Journal of Plant Biochemistry & Physiology
Open Access
ISSN: 2329-9029
+44 1478 350008
ISSN: 2329-9029
+44 1478 350008
Elena Ermilova, Valentina Filina and Zhanneta Zalutskaya
Saint-Petersburg State University, Russia
Scientific Tracks Abstracts: J Plant Biochem Physiol
Statement of the Problem: Sulfur (S) is an essential element among catalysts and intermediates of primary metabolism. S can be limiting in the environment and strongly influence ecosystem composition. During S deprivation, metabolism of Chlamydomonas cells is refocused on both scavenging the nutrient and remodeling primary metabolism. Although some signaling proteins and regulators of S-specific responses have been identified, the mechanisms triggering the coordinated responses in different cellular compartments are not absolutely clear. Previously, we have reported that nitric oxide is generated upon S deprivation. Purpose: The purpose of this study is to elucidate the role of nitric oxide (NO) and truncated hemoglobin 1 (THB1) in modulating early responses to S deficiency in different compartment of Chlamydomonas cells. Methodology & Theoretical Orientation: To examine transcriptional regulation of a subset of S limitation-responsive genes and role of NO and THB1 in signaling pathway associated with S deprivation, real-time PCR analysis and artificial microRNA method were employed. A comparative analysis of gene expression and NO generation in wild type, nitrate reductase mutants and THB1 knock-down transformant was utilized to understand the functional consequences of NO production. Findings: In S-free medium, Chlamydomonas cells produced NO apparently via nitrate reductase. We found that in S-limited cells NO is important to upregulate some S deficiency-inducible genes (THB1) and repress the others (FDX5, ARS1, ARS2, SULTR2, SLT1 and SLT2). THB1 is involved in this NO-dependent process. Conclusion & Significance: Together, the results demonstrated that THB1 has implicated to function as NO regulator (via conversion of NO into nitrate) and thereby initiate NO-based signaling cascades in S-depleted cells. Moreover, NO generation may be regarded as an early trigger, which contributes to Chlamydomonas adaptability to S starvation. Recent Publications 1. Aksoy M, Pootakham W, Pollock S V, Moseley J L, Gonzalez-Ballester D and Grossman A R (2013) Tiered regulation of sulfur deprivation responses in Chlamydomonas reinhardtii and identification of an associated regulatory factor. Plant Physiology 162:195-211. 2. Minaeva E, Zalutskaya Z, Filina V and Ermilova E (2017) Truncated hemoglobin 1 is a new player in Chlamydomonas reinhardtii acclimation to sulfur deprivation. PLOS One 12(10): e0186851. 3. Zalutskaya Z, Minaeva E, Filina V, Ostroukhova M and Ermilova E (2018) Regulation of sulfur deprivation-induced expression of the ferredoxin-encoding FDX5 gene Chlamydomonas reinhardtii in aerobic conditions. Plant Physiology and Biochemistry 123:18-23. 4. Zalutskaya Z, Filina V, Ostroukhova M and Ermilova E (2018) Regulation of alternative oxidase 1 in Chlamydomonas reinhardtii during sulfur starvation. European Journal of Protistology 63:26�??33. 5. Zhang Z, Shrager J, Jain M, Chang C W, Vallon O and Grossman A R (2004) Insights into the survival of Chlamydomonas reinhardtii during sulfur starvation based on microarray analysis of gene expression. Eukaryotic Cell 3(5):1331-1348.
Elena Ermilova is a full Professor and Head of Laboratory at Saint-Petersburg State University. She has her expertise in nitrogen metabolism and PII signal transduction in green and red algae, and land plants. She has extensively studied the unicellular green algae Chlamydomonas reinhardtii and identified new functions associated with stress acclimation. She also studies the regulation of sulfur metabolism.
E-mail: e.ermilova@spbu.ru