Researchers at the CAS Center for Excellence in Molecular Plant Sciences, led by Alberto Macho, have recently used CRISPR-Cas9-mediated genome editing to generate tomato plants with enhanced resistance to bacterial wilt disease. The resulting article, entitled “Reduced content of gamma-aminobutyric acid enhances resistance to bacterial wilt disease in tomato” was published online in Plant Biotechnology Journal on December 9th, 2024.

Bacteria within the Ralstonia solanacearum species complex cause devastating diseases in numerous crops, including tomato, potato, banana, eggplant, and pepper, among others, causing important losses in food production and industrial supply. Despite extensive efforts to enhance plant tolerance to disease caused by Ralstonia, efficient and sustainable approaches are still missing.

The group of Alberto Macho found before that Ralstonia promotes the production of gamma-aminobutyric acid (GABA) in plant cells; GABA can be used as nutrient by Ralstonia to sustain the massive bacterial replication during plant colonization (https://doi.org/10.1016/j.chom.2020.07.003). After that finding, this new study employed CRISPR-Cas9-mediated genome editing to mutate SlGAD2, which encodes the major glutamate decarboxylase responsible for GABA production in tomato, a major crop affected by Ralstonia. The resulting Slgad2 mutant plants show reduced GABA content, and enhanced tolerance to bacterial wilt disease upon Ralstonia inoculation. Slgad2 mutant plants did not show altered susceptibility to other tested biotic and abiotic stresses, and even showed enhanced tolerance to drought stress. Interestingly, Slgad2 mutant plants showed altered microbiome composition in roots and soil.

This study therefore reveals a strategy to enhance plant resistance to Ralstonia by the manipulation of plant metabolism leading to an impairment of bacterial fitness. This approach could be particularly efficient in combination with other strategies based on the manipulation of the plant immune system, paving the way to a sustainable solution to Ralstonia in agricultural systems.

The first author of this study is the PhD student Achen Zhao, and the corresponding author is Alberto P. Macho.

Zhao, A., Li, Q., Meng, P., Liu, P., Wu, S., Lang, Z., Song, Y. and Macho, A.P. (2024), Reduced content of gamma-aminobutyric acid enhances resistance to bacterial wilt disease in tomato. Plant Biotechnology Journal

Fig1. Slgad2 mutant plants show enhanced tolerance to Ralstonia and drought stress. 

Link to the article: https://doi.org/10.1111/pbi.14539

Contact: 

Dr. Alberto P. Macho, Principal Investigator

Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences

Email: alberto.macho@cemps.ac.cn