Induced resistance to Fusarium wilt of banana caused by Tropical Race 4 in Cavendish cv Grand Naine bananas after challenging with avirulent Fusarium spp.

Abstract

In the last century, Fusarium wilt of banana (FWB) destroyed the banana cultivar Gros Michel. The Cavendish cultivars saved the global banana industry, and currently they dominate global production (~50%) and the export trade (~95%). However, a new strain called Tropical Race 4 (TR4) surfaced in the late 1960’s, spread globally and greatly damages Cavendish plantations as well as manifold local varieties that are primarily grown by small holders. Presently, there is no commercially available replacement for Cavendish and hence control strategies must be developed and implemented to manage FWB. Here, we studied whether it is possible to induce resistance to TR4 by pre-inoculations with different Fusarium spp. Only pre-treatments with an avirulent Race 1 strain significantly reduced disease development of TR4 in a Cavendish genotype and this effect was stable at various nutritional and pH conditions. We then used transcriptome analysis to study the molecular basis of this response. Several genes involved in plant defence responses were up-regulated during the initial stages of individual infections with TR4 and Race 1, as well as in combined treatments. In addition, a number of genes in the ethylene and jasmonate response pathways as well as several gibberellin synthesis associated genes were induced. We observed upregulation of RGA2 like genes in all treatments. Hence, RGA2 could be a key factor involved in both R1 and TR4 resistance. The data support the hypothesis that activating resistance to Race 1 in Cavendish bananas affects TR4 development and provide a first insight of gene expression during the interaction between various Fusarium spp. and banana.

The Advance of Fusarium Wilt Tropical Race 4 in Musaceae of Latin America and the Caribbean: Current Situation

“…Measures such as quarantine, the destruction of infected plants, and the use of clean planting material are implemented by the governments of LAC member countries, but it is hard to control the spread of the fungus. Research on developing resistant varieties [ 21 ] and improving soil management practices is ongoing [ 22 , 66 , 67 ], but it is uncertain if this will be enough to mitigate the impact of TR4 on the banana industry in the region.…”

“…To address the threat of TR4, measures such as quarantine, the destruction of infected plants, and the use of clean planting material were implemented by the governments of Latin American countries. Additionally, research to develop resistant varieties [ 21 ] and improve soil management practices is also ongoing [ 22 ]. Undoubtedly, this disease constitutes a real and particular threat to the livelihoods of small- and medium-sized banana producers in LAC, who mostly lack the economic means to develop measures against yield loss along with the increase in yield production costs [ 23 , 24 , 25 ].…”

Identification of a Major QTL-Controlling Resistance to the Subtropical Race 4 of Fusarium oxysporum f. sp. cubense in Musa acuminata ssp. malaccensis

“…malaccensis that lack the TIR motif but has either a CC or no obvious motif at the amino terminus [ 59 , 60 ]. RGA2, which is a CC-NBS-LRR protein, similar to I2 and Fom-2 [ 61 , 62 ], appears to be important in mediating Foc -R1 and Foc -TR4 resistance [ 63 , 64 ]. Furthermore, we have the non-expressor of pathogenesis-related genes 1 (NPR1), which has significant roles in establishing systemic acquired resistance (SAR) and induced systemic resistance (ISR) [ 65 ].…”

Morphological Characterization and Fusarium Wilt Resistance of Triploid Banana Mutant Line (Musa acuminata Cola)

“…Based on supporting data showed that RGA2 could be a key factor involved in both R1 and TR4 resistance, whereaas TR4 development depend on activating resistance to Race 1. (García-Bastidas et al, 2022).…”