comparative transcriptome and genetic analysis indicated its endosperm-preferred expression and its likely paternal imprinted nature. These important features are modulated by RNA-directed DNA methylation (RdDM) of tandemly arranged TEs in its promoter. Upon perturbation of OsCLSY3 in transgenic lines, we observe defects in endosperm development and a loss of around 70% of all sRNAs. Interestingly, well-conserved endosperm-specific sRNAs (siren) that are vital for reproductive fitness in angiosperms are also dependent on OsCLSY3. We observed that many imprinted genes and seed development-associated genes are under the control of OsCLSY3. These results support an essential role of OsCLSY3 in rice endosperm development and imprinting, and propose similar regulatory strategies involving CLSY3 homologs among other cereals. Using a well-resolved spatial transcriptomics coupled with genetic data, this study identified rice CLSY3 chromatin remodeler as an upstream player in endosperm development. OsCLSY3 is imprinted and endosperm-specific, and, curiously, its expression is controlled by RdDM. [ABSTRACT FROM AUTHOR]

Foxtail millet is one of the oldest crops, and its endosperm contains up to 70% of starch. Grain filling is an important starch accumulation process associated with foxtail millet yield and quality. However, the molecular mechanisms of grain filling in foxtail millet are relatively unclear. Here, we investigate the genes and regulated miRNAs associated with starch synthesis and metabolism in foxtail millet using high-throughput small RNA, mRNA and degradome sequencing. The regulation of starch synthesis and quality is carried out mainly at the 15 DAA to 35 DAA stage during grain filling. The DEGs between waxy and non-waxy foxtail millet were significant, especially for GBSS. Additionally, ptc-miR169i_R+2_1ss21GA, fve-miR396e_L-1R+1, mtr-miR162 and PC-5p-221_23413 regulate the expression of genes associated with the starch synthesis pathway in foxtail millet. This study provides new insights into the molecular mechanisms of starch synthesis and quality formation in foxtail millet. [ABSTRACT FROM AUTHOR]

Key message: In Cyrtanthus mackenii, development of embryo and endosperm were differentially affected by fertilization of male gametes with DNA damage and mutations. Pollen irradiation with ionizing radiations has been applied in plant breeding and genetic research, and haploid plant induction has mainly been performed by male inactivation with high-dose irradiation. However, the fertilization process of irradiated male gametes and the early development of embryo and endosperm have not received much attention. Heavy-ion beams, a type of radiation, have been widely applied as effective mutagens for plants and show a high mutation rate even at low-dose irradiation. In this study, we analyzed the effects of male gametes of Cyrtanthus mackenii irradiated with a carbon-ion beam at low doses on fertilization. In immature seeds derived from the pollination of irradiated pollen grains, two types of embryo sacs were observed: embryo sac with a normally developed embryo and endosperm and embryo sac with an egg cell or an undivided zygote and an endosperm. Abnormalities in chromosome segregation, such as chromosomal bridges, were observed only in the endosperm nuclei, irrespective of the presence or absence of embryogenesis. Therefore, in Cyrtanthus, embryogenesis is strongly affected by DNA damage or mutations in male gametes. Moreover, various DNA contents were detected in the embryo and endosperm nuclei, and endoreduplication may have occurred in the endosperm nuclei. As carbon-ion irradiation causes chromosomal rearrangements even at low doses, pollen irradiation can be an interesting tool for studying double fertilization and mutation heritability. [ABSTRACT FROM AUTHOR]

Simple Summary: Sheep producers in many countries of the world usually feed their animals with natural or improved pastures. In these situations, pastures alone usually do not cover animal needs, and supplementation is required. By-products from the oil industry are extensively used in animal feeding, and endosperm and mesocarp expellers from grugru palm may play an important role in animal feeding in the countries where it is distributed. To assess the protein value of an ingredient, the extent and rate of rumen degradation are central characteristics. However, associative effects with other components of the diet occur, and rumen degradation of individual ingredients should be assessed in the usual feeding conditions of an animal. On these grounds, the objective of this study was to provide information about rumen degradation of endosperm and mesocarp expellers from grugru palm in sheep grazing natural or cultivated monophytic pastures, and supplemented with a mixture of both expellers. The use of this mixture slows down the rate of degradation of the pastures, the effect of which is more intense in animals grazing natural swards. Supplementation with this mixture also increases the average daily gain of sheep, more substantially with multi-species natural pastures. Twenty-four ewes (eight fistulated in the rumen) were assigned to a 2 × 2 factorial design. The treatments included the pasture grazed (natural mixed swards—NMS or cultivated monophytic (Brachiaria brizantha cv. Marandu) swards—CMS) and the level of supplementation: without supplement or with a 1% supplement (dry matter (DM)/live weight). The supplement included one-third endosperm expeller (ENE) and two-thirds mesocarp expeller (ME) from Acrocomia aculeata (Jacq.) Lodd. ex Mart. In sacco rumen degradation of ENE, ME, NMS, and CMS was assessed in fistulated sheep, as were rumen fermentation variables. Average daily gain (ADG) was assessed in non-fistulated animals during a 7-week period. Potential degradability of the DM and crude protein of the expellers was not affected by the type of pasture grazed or the level of supplementation (p > 0.05), but the fractional rate of degradation (c) of DM was three times faster (p < 0.01) for ME than for ENE. The potential degradability of neutral detergent fiber was 34% higher (p < 0.0001) for ENE, with no differences in c (p > 0.1). Supplementation slowed down the c of the DM of the pastures, especially in animals grazing NMS (24% lower). Treatments affected rumen pH, concentration of volatile fatty acids, and proportion of valerate, in different ways. The use of the supplement increased ADG of sheep (six-fold in sheep grazing NMS and 40% in those grazing CMS). The use of a mixture of one-third ENE plus two-thirds ME as a protein supplement in sheep grazing either multi-species natural pastures or monophytic swards of Brachiaria brizantha cv. Marandu slows down the fractional rate of degradation of the pastures, the effect of which is more intense in animals grazing natural swards. This supplementation also increases average daily gain, more substantially with multi-species natural pastures. [ABSTRACT FROM AUTHOR]

Abstract The yield potential of large-panicle rice is often limited by grain-filling barriers caused by the development of inferior spikelets (IS). Photoassimilates, which are the main source of rice grain filling, mainly enter the caryopsis through the dorsal vascular bundle. The distribution of assimilates between superior spikelets (SS) and IS is influenced by auxin-mediated apical dominance; however, the mechanism involved is still unclear. In this study, the effect of auxin signaling on the grain filling of SS and IS was investigated in two large-panicle japonica rice varieties, W1844 and CJ03. Compared to SS, IS displayed delayed initiation of filling and a significantly lower grain weight. Furthermore, the endosperm development in IS remained stagnant at the coenocytic stage. The development of the dorsal vascular bundle in the IS was also slow, and poor sucrose-unloading was observed during the initial grain filling stage. However, the endosperm development in IS immediately started after the improvement of dorsal vascular bundle development. GUS activity staining further revealed that indole-3-acetic (IAA) was localized in the dorsal vascular bundle and surrounding areas, suggesting that the low IAA content observed in the IS during the initial grain filling stage may have delayed the development of the dorsal vascular bundle. Therefore, these results demonstrate that IAA may control sugar transport and unloading by regulating dorsal vascular bundle development, consequently affecting endosperm development in IS.

Key message: The DNA methylation status at an epigenetic quantitative trait locus in the Arabidopsis chromosome 2 is linked to the formation of apomictic-like endosperms. Seed development in most angiosperms is coupled to fertilization of the maternal gametes by two sperm cells. However, apomictic species can reproduce asexually via seeds. This trait is of great agricultural interest, as it would fix complex genotypes and allow for pollen-independent seed production. However, engineering full apomixis requires three independent processes: apomeiosis, parthenogenesis and autonomous endosperm development. While the first two have been successfully engineered in some crops, the formation of autonomous endosperms remains a challenge. Although it is known that this trait is under epigenetic control, such as of DNA methylation, the underlying mechanisms remain mostly undiscovered. Here, using epigenetic recombinant inbred lines, we identified an epigenetic quantitative trait locus in the Arabidopsis chromosome 2, which correlates with permissiveness for the formation of asexual seeds: hypomethylation at this genomic region allows the formation of larger autonomous endosperms. Importantly, the methylation at this locus only correlates with asexual seed size, and not to the size of sexual seeds or that of other organs. With this, we aim to show that screening for epialleles is a promising strategy to uncover loci underlying relevant traits and could pave the way to identifying genes necessary for the engineering of apomixis. [ABSTRACT FROM AUTHOR]

Endosperm in angiosperms and placenta in eutherians are convergent innovations for efficient embryonic nutrient transfer. Despite advantages, this reproductive strategy incurs metabolic costs that maternal parents disproportionately shoulder, leading to potential inter-parental conflict over optimal offspring investment. Genomic imprinting—parent-of-origin-biased gene expression—is fundamental for endosperm and placenta development and has convergently evolved in angiosperms and mammals, in part, to resolve parental conflict. Here, we review the mechanisms of genomic imprinting in these taxa. Despite differences in the timing and spatial extent of imprinting, these taxa exhibit remarkable convergence in the molecular machinery and genes governing imprinting. We then assess the role of parental conflict in shaping evolution within angiosperms and eutherians using four criteria: 1) Do differences in the extent of sibling relatedness cause differences in the inferred strength of parental conflict? 2) Do reciprocal crosses between taxa with different inferred histories of parental conflict exhibit parent-of-origin growth effects? 3) Are these parent-of-origin growth effects caused by dosage-sensitive mechanisms and do these loci exhibit signals of positive selection? 4) Can normal development be restored by genomic perturbations that restore stoichiometric balance in the endosperm/placenta? Although we find evidence for all criteria in angiosperms and eutherians, suggesting that parental conflict may help shape their evolution, many questions remain. Additionally, myriad differences between the two taxa suggest that their respective biologies may shape how/when/where/to what extent parental conflict manifests. Lastly, we discuss outstanding questions, highlighting the power of comparative work in quantifying the role of parental conflict in evolution. [ABSTRACT FROM AUTHOR]

Abstract Background Bread wheat (Triticum aestivum L.) endosperm contains starch and proteins, which determine the final yield, quality, and nutritional value of wheat grain. The preferentially expressed endosperm genes can precisely provide targets in the endosperm for improving wheat grain quality and nutrition using modern bioengineering technologies. However, the genes specifically expressed in developing endosperms remain largely unknown. Results In this study, 315 preferentially expressed endosperm genes (PEEGs) in the spring wheat landrace, Chinese Spring, were screened using data obtained from an open bioinformatics database, which reveals a unique grain reserve deposition process and special signal transduction in a developing wheat endosperm. Furthermore, transcription and accumulation of storage proteins in the wheat cultivar, XC26 were evaluated. The results revealed that 315 PEEG plays a critical role in storage protein fragment deposition and is a potential candidate for modifying grain quality and nutrition. Conclusion These results provide new insights into endosperm development and candidate genes and promoters for improving wheat grain quality through genetic engineering and plant breeding techniques.

Summary Starch is synthesized as insoluble, semicrystalline particles within plant chloroplast and amyloplast, which are referred to as starch grains (SGs). The size and morphology of SGs in the cereal endosperm are diverse and species–specific, representing a key determinant of the suitability of starch for industrial applications. However, the molecular mechanisms modulating SG size in cereal endosperm remain elusive. Here, we functionally characterized the rice (Oryza sativa) mutant substandard starch grain7 (ssg7), which exhibits enlarged SGs and defective endosperm development. SSG7 encodes a plant–specific DUF1001 domain‐containing protein homologous to Arabidopsis (Arabidopsis thaliana) CRUMPLED LEAF (AtCRL). SSG7 localizes to the amyloplast membrane in developing endosperm. Several lines of evidence suggest that SSG7 functions together with SSG4 and SSG6, known as two regulators essential for SG development, to control SG size, by interacting with translocon‐associated components, which unveils a molecular link between SG development and protein import. Genetically, SSG7 acts synergistically with SSG4 and appears to be functional redundancy with SSG6 in modulating SG size and endosperm development. Collectively, our findings uncover a multimeric functional protein complex involved in SG development in rice. SSG7 represents a promising target gene for the biotechnological modification of SG size, particularly for breeding programs aimed at improving starch quality. [ABSTRACT FROM AUTHOR]

Six sorghum varieties containing different amylose were selected to investigate the structural and physicochemical characteristics of starches and endosperm texture of grains. The results showed that the outer layer endosperm of sorghum grain changed from waxy to corneous, and its starch granules were more compactly packed and exhibited the spindle‐shaped holes with the increase of amylose content. Higher amylose starch granules exhibited fewer and smaller micropores on the surface and were more likely to deform and agglomerate into larger amorphous particles after heated. Amylose content of sorghum starches was negatively correlated to granule size, relative crystallinity, and the proportion of the long branch chains (DP = 25–36 and > 36), whereas positively correlated to the proportion of the short branch chains (DP = 6–12 and 13–24). Amylose content had negative correlations with To, Tp, ΔH, PV, and SDS (p < .05), positive corrections with FV, SB, and RDS (p < .05), and no correlations with Tc, HPV, BD, and RS. It could be concluded that amylose content affected the endosperm texture of sorghum grain and had strong correlations with structural and physicochemical properties of sorghum starch. These findings may help identify uses for these sorghum varieties in baijiu production. [ABSTRACT FROM AUTHOR]

ABSTRACT Dormancy in barley has been thoroughly studied and shown to negatively impact malt quality, resulting in selection against dormancy. However, reduced dormancy coincides with increased preharvest sprout (PHS) risk, thus sparking a new interest in integrating dormancy back into American barley lines if the negative effects of dormancy on malt quality can be overcome. We evaluated the dormancy and hydration index (HYI) in a biparental mapping population to determine the genotypes that would protect against PHS but have good malt quality. We found 4 HYI QTLs and 4 dormancy QTLs, one of which was near the well‐described SD2 QTL. The HYI QTLs were pleiotropically related to seed size (1H), dormancy (5H) and malt quality (2H). Lines with dormancy (5H) and increased HYI (2H and 3H) had malt quality similar to nondormant lines while maintaining PHS resistance, suggesting improvements in HYI could be the key to overcoming the negative effects of dormancy in malting. [ABSTRACT FROM AUTHOR]

Biofortification of provitamin A in maize is an attractive and sustainable remedy to the problem of vitamin A deficiency in developing countries. The utilization of molecular markers represents a promising avenue to facilitate the development of provitamin A (PVA)-enriched maize varieties. We screened 752 diverse tropical yellow/orange maize lines using kompetitive allele-specific PCR (KASP) makers to validate the use of KASP markers in PVA maize breeding. To this end, a total of 161 yellow/orange inbred lines, selected from among the 752 lines, were evaluated for their endosperm PVA and other carotenoid compounds levels in two separate trials composed of 63 and 98 inbred lines in 2020 and 2021, respectively. Significant differences (p < 0.001) were observed among the yellow maize inbred lines studied for all carotenoid profiles. An inbred line TZMI1017, introduced by the International Institute of Tropical Agriculture (IITA) showed the highest level of PVA (12.99 µg/g) and β-carotene (12.08 µg/g). The molecular screening showed 43 yellow maize inbred lines carrying at least three of the favorable alleles of the KASP markers. TZMI1017 inbred line also carried the favorable alleles of almost all markers. In addition, nine locally developed inbred lines had medium to high PVA concentrations varying from 5.11 µg/g to 10.76 µg/g and harbored the favorable alleles of all the KASP PVA markers. Association analysis between molecular markers and PVA content variation in the yellow/orange maize inbred lines did not reveal a significant, predictable correlation. Further investigation is warranted to elucidate the underlying genetic architecture of the PVA content in this germplasm. However, we recommend strategic utilization of the maize-inbred lines with higher PVA content to enhance the PVA profile of the breeding program's germplasm. [ABSTRACT FROM AUTHOR]

In angiosperms, seed size is a critical trait that is influenced by the complex interplay between the endosperm and seed coat. The HAIKU (IKU) pathway, involving the transcription factor WRKY10, plays a crucial role in regulating seed size in Arabidopsis thaliana. However, the downstream targets of WRKY10 and their roles in seed size determination remain largely unexplored. Here, we identified LACCASE2 (LAC2), a laccase gene involved in lignin biosynthesis, as a new downstream target of WRKY10. We observed that the expression of LAC2 was upregulated in the mini3 mutant, which is defective in WRKY10. We demonstrated that WRKY10 directly binds to the promoter of miR397a, activating its expression. miR397a, in turn, represses the expression of LAC2. Genetic analyses revealed that a mutation in LAC2 or overexpression of miR397a partially rescued the small seed phenotype of the MINISEED3 (MINI3) mutant mini3. Conversely, the overexpression of LAC2 in the wild type led to a decrease in seed size. These findings suggest that LAC2 functions as a negative regulator of seed size, and its expression is modulated by WRKY10 through miR397a. Our study uncovers a novel WRKY10-miR397a-LAC2 pathway that regulates seed size in Arabidopsis, providing new insights into the complex regulatory network governing seed development in plants. [ABSTRACT FROM AUTHOR]

Double fertilization in angiosperms results in the formation of a second zygote, the fertilized endosperm. Unlike its embryo sibling, the endosperm is a transient structure that eventually undergoes developmentally controlled programmed cell death (PCD) at specific time points of seed development or germination. The nature of endosperm PCD exhibits a considerable diversity, both across different angiosperm taxa and within distinct endosperm tissues. In endosperm-less species, PCD might cause central cell degeneration as a mechanism preventing the formation of a fertilized endosperm. In most other angiosperms, embryo growth necessitates the elimination of surrounding endosperm cells. Nevertheless, complete elimination of the endosperm is rare and, in most cases, specific endosperm tissues persist. In mature seeds, these persisting cells may be dead, such as the starchy endosperm in cereals, or remain alive to die only during germination, like the cereal aleurone or the endosperm of castor beans. In this review, we explore current knowledge surrounding the cellular, molecular, and genetic aspects of endosperm PCD, and the influence environmental stresses have on PCD processes. Overall, this review provides an exhaustive overview of endosperm PCD processes in angiosperms, shedding light on its diverse mechanisms and its significance in seed development and seedling establishment. [ABSTRACT FROM AUTHOR]

SUMMARY: The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies. Significance Statement: Within seeds a specialized structure is responsible for nourishing the embryo during its development. These nourishing tissues are also important sources of staple foods and feed. Here, we provide gene expression datasets of nourishing tissues of early diverging angiosperms, and use this information for a meta‐analysis to identify pathways conserved, or divergent, throughout evolution. Thus, we aim to provide a resource for gene discovery for seed biology studies. [ABSTRACT FROM AUTHOR]

Summary: Arabidopsis lamin analogs CROWDED NUCLEIs (CRWNs) are necessary to maintain nuclear structure, genome function, and proper plant growth. However, whether and how CRWNs impact reproduction and genome‐wide epigenetic modifications is unknown. Here, we investigate the role of CRWNs during the development of gametophytes, seeds, and endosperm, using genomic and epigenomic profiling methods.We observed defects in crwn mutant seeds including seed abortion and reduced germination rate. Quadruple crwn null genotypes were rarely transmitted through gametophytes. Because defects in seeds often stem from abnormal endosperm development, we focused on crwn1 crwn2 (crwn1/2) endosperm. These mutant seeds exhibited enlarged chalazal endosperm cysts and increased expression of stress‐related genes and the MADS‐box transcription factor PHERES1 and its targets.Previously, it was shown that PHERES1 expression is regulated by H3K27me3 and that CRWN1 interacts with the PRC2 interactor PWO1. Thus, we tested whether crwn1/2 alters H3K27me3 patterns. We observed a mild loss of H3K27me3 at several hundred loci, which differed between endosperm and leaves.These data indicate that CRWNs are necessary to maintain the H3K27me3 landscape, with tissue‐specific chromatin and transcriptional consequences. [ABSTRACT FROM AUTHOR]

Spatiotemporal regulation of gene expression by polycomb repressive complex 2 (PRC2) is critical for animal and plant development. The Arabidopsis fertilization independent seed (FIS)-PRC2 complex functions specifically during plant reproduction from gametogenesis to seed development. After a double fertilization event, triploid endosperm proliferates early, followed by the growth of a diploid embryo, which replaces the endosperm in Arabidopsis and many dicots. Key genes critical for endosperm proliferation such as IKU2 and MINI3 are activated after fertilization. Here we report that two MADS-box AGAMOUS-LIKE (AGL) proteins associate with the key endosperm proliferation loci and recruit the FIS-PRC2 repressive complex at 4–5 days after pollination (DAP). Interestingly, AGL9 and AGL15 only accumulate toward the end of endosperm proliferation at 4–5 DAP and promote the deposition of H3K27me3 marks at key endosperm proliferation loci. Disruption of AGL9 and AGL15 or overexpression of AGL9 or AGL15 significantly influence endosperm proliferation and cellularization. Genome-wide analysis with cleavage Under Targets and tagmentation (CUT&Tag) sequencing and RNA sequencing revealed the landscape of endosperm H3K27me3 marks and gene expression profiles in Col-0 and agl9 agl15. CUT&Tag qPCR also demonstrated the occupancy of the two MADS-box proteins and FIS-PRC2 on a few representative target loci. Our studies suggest that MADS-box proteins could potentially recruit PRC2 to regulate many other developmental processes in plants or even in fungi and animals. AGL9 and AGL15 accumulate toward the end of endosperm proliferation and recruit the FIS-PRC2 complex to repress the expression of two key genes for endosperm proliferation. Other key endosperm proliferation loci repressed by the FIS-PRC2 complex are also revealed through CUT&Tag and RNA-seq analysis. [ABSTRACT FROM AUTHOR]

The malting industry faces a dilemma in which barley, initially containing low deoxynivalenol levels, occasionally exhibits an unexpected increase in deoxynivalenol levels during malting. In the current study, we investigated mycotoxin accumulation and hyphal localization in single kernels from Fusarium head blight infected barley and malt samples which showed an aberrant behavior of deoxynivalenol increases during malting. While deoxynivalenol levels in these bulk barley samples already ranged from <0.20 to 1.27 µg/g, they further increased on average by approximately 500% after malting, along with Fusarium growth. In addition, deoxynivalenol-3-glucoside and 3-acetyl deoxynivalenol levels increased from <0.20 µg/g to the mean levels of 2.47 µg/g and 1.03 µg/g in the bulk malt, respectively. In the investigation of single kernels, results showed that only 7% of barley single kernels (n = 385) had deoxynivalenol >1.00 μg/g, with the maximum level of 35.97 μg/g. However, 31% of malt single kernels contained deoxynivalenol >1.00 μg/g and up to 255.43 μg/g. Deoxynivalenol-3-glucoside and 3-acetyl deoxynivalenol were found in 40% of malt single kernels. Fungal hyphae were observed in the aleurone layer and embryo of barley kernels with deoxynivalenol >10.00 μg/g, in addition to the husk and vascular bundles of kernels with deoxynivalenol <1.00 μg/g. Hyphae spread largely in these tissues following malting, and even into the endosperm and pericarp cavities of extremely high deoxynivalenol kernels (i.e., >100.00 μg/g). [ABSTRACT FROM AUTHOR]

Background: Wheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to various environmental conditions, including high night temperatures (HNTs). Flag leaves and seed-associated bracts (glumes, awn, palea, and lemma) provide nutrients to the developing seed. However, the specific metabolic roles of these tissues are uncertain, especially their dynamics at different developmental stages and the time in a day. Tissue- and time-dependent metabolite profiling may hint at the metabolic roles of tissues and the mechanisms of how HNTs affect daytime metabolic status in early grain development. Results: The metabolite profiles of flag leaf, bract, seed (embryo and endosperm), and entire spike were analyzed at 12:00 (day) and 23:00 (night) on 2, 4, and 6 days after fertilization under control and HNT conditions. The metabolite levels in flag leaves and bracts showed day/night oscillations, while their behaviors were distinct between the tissues. Some metabolites, such as sucrose, cellobiose, and succinic acid, showed contrasting oscillations in the two photosynthetic tissues. In contrast, seed metabolite levels differed due to the days after fertilization rather than the time in a day. The seed metabolite profile altered earlier in the HNT than in the control condition, likely associated with accelerated grain development caused by HNT. HNT also disrupted the day/night oscillation of sugar accumulation in flag leaves and bracts. Conclusions: These results highlight distinct metabolic roles of flag leaves and bracts during wheat early seed development. The seed metabolite levels are related to the developmental stages. The early metabolic events in the seeds and the disruption of the day/night metabolic cycle in photosynthetic tissues may partly explain the adverse effects of HNT on grain yield. [ABSTRACT FROM AUTHOR]

Summary: Endosperm is the main storage organ in cereal grain and determines grain yield and quality. The molecular mechanisms of heat shock proteins in regulating starch biosynthesis and endosperm development remain obscure.Here, we report a rice floury endosperm mutant flo24 that develops abnormal starch grains in the central starchy endosperm cells. Map‐based cloning and complementation test showed that FLO24 encodes a heat shock protein HSP101, which is localized in plastids. The mutated protein FLO24T296I dramatically lost its ability to hydrolyze ATP and to rescue the thermotolerance defects of the yeast hsp104 mutant.The flo24 mutant develops more severe floury endosperm when grown under high‐temperature conditions than normal conditions. And the FLO24 protein was dramatically induced at high temperature. FLO24 physically interacts with several key enzymes required for starch biosynthesis, including AGPL1, AGPL3 and PHO1. Combined biochemical and genetic evidence suggests that FLO24 acts cooperatively with HSP70cp‐2 to regulate starch biosynthesis and endosperm development in rice.Our results reveal that FLO24 acts as an important regulator of endosperm development, which might function in maintaining the activities of enzymes involved in starch biosynthesis in rice. [ABSTRACT FROM AUTHOR]

Summary: Sorghum, known for its nutritional value, health benefits and gluten‐free status, is now widely produced and suitable for human consumption in developed regions due to advancements in sorghum research and processing techniques. The research looked at how well the husking fraction time unit (HFTU) technique worked by examining its effects on the nutritional value of three varieties of sorghum grain. The efficiency of the husking process was assessed at 87% for concentrated and redistributed nutritional contents and 60% for variation of mineral contents based on bran/ endosperm. The technique reduced the T.K.W. compared to whole grain to the endosperm (grits). Moreover, the redistribution of the crude protein % showed the precision of the HFTU procedure by demonstrating an average of 26.6% as a variation ratio of the bran/endosperm in the data set. Contrary to the content of the total dietary fibre content, for example, the variation of TDF % attributed to bran/endosperm was 10.9%. On the other hand, the average ash % of whole grains (hummer) and husked products (TM05C) was increased by 33.2% based on averages of 1.5% and 2.1%, respectively. Accordingly, it was approved that the HFTU procedure effectively separated the endosperm (grits) and bran. This study also found that minerals such as Ca, Cu, Fe, K, Mg, Mn, Na, P, S and Zn changed over 30‐to‐80‐time units by 29%, 13%, 8%, 4%, 17%, 18%, 1%, 13%, 6% and 12% in the bran and endosperm. The HFTU process has influenced the colour attributes of variation sorghum varieties, particularly within a time scale of 80 (S) units. The research revealed that the husking technique substantially impacted the different sorghum grain varieties' nutritional composition and colour properties. The method can be useful for developers in enhancing sorghum grain products' nutritional properties attributed to various varieties and regions, allowing them to provide high nutritional quality sourced from sustainable products. [ABSTRACT FROM AUTHOR]

The development of a method to obtain callus of the European white elm, Ulmus laevis, may be a further contribution to the research on elm dieback. In the present study, a seed disinfestation method was developed to extract viable zygotic embryos. Different culture media and combinations of growth regulators were also tested to produce callus and seedlings of European white elm. The growth potential of callus in light and darkness was also investigated to determinate the exact weight gain over a specific period of time. The results of the experiments can be used as a tool for the rapid culture of callus and elm seedlings in large quantities without environmental influences. After selection of a suitable culture medium among those tested, WPM medium proved to be the most effective. It was shown that callus cultures grown in the presence of the regulators 4.646 µM/l kinetin and 4.440 µM/l 6-benzylaminipurine showed the highest quality, as did seedlings with the addition of 1.444 µM/l gibberellin A along with 4.440 µM/l 6-benzylaminipurine in the culture. Thidiazuron proved to be the compound causing rapid browning and subsequent tissue death. [ABSTRACT FROM AUTHOR]

Abstract The microhardness of individual morphological structures of the hard coat of the seed of Gleditsia triacanthos L. was measured. Measurements were made on the transverse and frontal planes. Based on the differences in the hardness of the two planes, the anisotropy of the seed coat was revealed. The entire seed coat has a special hardness which can be compared with the hardness of hardwood like oat wood. An interesting feature was the hardness of the endosperm, comparable to the hardness of the epidermis. Further study of the processes that occur in seeds during imbibition is based on the obtained data. Mathematical modeling methods are the most promising for these tasks; they will help to identify the points of fragility and the points of the greatest tension in the seed coat. These results will allow us to find the best ways to destroy the seed coat and to accelerate the germination. Research of physical properties of the seed coat is of practical importance in the fact that in the future it will allow reducing of the hard-seeding and increasing the germination of seeds. The obtained data allows us to represent the initial hardness of the seed coat.

Alpha-synuclein (α-syn) is a cytoplasmic protein commonly found in the nervous system. In solution, α-syn adopts disordered unfolded conformations, although it can also form α-helices upon binding to lipid membranes. Under conditions that are not yet fully understood, α-syn can misfold and aggregate, giving rise to β-sheet rich amyloid fibrils, which then tend to accumulate in degenerating neurons. This leads to Parkinson's disease (PD) and several other conditions collectively termed synucleinopathies. Development of disease-modifying treatments requires detailed understanding of structure and dynamics of α-syn's misfolded aggregates. We have employed 1000 ns long, all-atom molecular dynamics simulations to investigate the interaction of monomeric α-syn38-95 fragments, which contain the most important amyloidogenic regions, with preformed fibrillar seeds composed of staggered, β-sheet rich α-syn chains of matching length. The simulations indicate that α-syn38-95 monomers tend to form aggregates with the fibrillar seeds, although we have not observed alignment of the monomeric chains with β-strands of the fibril. To analyze the stability of these aggregates, we have employed the essential collective dynamics method, which allows making accurate assessment of dynamical coupling across individual atoms in macromolecules and supramolecular complexes. The analysis revealed extensive dynamical coupling across initially monomeric α-syn chains and the fibrillar seeds including distal regions thereof that did not contact the monomer directly. We have discussed structural origins of these long-range interactions, their impacts for the stability of α-syn aggregates, and potential implications for the development of anti-PD treatments. [ABSTRACT FROM AUTHOR]

Abstract Background The endosperm serves as the primary source of nutrients for maize (Zea mays L.) kernel embryo development and germination. Positioned at the base of the endosperm, the transfer cells (TCs) of the basal endosperm transfer layer (BETL) generate cell wall ingrowths, which enhance the connectivity between the maternal plant and the developing kernels. These TCs play a crucial role in nutrient transport and defense against pathogens. The molecular mechanism underlying BETL development in maize remains unraveled. Results This study demonstrated that the MYB-related transcription factor ZmMYBR29, exhibited specific expression in the basal cellularized endosperm, as evidenced by in situ hybridization analysis. Utilizing the CRISPR/Cas9 system, we successfully generated a loss-of-function homozygous zmmybr29 mutant, which presented with smaller kernel size. Observation of histological sections revealed abnormal development and disrupted morphology of the cell wall ingrowths in the BETL. The average grain filling rate decreased significantly by 26.7% in zmmybr29 mutant in comparison to the wild type, which impacted the dry matter accumulation within the kernels and ultimately led to a decrease in grain weight. Analysis of RNA-seq data revealed downregulated expression of genes associated with starch synthesis and carbohydrate metabolism in the mutant. Furthermore, transcriptomic profiling identified 23 genes that expressed specifically in BETL, and the majority of these genes exhibited altered expression patterns in zmmybr29 mutant. Conclusions In summary, ZmMYBR29 encodes a MYB-related transcription factor that is expressed specifically in BETL, resulting in the downregulation of genes associated with kernel development. Furthermore, ZmMYBR29 influences kernels weight by affecting the grain filling rate, providing a new perspective for the complementation of the molecular regulatory network in maize endosperm development.

The developmental patterns of the embryo, endosperm, pericarp, and seed coat during the growth process of Phyllostachys edulis seeds were revealed in this study, flowering P. edulis was used as the material in the Haiyang Mountain, Guilin, seeds at different stages were collected and fixed. Paraffin sectioning method was employed, and the structural changes of the embryo, endosperm, pericarp, and seed coat were observed under a microscope. The results were as follows: (1) Fertilization and zygote formation in P. edulis were completed within 1 d after flowering, and the zygote entered a dormant period lasting about 5 d. The embryo underwent the stages of proembryo, coleoptile stage, embryonic growth, and mature embryo, and reached basic maturity after 40 d post-flowering. The developmental type of the embryo was categorized as monocotyledonous. (2) The endosperm developed earlier than the embryo, and its development type was categorized as nuclear endosperm, which went through four stages: free nuclear, cellularization, cell differentiation, and maturation. In the stage of cell differentiation, starch endosperm cells and aleurone layer cells were formed. The starch endosperm cells mainly accumulated starch granules, while the aleurone layer cells mainly accumulated mineral elements, lipids, and proteins, etc. (3) One day after flowering, the cells of the pericarp and seed coat exhibited regular shape, rich in contents, and intact in structure. From 10-20 d after flowering, the number of layers of endocarp and ectocarp and seed coat decreased, the shape changed, and starch granules began to appear in the mesocarp cells. From 20-60 d after flowering, as the nutrient substances of endosperm cells accumulated and their volume increased, mechanical pressure was exerted outward, resulting in the gradual dissolution of mesocarp cells, leaving only remnants of cell walls. The ectocarp cells were elongated with thickened cell walls, forming a protective structure together with the remaining cell walls of the mesocarp cells. The cortex played a crucial role in synthesizing and transporting nutrients, as well as protecting the development of the embryo and endosperm throughout the seed development process. The results of this study provide a theoretical basis for improving the reproductive biology in bamboo species and understanding the development of embryo and endosperm in bamboo plants.

We have a limited number of landraces and only a few of them have been used in breeding programs. In the Korean peninsula, maize was introduced before the middle of the 16th century and cultivated widely thereafter. Over 3000 Korean maize landraces have been collected and deposited in the Genebank of the National Agrobiodiversity Center, Korea, which is about a half of total maize germplasm stored in the Genebank. The majority of Korean maize accessions have been maintained as local landraces, implying the preservation of diverse morphological traits with a wide range of variation. However, there has been a few studies for discovering phenotypic characteristics of the Korean maize landraces. We collected phenotype data of 2699 maize germplasm which can be divided by geographic origin (Korean or overseas) and breeding progress (landraces or breeding lines). Principal component analysis demonstrated that the phenotypic variations of the collected maize germplasm were largely explained by flowering time, kernel yields, and stalk diameter traits. From the phenotype data analysis, 276 accessions were selected as a core collection. We also investigated endosperm phenotypes for the core collection and found novel multilayer aleurone germplasms. This indicates that Korean landraces have maintained the original genetic variation which has largely been lost during the modern breeding programs. These findings suggest that the core collection could be a valuable resource for understating and exploiting maize germplasm.

BackgroundH2A.X is an H2A variant histone in eukaryotes, unique for its ability to respond to DNA damage, initiating the DNA repair pathway. H2A.X replacement within the histone octamer is mediated by the FAcilitates Chromatin Transactions (FACT) complex, a key chromatin remodeler. FACT is required for DEMETER (DME)-mediated DNA demethylation at certain loci in Arabidopsis thaliana female gametophytes during reproduction. Here, we sought to investigate whether H2A.X is involved in DME- and FACT-mediated DNA demethylation during reproduction.ResultsH2A.X is encoded by two genes in Arabidopsis genome, HTA3 and HTA5. We generated h2a.x double mutants, which displayed a normal growth profile, whereby flowering time, seed development, and root tip organization, S-phase progression and proliferation were all normal. However, h2a.x mutants were more sensitive to genotoxic stress, consistent with previous reports. H2A.X fused to Green Fluorescent Protein (GFP) under the H2A.X promoter was highly expressed especially in newly developing Arabidopsis tissues, including in male and female gametophytes, where DME is also expressed. We examined DNA methylation in h2a.x developing seeds and seedlings using whole genome bisulfite sequencing, and found that CG DNA methylation is decreased genome-wide in h2a.x mutant endosperm. Hypomethylation was most striking in transposon bodies, and occurred on both parental alleles in the developing endosperm, but not the embryo or seedling. h2a.x-mediated hypomethylated sites overlapped DME targets, but also included other loci, predominately located in heterochromatic transposons and intergenic DNA.ConclusionsOur genome-wide methylation analyses suggest that H2A.X could function in preventing access of the DME demethylase to non-canonical sites. Overall, our data suggest that H2A.X is required to maintain DNA methylation homeostasis in the unique chromatin environment of the Arabidopsis endosperm.

Background: The endosperm serves as the primary source of nutrients for maize (Zea mays L.) kernel embryo development and germination. Positioned at the base of the endosperm, the transfer cells (TCs) of the basal endosperm transfer layer (BETL) generate cell wall ingrowths, which enhance the connectivity between the maternal plant and the developing kernels. These TCs play a crucial role in nutrient transport and defense against pathogens. The molecular mechanism underlying BETL development in maize remains unraveled. Results: This study demonstrated that the MYB-related transcription factor ZmMYBR29, exhibited specific expression in the basal cellularized endosperm, as evidenced by in situ hybridization analysis. Utilizing the CRISPR/Cas9 system, we successfully generated a loss-of-function homozygous zmmybr29 mutant, which presented with smaller kernel size. Observation of histological sections revealed abnormal development and disrupted morphology of the cell wall ingrowths in the BETL. The average grain filling rate decreased significantly by 26.7% in zmmybr29 mutant in comparison to the wild type, which impacted the dry matter accumulation within the kernels and ultimately led to a decrease in grain weight. Analysis of RNA-seq data revealed downregulated expression of genes associated with starch synthesis and carbohydrate metabolism in the mutant. Furthermore, transcriptomic profiling identified 23 genes that expressed specifically in BETL, and the majority of these genes exhibited altered expression patterns in zmmybr29 mutant. Conclusions: In summary, ZmMYBR29 encodes a MYB-related transcription factor that is expressed specifically in BETL, resulting in the downregulation of genes associated with kernel development. Furthermore, ZmMYBR29 influences kernels weight by affecting the grain filling rate, providing a new perspective for the complementation of the molecular regulatory network in maize endosperm development. [ABSTRACT FROM AUTHOR]

Transcription factors (TFs) regulate gene expression by binding to specific sequences on DNA through their DNA-binding domain (DBD), a universal process. This update conveys information about the diverse roles of TFs, focusing on the NACs (NAM-ATAF-CUC), in regulating target-gene expression and influencing various aspects of plant biology. NAC TFs appeared before the emergence of land plants. The NAC family constitutes a diverse group of plant-specific TFs found in mosses, conifers, monocots, and eudicots. This update discusses the evolutionary origins of plant NAC genes/proteins from green algae to their crucial roles in plant development and stress response across various plant species. From mosses and lycophytes to various angiosperms, the number of NAC proteins increases significantly, suggesting a gradual evolution from basal streptophytic green algae. NAC TFs play a critical role in enhancing abiotic stress tolerance, with their function conserved in angiosperms. Furthermore, the modular organization of NACs, their dimeric function, and their localization within cellular compartments contribute to their functional versatility and complexity. While most NAC TFs are nuclear-localized and active, a subset is found in other cellular compartments, indicating inactive forms until specific cues trigger their translocation to the nucleus. Additionally, it highlights their involvement in endoplasmic reticulum (ER) stress-induced programmed cell death (PCD) by activating the vacuolar processing enzyme (VPE) gene. Moreover, this update provides a comprehensive overview of the diverse roles of NAC TFs in plants, including their participation in ER stress responses, leaf senescence (LS), and growth and development. Notably, NACs exhibit correlations with various phytohormones (i.e., ABA, GAs, CK, IAA, JA, and SA), and several NAC genes are inducible by them, influencing a broad spectrum of biological processes. The study of the spatiotemporal expression patterns provides insights into when and where specific NAC genes are active, shedding light on their metabolic contributions. Likewise, this review emphasizes the significance of NAC TFs in transcriptional modules, seed reserve accumulation, and regulation of seed dormancy and germination. Overall, it effectively communicates the intricate and essential functions of NAC TFs in plant biology. Finally, from an evolutionary standpoint, a phylogenetic analysis suggests that it is highly probable that the WRKY family is evolutionarily older than the NAC family. [ABSTRACT FROM AUTHOR]

During maize endosperm filling, sucrose not only serves as a source of carbon skeletons for storage-reserve synthesis but also acts as a stimulus to promote this process. However, the molecular mechanisms underlying sucrose and endosperm filling are poorly understood. In this study, we found that sucrose promotes the expression of endosperm-filling hub gene Opaque2 (O2), coordinating with storage-reserve accumulation. We showed that the protein kinase SnRK1a1 can attenuate O2-mediated transactivation, but sucrose can release this suppression. Biochemical assays revealed that SnRK1a1 phosphorylates O2 at serine 41 (S41), negatively affecting its protein stability and transactivation ability. We observed that mutation of SnRK1a1 results in larger seeds with increased kernel weight and storage reserves, while overexpression of SnRK1a1 causes the opposite effect. Overexpression of the native O2 (O2-OE), phospho-dead (O2-SA), and phospho-mimetic (O2-SD) variants all increased 100-kernel weight. Although O2-SA seeds exhibit smaller kernel size, they have higher accumulation of starch and proteins, resulting in larger vitreous endosperm and increased test weight. O2-SD seeds display larger kernel size but unchanged levels of storage reserves and test weight. O2-OE seeds show elevated kernel dimensions and nutrient storage, like a mixture of O2-SA and O2-SD seeds. Collectively, our study discovers a novel regulatory mechanism of maize endosperm filling. Identification of S41 as a SnRK1-mediated phosphorylation site in O2 offers a potential engineering target for enhancing storage-reserve accumulation and yield in maize. Sucrose promotes O2 expression for endosperm filling, which is attenuated by SnRK1a1 through phosphorylation modification and protein degradation. The sucrose-SnRK1a1-O2 regulatory pathway offers potentials for maize yield and nutrient quality improvement through phosphorylation modification. [ABSTRACT FROM AUTHOR]

Key message: Modification of silent latent endosperm-enabled promoters (SLEEPERs) allows the ectopic activation of non-expressed metabolic genes in rice callus Metabolic engineering in plants typically involves transgene expression or the mutation of endogenous genes. An alternative is promoter modification, where small changes in the promoter sequence allow genes to be switched on or off in particular tissues. To activate silent genes in rice endosperm, we screened native promoters for near-miss cis-acting elements that can be converted to endosperm-active regulatory motifs. We chose rice PHYTOENE SYNTHASE 1 (PSY1), encoding the enzyme responsible for the first committed step in the carotenoid biosynthesis pathway, because it is not expressed in rice endosperm. We identified six motifs within a 120-bp region, upstream of the transcriptional start site, which differed from endosperm-active elements by up to four nucleotides. We mutated four motifs to match functional elements in the endosperm-active BCH2 promoter, and this promoter was able to drive GFP expression in callus and in seeds of regenerated plants. The 4 M promoter was not sufficient to drive PSY1 expression, so we mutated the remaining two elements and used the resulting 6 M promoter to drive PSY1 expression in combination with a PDS transgene. This resulted in deep orange callus tissue indicating the accumulation of carotenoids, which was subsequently confirmed by targeted metabolomics analysis. PSY1 expression driven by the uncorrected or 4 M variants of the promoter plus a PDS transgene produced callus that lacked carotenoids. These results confirm that the adjustment of promoter elements can facilitate the ectopic activation of endogenous plant promoters in rice callus and endosperm and most likely in other tissues and plant species. [ABSTRACT FROM AUTHOR]

Sweet corn (Zea mays L.) cultivars must meet stringent quality standards to be accepted in the marketplace. Breeding for eating‐quality traits, such as sweetness, typically involves taste ratings or quantification of carbohydrate content. Total soluble solids (TSS) content is used as a proxy for sweetness in many fruit crops. Using a diallel of near‐isogenic corn lines for sugary1, shrunken2, waxy1, and wild‐type (WT) endosperm types, a combining ability analysis for carbohydrate traits and TSS content determined the relationship of these traits over three harvest dates. Variation existed for total sugar, sucrose, glucose, fructose, total polysaccharides, and starch content within and across endosperm types and harvest dates, but strong correlations with TSS content were present only when assessed across all endosperm types. Strong similarities existed among WT, waxy1, and sugary1 near‐isogenic lines for general combining ability for carbohydrate traits, while shrunken2 near‐isogenic lines had different desirable combiners. Line C40 was a desirable general combiner for carbohydrate traits among WT, waxy1, and sugary1 endosperm types, while Ia5125, P39, and Ia453 were desirable general combiners for shrunken2 endosperm. This experiment also determined that TSS content is not a useful trait in sweet corn breeding for quality traits. Core Ideas: Variation existed for carbohydrate traits among hybrids within and across endosperm types and harvest dates.Variation existed for total soluble solids (TSS) content across endosperm types and for hybrids within an endosperm type.TSS differed between 19 and 22 or 25 days after pollination for su1, sh2, and wx1 endosperm.TSS content correlates with soluble carbohydrates only when assessed across all endosperm types.Wild‐type, wx1, and su1 near‐isogenic lines exhibit strong similarities for carbohydrate trait general combining ability. [ABSTRACT FROM AUTHOR]

In cereal grains, starch is synthesized by the concerted actions of multiple enzymes on the surface of starch granules within the amyloplast. However, little is known about how starch-synthesizing enzymes access starch granules, especially for amylopectin biosynthesis. Here, we show that the rice (Oryza sativa) floury endosperm9 (flo9) mutant is defective in amylopectin biosynthesis, leading to grains exhibiting a floury endosperm with a hollow core. Molecular cloning revealed that FLO9 encodes a plant-specific protein homologous to Arabidopsis (Arabidopsis thaliana) LIKE EARLY STARVATION1 (LESV). Unlike Arabidopsis LESV, which is involved in starch metabolism in leaves, OsLESV is required for starch granule initiation in the endosperm. OsLESV can directly bind to starch by its C-terminal tryptophan (Trp)-rich region. Cellular and biochemical evidence suggests that OsLESV interacts with the starch-binding protein FLO6, and loss-of-function mutations of either gene impair ISOAMYLASE1 (ISA1) targeting to starch granules. Genetically, OsLESV acts synergistically with FLO6 to regulate starch biosynthesis and endosperm development. Together, our results identify OsLESV-FLO6 as a non-enzymatic molecular module responsible for ISA1 localization on starch granules, and present a target gene for use in biotechnology to control starch content and composition in rice endosperm. The non-enzymatic protein LIKE EARLY STARVATION1 and the starch-binding protein FLOURY ENDOSPERM6 form a functional complex to facilitate ISAMYLASE1 targeting to starch granules in rice endosperm. [ABSTRACT FROM AUTHOR]

The adaptive significance of phenotypic differences between females and males can provide insights into sex‐specific selection and the evolution of sexual dimorphism. Dioecious plants commonly exhibit sexual dimorphism in height, although its ecological and evolutionary significance have rarely been examined experimentally. Here, we investigate the functional consequences of the temporal reversal of height dimorphism for pollen and seed dispersal in dioecious Rumex hastatulus Baldw., a species in which males are taller than females at flowering and the reverse pattern occurs at fruiting. Populations of this colonizing weed are wind‐pollinated and seeds are wind‐dispersed. In a glasshouse experiment we manipulated the height of pollen donors and using sex‐specific genetic markers compared the paternal success of males of contrasting height and investigated whether seed families showed evidence of sexual dimorphism in early life‐history traits. In a second glasshouse experiment using fruiting plants we also examined how female height influenced the distance that seeds were dispersed. We found that taller males had significantly higher siring success than males of equivalent height to flowering females. Similarly, taller females dispersed fruit to greater distances than shorter females. Female seeds were significantly heavier than male seeds and germinated more rapidly, although early seedling growth was greater in males. Our study suggests that the striking sex reversal of height in R. hastatulus likely functions to optimize the contrasting reproductive functions of the sexes by promoting increased pollen and seed dispersal distances. Improved dispersal quality could limit inbreeding and reduce local mate and resource competition within populations. [ABSTRACT FROM AUTHOR]

In the safety risk assessment of genetically modified (GM) crops, it is imperative to evaluate potential unintended effects derived from genetic manipulation. Here, we analyzed the differential proteomic signatures and compositional equivalence of two GM insect- and herbicide-resistant maize cultivars (named here as GM1 and GM2), extensively cultivated and commercialized in Brazil, and their respective conventional counterparts (CON1 and CON2). Complementary 2-DE-based and bottom-up shotgun proteomic analysis were used. All cultivars presented similar chemical compositions between the GMs and CONs, with values expected for Zea mays species. A total of 22 and 21 differentially expressed proteins (DEPs) were identified in the 2-DE proteomic analysis for the GM1 vs. CON1 and GM2 vs. CON2 comparisons, respectively. In same order, 11 and 16 DEPs were identified in the bottom-up shotgun proteomic. DEPs were related to various biological processes including metabolism, energy, storage, defense, and cell stress. Vicilin-like embryo storage protein, tubulin, ADP-glucose pyrophosphorylase endosperm large subunit, globulin-1, and cytosolic 3-phosphoglycerate kinase, were consistently identified using both proteomic approaches. Of particular interest, vicilin-like embryo, identified as a natural allergen in maize, was down-regulated in the GM1 event compared to CON1. Our findings provide insights into potential unintended effects revealed through proteomic methodologies, utilizing both gel-based and gel-free techniques to identify alterations in protein abundance influenced by transgenic modification. [ABSTRACT FROM AUTHOR]

Reducing production costs, known as scaling, is a significant obstacle in the advancement of cultivated meat. The cultivation process hinges on several key components, e.g., cells, media, scaffolds, and bioreactors. This study demonstrates an innovative approach, departing from traditional stainless steel or glass bioreactors, by integrating food-grade plant-based scaffolds and thermoplastic film bioreactors. While thermoplastic films are commonly used for constructing fluidic systems, conventional welding methods are cost-prohibitive and lack rapid prototyping capabilities, thus inflating research and development expenses. The developed laser welding technique facilitates contamination-free and leakproof sealing of polyethylene films, enabling the efficient fabrication of macrofluidic systems with various designs and dimensions. By incorporating food-grade plant-based scaffolds, such as rice seeded with bovine mesenchymal stem cells, into these bioreactors, this study demonstrates sterile cell proliferation on scaffolds within macrofluidic systems. This approach not only reduces bioreactor prototyping and construction costs but also addresses the need for scalable solutions in both research and industrial settings. Integrating single-use bioreactors with minimal shear forces and incorporating macro carriers such as puffed rice may further enhance biomass production in a scaled-out model. The use of food-grade plant-based scaffolds aligns with sustainable practices in tissue engineering and cultured-meat production, emphasizing its suitability for diverse applications. [ABSTRACT FROM AUTHOR]

Flowering plants, also known as angiosperms, emerged approximately 150 to 200 million years ago. Since then, they have undergone rapid and extensive expansion, now encompassing around 90% of all land plant species. The remarkable diversification of this group has been a subject of in-depth investigations, and several evolutionary innovations have been proposed to account for their success. In this primer, we will specifically focus on one such innovation: the advent of seeds containing endosperm. Butel and Köhler give an overview of the process of reproduction in flowering plants. [ABSTRACT FROM AUTHOR]