Enhancing Phytoremediation Efficacy in Plants Cultivated in Heavy Metal-Contaminated Soil Under Drought Stress: Understanding Plant Responses and Genetic Engineering Strategies

The contamination of soil by heavy metals poses a significant challenge, impacting various living organisms. Phytoremediation has emerged as an environmentally friendly approach for reclaiming soil polluted by heavy metals. The efficacy of phytoremediation depends on the ability of plants to thrive in soil contaminated with heavy metals. The anticipated changes in climate, particularly the predicted increase in the intensity and frequency of drought, are expected to influence the efficiency of phytoremediation by affecting plant performance. Numerous studies have explored the responses of plants to either drought or heavy metal stress individually. Yet, the impact of interaction of these two stresses on plants remains incompletely understood. The complexity of predicting plants' reactions to combined stresses underscores the importance of understanding their responses both separately and in combination. This comprehension is crucial for the development of plants capable of withstanding both heavy metals and drought stress. Use of such plants can serve as a pivotal strategy to augment the effectiveness of phytoremediation, particularly in the context of evolving climatic conditions. The progress in modern biotechnological tools has enabled the rapid development of engineered crop plants with enhanced traits through the transfer of desirable genes. Genetic engineering has yielded various transgenic plants, incorporating genes associated with stress responses, showcasing notable tolerance to both drought and heavy metals. This review compiles up-to-date research on how plants respond to drought, heavy metal toxicity, and their combination. It explores the potential of genetically engineered plants to address these challenges, discusses recent advancements, and highlights current research gaps in the field.