Improved tolerance of recombinant Chlamydomonas rainhardtii with putative 2-amino-3-carboxymuconate-6-semialdehyde decarboxylase from Pyropia yezoensis to nitrogen starvation

2021 ◽  
Vol 60 (1) ◽  
pp. 63-69
Author(s):  
Seo-jeong Park ◽  
Joon Woo Ahn ◽  
Jong-il Choi
Keyword(s):  
Nitrogen Starvation ◽  
Pyropia Yezoensis

scholarly journals Enhanced Autophagic Activity Improved the Root Growth and Nitrogen Utilization Ability of Apple Plants under Nitrogen Starvation

2021 ◽  
Vol 22 (15) ◽  
pp. 8085
Author(s):  
Liuqing Huo ◽  
Zijian Guo ◽  
Qi Wang ◽  
Li Cheng ◽  
Xin Jia ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Root Growth ◽  
Nitrogen Starvation ◽  
Degradation Pathway ◽  
Physiological Status ◽  
Hydroponic System ◽  
Nitrogen Levels ◽  
Nitrogen Concentrations ◽  
Nitrogen Nutrients ◽  
Autophagic Activity

Autophagy is a conserved degradation pathway for recycling damaged organelles and aberrant proteins, and its important roles in plant adaptation to nutrient starvation have been generally reported. Previous studies found that overexpression of autophagy-related (ATG) gene MdATG10 enhanced the autophagic activity in apple roots and promoted their salt tolerance. The MdATG10 expression was induced by nitrogen depletion condition in both leaves and roots of apple plants. This study aimed to investigate the differences in the growth and physiological status between wild type and MdATG10-overexpressing apple plants in response to nitrogen starvation. A hydroponic system containing different nitrogen levels was used. The study found that the reduction in growth and nitrogen concentrations in different tissues caused by nitrogen starvation was relieved by MdATG10 overexpression. Further studies demonstrated the increased root growth and the higher nitrogen absorption and assimilation ability of transgenic plants. These characteristics contributed to the increased uptake of limited nitrogen nutrients by transgenic plants, which also reduced the starvation damage to the chloroplasts. Therefore, the MdATG10-overexpressing apple plants could maintain higher photosynthetic ability and possess better growth under nitrogen starvation stress.

scholarly journals Correction to: Cell wall and organelle modifications during nitrogen starvation in Nannochloropsis oceanica F&M-M24

2021 ◽  
Author(s):  
Bianca Roncaglia ◽  
Alessio Papini ◽  
Graziella Chini Zittelli ◽  
Liliana Rodolfi ◽  
Mario R. Tredici
Keyword(s):  
Cell Wall ◽  
Nitrogen Starvation ◽  
Nannochloropsis Oceanica

scholarly journals Cell wall and organelle modifications during nitrogen starvation in Nannochloropsis oceanica F&M-M24

2021 ◽  
Author(s):  
Roncaglia Bianca ◽  
Papini Alessio ◽  
Chini Zittelli Graziella ◽  
Rodolfi Liliana ◽  
Mario R. Tredici
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Lipid Droplets ◽  
Nitrogen Starvation ◽  
Photosynthetic Apparatus ◽  
Ultrastructural Changes ◽  
Total Biomass ◽  
Nannochloropsis Oceanica ◽  
Final Phase ◽  
Cell Functions

AbstractNannochloropsis oceanica F&M-M24 is able to increase its lipid content during nitrogen starvation to more than 50% of the total biomass. We investigated the ultrastructural changes and the variation in the content of main cell biomolecules that accompany the final phase of lipid accumulation. Nitrogen starvation induced a first phase of thylakoid disruption followed by chloroplast macroautophagy and formation of lipid droplets. During this phase, the total amount of proteins decreased by one-third, while carbohydrates decreased by 12–13%, suggesting that lipid droplets were formed by remodelling of chloroplast membranes and synthesis of fatty acids from carbohydrates and amino acids. The change in mitochondrial ultrastructure suggests also that these organelles were involved in the process. The cell wall increased its thickness and changed its structure during starvation, indicating that a disruption process could be partially affected by the increase in wall thickness for biomolecules recovery from starved cells. The wall thickness in strain F&M-M24 was much lower than that observed in other strains of N. oceanica, showing a possible advantage of this strain for the purpose of biomolecules extraction. The modifications following starvation were interpreted as a response to reduction of availability of a key nutrient (nitrogen). The result is a prolonged survival in quiescence until an improvement of the environmental conditions (nutrient availability) allows the rebuilding of the photosynthetic apparatus and the full recovery of cell functions.

scholarly journals Recovery of Unicellular Cyanobacteria from Nitrogen Chlorosis: A Model for Resuscitation of Dormant Bacteria

2021 ◽  
pp. 1-10
Author(s):  
Niels Neumann ◽  
Sofia Doello ◽  
Karl Forchhammer
Keyword(s):  
Nitrogen Starvation ◽  
Oxygenic Photosynthesis ◽  
Cellular Activity ◽  
Input Output ◽  
Minimal Set ◽  
Operation System ◽  
Developmental Transitions ◽  
The Awakening ◽  
Output System ◽  
Basic Input

Nitrogen starvation induces developmental transitions in cyanobacteria. Whereas complex multicellular cyanobacteria of the order Nostocales can differentiate specialized cells that perform nitrogen fixation in the presence of oxygenic photosynthesis, non-diazotrophic unicellular strains, such as <i>Synechococcus elongatus</i> or <i>Synechocystis</i> PCC 6803, undergo a transition into a dormant non-growing state. Due to loss of pigments during this acclimation, the process is termed chlorosis. Cells maintain viability in this state for prolonged periods of time, until they encounter a useable nitrogen source, which triggers a highly coordinated awakening process, termed resuscitation. The minimal set of cellular activity that maintains the viability of cells during chlorosis and ensures efficient resuscitation represents the organism’s equivalent of the BIOS, the basic input/output system of a computer, that helps “booting” the operation system after switching on. This review summarizes the recent research in the resuscitation of cyanobacteria, representing a powerful model for the awakening of dormant bacteria.

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