Ecology of endomycorrhizal association in black pepper (Piper nigrum L.), South India

Arbuscular mycorrhizal fungi (AMF) are crucial root symbionts that play a significant role in nutrient absorption, crop productivity, and soil health. However, it has become essential to understand the ideal environmental conditions that can maximize AMF benefits in crop yield and soil health as a valuable biofertilizer. Accordingly, a comprehensive ecological study of AMF in black pepper (Piper nigrum L.) fields was conducted. The study aimed to identify AMF diversity and population characteristics over a broad area of black pepper fields in Kerala, South India, and to analyse various factors influencing AMF symbiosis in crops. It also focused on identifying the agroclimatic, soil, and crop influencers that impact mycorrhizae in traditional crop fields. Altogether, nine genera and 29 AMF species are identified from the randomly sampled black pepper fields (of diverse varieties of the crop) that belong to two different soil orders and 13 different soil series in the region. Among them, three genera and 22 species were new reports from black pepper. Acaulospora laevis and Funneliformis badius were the most commonly found species. Seasonal analysis showed a significant increase in spore density during the monsoon season, while root colonization exhibited varying patterns. Correlational studies and principal component analysis enabled the identification of specific soil and plant factors individually and in combinations influencing mycorrhizal activities. Overall, the study underscores the significance of ecological research on AMF symbiosis in specific crops and specific soil systems.