How do plants naturally respond to environmental stresses like drought, and what roles do proline and betaine play in this response?

Plants under stress, such as drought, produce compatible solutes like proline, betaine, sugars and polyols to combat osmotic stresses. Proline and betaine, in particular, are effective in osmotic adjustment, helping maintain cellular functions and scavenge reactive oxygen species (ROS), providing an additional layer of defense. They improve salt tolerance by boosting antioxidant defense systems.

What are Glutathione S-transferases (GSTs) and glyoxalase I (Gly I), and why are they important for lentil resilience under drought conditions?

Glutathione S-transferases (GSTs) and glyoxalase I (Gly I) are essential enzymes that aid in stress resistance through detoxification. Supplementing lentils with proline and betaine can enhance GST and Gly I activity, boosting plant resilience under drought conditions. This is particularly important for drought-sensitive crops like lentils.

What were the key findings regarding proline and betaine's effects on lentil seedlings subjected to drought stress in the study?

Researchers found that drought stress increases glutathione (GSH), glutathione disulfide (GSSG), and hydrogen peroxide (H2O2) levels while affecting GST and Gly I activities. However, treating lentil seedlings with 15 mM of betaine or proline during drought stress resulted in increased GSH content, sustained high GST and Gly I activities, and decreased GSSG content and H2O2 levels. Proline showed a slightly better protective effect than betaine.

How do proline and betaine contribute to enhancing drought tolerance in lentils, and what are the implications for sustainable agriculture?

Proline and betaine protect plants from oxidative stress by reducing H2O2 levels and boosting antioxidant defenses. Proline, in particular, was more effective in certain drought conditions, suggesting its potential for enhancing drought tolerance in lentils. These findings support the integration of proline and betaine treatments into agricultural practices to improve crop resilience and ensure food security in drought-prone areas. More research can be done on different application methods.

What are Reactive Oxygen Species (ROS), and how do proline and betaine protect plants from their damaging effects during drought stress?

Reactive Oxygen Species (ROS) like O2-, O2, OH, and H2O2 can cause cellular damage, disrupt metabolism, and accelerate aging in plants, ultimately leading to plant death. Proline and betaine can scavenge ROS, providing an additional layer of defense against the damaging effects of oxidative stress. Understanding how to manage and mitigate ROS damage is vital for improving crop yields and resilience in agriculture.

Resilient lentil plant protected by proline and betaine in a drought-stricken field.

Beat Drought Stress: How Proline and Betaine Can Save Your Lentils

Theo Raines in Science & Nature August 2025 • 4 min read.

"Discover the power of proline and betaine in boosting lentil resilience under drought conditions. A practical guide for gardeners and farmers."

Plants face numerous environmental challenges, from scorching droughts to chilling cold and high salinity. These stresses often lead to oxidative stress, where reactive oxygen species (ROS) form and wreak havoc on plant cells. These ROS, including free radicals like O2-, O2, OH, and non-radicals like H2O2, can cause cellular damage, disrupt metabolism, and accelerate aging, ultimately leading to plant death. Drought, in particular, is a major limiting factor in crop productivity, impacting nearly all plant functions.

To combat these osmotic stresses, many plants naturally produce compatible solutes such as proline, betaine, sugars, and polyols. Proline and betaine are among the most effective, aiding in osmotic adjustment and helping plants maintain cellular functions under stress. Beyond their osmoprotective roles, proline and betaine can also scavenge ROS, providing an additional layer of defense. They've been shown to improve salt tolerance by boosting antioxidant defense systems.

Glutathione S-transferases (GSTs) and glyoxalase I (Gly I) are vital enzymes that play a key role in stress resistance through detoxification. Lentils, as an important but drought-sensitive pulse crop, can benefit significantly from understanding how these enzymes are regulated. This article explores the roles of GST and Gly-I in lentils under drought conditions, supplemented with proline and betaine, to reveal how these compounds enhance plant resilience.

Proline and Betaine: The Dynamic Duo Against Drought

Resilient lentil plant protected by proline and betaine in a drought-stricken field.

In a study focusing on lentil seedlings, researchers investigated how proline (Pro) and betaine (Bet) could modulate glutathione S-transferase (GST) and glyoxalase I (Gly I) activity when plants were subjected to drought stress. The study began by screening seven lentil varieties to identify which had the highest inherent GST and Gly I activity. BARI mosur 2 emerged as the top performer and was selected for further detailed analysis.

The research revealed that drought stress led to a significant increase in glutathione (GSH), glutathione disulfide (GSSG), and hydrogen peroxide (H2O2) levels, along with changes in GST and Gly I activities. Interestingly, GST activity initially decreased in the early stages of drought before increasing later on. However, when the lentil seedlings were treated with 15 mM of either betaine or proline during drought stress, the results were striking:

GSH content increased, helping maintain a healthy cellular environment.
GST and Gly I activities were sustained at high levels, promoting detoxification.
GSSG content and H2O2 levels decreased, reducing oxidative damage.
These effects were more pronounced with proline than with betaine, indicating superior protection.

These findings highlight the critical roles of proline and betaine in upregulating the lentil's homeostasis under stress. By maintaining high GST and Gly I activities while reducing harmful ROS, these compounds help protect cells from the adverse effects of drought. Proline, in particular, showed a slightly better protective effect than betaine, suggesting it might be more effective in certain drought conditions. Overall, both compounds provide a protective mechanism against drought-induced oxidative stress by modulating antioxidant defense systems and reducing H2O2 levels.

Boosting Lentil Resilience for a Sustainable Future

Proline and betaine offer a promising strategy for enhancing drought tolerance in lentils. By reducing H2O2 levels and boosting antioxidant defenses, these compounds protect plants from oxidative stress, ensuring better survival and productivity during drought conditions. These findings support integrating proline and betaine treatments into agricultural practices to enhance crop resilience and ensure food security in drought-prone regions.