Interactions Between Phenolic Acids and Microorganisms in Rhizospheric Soil From Continuous Cropping of Panax notoginseng

Abstract

Large-scale intensive cultivation has made continuous cropping soil sickness more serious for Panax notoginseng in Yunnan. Autotoxic substances can promote the occurrence of continuous cropping soil sickness. Phenolic acids exert a strong autotoxic effect on P. notoginseng. Based on UPLC-MS/MS, the levels of six phenolic acids with the strongest autotoxicity of P. notoginseng rhizospheric soil were tested. Based on Illumina MiSeq high-throughput sequencing technology, the variation in the microbial diversity in the rhizospheric soil was used as an index to explore the interactions between phenolic acids and the soil microorganisms of the P. notoginseng rhizosphere. (1) Continuous P. notoginseng cropping significantly changed the microbial community structure. Continuous cropping increased bacterial Chao1 index and Shannon index and decreased fungal Shannon index. After P. notoginseng disease, bacterial Shannon index reduced and fungal Chao1 index decreased. (2) Phenolic acid significantly changed the bacterial community structure. VA significantly reduced the bacterial Shannon index. Exogenous p-HA, FA, SA, and VA significantly increased the fungal Chao1 index and p-HA showed the most significant effect. Para-HA affected bacterial specificity, and VA affected fungal specificity. (3) VA was positively correlated with most fungi and bacteria. Para-HA was positively correlated with Lelliottia and Flavobacterium. Para-HA was also positively correlated with plant pathogens (Fusarium and Ilyonectria). Para-HA and VA were able to promote the growth of primary pathogenic bacteria. Thus, p-HA and VA are the main phenolic acid-autotoxin substances in P. notoginseng under continuous cropping. (4) A correlation analysis of soil environmental factors associated with fungal and bacterial communities showed that AK, TN, OM, and HN were most strongly correlated with soil microorganisms. (5) The microorganisms in the rhizosphere of 3-year-old soil planted with P. notoginseng exhibited obvious effects on the degradation of the four phenolic acids. The effect of soil microorganisms on phenolic acids was first-order kinetic degradation with a high degradation rate and a half-life of less than 4.5 h. The results showed that phenolic acids could promote the growth of pathogenic bacteria. And the interaction between rhizospheric soil microorganisms and phenolic acids was the main cause of the disturbance of P. notoginseng rhizosphere microflora.

Effects of Organic Acid Root Exudates of Malus hupehensis Rehd. Derived from Soil and Root Leaching Liquor from Orchards with Apple Replant Disease

“…Toxins produced by apple roots include rhizomatites, rhizotin, light cinnamic acid, and light benzoic acid, which are associated with apple reimplantation disorders [ 12 ]. The effects of phenolic acids on plant growth mainly include the inhibition of seed germination, seedling root growth, seedling ion absorption, the activity of protective enzymes, hormone metabolism, the destruction of the structure of root cell membranes, and interference with DNA replication and RNA transcription, and other physiological and biochemical processes [ 13 , 14 ].…”

Vanillin, a Newly Discovered Autotoxic Substance in Long-Term Potato Continuous Cropping Soil, Inhibits Plant Growth by Decreasing the Root Auxin Content and Reducing Adventitious Root Numbers

“…Moreover, different rates of decomposition of phenolic acids have been observed in soil . The soil pH, temperature, and soil microorganisms were the main factors that affect the rate of degradation. , In continuous cropping, autotoxicity is primarily caused by the prolonged accumulation of autotoxic substances in the soil. Therefore, the occurrence of root secretions at a specific time does not necessarily imply the presence of an accumulated autotoxic substance in the soil.…”

“…According to the research, , aboveground leaching and stubble decomposition also affect the type and content of autotoxic substances. Moreover, different rates of decomposition of phenolic acids have been observed in soil . The soil pH, temperature, and soil microorganisms were the main factors that affect the rate of degradation. , In continuous cropping, autotoxicity is primarily caused by the prolonged accumulation of autotoxic substances in the soil.…”

“…16 Autotoxicity is one of the main factors causing a potato continuous cropping obstacle and is an abiotic stress, in which damage to plant roots by autotoxic substances eventually leads to plant growth inhibition. 17,18 Autotoxic substances can enter soil via three pathways: (1) leaching from the aboveground parts of the plant, (2) root secretions, and (3) stubble decomposition. 19 With an increase in continuous cropping years, toxin accumulation will also continue to increase.…”

Continuous planting Eucalyptus plantations in subtropical China: Soil phenolic acid accumulation and adsorption physiognomies

“…Most phenolic acids in soil normally promote the growth of their source plants by allelopathic inhibition of other plants (Lockwood et al, 2013). On the other hand, many studies have suggested that the accumulation of phenolic acids in soil is one of the important factors that hinder continuous mono-cropping (Qu and Wang, 2008;Bao et al, 2022), directly or indirectly alter the soil's microbial population, encourages soil sickness (Wu and Lin, 2020) and excessive concentrations of phenolic acids can inhibit the growth of plants (Kato-Noguchi and Kurniadie, 2021).…”