The Role of Grafting in the Resistance of Tomato to Viruses

Abstract

Grafting is routinely implemented in modern agriculture to manage soilborne pathogens such as fungi, oomycetes, bacteria, and viruses of solanaceous crops in a sustainable and environmentally friendly approach. Some rootstock/scion combinations use specific genetic resistance mechanisms to impact also some foliar and airborne pathogens, including arthropod or contact-transmitted viruses. These approaches resulted in poor efficiency in the management of plant viruses with superior virulence such as the strains of tomato spotted wilt virus breaking the Sw5 resistance, strains of cucumber mosaic virus carrying necrogenic satellite RNAs, and necrogenic strains of potato virus Y. Three different studies from our lab documented that suitable levels of resistance/tolerance can be obtained by grafting commercial tomato varieties onto the tomato ecotype Manduria (Ma) rescued in the framework of an Apulian (southern Italy) regional program on biodiversity. Here we review the main approaches, methods, and results of the three case studies and propose some mechanisms leading to the tolerance/resistance observed in susceptible tomato varieties grafted onto Ma as well as in self-grafted plants. The proposed mechanisms include virus movement in plants, RNA interference, genes involved in graft wound response, resilience, and tolerance to virus infection.

Comparative Transcriptome Analysis in Homo- and Hetero-Grafted Cucurbit Seedlings

“…AP2/ERF is the second largest family of TFs in the plants (Nakano et al, 2006). Quite similar to our findings, Spano et al (2020) reported upregulated AP2/ERF and xyloglucan hydrolase in the self-grafted tomato plants. The abovementioned results of the transcriptional analysis of the grafted watermelon seedlings might provide an understanding of the interactions between the ERF genes and ethylene-dependent mechanisms during the healing process of watermelon grafted on interspecific squash.…”

Rootstock-Mediated Genetic Variance in Cadmium Uptake by Juvenile Cacao (Theobroma cacao L.) Genotypes, and Its Effect on Growth and Physiology

“…Grafting is an ancient technique used to propagate plants vegetatively by combining desirable agronomic traits of the rootstock with those of the scion. It has been used in several plant species targeting a wide spectrum of traits, for instance, resistance to pathogens ( Boughalleb et al, 2007 ; Rivard and Louws, 2008 ; Spanò et al, 2020 ); tolerance to abiotic stress factors, such as water deficit, ( Liu et al, 2016 ), heavy metals ( Rouphael et al, 2008 ), and salinity ( Yanyan et al, 2018 ; Suárez-Hernández et al, 2019 ); improved fruit quality ( Davis and Perkins-Veazie, 2005 ); higher yields ( Cardinal et al, 2007 ); and architectural changes in scions ( Eltayb et al, 2014 ). However, breeding rootstocks for tree crops is slower than scion breeding for the same species.…”

Monitoring of Salinity, Temperature, and Drought Stress in Grafted Watermelon Seedlings Using Chlorophyll Fluorescence

“…As the use of grafted seedlings has increased in response to various stressors, the domestic seedling market is developing into specialized seedling production facilities with expertise in facility gardening, smart farms, and grafting machines ( Kwack et al, 2021 ). The development of the seedling industry reflects various cultivation management objectives, such as of soil-borne diseases in the growing environment, climate change, and increases in fruit production ( Rahmatian et al, 2014 ; Spanò et al, 2020 ). Furthermore, seedling industries have been used small container (plug tray having different sizes) for the efficient production of seedlings as it occupies small space and cost effective.…”