Project description:Pollen tubes extend through pistil tissues and are guided to ovules where they release sperm for fertilization. Although pollen tubes can germinate and elongate in a synthetic medium, their trajectory is random and their growth rates are slower compared to growth in pistil tissues. Furthermore, interaction with the pistil renders pollen tubes competent to respond to guidance cues secreted by specialized cells within the ovule. The molecular basis for this potentiation of the pollen tube by the pistil remains uncharacterized. We used a surgical procedure to obtain large quantities of uncontaminated pollen tubes that grew through the pistil and defined their transcriptome by microarray analysis. We also characterized the transcriptome of in vitro-grown pollen tubes (for 0.5hours or 4hours) and dessicated mature pollen in Arabidopsis. Experiment Overall Design: Pollen and pollen tubes were collected as described in the protocols section for RNA extraction and hybridization on Affymetrix ATH1 Genechip microarrays.
Project description:We used tomato pollen in order to identify pollen stage-specific small non-coding RNAs (sncRNAs) and their target mRNAs. We further deployed elevated temperatures to discern stress responsive sncRNAs. For this purpose high throughput sncRNA-sequencing was performed for three-replicated sncRNAs libraries derived from tomato tetrad, post-meiotic, and mature pollen under control and heat stress conditions.
Project description:Transcriptome profiling of three developmental stages of immature male gametophyte intobacco (Nicotiana tabacum) Total RNA isolated from tobacco microspores and early and late bicellular pollen was hybridised on Agilent Tobacco Gene Expression Microarray 4x44K in two biological replicates per sample
Project description:In angiosperms, stigma provides initial nutrients and guidance cues for pollen grain germination and tube growth. However, little is known about genes that regulate these processes in rice. Here we generate rice stigma-specific gene expression profiles through comparing genome-wide expression patterns of hand dissected unpollinated stigma at anthesis with seven tissues including seedling shoot, seedling root, mature anther, ovary at anthesis, seeds of five days after pollination, 10-day-old embryo, 10-day-old endosperm as well as suspension cultured cells by using 57K Affymetrix rice whole genome array. In total, we identified 665 probe sets (550 genes) to be expressed specifically or predominantly in the stigma papillar cells of rice. Real-Time quantitative RT-PCR analysis of 34 selected genes confirmed their stigma-specific expression. The expression of five selected genes was further validated by RNA in situ hybridization. Gene annotation shows that several auxin-signaling components, transporters and stress-related genes are significantly overrepresented in the rice stigma gene set. We also found that genes involved in cell wall metabolism and cellular communication appear to be conserved in the stigma between rice and Arabidopsis. Our results indicate that the stigmas appear to have conserved and novel molecular functions between rice and Arabidopsis. Experiment Overall Design: We generate rice stigma-specific gene expression profiles through comparing genome-wide expression patterns of hand dissected unpollinated stigma at anthesis with seven tissues including seedling shoot, seedling root, mature anther, ovary at anthesis, seeds of five days after pollination, 10-day-old embryo, 10-day-old endosperm as well as suspension cultured cells by using 57K Affymetrix rice whole genome array.
Project description:Cotton (Gossypium hirsutum L.), a crucial global fiber and oil seed crop, faces a diverse biotic and abiotic stresses. Among these, temperature stress strongly influence its growth, prompting adaptive physiological, biochemical and molecular changes. In this study, we explored the proteomic changes underscoring the heat stress tolerance in the leaves of two locally developed cotton genotypes, i.e., heat tolerant (GH-Hamaliya Htol) and heat susceptible (CIM-789 Hsus), guided by morpho-physiological and biochemical analysis. These genotypes were sown at two different temperatures, control (35ºC) and stress (45ºC) in glass house, in randomized complete block design (RCBD) in three replications. At the flowering stage, a label-free quantitative shotgun proteomics of cotton leaves revealed the differential expression of 701 and 1270 proteins in the tolerant and susceptible genotype compared to the control, respectively. Physiological and biochemical analysis showed that the heat-tolerant genotype responded uniquely to stress by maintaining the net photosynthetic rate (Pn)( 25.2-17.5µmolCO2m-2S-1), chlorophyll (8.5-7.8mg/g FW), and proline contents (4.9-7.4 µmole/g) compared to control, supported by the upregulation of many proteins involved in several pathways including photosynthesis, oxidoreductase activity, response to stresses, translation, transporter activities as well asprotein and carbohydrate metabolic processes. In contrast, the distinctive pattern of protein downregulation involved in stress response, oxidoreductase activity, and carbohydrate metabolism was observed in susceptible plants. Thus, in this study, the specific proteins that increased in abundance under heat stress tolerance mechanism can be used as markers in future for producing the heat tolerant cotton genotypes without compromising the yield.
Project description:Allergen-bearing extracellular nanovesicles, termed “pollensomes”, are released by pollen during germination. These extracellular vesicles (EVs) may play an important role in pollen-pistil interaction during fertilization, stabilizing the secreted bioactive molecules and allowing long-distance signaling. However, the molecular composition and the biological role of these EVs are still unclear. The present study had two main aims: (I) to clarify whether pollen germination is needed to release pollensomes, or if they can be secreted also in high humidity conditions; and (II) to investigate the molecular features of pollensomes following the most recent guidelines for EVs isolation and identification. To do so, pollensomes were isolated from hydrated and germinated kiwi (Actinidia chinensis Planch.) pollen, and characterized using imaging techniques, immunoblotting, and proteomics. These analyses revealed that only germinated kiwi pollen released detectable concentrations of nanoparticles compatible with small EVs for shape and protein content. Moreover, a plant homolog of ALIX, which is a well-recognized and accepted marker of small EVs and exosomes in mammals, was found in pollensomes. The presence of this protein, along with other proteins involved in endocytosis, is consistent with the hypothesis that pollensomes could comprehend a prominent subpopulation of plant exosome-like vesicles.