Strategies for Balancing Growth and Defence Against Biotic Stress in Legumes

Legumes are a rich source of protein and oil for human consumption and livestock feed, but pathogens and insect pests threaten their quality and yields. Balancing growth and defence against pests and pathogens is critical for plants to maintain high productivity. Insufficient defence responses result in severe yield losses, but excessive constitutive or inducible defence responses inhibit plant growth and development, also decreasing yields. Here, we review the complex relationship between defence responses and growth of leguminous plants, focusing on important legumes such as cultivated soybean (Glycine max) and barrel clover (Medicago truncatula). In addition, we examine the interaction between symbiotic nitrogen fixation and defences in legumes and describe current plant breeding strategies to optimise the balance between plant defence and growth. This review summarises the balance between growth and defence in leguminous plants, providing a theoretical basis for breeding strategies to develop stable varieties that balance growth and resistance to improve yield.