Concerto on Chromatin: Interplays of Different Epigenetic Mechanisms in Plant Development and Environmental Adaptation

Epigenetic mechanisms such as DNA methylation, histone post-translational modifications, chromatin remodeling, and noncoding RNAs, play important roles in regulating plant gene expression, which is involved in various biological processes including plant development and stress responses. Increasing evidence reveals that these different epigenetic mechanisms are highly interconnected, thereby contributing to the complexity of transcriptional reprogramming in plant development processes and responses to environmental stresses. Here, we provide an overview of recent advances in understanding the epigenetic regulation of plant gene expression and highlight the crosstalk among different epigenetic mechanisms in making plant developmental and stress-responsive decisions. Structural, physical, transcriptional and metabolic bases for these epigenetic interplays are discussed.

Review: Pengaruh Tanaman Obat Yang Beraktivitas Hipertensi Terhadap Ekspresi Gen Reseptor ACE-1 dan ACE 2

Hipertensi adalah salah satu penyakit dengan angka kesakitan dan kematian yang terus meningkat, termasuk di Indonesia. Dalam mengatasi hipertensi obat-obatan seperti ACE inhibitor berperan dalam menurunkan tekanan darah diastol dan sistol, namun tanaman obat seperti ekstrak buah hawthorn, buah zaitun (Olea europaea L.), Hibiscus Sabdariffa, Allium Sativum dan Allium Cepa juga memiliki efek sebagai antihipertensi dengan harga yang relatif murah, mudah didapat, efek samping yang lebih rendah dibandingkan dengan obat sintesis atau kimia lainnya. Review jurnal ini ditujukan untuk mengetahui berbagai tanaman obat yang memiliki aktivitas hipertensi dan berpengaruh terhadap ekspresi gen reseptor hipertensi ACE1 dan ACE2. Penelusuran referensi dilakukan melalui database PubMed, Science Direct, dan Google Scholar, dengan kata kunci “Medicinal Plant”, “Gene expression”, “Angiotensin Converting Enzyme 1”, “Angiotensin Converting Enzyme 2”, dan“Antihypertension”. Tanaman obat digunakan sebagai terapi alternatif penurun tekanan darah tinggi dan merupakan salah satu cara pengobatan non farmakologis hipertensi. Hal ini menunjukkan bahwa tanaman obat memiliki pengaruh dalam menurunkan tekanan darah tinggi karena kandungan senyawa yang ada dalam masing-masing tanaman sehingga mampu menghambat reseptor hipertensi ACE1 dan ACE2 dengan berbagai metode ekspresi gen. Banyak tanaman obat yang telah diteliti memiliki aktivitas sebagai antihipertensi. Dari 14 tanaman obat dengan aktivitas sebagai anti hipertensi, sebanyak 90% tanaman berpengaruh terhadap ekspresi gen Angiotensin Converting Enzyme 1 (ACE 1), dan sebanyak 10% tanaman memiliki pengaruh terhadap Angiotensin Converting Enzyme 2 (ACE 2). Tanaman obat yang telah ditemukan dan memiliki aktivitas terhadap ekspresi gen Angiotensin Converting Enzyme 1 (ACE 1) paling banyak merupakan tanaman obat dengan family Poaceae, Oleaceae, dan Zingiberaceae.

Analysis of Gene Expression Changes in Plants Grown in Salty Soil in Response to Inoculation with Halophilic Bacteria

Soil salinity is an increasing problem facing agriculture in many parts of the world. Climate change and irrigation practices have led to decreased yields of some farmland due to increased salt levels in the soil. Plants that have tolerance to salt are thus needed to feed the world’s population. One approach addressing this problem is genetic engineering to introduce genes encoding salinity, but this approach has limitations. Another fairly new approach is the isolation and development of salt-tolerant (halophilic) plant-associated bacteria. These bacteria are used as inoculants to stimulate plant growth. Several reports are now available, demonstrating how the use of halophilic inoculants enhance plant growth in salty soil. However, the mechanisms for this growth stimulation are as yet not clear. Enhanced growth in response to bacterial inoculation is expected to be associated with changes in plant gene expression. In this review, we discuss the current literature and approaches for analyzing altered plant gene expression in response to inoculation with halophilic bacteria. Additionally, challenges and limitations to current approaches are analyzed. A further understanding of the molecular mechanisms involved in enhanced plant growth when inoculated with salt-tolerant bacteria will significantly improve agriculture in areas affected by saline soils.

Lasting consequences of psyllid (Bactericera cockerelli L.) infestation on tomato plant gene expression

Background. The tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S. and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’. Currently, the only effective strategies for controlling the diseases associated with this pathogen involve regular pesticide applications to manage psyllid population density. However, such practices are unsustainable and will eventually lead to widespread pesticide resistance in psyllids. Therefore, new control strategies must be developed to increase host-plant resistance to insect vectors. For example, expression of constitutive and inducible plant defenses can be improved through selection. Currently, it is still unknown whether psyllid infestation has any lasting consequences on tomato plant defense or tomato plant gene expression in general. Results. In order to characterize the genes putatively involved in tomato defense against psyllid infestation, RNA was extracted from psyllid-infested and uninfested tomato leaves (Moneymaker) three weeks post-infestation. Transcriptome analysis identified 362 differentially expressed genes. These differentially expressed genes were primarily associated with defense responses to abiotic/biotic stress, transcription/translation, cellular signaling/transport, and photosynthesis. These gene expression changes suggested that tomato plants underwent a reduction in plant growth/health in exchange for improved defense against stress that was observable three weeks after psyllid infestation. Consistent with these observations, tomato plant growth experiments determined that the plants were shorter three weeks after psyllid infestation. Furthermore, psyllid nymphs had lower survival rates on tomato plants that had been previously psyllid infested. Conclusion. These results suggested that psyllid infestation has lasting consequences for tomato gene expression, defense, and growth.

Assessment of Local and Systemic Changes in Plant Gene Expression and Aphid Responses during Potato Interactions with Arbuscular Mycorrhizal Fungi and Potato Aphids

This research examined aphid and plant responses to distinct levels (none, low, and high) of arbuscular mycorrhizal (AM) fungal root colonization by studying the association between potato aphids (Macrosiphum euphorbiae), potatoes (Solanum tuberosum), and AM fungi (Rhizophagus intraradices). It extends knowledge on gene expression changes, assessed by RT–qPCR, of ten defense-related genes at two time-points post-herbivory (24 h and 10 days), focusing on aphid-infested local leaves, non-infested systemic leaves, and roots. The results showed that aphid fitness was not altered by AM symbiosis. At 24 h, ETHYLENE RECEPTOR 1 gene expression was repressed in roots of aphid-infested non-mycorrhizal plants and aphid-infested plants with a high level of AM fungal root colonization, but not on aphid-infested plants with a low level of AM fungal root colonization. At 10 days, ALLENE OXIDE CYCLASE and POTATO TYPE I PROTEASE INHIBITOR were upregulated exclusively in local leaves of aphid-infested plants with a low level of AM fungal root colonization. In addition, local and systemic changes in plant gene expression appeared to be regulated exclusively by AM status and aphid herbivory. In summary, the gene expression data provide insights on mycorrhizal potato responses to aphid herbivory and serve as a starting point for future studies using this system.