scholarly journals An L-type lectin receptor-like kinase promotes starch accumulation during rice pollen maturation

Development ◽  
2021 ◽  
pp. dev.196378
Author(s):  
Zhiyuan He ◽  
Ting Zou ◽  
Qiao Xiao ◽  
Guoqiang Yuan ◽  
Miaomiao Liu ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Pollen Grains ◽  
Starch Accumulation ◽  
Male Sterile ◽  
Pollen Maturation ◽  
Lectin Receptor ◽  
Rice Mutant ◽  
Receptor Like Kinase ◽  
Mutant Pollen

Starch accumulation is key for the maturity of rice pollen grains; however, the regulatory mechanism underlying this process remains unknown. Here, we isolated a male-sterile rice mutant, abnormal pollen 1 (ap1), which produces nonviable pollen grains with defective starch accumulation. Functional analysis revealed that AP1 encodes an active L-type lectin receptor-like kinase (L-LecRLK). AP1 is localized to the plasma membrane and its transcript is highly accumulated in pollen during the starch synthesis phase. RNA-seq and phosphoproteomic analysis revealed that the expression/phosphorylation levels of numerous genes/proteins involved in starch and sucrose metabolism pathway were significantly altered in the mutant pollen, including a known rice UDP-glucose pyrophosphorylase (OsUGP2). We further found that AP1 physically interacts with OsUGP2 to elevate its enzymatic activity likely through targeted phosphorylation. These findings revealed a novel role of L-LecRLK in controlling pollen maturity via modulating sucrose and starch metabolism.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

Suppression of starch synthesis in rice stems splays tiller angle due to gravitropic insensitivity but does not affect yield

2015 ◽  
Vol 42 (1) ◽  
pp. 31 ◽  
Author(s):  
Masaki Okamura ◽  
Tatsuro Hirose ◽  
Yoichi Hashida ◽  
Ryu Ohsugi ◽  
Naohiro Aoki
Keyword(s):  
Double Mutant ◽  
Oryza Sativa L ◽  
Starch Content ◽  
Large Subunit ◽  
Starch Synthesis ◽  
Starch Accumulation ◽  
Gravitropic Response ◽  
Rice Mutant ◽  
Matter Production ◽  
Tiller Angle

In rice (Oryza sativa L.), tiller angle – defined as the angle between the main culm and its side tillers – is one of the important factors involved in light use efficiency. To clarify the relationship between tiller angle, gravitropism and stem-starch accumulation, we investigated the shoot gravitropic response of a low stem-starch rice mutant which lacks a large subunit of ADP-glucose pyrophosphorylase (AGP), called OsAGPL1 and exhibits relatively spread tiller angle. The insensitive gravitropic response exhibited by the mutant led us to the conclusion that insensitivity of gravitropism caused by stem-starch reduction splayed the tiller angle. Furthermore, since another AGP gene called OsAGPL3 was expressed at considerable levels in graviresponding sites, we generated a double mutant lacking both OsAGPL1 and OsAGPL3. The double mutant exhibited still lower stem-starch content, less sensitive gravitropic response and greater tiller angle spread than the single mutants. This indicated that the expansion of the tiller angle caused by the reduction in starch level was intense according to the extent of the reduction. We found there were no significant differences between the double mutant and wild-type plants in terms of dry matter production. These results provided new insight into the importance of stem-starch accumulation and ideal plant architecture.

scholarly journals Rice LecRK5 phosphorylates a UGPase to regulate callose biosynthesis during pollen development

2020 ◽  
Vol 71 (14) ◽  
pp. 4033-4041
Author(s):  
Bin Wang ◽  
Ruiqiu Fang ◽  
Jia Zhang ◽  
Jingluan Han ◽  
Faming Chen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Male Gametophyte ◽  
Phosphorylation Site ◽  
Anther Development ◽  
Male Sterile ◽  
Callose Deposition ◽  
Vitro Assay ◽  
Lectin Receptor ◽  
Receptor Like Kinase

Abstract The temporary callose layer surrounding the tetrads of microspores is critical for male gametophyte development in flowering plants, as abnormal callose deposition can lead to microspore abortion. A sophisticated signaling network regulates callose biosynthesis but these pathways are poorly understood. In this study, we characterized a rice male-sterile mutant, oslecrk5, which showed defective callose deposition during meiosis. OsLecRK5 encodes a plasma membrane-localized lectin receptor-like kinase, which can form a dimer with itself. Moreover, normal anther development requires the K-phosphorylation site (a conserved residue at the ATP-binding site) of OsLecRK5. In vitro assay showed that OsLecRK5 phosphorylates the callose synthesis enzyme UGP1, enhancing callose biosynthesis during anther development. Together, our results demonstrate that plasma membrane-localized OsLecRK5 phosphorylates UGP1 and promotes its activity in callose biosynthesis in rice. This is the first evidence that a receptor-like kinase positively regulates callose biosynthesis.

scholarly journals SDG711 Is Involved in Rice Seed Development through Regulation of Starch Metabolism Gene Expression in Coordination with Other Histone Modifications

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiaoyun Liu ◽  
Junling Luo ◽  
Tiantian Li ◽  
Huilan Yang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Seed Development ◽  
Starch Synthesis ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Body Region ◽  
Rice Seed ◽  
Normal Seed ◽  
Gene Body Region ◽  
Metabolism Gene

AbstractSDG711 is a histone H3K27me2/3 transmethylase in rice, a homolog of CLF in Arabidopsis, and plays key roles in regulating flowering time and panicle development. In this work, we investigated the role of SDG711 in rice seed development. Overexpression and downregulation of SDG711 lead to a decrease and increase in the expression level of genes related to starch accumulation, resulting in smaller seeds or even seed abortion. ChIP assay showed that SDG711-mediated H3K27me3 changed significantly in genes related to endosperm development, and SDG711 can directly bind to the gene body region of several starch synthesis genes and amylase genes. In addition, H3K4me3 and H3K9ac modifications also cooperate with H3K27me3 to regulate the development of the endosperm. Our results suggest that the crosstalk between SDG711-mediated H3K27me3 and H3K4me3, and H3K9ac are involved in starch accumulation to control normal seed development.

An ultrastructural study of pollen development in tomato (Lycopersicon esculentum). II. Pollen maturation

1993 ◽  
Vol 71 (8) ◽  
pp. 1048-1055 ◽  
Author(s):  
P. L. Polowick ◽  
V. K. Sawhney
Keyword(s):  
Lycopersicon Esculentum ◽  
Vegetative Cell ◽  
Generative Cell ◽  
Pollen Grains ◽  
Mature Pollen ◽  
Ultrastructural Changes ◽  
Second Phase ◽  
Cell Cytoplasm ◽  
Pollen Maturation

The maturation of tomato pollen grains encompassed several ultrastructural changes. The generative cell separated from the intine and was free in the cytoplasm of the vegetative cell. This process coincided with the appearance of starch in plastids and the division of elongated mitochondria. This stage was followed by a second phase of vacuolation in the vegetative cell cytoplasm. Starch was still abundant at this stage, as were mitochondria, endoplasmic reticulum (ER), and ribosomes. Lipid droplets were the prominent feature of mature pollen grains. Each droplet was surrounded by rough ER (RER), suggesting the role of RER in lipid accumulation and mobilization. Long stretches of ER were present at early stages of maturation, and stacks of up to 50 strands of RER were abundant in mature pollen. The plastids in mature pollen were devoid of starch and had few internal membranes. Mitochondria were abundant and spherical with parallel cristae. In many cases, the cytoplasm at the periphery of the mature pollen grain was dense, forming a distinct zone, and contained only ER. The generative cell cytoplasm had mitochondria, ER, and actin-like filaments but no plastids. The pollen wall at maturity had a lamellated foot layer, a lightly sculptured tectum, and broad intine. The intine was layered in the region of the pollen aperture. Key words: Lycopersicon esculentum, pollen grains, tomato, ultrastructure.

scholarly journals SDG711 is Involved in Rice Seed Development Through Regulation of Starch Metabolism Gene Expression in Coordination With Other Histone Modifications

2020 ◽  
Author(s):  
Xiaoyun Liu ◽  
Junling Luo ◽  
Tiantian Li ◽  
Huilan Yang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Seed Development ◽  
Starch Synthesis ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Body Region ◽  
Rice Seed ◽  
Normal Seed ◽  
Gene Body Region ◽  
Metabolism Gene

Abstract SDG711 is a histone H3K27me2/3 transmethylases in rice, homolog ofCLFin Arabidopsis, that plays key roles in regulating of flowering time and panicle development. In this work, we investigated that the role of SDG711 in rice seed development. Overexpression and down-regulation of SDG711lead to the decrease and increase of the expression level of genes related to starch accumulation, resulting in smaller seed or even seed abortion. ChIP assay showed that SDG711-mediated H3K27me3 changed significantly in genes related to endosperm development and SDG711 can directly bind to the gene body region of several starch synthesis genes and amylase genes. In addition, H3K4me3 and H3K9ac modifications also cooperate with H3K27me3 to regulate the development of endosperm. Our results suggested that the crosstalk of SDG711-mediated H3K27me3 with H3K4me3 and H3K9ac are involved in starch accumulation to control normal seed development.

scholarly journals Arabidopsis ECERIFERUM3 (CER3) Plays a Critical Role in Maintaining Hydration for Pollen-Stigma Recognition during Fertilization

2019 ◽  
Author(s):  
Faqing Xu ◽  
Xiaojing Li ◽  
Zhongnan Yang ◽  
Sen Zhang
Keyword(s):  
Critical Role ◽  
Pollen Grains ◽  
Underlying Mechanism ◽  
Recognition System ◽  
Development Stage ◽  
Male Sterile ◽  
Foreign Pollen ◽  
Compatible Pollen ◽  
Mutant Pollen

ABSTRACTPlants distinguish the pollen grains that land on their stigmas, only allowing compatible pollen to fertilize female gametes. To analyze the underlying mechanism, conditional male-sterile mutations with affected pollen coat and disrupted pollen-stigma recognition were isolated and described. The mutant pollen failed to germinate, but germinated in vitro, suggesting that they are viable. In mutants, stigma cells that contacted their own pollen generated callose, a carbohydrate produced in response to foreign pollen. High humidity restored pollen hydration and successful fertilization, indicating defective dehydration in pollen-stigma interaction. Further analysis results from mixed pollination experiments demonstrated that the mutant pollen specifically lacked a functional pollen-stigma recognition system. The sterile plants lacked stem waxes and displayed postgenital fusion between aerial floral organs. In addition, the mutant pollen was deficient in long-chain lipids and had excess tryphine. Transmission electron microscopy observation showed that mutant pollen had almost the same surface structure as the wild type at bicellular pollen stage. However, abnormal plastoglobuli were observed in the plastids of the mutant tapetum, which was indicative of altered lipid accumulation. CER3 transcript was found in anther tapetum and microspores at development stage 9 while CER3-GFP fusion protein was localized to the cell plasma membrane. Our data reveal that CER3 is required for biosynthesis of tryphine lipids which play a critical role in maintaining hydration for pollen-stigma recognition during fertilization.

Phenotypic characterization, genetic analysis, and molecular mapping of a new mutant gene for male sterility in rice

Genome ◽  
2008 ◽  
Vol 51 (4) ◽  
pp. 303-308 ◽  
Author(s):  
Ling Zuo ◽  
Shuangcheng Li ◽  
Mingguang Chu ◽  
Shiquan Wang ◽  
Qiming Deng ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Molecular Mapping ◽  
Spontaneous Mutation ◽  
Recessive Gene ◽  
Pollen Grains ◽  
Mutant Gene ◽  
Phenotypic Characterization ◽  
Chromosome 4 ◽  
Male Sterile ◽  
Rice Mutant

xs1 is a male-sterile rice mutant derived from a spontaneous mutation. The floret of the mutant, consisting of 6 stamens and 1 pistil, looks the same as that of the wild type except that the filaments are long and thin and the anthers are withered in white transparence. It is confirmed that xs1 is a no-pollen type of male-sterile mutant, for no pollen grains can be stained with I2–KI solution and the anther locules are always hollow. Anther transverse sections indicate that the mutant microspores are abnormally condensed and agglomerated to form a deeply stained cluster at the late microspore stage, which results in cessation of the vacuolation process of microspores, and, therefore, the mutant forms no functional pollens for reproduction. Genetic analysis of 4 F2 populations and 3 BC1F1 populations revealed that the mutation is controlled by a single recessive gene, termed VR1 (Vacuolation retardation 1). Screening of 432 F2 mutant individuals derived from the cross of xs1 × G603 with simple sequence repeat markers revealed that VR1 is located between the molecular markers RM17411 and RM5030, at distances of 0.7 and 1.5 cM, respectively, on chromosome 4. VR1 is a new male fertility controlling gene located on chromosome 4 in rice.

Protein synthetic activity during normal pollen development and during induced pollen embryogenesis in Hyoscyamus niger

1984 ◽  
Vol 62 (12) ◽  
pp. 2493-2513 ◽  
Author(s):  
V. Raghavan
Keyword(s):  
Vegetative Cell ◽  
Generative Cell ◽  
Pollen Grains ◽  
Synthetic Activity ◽  
Pollen Embryogenesis ◽  
Starch Accumulation ◽  
Hyoscyamus Niger ◽  
Amino Acid Incorporation ◽  
Pollen Maturation ◽  
Germinating Pollen

Protein synthetic activity during maturation, germination, and embryogenic phases of pollen grains of Hyoscyamus niger (L.) was investigated by means of autoradiography of incorporation of [3H]arginine, [3H]leucine, [3H]lysine, and [3H]tryptophan. Silver grain counts showed that during pollen maturation, peaks of incorporation of [3H]arginine and [3H]lysine occurred before the onset of vacuolation in the uninucleate pollen grains and as starch accumulation was initiated in the bicellular pollen grains. In the latter, labeled amino acids were mostly incorporated into the vegetative cell and very little appeared in the generative cell. [3H]leucine and [3H]tryptophan were not incorporated into uninucleate pollen grains at any stage of their development, although they were localized in the vegetative cell of bicellular pollen grains. In germinating pollen grains the nucleus of the vegetative cell, the generative cell, and sperms did not incorporate the isotopes. While the majority of pollen grains incorporated [3H]arginine, [3H]leucine, [3H]lysine, and [3H]tryptophan immediately after culture of anthers, during further periods of culture, protein synthetic activity persisted only in a small number of uninucleate, nonvacuolate, and densely staining "embryogenically determined" pollen grains confined to the periphery of the anther locule. Subsequent division of these pollen grains was accompanied by incorporation of [3H]arginine, [3H]leucine, and [3H]lysine into the vegetative cell or into both the vegetative cell and generative cell. It is suggested that, in contrast to the 3H-labeled amino acid incorporation pattern observed in pollen grains during their normal ontogeny, a significant change associated with embryogenic induction is the incorporation of [3H]leucine and [3H]tryptophan into embryogenically determined uninucleate pollen grains and of [3H]arginine, [3H]leucine, and [3H]lysine into the generative cell of bicellular pollen grains.

scholarly journals bHLH Transcription Factor NtMYC2a Regulates Carbohydrate Metabolism during the Pollen Development of Tobacco (Nicotiana tabacum L. cv. TN90)

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 17
Author(s):  
Shiquan Bian ◽  
Tian Tian ◽  
Yongqiang Ding ◽  
Ning Yan ◽  
Chunkai Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nicotiana Tabacum ◽  
Transgenic Plants ◽  
Carbohydrate Metabolism ◽  
Pollen Development ◽  
Starch Accumulation ◽  
Bhlh Transcription Factor ◽  
Pollen Maturation ◽  
Nicotiana Tabacum L

Basic helix-loop-helix (bHLH) transcription factor MYC2 regulates plant growth and development in many aspects through the jasmonic acid (JA) signaling pathway, while the role of MYC2 in plant carbohydrate metabolism has not been reported. Here, we generated NtMYC2a-overexpressing (NtMYC2a-OE) and RNA-interference-mediated knockdown (NtMYC2a-RI) transgenic plants of tobacco (Nicotiana tabacum L. cv. TN90) to investigate the role of NtMYC2a in carbohydrate metabolism and pollen development. Results showed that NtMYC2a regulates the starch accumulation and the starch-sugar conversion of floral organs, especially in pollen. The RT-qPCR analysis showed that the expression of starch-metabolic-related genes, AGPs, SS2 and BAM1, were regulated by NtMYC2a in the pollen grain, anther wall and ovary of tobacco plants. The process of pollen maturation was accelerated in NtMYC2a-OE plants and was delayed in NtMYC2a-RI plants, but the manipulation of NtMYC2a expression did not abolish the pollen fertility of the transgenic plants. Intriguingly, overexpression of NtMYC2a also enhanced the soluble carbohydrate accumulation in tobacco ovaries. Overall, our results demonstrated that the bHLH transcription factor NtMYC2a plays an important role in regulating the carbohydrate metabolism during pollen maturation in tobacco.

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