Effects of Meloidogyne incognita on the fungal community in tobacco rhizosphere

Abstract

The often widespread and serious Root-Knot Nematode (RKN) disease is an important soil-borne disease affecting tobacco production. This study aimed to understand micro-ecological changes caused by RKN disease and interactions between disease and rhizosphere soil fungal communities. The 18S rRNA gene sequencing was used to study changes in rhizosphere fungal community of tobacco plants having RKN disease. In June 2018, a paired comparison was performed between rhizosphere fungal community structures of healthy tobacco plants and those with RKN disease in Yuxi and Jiuxiang, Yunnan Province, China. Compared with uninfested soil, the OTU abundance, Shannon, ACE and Chao1 indexes of infested soil in the two tobacco areas showed a decreasing trend. Principal Coordinate Analysis showed fungal communities of infested soil and uninfested soil in the two tobacco areas were clustered in different areas, and the community composition was significantly different. Moreover, the dominant fungi community and relative abundance are significantly different at phylum, genus and species levels. More beneficial fungi, such as Penicillium and Aspergillus, were found in soil samples of healthy plants, whereas more pathogenic fungi, such as Phoma and Alternaria, were found in soil samples of diseased plants. In conclusion, changes in fungal community structure and decreases in species diversity and richness were important characteristics of rhizosphere soils from diseased tobacco plants. Disequilibrium in the tobacco rhizosphere micro-ecosystem may allow the development of RKN disease and other more complex diseases.

Different Response Mechanisms of Rhizosphere Microbial Communities in Two Species of Amorphophallus to Pectobacterium carotovorum subsp. carotovorum Infection

“…Our results indicate that in infected A. konjac plants, the relative abundance of Fusarium in the rhizosphere was higher than that in healthy plants, but the abundance in infected A. muelleri was significantly lower than that in healthy plants. Penicillium can participate in the decomposition of organic matter, promote the cycles of C, N, P, and other elements, and can degrade a variety of environmentally harmful substances (Xiaolong et al, 2022). The relative abundance of Penicillium was lower in infected A. konjac than in healthy plants but higher in infected A. muelleri plants than in healthy plants.…”

“…Fungal diversity was analyzed using the universal primers TS1 F (5′-ACTTGGTCATTTAGAG-GAAGTAA-3′) and ITS2 R (5′-BGCTGCGTTCTTCATC-GATGC-3′). The polymerase chain reaction (PCR) amplification procedure was described by Xiaolong et al (2022) and Zheng et al (2022). The PCR product was recovered using a 2% agarose gel, further purified using the AxyPrep DNA Gel Extraction Kit (Axygen, Union City, CA, USA) according to the manufacturer's instructions, and sent to Shanghai Majorbio Bio-pharm Technology Co., Ltd. (Shanghai, China) for sequencing on the Illumina MiSeq PE300 platform (Illumina, San Diego, CA, USA).…”

“…The occurrence of soil-borne diseases is closely related to the imbalance of the soil microecosystem (Kim and Anderson, 2018;Raaijmakers et al, 2009;She et al, 2017), and soil physical and chemical properties, climatic conditions, geographical location, and rhizosphere microbial diversity all play important roles in the occurrence of soil-borne diseases (Ahmed et al, 2022a;Cai et al, 2021). Among them, rhizosphere soil microorganisms have attracted considerable attention in recent years as the most physiologically active part of the rhizosphere soil microecological environment (Xiaolong et al, 2022;Zheng et al, 2022). Mendes et al (2013) and Dong et al (2019) indicated that most disease resistance and developmental mechanisms in plants are directly related to rhizosphere microorganism diversity.…”

Meloidogyne enterolobii-induced Changes in Guava Root Exudates Are Associated With Root Rotting Caused by Neocosmospora falciformis

“…In our study, the enrichment of NP root exudates in amino acids, carbohydrates, and sucrose probably favored microorganisms capable of converting urea or other nitrogenous compounds into 1,5-dinitrobiuret. This hypothesis is plausible, since several plant-parasitic nematodes are known to cause changes in root exudates and shifts in the rhizosphere's microbial community (Wang and Bergeson, 1974;Wang et al, 1975;van Gundy et al, 1977;Yeates et al, 1998Yeates et al, , 1999Denton et al 1999;Tu et al, 2003;Dromph et al, 2006;Hasse et al, 2007;Wurst et al 2009;Tian et al, 2015;Lamelas et al, 2020;Xiaolong et al, 2022). Some soil bacteria use the enzyme biuret hydrolase to decompose biuret (Cameron et al, 2011;Aukema et al, 2020).…”

“…Parasitism by M. incognita led to an increase of sugars and electrolytes in tomato root exudates (Wang and Bergeson, 1974;Wang et al, 1975). Several other nematodes have also been found to cause "leaking" of carbon-and nitrogen-rich compounds, resulting in changes in the rhizosphere's microbial community (Yeates et al, 1998(Yeates et al, , 1999Denton et al 1999;Tu et al, 2003;Dromph et al, 2006;Hasse et al, 2007;Wurst et al 2009;Tian et al, 2015;Lamelas et al, 2020;Xiaolong et al, 2022). Khan (1993) and Evans and Haydock (1993) suggested that changes in root exudates could be involved in synergistic interactions involving nematodes and soilborne fungi.…”