(E and J) Tricellular pollen stage. 3 words related to pollen: spore, pollinium, ragweed pollen. A complementation vector, pBIN-DET2-Ubi-bar, which included the entire DET2-coding region, 3.0 kbp of the 5′ promoter region, 1.4 kbp of the 3′ downstream region, and the bar gene, was introduced into heterozygous tde1 plants (TDE1/tde1) using floral dip methods. The phenotype of male sterility, however, was not linked to the T-DNA (data not shown, see below), thus it is considered that the mutation was introduced during the transformation process. No structural difference was found between the wild type and tde1. As nouns the difference between grain and exine is that grain is (uncountable) the harvested seeds of various grass food crops eg: wheat, corn, barley or grain can be a branch of a tree; a stalk or stem of a plant while exine is (botany|palynology) the outer layer of a pollen grain or spore; the exosporium. Exine & intine. Biol, Transgenic studies on the involvement of cytokinin and gibberellin in male development, GUS fusions: β-glucuronidase as a sensitive and versatile gene fusion marker in higher plants, A role for brassinosteroids in light-dependent development of Arabidopsis, CYP703 is an ancient cytochrome P450 in land plants catalyzing in-chain hydroxylation of lauric acid to provide building blocks for sporopollenin synthesis in pollen, Callose (β-1,3 glucan) is essential for Arabidopsis pollen wall patterning, but not tube growth, Phenols as integrated compounds of sporopollenin from, Ultrastructure of microsporogenesis and microgametogenesis in, DEX1, a novel plant protein is required for exine pattern formation during development in, A comparative ultrastructural analysis of exine pattern development in wild-type, Biogenesis and function of the lipidic structures of pollen grains, Tetrad pollen formation in quarted mutants of Arabidopsis thaliana is associated with persistence of pectic polysaccharides of the pollen mother cell wall, Pollen exine: the sporopollenin enigma and the physics of pattern. (I and M) Late bicellular pollen stage. The amount of the accumulation in tde1 became lower than that at the previous stage. 2007). This centrifugation experiment suggested that a family of coated vesicles (CVs), which are present throughout the meiocyte cytoplasm, are likely to be associated with large assemblages of smooth ER and with plasma membrane, and that the CVs are responsible for reticulate patterning (Sheldon and Dickson 1983). Based on macroscopic screening of about 3,000 lines of Arabidopsis thaliana ecotype Columbia (Col), mutagenized with T-DNA, we identified a sterile mutant (KE-1903) that had completely empty siliques. body, the absorption of the intine, andl develop-ment of fragility in the exine. 2004). Further, the globular sporopollenin aggregation was not observed on the microspores at the early uninucleate microspore stage. It has been shown that the plasma membrane in the dex1 and nef1 mutants is shallower than that in the wild type (Paxson-Sowders et al. Pollen is surrounded by an outer sculptured thick wall, the exine. Finally, microspores without exine are formed in these mutants. 4H). In order to confirm if the tde1 mutation affected the expression of genes involved in the pollen exine formation, mRNA accumulation of these genes was determined by qRT–PCR (Supplementary Fig. A detailed observation of pollen wall development was also carried out using TEM. 1997, Ariizumi et al. The genotypes of the resulting F2 plants were determined using InDel markers in the Cereron Arabidopsis polymorphism collection (http://www.arabidopsis.org/Cereron/index.html). Distinctive pollen wall patterns vary between species but are conserved within species. 3A, C) and in the middle uninucleate microspore stage were observed (Fig. This indicates that the tde1 pollen grains are viable, but may not reach the stigmatic surface due to short filament length. Aniline blue staining was performed according to Ariizumi et al. This experiment demonstrated that brassinolide application rescued the reproductive phenotypes as well as the vegetative phenotypes, including primexine and probacula formation and male sterility (Supplementary Fig. 2004). The intine is composed of cellulose, pectic polymer hydrolytic enzymes, and hydrophobic proteins and is largely regulated by microspores, but the exact mechanism of its formation is still unclear [3,4]. 4I. Based on the phenotype of male sterility, the TDE1 gene was mapped between an InDel marker CER449022 on a bacterial artificial chromosome (BAC) clone F12M22 and an InDel marker CER449589 on an adjacent BAC clone F16M14. This sporopollenin deposition within the primexine produces a columnae-like structure of exine, the probacula. So thickened portions of intine occur under pores. Surprisingly, microspores with a reticulate exine structure were also observed in tde1 at the same stage (Fig. However, these defective microspores eventually degrade in the locule. 1988). Thus the TDE1 gene was cloned using a map-based and candidate gene approach. It is predicted that the NEF1 encodes a membrane protein that maintains the envelope integrity in the plastids (Ariizumi et al. Her research interests include Bio-fertilizers, Plant-Microbe Interactions, Molecular Microbiology, Soil Fungi, and Fungal Ecology. Supplementary material mentioned in the article is available to online subscribers at the journal website www.pcp.oxfordjournals.org. The PCR products obtained using genomic DNA as a template are also shown (g). Intine became thicker than in the previous stage both in the wild type and in tde1. Search for other works by this author on: Disruption of the novel plant protein NEF1 affects lipid accumulation in the plastids of the tapetum and exine formation of pollen, resulting in male sterility in, Pollen exine pattern formation is dependent on three major developmental processes in Arabidopsis thaliana, Gibberellin regulates Arabidopsis floral development via suppression of DELLA protein function, Maize polyubiquitin genes: structure, thermal perturbation of expression and transcript splicing, and promoter activity following transfer to protoplasts by electroporation, BRASSINOSTEROIDS: essential regulators of plant growth and development, Annu. (D and H) Pollen tube elongation was visualized with aniline blue staining in the wild type and in tde1. This vector was then introduced into the plant by the floral dip method (Clough and Bent 1998). Intine is situated interior to exine. 1997). To test the recovery of the phenotypes observed in tde1, mutant seeds were sown on the media including brassinolide according to the procedure reported by Li et al. Hence, exine is also more resistant and harder than the inner layer of the pollen, which is the intine. Eventually the young, vegetative cell emerges from the cyst structure leaving behind a lpartially digested exine. 4B, F). Terms of Use and Privacy Policy: Legal. Except in the case of some submerged aquatic plants, the mature pollen grain has a double wall. Though BRs were originally identified from pollen in Brassica napus in 1979 (Clouse and Sasse 1998), how BRs regulate pollen development has been poorly understood. The intine, made of cellulose, is a thin wall just inside the exine surrounding the generative cells inside the pollen shell. Intine is the inner layer of a pollen grain containing cellulose and pectin. Pollen is the actual male gametophyte of seed plants. 2005). Compare the Difference Between Similar Terms. Moreover, a further difference between exine and intine is that the exine is more resistant and thicker, while the intine is less resistant and thinner. (I) Pollen germination after self-pollination in tde1. 2004), and the hkm membrane is deeper than that in the wild type (Ariizumi et al. The defective in exine formation 1 (dex1) mutant is characterized by an abnormal random deposition of sporopollenin on the microspore plasma membrane, which results in pollen degeneration (Paxson-Sowders et al. The key difference between exine and intine is that exine is the outer layer of a pollen grain containing sporopollenin, while intine is the inner layer of a pollen grain containing cellulose and pectin. 4D), whereas neither pollen attachment nor germination was visible on the tde1 papilla cells (Fig. (2003) (Supplementary Table S1). On the other hand, intine formation appeared similar to that in the wild type. 1999, Meuter-Gerhards et al. Exine has important roles in providing structural and physical support to the microspore cytoplasm, as well as protection from environmental stresses, and in the species‐specific interaction of pollen with the stigma (Zinkl et al., 1999). In this species the difference between A and B pollen is in size, exine thickness and structure, the presence of meridional ridges in B and subsidiary colpi in A. The sepal, petal and stamen were clearly shorter than those in the wild type (Fig. It has been suggested that the DEX1 protein is a component of either the primexine matrix or the endoplasmic reticulum (ER) and is involved in the assembly of primexine (Paxson-Sowders et al. Further study is needed to identify factors involved in constructing reticulate exine architecture from sporopollenin aggregates. (A) A portion of the nucleotide and amino acid sequences of the TDE1 gene in the wild type (WT) and the tde1 mutant (tde1). In our current study, we found that the TDE1 gene was identical to the DET2 gene, and that the tde1 primexine- and probacula-defective phenotypes were BR dependent. 1. Vegetative nucleus (VN) with prominent nucleolus and start of generative cell (GN). The tde1 pistils were pollinated by the pollen grains of a heterozygous det2-1 plant. In contrast, the tde1 membrane structure was similar to that in the wild type (Fig. Our results suggest that BRs are involved in the primexine and probacula formation during the early process of exine patterning. All microspores in the locules of the tde1 mutant were aberrant, indicating that the phenotype was uniform. 2001). Bar = 100 μm (B–D, F–I). Sporopollenin aggregates accumulated on the locule wall at the highest levels during the early uninucleate microspore stage of tde1 (Fig. Although the exine pattern varies between species, in general it is divided into two main layers: an outer sculpted layer, the sexine, and an inner layer, the … (C and F) Middle uninucleate microspore stage. Degree in Plant Science, M.Sc. Next, the tde1 mutant was grown in the presence of brassinolide to determine whether the phenotypes were recovered. Each cDNA sample was diluted 1 : 30 in water, and 5 μl of this dilution was used as template for the qRT–PCR. It is suggested that the MS2 protein encodes a fatty acyl reductase, which might reduce very long chain fatty acids to fatty alcohol, and it is postulated that this reaction is one of the steps in the formation of sporopollenin (Aarts et al. So, this is the key difference between exine and intine. Whereas the exine is sporophytic, the intine is secreted by the microspore (gametophytic origin) around the ring-vacuolated microspore (late uninucleate) stage (Owen and Makaroff, 1995). Based on the Southern blot analysis, we identified that three plants were homozygous for the deletion at the TDE1 locus. S3). (J and N) Tricellular pollen stage. It is likely that these factors act on exine patterning from the early uninucleate to the middle uninucleate microspore stage, when the exine formation was restored in the tde1 mutant. 1996). 2003). The anther size in the tde1 mutant was smaller than that in the wild type (Fig. In the flp1 mutant, many parts of the exine appeared to have broken apart after formalin/alcohol/acetic acid (FAA) treatment, although the microspores and their exine were visually normal without this treatment (Ariizumi et al. The four previously isolated mutants (dex1, nef1, cals5/lap1 and hkm) have something in common in terms of their abnormal membrane structure. 1A, D; white arrows). 2004), the tde1 mutant formed the thin primexine. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. The rela-tively few terms presented in this diagram ap- ... a stricter sense, the pollen exine) is the difference No structural difference was found between the wild type and tde1. 2001, Ito and Shinozaki 2002, Ariizumi et al. This result confirmed that TDE1 is the DET2 gene. Excluding the siliques, 330 bp of the DET2/TDE1 gene product was detected in all of the tissues tested (Fig. “Image from page 727 of “Anatomie et physiologie végétales à l’usage des étudiants en sciences naturelles des universités, des élèves à l’Institut agronomique, des écoles d’agriculture, etc” (1900)” By Internet Archive Book Images ( No known copyright restrictions) via Flickr. Besides, it is more resistant to harsh environmental conditions. Male sterility segregation ratios of the tde1 mutant. 78i; Hesse & Kubitzki 1983: fig. In the tde1 mutant, the globular sporopollenin aggregation was randomly deposited on the plasma membrane (Fig. Wild-type and tde1 microspore development was similar from this stage onward. Intine became thicker than that in the previous stage. White arrows indicate the tapetally derived sporopollenin deposited on the callose wall. The dehydrated tissues were soaked in a mixture of 100% ethanol and propylene oxide (1 : 1, v/v) for 30 min, 100% propylene oxide for 30 min twice, then incubated in propylene oxide and Spurr's resin (1 : 2, v/v) for 12 h. Subsequently, tissues were embedded in Spurr's resin for 3 d at 60°C. 2D, E, I, J. Exine development in the wild type (A–E) and the tde1 mutant (F–J). Sheldon and Dickson (1983) employed a centrifugation experiment that enables displacement of cytoplasmic components of meiocytes by the centrifugation of developing anthers. The absence of normal sporopollenin deposition in the male sterility2 (ms2) mutant has been demonstrated by an acetolysis experiment (Aarts et al. To gain information about pollen development in the tde1 mutant, TEM analysis was carried out with anther sections at each stage from the tetrad stage to the tricellular pollen stage (Fig. However, the undulant membrane structure looked similar to that in the wild type. The intine secreted by the microspore is a relatively simple layer comprising cellulose, pectin and various proteins (Brett and Waldron, 1990). As a result tde1 mutants show formation of an unusual sporopollenin aggregate prior to formation of a fundamental reticulate exine structure. Furthermore, exine has folds and spikes while they are absent in intine. (B and G) Early uninucleate microspore stage. When the tde1 pollen grains were artificially applied to their pistil (self-pollination), the tde1 pollen grains germinated well, as shown in Fig. In the hkm mutant, the thinner primexine is formed, and sporopollenin eventually anchors to the plasma membrane. Bar = 1.0 μm. The ACT2 gene was used as a control in qRT–RCR. From Cutis Marmorata Cutis marmorata is characterized by a symmetrical, lacy, reticular, red-purple mottling of the skin after exposure to cold temperatures. Occasional. We suspected that the tde1 mutant would be defective in BR biosynthesis or its signal transduction because the phenotypes including dark green leaves, dwarf and reduced fertility are characteristics observed in other BR mutants (Clouse and Sasse 1998). The exine also plays an important role in the species-specific adhesion of pollen grains to the female stigma cells (Zinkl et al. Exine punctation and apertures are well developed. These successful complementation experiments indicate that the phenotypes observed during the early process of exine formation in the tde1 mutant are dependent on BR synthesis. Nexine and intine formation also commenced at this stage, and reticulate patterning was almost completed. The tde1 mutant contains a 7 bp deletion in the DET2 gene. Tohru Ariizumi, Takahiro Kawanabe, Katsunori Hatakeyama, Shusei Sato, Tomohiko Kato, Satoshi Tabata, Kinya Toriyama, Ultrastructural Characterization of Exine Development of the transient defective exine 1 Mutant Suggests the Existence of a Factor Involved in Constructing Reticulate Exine Architecture from Sporopollenin Aggregates, Plant and Cell Physiology, Volume 49, Issue 1, January 2008, Pages 58–67, https://doi.org/10.1093/pcp/pcm167. Method ( an et al in Arabidopsis, the undulant membrane structure was observed by TEM from the cyst leaving. Central cytoplasmic part is the DET2 mutants has not yet been reported the. 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D ) Middle uninucleate microspore stage the defective phenotype ( e.g a distinct sequence of amino!, vegetative cell emerges from the microspore plasma membrane structure looked similar to that in the type! Normal reticulate exine was formed at the Middle uninucleate microspore stage but observed... Definition is - the inner layer of a distinct sequence of 26 amino acids the! Kameyama, 519-0212 Japan transcripts of DET2/TDE1 and ACTIN2 in a similar manner ( Fig of seed plants be lysed! Encodes a membrane protein that maintains the envelope integrity in the previous stage both in the protein release made!