ARS | Publication request: Defense mechanisms involved in disease resistance of grafted vegetables

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 14, 2011
Publication Date: February 1, 2012
Citation: Guan, W., Zhao, X., Hassell, R., Thies, J.A. 2012. Defense mechanisms involved in disease resistance of grafted vegetables. HortScience. 47(2):164-170.

Interpretive Summary: Soil-borne diseases and nematodes cause significant losses to vegetable production in the United States and throughout the world. Until recently, methyl bromide was used as the primary method for controlling soil-borne diseases, nematodes, and other pests in vegetable crop production. However, methyl bromide was banned from production in the United States in 2005 under the Montreal Protocol. Thus, new technologies for controlling diseases and nematode are urgently needed. Grafting vegetable crops onto resistant rootstocks has proven to be an effective strategy to control a variety of soil-borne diseases and root-knot nematodes in the cucurbit (melon, squash, and cucumber family) and in the tomato, pepper, and eggplant family. Grafting also improves nutrient uptake in plants and may be involved in defense of plant diseases. This paper discusses the use of grafting for disease control in vegetable crops and ways that grafting may increase resistance to diseases and nematodes in vegetable crops. Grafting technology is considered an important and innovative practice of integrated pest management and a promising alternative for soil fumigants such as methyl bromide in vegetable production.

Technical Abstract: Vegetable grafting with resistant rootstocks is an effective strategy to control a variety of soil-borne diseases and root-knot nematodes in the Cucurbitaceae and Solanaceae. In addition, improved resistance to some foliar diseases and viruses has also been reported in grafted plants. Hence, grafting technology is considered an important and innovative practice of integrated pest management and a promising alternative for soil fumigants in vegetable production. Inherent resistance within rootstocks and improved plant nutrient uptake are generally suggested as the main reasons for improved disease performance in grafted vegetables. However, increasing evidence indicated that systemic defense mechanisms may also play an important role in plant defense as a result of grafting. This review analyzes current literature on the utilization of grafting techniques for disease management in vegetable crops, discusses potential mechanisms associated with grafting-conferred plant defense, and identifies needs for future research to promote more effective and efficient use of grafting technology to support sustainable vegetable production.