Root-knot nematodes (Meloidogyne incognita) are a major threat to global agriculture, infecting a wide range of crops and causing extensive yield losses. These parasites induce the formation of galls—knot-like structures in plant roots that serve as feeding sites. While their economic impact is well-known, the precise molecular mechanisms behind gall formation and the plant’s response to nematode infection remain poorly understood. Previous research has focused on root-wide transcriptome analyses but lacked the resolution needed to detect the intricate cellular changes. This gap has driven the need for more detailed studies on the genetic reprogramming initiated by nematode invasion.
Published (DOI: /10.1093/hr/uhae206) on July 26, 2024, in Horticulture Research, a study led by researchers from the University of Tennessee, Knoxville, explores how M. incognita manipulates the transcriptome and spliceome of tomato roots. By examining gene expression and alternative splicing at two critical infection stages, the team reveals key molecular changes within the galls and surrounding tissues. These insights are crucial for understanding the parasitic strategy used by nematodes to hijack plant systems.
The study reveals that M. incognita causes extensive changes in the transcriptome of tomato roots, both locally within the galls and systemically in adjacent tissues. At the early infection stage (4 days post-inoculation), 63.5% of differentially expressed genes (DEGs) in the galls showed similar regulation in surrounding tissues, pointing to coordinated intercellular communication. Defense-related genes were downregulated, while those associated with cell cycle processes were upregulated, especially in fully developed galls (11 days post-inoculation). Additionally, the research identified 9,064 alternative splicing events across 2,898 genes, with suppressed intron retention and exon skipping, particularly in neighboring cells. Transgenic hairy root experiments validated that certain splicing variants significantly influence gall formation and nematode egg production, underscoring the critical role of alternative splicing in plant-nematode interactions.
“This study provides unprecedented insights into how nematodes reprogram plant gene expression and splicing to establish feeding sites,” said Dr. Tarek Hewezi, the study's corresponding author. “Understanding these mechanisms could lead to novel approaches in developing nematode-resistant crops through targeted genetic interventions.”
The findings hold significant promise for agricultural advancements, especially in breeding crops resistant to root-knot nematodes. By identifying the key genes and splicing events involved in gall formation, researchers can work towards engineering plants with enhanced resistance, reducing reliance on chemical nematicides. Moreover, the study's discoveries regarding systemic gene regulation could offer broader strategies for managing plant-parasite interactions, benefiting other crops affected by similar pests. This research represents a critical step toward more sustainable agricultural practices, especially as nematode threats continue to rise globally.
###
References
DOI
10.1093/hr/uhae206
Original Source URL
https://doi.org/10.1093/hr/uhae206
Funding information
This work was supported by funds from The University of Tennessee, Institute of Agriculture and the California food producers.
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.