The effect of intercropping leguminous green manure on theanine accumulation in the tea plant: A metagenomic analysis

Abstract

Intercropping is a widely recognised technique that contributes to agricultural sustainability. While intercropping leguminous green manure offers advantages for soil health and tea plants growth, the impact on the accumulation of theanine and soil nitrogen cycle are largely unknown. The levels of theanine, epigallocatechin gallate and soluble sugar in tea leaves increased by 52.87% and 40.98%, 22.80% and 6.17%, 22.22% and 29.04% in intercropping with soybean–Chinese milk vetch rotation and soybean alone, respectively. Additionally, intercropping significantly increased soil amino acidnitrogen content, enhanced extracellular enzyme activities, particularly β‐glucosidase and N‐acetyl‐glucosaminidase, as well as soil multifunctionality. Metagenomics analysis revealed that intercropping positively influenced the relative abundances of several potentially beneficial microorganisms, including Burkholderia, Mycolicibacterium and Paraburkholderia. Intercropping resulted in lower expression levels of nitrification genes, reducing soil mineral nitrogen loss and N2O emissions. The expression of nrfA/H significantly increased in intercropping with soybean–Chinese milk vetch rotation. Structural equation model analysis demonstrated that the accumulation of theanine in tea leaves was directly influenced by the number of intercropping leguminous green manure species, soil ammonium nitrogen and amino acid nitrogen. In summary, the intercropping strategy, particularly intercropping with soybean–Chinese milk vetch rotation, could be a novel way for theanine accumulation.

The Effects of Soybean–Tea Intercropping on the Photosynthesis Activity of Tea Seedlings Based on Canopy Spectral, Transcriptome and Metabolome Analyses

“…This altered microclimate satisfies the tea plant's preference for shade, diffuse light, moisture, warmth and acidic soil, helping to improve tea yield and quality. So far, studies on intercropping soybean in tea plantations have mainly focused on the improvement in tea quality from the perspective of rhizosphere soil nutrients and microbial communities, leaf nutritional physiology, functional genes and metabolite changes [20][21][22]. The soybean-tea intercropping system improved nutrient absorption and tea quality by regulating the abundance of beneficial microorganisms in soil [16].…”