Microbiome transplant can effectively manage root-knot nematode infectivity in tomato

Abstract

A critical factor in alleviating nematode menace in horticultural crops is discerning the nature of microbial communities associated with roots and rhizosphere. Root-knot nematodes (Meloidogyne spp.) are one of the major constraints for obtaining high yields of vegetable crops. Root-knot nematode-infected and uninfected plants occur in agricultural fields. Most biocontrol strategies used for nematode management focus on introducing a single bioagent. Recently, microbiome transplant has been found effective in curing human diseases and is also used to cure animals. Here we evaluated the role played by the microbial communities in managing M. incognita infection on tomatoes grown in protected cultivation by transplanting the microbial slurry extracted from the rhizosphere soil of the healthy plants and those infected with the root-knot nematode. The relative abundance of Gram-negative bacteria (11.11 % and 16.08 %) and anaerobes (39.58 % and 16.59 %) phospholipid fatty acids (PLFA) was significantly higher in healthy roots and rhizosphere soil. In contrast, Gram-positive bacteria (21.52 % and 37.61 %) were comparatively higher in nematode-infected roots and rhizosphere soil. Nematode penetration and reproduction indices were significantly reduced (34–43 %) by inoculating the healthy plant's unfiltered microbial slurry. However, inoculation with unfiltered microbial slurry from the rhizosphere soil of infected plants increased (8–26 %) nematode penetration and reproduction. Plant growth and fruit yield (13.1 %) of tomatoes were positively influenced by unfiltered microbial slurry from the rhizosphere soil of healthy plants. The significant role of the healthy microbiome transplant in reducing nematode invasion and reproduction and increasing the crop yield of tomatoes grown in protected cultivation suggests that microbial transplants could be an approach to managing plant nematodes.