Identification and pathogenicity of Botryosphaeriaceae species associated with root and stem rot of sweet potato in Brazil

Abstract

The sweet potato (Ipomoea batatas) is characterized by the production of tuberous roots rich in starch and is one of the most produced and consumed vegetables in Brazil. Botryosphaeriaceae, among other fungi, are known to cause root and stem rot of sweet potato. However, no representative and accurate study has been performed for the correct identification of these fungal species in sweet potato in Brazil. Therefore, this study aimed to identify the Botryosphaeriaceae species associated with root and stem rot of sweet potato and confirm their pathogenicity. Tuberous roots and stems of sweet potato with rot symptoms were collected in production fields and markets and used for fungal isolations. The identification of fungi was based on the morphology of reproductive structures and phylogenetic analyses of the gene regions ITS, tef1‐α, and rpb2. The following species were identified: Lasiodiplodia theobromae, L. hormozganensis, Macrophomina phaseolina, M. euphorbiicola, M. pseudophaseolina, and Neoscytalidium dimidiatum. For the pathogenicity test, one representative isolate for each species was inoculated in healthy tuberous roots and in 30‐day‐old healthy seedlings. Black and necrotic lesions on tuberous roots and stems were observed in all replications and resulted in the death of some seedlings. This is the first report of L. hormozganensis, M. pseudophaseolina, and M. euphorbiicola, as causal agents of the stem and root rot of sweet potato and N. dimidiatum as a causal agent of stem rot worldwide.

Pest categorisation of Neoscytalidium dimidiatum

“…(Suwannarach et al., 2018 ; Chang et al., 2020 ), Citrus spp. (Polizzi et al., 2009 ; Adesemoye et al., 2014 ; Al‐Sadi et al., 2014 ; Mayorquin et al., 2016 ; Alananbeh et al., 2020 ; Espargham et al., 2020 ), Cucumis melo (Mirtalebi et al., 2019), Diospyros kaki (Ören et al., 2020a ), Ficus benjamina (Al‐Bedak et al., 2018 ), F. carica (Ray et al., 2010 ; Xu et al., 2015 ; Gusella et al., 2021 ; Güney et al., 2022a ), Ipomoea batatas (de Mello et al., 2019 , 2021 ), Juglans regia (Chen et al., 2013 ; Derviş et al., 2019b ), Lavender spp. (Güney et al., 2021 ), Malus spp.…”

“…F. foetida ) Asparagaceae Green aloe Johnston ( 1960 ) Gladiolus sp. Iridaceae Gladiolus French ( 1989 ) Grevillea agrifolia Proteaceae Blue grevillea Pavlic et al ( 2008 ) Hevea brasiliensis Euphorbiaceae Rubber tree Jayasinghe and Silva ( 1994 ) Hymenocallis littoralis Amarillidaceae White spider lily Nurul Nadiah et al ( 2017 ) Ipomoea batatas Convovulaceae Sweet potato Johnston ( 1960 ); de Mello et al ( 2019 , 2021 ) Jatropha curcas Euphorbiaceae Physic nut Machado et al ( 2012 ); Coutinho et al ( 2018 ) Juglans californica Juglandaceae California black walnut French ( 1987 ) Juglans regia Juglandaceae Walnut …”

“…F. nitida )MoraceaeBenjamin figAl‐Bedak et al (2018) F. carica MoraceaeFigGeorghiou and Papadopoulos (1957); French (1987, 1989); Ray et al (2010); Xu et al (2015); Gusella et al (2021; Gűney et al., 2022a) Furcraea gigantea (syn. F. foetida )AsparagaceaeGreen aloeJohnston (1960) Gladiolus sp.IridaceaeGladiolusFrench (1989) Grevillea agrifolia ProteaceaeBlue grevilleaPavlic et al (2008) Hevea brasiliensis EuphorbiaceaeRubber treeJayasinghe and Silva (1994) Hymenocallis littoralis AmarillidaceaeWhite spider lilyNurul Nadiah et al (2017) Ipomoea batatas ConvovulaceaeSweet potatoJohnston (1960); de Mello et al (2019, 2021) Jatropha curcas EuphorbiaceaePhysic nutMachado et al (2012); Coutinho et al (2018) Juglans californica JuglandaceaeCalifornia black walnutFrench (1987) Juglans regia JuglandaceaeWalnutSommer (1955); Farr et al (2005); Chen et al (2013); Derviş et al (2019b) Lavandula sp.LamiaceaeLavenderGüney et al (2021) Magnolia grandiflora MagnoliaceaeBull bayJamali and Banihashemi (2010) Malus domestica RosaceaeAppleMathur (1979); Ören et al (2022a) Mangifera indica AnacardiaceaeMangoMendes et a...…”

“…(Suwannarach et al, 2018;Chang et al, 2020), Citrus spp. (Polizzi et al, 2009;Adesemoye et al, 2014;Al-Sadi et al, 2014;Mayorquin et al, 2016;Alananbeh et al, 2020;Espargham et al, 2020), Cucumis melo (Mirtalebi et al, 2019), Diospyros kaki ( € Oren et al, 2020a), Ficus benjamina (Al-Bedak et al, 2018), F. carica (Ray et al, 2010;Xu et al, 2015;Gusella et al, 2021;G € uney et al, 2022a), Ipomoea batatas (de Mello et al, 2019Mello et al, , 2021, Juglans regia (Chen et al, 2013;Dervis ß et al, 2019b) Oren et al, 2021;Sha et al, 2022), Mangifera indica (Ray et al, 2010;Sakalidis et al, 2011;Ismail et al, 2013;Coutinho et al, 2018), Melissa officinalis ( € Ozer et al, 2022), Morus spp. (Oksal, 2022) (Hashemi and Mohammadi, 2016), Prunus spp.…”

Species diversity of fusarioid genera associated with sweet potato in Brazil, including the description of a new species

“…batatas , Rhizopus sp., Ceratocystis fimbriata and Diaporthe destruens (formerly Plenodomus destruens ; syn. Phomopsis destruens ) (Pio‐Ribeiro et al., 2016); root and stem rot have been reported caused by Macrophomina , Lasiodiplodia and Neoscytalidium (Mello et al., 2021).…”