Interspecific Root Interactions Enhance Disease Resistance of Peanut by Intercropped Millet

Intercropping is commonly practiced worldwide because of its yield advantages, resource use efficiency and disease resistance. However, the knowledge of disease resistance via belowground root interactions in cereal/legume intercropping systems remains quite limited. Pot experiments were conducted to quantify the effect of root interactions by intercropped millet on peanut disease under conditions of full, partial and no root interactions based on TMT (tandem mass tag) labelling. Disease incidence and disease index were assessed at flowering stage and antioxidant enzymes in peanut leaves were analyzed. The results showed that root rot disease and leaf spot disease of peanut were alleviated by intercropped millet through root interspecific interactions from below-ground in the cereal/legume intercropping. The contents of chlorophyll and the nutrient contents of peanut were increased in peanut by root interactions, which indicated that the growth of peanut were improved. The number of bacteria, fungi and actinomycetes was increased by 57.3, 133 and 49.7% in peanut rhizosphere of full root interactions compared to the treatment without root interactions, respectively. There were 10 differentially expressed protein spots in intercropped peanut roots, which were involved in response to disease. The results showed that stress-response proteins displayed a differential expression levels in intercropped peanut, the disease resistance was improved via up-regulated proteins including class III acidic endochitinase, and down-regulated pectinesterase, and lipoxygenase etc. The results indicated that the intercropping root intermingling could contribute to the resistance to disease of intercropped species via improvement of nutrient acquisition and differential expressed stress-response proteins. The present study provides a new insight into plant disease control in cereal and legume intercropping by root interspecific interactions. (C) 2020 Friends Science Publishers