Bản tin ngày thứ hai 29-8-2022
Bản tin ngày thứ hai 29-8-2022
Researchers Prove Multigene Bioengineering of Photosynthesis Increases Soybean Yields
For the first time, researchers from the research project Realizing Increased Photosynthetic Efficiency (RIPE) have proven in field trials that the multigene bioengineering of photosynthesis increases the yield of soybeans. After more than a decade, the collaborative team led by the University of Illinois and scientists at Lancaster University has transgenically altered soybean plants to increase the efficiency of photosynthesis, resulting in greater yields without loss of quality.
The researchers at RIPE have been working to improve the 100+ step process of photosynthesis for over a decade. In this first-of-its-kind work, the RIPE researchers improved the VPZ construct of the soybean plant to improve photosynthesis and then conducted field trials to see if yield would be improved as a result. The PVZ construct has three genes that code for proteins of the xanthophyll cycle, a pigment cycle that helps in the photoprotection of the plants. In full sunlight, the xanthophyll cycle is activated in the leaves to protect them from damage and to dissipate excess energy. When the leaves are shaded, this photoprotection switches off so the leaves can continue the photosynthesis process. It takes several minutes for the plant to switch off the protective mechanism, which costs the plant valuable time that could have been used for photosynthesis.
The research team soon discovered that the overexpression of the three genes from the VPZ construct accelerates photosynthesis, so every time a leaf transitions from light to shade, the photoprotection switches off faster. Leaves gain extra minutes of photosynthesis which, when added up throughout the entire growing season, increases the total photosynthetic rate. This RIPE research has shown that despite achieving more than a 20 percent increase in yield, seed quality was not impacted.
For more details, read the news releases from RIPE and the University of Lancaster.
Experts Discover and Start to Crack the Epigenetic Code
Pennsylvania State University molecular plant geneticists conducted the first-ever investigation on epigenetic reprogramming code and the reprogramming effects, which are vital for breeding crops that can withstand extreme weather caused by climate change.
When plants sense environmental triggers such as drought or extreme weather, they naturally reprogram their genetic material for survival. To breed more resilient crops, the researchers stress that the chemical code that turns on those changes can be deciphered and duplicated. Reprogramming can result in the expressing and overexpressing of some genes, while others are silenced.
In a previous study, the researchers found that manipulating the gene MSH1 enabled them to control a broad array of plant-resiliency networks. When MSH1 was silenced, the plant was induced to detect stress and adjust its growth, change root configuration, delay flowering time, etc.
In their latest study, they manipulated MSH1 to trigger at least four distinct nongenetic states to impact plant stress response and growth vigor. Upon comparing the data from these states, they were able to pinpoint gene targets of epigenetic change within the genome where they could locate and decode data vital for plant growth.
Find out more from Penn State.

An alanine to valine mutation of glutamyl-tRNA reductase enhances 5-aminolevulinic acid synthesis in rice

Theoretical and Applied Genetics August 2022; vol. 135: 2817–2831
Figure: 5-aminolevulinic acid in rice

Key message

An alanine to valine mutation of glutamyl-tRNA reductase’s 510th amino acid improves 5-aminolevulinic acid synthesis in rice.


5-aminolevulinic acid (ALA) is the common precursor of all tetrapyrroles and plays an important role in plant growth regulation. ALA is synthesized from glutamate, catalyzed by glutamyl-tRNA synthetase (GluRS), glutamyl-tRNA reductase (GluTR), and glutamate-1-semialdehyde aminotransferase (GSAT). In Arabidopsis, ALA synthesis is the rate-limiting step in tetrapyrrole production via GluTR post-translational regulations. In rice, mutations of GluTR and GSAT homologs are known to confer chlorophyll deficiency phenotypes; however, the enzymatic activity of rice GluRS, GluTR, and GSAT and the post-translational regulation of rice GluTR have not been investigated experimentally. We have demonstrated that a suppressor mutation in rice partially reverts the xantha trait. In the present study, we first determine that the suppressor mutation results from a G → A nucleotide substitution of OsGluTR (and an A → V change of its 510th amino acid). Protein homology modeling and molecular docking show that the OsGluTRA510V mutation increases its substrate binding. We then demonstrate that the OsGluTRA510V mutation increases ALA synthesis in Escherichia coli without affecting its interaction with OsFLU. We further explore homologous genes encoding GluTR across 193 plant species and find that the amino acid (A) is 100% conserved at the position, suggesting its critical role in GluTR. Thus, we demonstrate that the gain-of-function OsGluTRA510V mutation underlies suppression of the xantha trait, experimentally proves the enzymatic activity of rice GluRS, GluTR, and GSAT in ALA synthesis, and uncovers conservation of the alanine corresponding to the 510th amino acid of OsGluTR across plant species.
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