Abiotic Stress Responses in Forage Crops and Grasses: The Role of Secondary Metabolites and Biotechnological Interventions

RADHA SIVARAJAN SAJEEVAN^1*Udit Nandan Mishra²JYOTI CHAUHAN³Rajesh Singhal⁴Hirdayesh Anuragi⁵Prajjal Dey⁶Dalpat Lal⁷Saurabh Pandey⁸NK Gupta⁹JAJATI KESHARI NAYAK¹⁰Aparna Tripathi¹¹Mahendra Singh⁴Monika Yadav⁴

• ¹Swedish University of Agricultural Sciences, Uppsala, Sweden
• ²Sri Sri University, Cuttack, Odisha, India
• ³Noida International University, Noida, Uttar Pradesh, India
• ⁴Indian Grassland and Fodder Research Institute (ICAR), Jhānsi, Uttar Pradesh, India
• ⁵Central Agroforestry Research Institute (CAFRI), Jhansi, Uttar Pradesh, India
• ⁶Sher-e-Kashmir University of Agricultural Sciences and Technology, Srinagar, Jammu and Kashmir, India
• ⁷Agriculture University, Jodhpur, Jodhpur, Rajasthan, India
• ⁸Guru Nanak Dev University, Amritsar, Punjab, India
• ⁹Sri Karan Narendra Agriculture University, Jobner, Rajasthan, India
• ¹⁰Department of Biological Sciences, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
• ¹¹Department of Agriculture, Jagan Nath University, Jaipur, India

Forage crops and grasses play crucial roles in global agriculture, serving as primary sources of livestock feed. However, various abiotic stresses, such as drought, salinity, extreme temperatures, and heavy metals, frequently challenge their productivity, quality, and resilience.In response to these stressors, plants activate defense mechanisms, including the production of secondary metabolites (SMs). This review exclusively examines the diverse impacts of abiotic stresses on forage crops and grasses' physiological processes, growth, development, yield, and quality. We delve into the synthesis, types, and role of SMs in mediating stress responses, conferring adaptation and resilience to adverse environmental conditions in forage crops and grasses. Furthermore, we examine the regulatory mechanisms governing secondary metabolite (SM) production in response to abiotic stress. This is crucial for developing strategies to enhance stress tolerance and improve forage productivity and quality. Finally, the review discusses emerging biotechnological interventions for improving forage crop performance under abiotic stress. Different omics technologies, gene editing, and pathway engineering offer promising avenues that enable precise manipulation of key regulatory genes and metabolic pathways, with enhanced SMs biosynthesis to engineer resilient crops tailored to specific environmental challenges. This review obtains a strong correlation of SMs with improving fodder and forage crop tolerance to varying degree of stresses by regulating antioxidant activity, osmotic homeostasis, and membrane stability, ultimately enhancing plant viability, productivity, and quality under diverse stress conditions. Further, unraveling the intricate interplay between abiotic stresses, SMs, and biotechnological interventions is pivotal for advancing forage crop resilience and ensuring global food security amidst changing environmental conditions.