Transcriptome analysis reveals molecular mechanisms underlying chloroplast biogenesis in albino Agave angustifolia plantlets.

Albino plants display partial or complete loss of photosynthetic pigments and defective thylakoid membrane development, consequently impairing plastid function and development. These distinctive attributes render albino plants excellent models for investigating chloroplast biogenesis. Despite their potential, limited exploration has been conducted regarding the molecular alterations underlying these phenotypes, extending beyond photosynthetic metabolism. In this study, we present a novel de novo transcriptome assembly of an albino somaclonal variant of Agave angustifolia Haw., which spontaneously emerged during the micropropagation of green plantlets. Additionally, RT-qPCR analysis was employed to validate the expression of genes associated with chloroplast biogenesis, and plastome copy numbers were quantified. This research aims to gain insight into the molecular disruptions affecting chloroplast development and ascertain whether the expression of critical genes involved in plastid development and differentiation is compromised in albino tissues of A. angustifolia. Our transcriptomic findings suggest that albino Agave plastids exhibit high proliferation, activation of the protein import machinery, altered transcription directed by PEP and NEP, dysregulation of plastome expression genes, reduced expression of photosynthesis-associated nuclear genes, disruption in the tetrapyrrole and carotenoid biosynthesis pathway, alterations in the plastid ribosome, and an increased number of plastome copies, among other alterations.

Detection of Histone Modifications Associated with miRNAs.

The posttranslational modifications of histones and miRNAs are key epigenetic mechanisms participating in the development, growth, and reproduction of plants. Recently, coordination between these two mechanisms has been demonstrated; each mechanism can be controlled by the other for the regulation of several biological processes. For example, the acetylation of histone H3, a key modification for chromatin remodeling and gene activation, has been linked to the actions of miRNA. In this work, we describe a method for the isolation and immunodetection of two posttranslational modifications in the residues of lysine 9 and 27 of H3, which have been associated with long miRNAs in plants.

Localization of miRNAs by In Situ Hybridization in Plants Using Conventional Oligonucleotide Probes.

Among the epigenetic mechanisms studied with a greater interest in the last decade are the microRNAs (miRNAs). These small noncoding RNA sequences that are approximately 17-22 nucleotides in length play an essential role in many biological processes of various organisms, including plants. The analysis of spatiotemporal expression of miRNAs provides a better understanding of the role of these small molecules in plant development, cell differentiation, and other processes; but such analysis is also an important method for the validation of biological functions. In this work, we describe the optimization of an efficient protocol for the spatiotemporal analysis of miRNA by in situ hybridization using different plant tissues embedded in paraffin. Instead of LNA-modified probes that are typically used for this work, we use conventional oligonucleotide probes that yield a high specificity and clean distribution of miRNAs.

An efficient immunodetection method for histone modifications in plants.

BACKGROUND: Epigenetic mechanisms can be highly dynamic, but the cross-talk among them and with the genome is still poorly understood. Many of these mechanisms work at different places in the cell and at different times of organism development. Covalent histone modifications are one of the most complex and studied epigenetic mechanisms involved in cellular reprogramming and development in plants. Therefore, the knowledge of the spatial distribution of histone methylation in different tissues is important to understand their behavior on specific cells. RESULTS: Based on the importance of epigenetic marks for biology, we present a simplified, inexpensive and efficient protocol for in situ immunolocalization on different tissues such as flowers, buds, callus, somatic embryo and meristematic tissue from several plants of agronomical and biological importance. Here, we fully describe all the steps to perform the localization of histone modifications. Using this method, we were able to visualize the distribution of H3K4me3 and H3K9me2 without loss of histological integrity of tissues from several plants, including Agave tequilana, Capsicum chinense, Coffea canephora and Cedrela odorata, as well as Arabidopsis thaliana. CONCLUSIONS: There are many protocols to study chromatin modifications; however, most of them are expensive, difficult and require sophisticated equipment. Here, we provide an efficient protocol for in situ localization of histone methylation that dispenses with the use of expensive and sensitive enzymes. The present method can be used to investigate the cellular distribution and localization of a wide array of proteins, which could help to clarify the biological role that they play at specific times and places in different tissues of various plant species.