ABSTRACT
Influence of Pleurotusspent mushroom substrate on root-knot nematode infection and soil microbial dynamics

Jenjira Chobyen1, Pornsuk Chaisuk1, Yupa Chromkaew2, 3, Nakarin Jeeatid2, Krit Sujarittam4, Terd Disayathanoowat3, 4, 6, Milan Chameera Samarakoon1*, and Nilita Mukjang1, 3, 4*
 
Spent mushroom substrate (SMS) offers a sustainable approach to managing plant-parasitic nematodes, particularly root-knot nematodes (RKNs; Meloidogyne spp.), which cause severe root damage and yield loss in crops including Capsicum spp. This research investigated the effect of Pleurotus spp. The SMS on chili root-knot disease and the dynamic of the soil bacterial community of six treatments which are sterile soil with Meloidogyne spp. inoculation (SN), sterile soil control (SC), live soil with nematode inoculation (LN), live soil control (LC), live soil mixed with 15% SMS and nematode inoculation (MN), and live soil mixed with 15% SMS control (MC). Before treatment application, the antagonistic activity of Pleurotus spp. was evaluated, revealing RKN-inhibitory effects, with about 40% immobilization of second-stage juveniles (J2) by mycelium after 24 h and up to 67.5% paralysis caused by the fungal culture filtrate. Pleurotus SMS-amended soil treatments reduced root gall formation by approximately 85%-90%. Regarding changes in the bacterial community, it was found that bacterial communities profiling revealed that the application of SMS had no negative impact on soil bacterial diversity. Bacterial community composition differed markedly between sterilized and live soils, while SMS-amended soil treatments closely resembled live soils, with higher relative abundances of Actinobacteriota (41%-48%) and detectable Acidobacteriota (3%-4%), groups associated with soil health and plant growth promotion. In contrast, sterilized soil treatments were dominated by Bacilli (49%-56%). These findings indicated that SMS play a crucial role in promoting plant growth and assisting in RKN control without affecting the indigenous soil bacterial community.
Key words: Biological control, Capsicum, Meloidogyne, microbiome, next-generation sequencing.
1Chiang Mai University, Faculty of Agriculture, Department of Entomology and Plant Pathology, Chiang Mai 50200, Thailand.
2Chiang Mai University, Faculty of Agriculture, Department of Plant and Soil Sciences, Chiang Mai 50200, Thailand.
3Chiang Mai University, Faculty of Science, Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai 50200, Thailand.
4Chiang Mai University, Faculty of Engineering, Department of Mechanical Engineering, Chiang Mai 50200, Thailand.
5Chiang Mai University, Faculty of Science, Department of Biology, Chiang Mai 50200, Thailand.
6Chiang Mai University, Research Center of Deep Technology in Beekeeping and Bee Products for Sustainable Development Goals (SMART BEE SDGs), Chiang Mai 50200, Thailand.
*Corresponding authors (nilita.m@cmu.ac.th; milanchameerasamar.s@cmu.ac.th)