Researchers find key elements affecting osmotic stress in plants

New Delhi: Extreme variations in environmental conditions, such as temperature and precipitation, cause several abiotic stresses on the plants. Researchers from the National Institute of Plant Genome Research, New Delhi, and the Kurukshetra University, Kurukshetra, have identified a potential candidate to grow plants that can withstand multiple abiotic stresses.

Plants are constantly exposed to extreme weather conditions and thus undergo abiotic stresses due to drought, heat, cold, and salinity. While growing under such conditions, plants tend to minimize their growth as most of their resources and energy are utilized to combat stress. This adversely affects their productivity, affecting food security.

“It is important to improve plants that can flourish well under multiple stresses, as stresses usually occur in combinations. One of the major consequences of these abiotic stresses, especially due to drought and salinity, resulting in changes in the osmotic pressure and causing hyperosmotic stress in plants,” says Dr Manoj Prasad, the lead researcher.

It is crucial to have a proper understanding of perception and the following stress responses for improving plants so that they can maintain the osmotic status of the cell even under stressful conditions.

“Although the molecular mechanisms that occur in plants after the initiation of hyperosmotic stress has been studied in detail, the understanding of how plants sense this stress was limited,” explains Dr Prasad.

A recent study by Wang et al. has revealed the role of a plant protein named SEUSS during hyperosmotic stress perception in plants. When extracellular fluid osmolarity exceeds, that of the intracellular fluid, cells, and tissues experience hyperosmotic stress.

“The earliest implication of hyperosmotic stress in plants is a decrease in the cell volume, which results in molecular crowding within the plant cell. Upon increase in crowding, SEU protein forms condensate within the cell’s nucleus. After that, it induces the expression of stress-tolerance genes; thus, imparting tolerance to plants against hyperosmotic stress,” the researchers mention.

Working with Arabidopsis mutant plants, which are widely used for basic research in genetics and molecular biology, the researchers found that the gene SEU exhibited enhanced susceptibility to osmotic stress treatments and lesser survival rates when compared to the wild type plants indicating SEU as a positive regulator of tolerance against osmotic stress. 

It was also seen that SEU has dual roles in regulating the plant’s growth and development under normal conditions and in regulating stress-responsive genes under stress conditions. 

“The phylogenetic analysis has revealed that the homologs of SEU are also present in some economically important plant species such as wheat, maize and several Brassica family members. This suggests that SEU-mediated tolerance to hyperosmotic stress might be conserved in the plant kingdom,” informs Dr Prasad. 

Since hyperosmotic stress results from different types of abiotic stresses, the transgenic plants expressing SEU might provide tolerance to multiple stresses. It is vital to improve plants that can flourish well under multiple stresses, as stresses usually occur in combinations. 

“SEU could be a potential candidate to be used in genetic engineering to develop newer varieties of stress-resilient crops belonging to different families,” the researchers submit.

The study also opens new doors in the field of plant biology that will enhance the current knowledge of mechanisms and provide with better candidates for crop improvement. 

The team comprises, Besides Dr Manoj Prasad, the team comprises Shambhavi Sharma and Ashish Prasad. The article has been published in Trends in Plant Science. (India Science Wire)