Sources of resistance in Musa to Xanthomonas campestris pv. musacearum, the causal agent of banana xanthomonas wilt

G V Nakato,M Nyine,T A Coutinho,G Mahuku,R Swennen,E Were,J Doležel,P Christelová,B Uwimana

doi:10.1111/ppa.12945

Abstract

It is claimed that, with the exception of Musa balbisiana, all banana varieties are susceptible to bacterial wilt caused by Xanthomonas campestris pv. musacearum (Xcm). Despite being resistant to Xcm infection, M. balbisiana is not preferred for breeding because it belongs to the BB genome subgroup, while most edible bananas are of the A genome. To identify potential sources of resistance to Xcm, 72 banana accessions representing the Musa genetic diversity were evaluated in an outdoor confined potted trial. The midribs of the youngest leaf of 3‐month‐old banana plants were inoculated with 108 CFU mL−1 of Xcm isolate USY13P, and symptom development assessed weekly for 4 months. Results confirmed that M. balbisiana genotypes are indeed resistant to Xcm. Varieties within the Musa acuminata subsp. zebrina (AA) set were further identified as potentially useful sources of Xcm resistance. These findings reveal the potential to develop banana and plantain varieties with tolerance to Xcm.

Highlights

Bananas are an important staple and income-generating crop for many farmers in tropical and subtropical climates (Padam et al, 2014)
The lowest disease index (DI) value was reported for M. balbisiana while the highest was reported for M. acuminata subsp. malaccensis (Table 1)
Breeding for host plant resistance to pathogens is an important aspect for sustainable crop production

Summary

Introduction

Bananas are an important staple and income-generating crop for many farmers in tropical and subtropical climates (Padam et al, 2014). Bananas belong to the genus Musa, which together with Ensete and Musella, belong to the family Musaceae. The genus Musa was divided into the section Ingentimusa with chromosome number 2n = 14; Callimusa and Australimusa with chromosome number 2n = 20 (Musa beccarii, which is part of Callimusa section, has 18 chromosomes); and Eumusa and Rhodochlamys with chromosome number 2n = 22 (Christelova et al, 2011a). Research has shown that banana is highly vulnerable to diseases due to the genetic uniformity (Tripathi et al, 2008). Known as xanthomonas wilt, caused by Xanthomonas campestris pv. Musacearum (Xcm), is regarded as the most devastating disease of banana in East and Central Africa (Nakato et al, 2018) Known as xanthomonas wilt, caused by Xanthomonas campestris pv. musacearum (Xcm), is regarded as the most devastating disease of banana in East and Central Africa (Nakato et al, 2018)

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Conclusion