First Report of Botryosphaeria dothidea, Diplodia seriata, and Neofusicoccum luteum Associated with Canker and Dieback of Grapevines in Tunisia

Abstract

In 2011, common symptoms of grapevine dieback were frequently observed in 2- to 5-year-old table grape (Vitis vinifera L.) cvs. in four vineyards located in northern Tunisia. The symptoms included dead spur and cordons, shoot dieback, and sunken necrotic bark lesions, which progressed into the trunk resulting in the death of large sections of the vine. Longitudinal and transversal sections of cordons and spurs from symptomatic vines revealed brown wedge-shaped cankers of hard consistency. Twelve symptomatic samples from spur and cordons were collected, surface disinfected by dipping into 5% (v/v) sodium hypochlorite for 2 min, and small pieces from the edge of necrotic and healthy tissue were removed and plated onto potato dextrose agar (PDA) at 25°C in the dark. Based on colony and conidia morphological characteristics, isolates were divided in three species, named Diplodia seriata, Botryosphaeria dothidea, and Neofusicoccum luteum. D. seriata colonies were gray-brown with dense aerial mycelium producing brown cylindric to ellipsoid conidia rounded at both ends and averaged 22.4 × 11.7 μm (n = 50). B. dothidea colonies were initially white with abundant aerial mycelium, gradually becoming dark green olivaceous. Conidia were fusiform to fusiform elliptical with a subobtuse apex and averaged 24.8 × 4.7 μm (n = 50). N. luteum colonies were initially pale to colorless, gradually darkening with age and becoming gray to dark gray producing a yellow pigment that diffuses into the agar. Conidia were hyaline, thin-walled, aseptate, fusiform to fusiform elliptical, and averaged 19.8 × 5.5 μm (n = 50). Identity of the different taxa was confirmed by sequence analyses of the internal transcribed spacer (ITS1-5.8S-ITS2) region of the rDNA and part of the elongation factor 1-alpha (EF1-α) gene. BLAST analysis of sequences indicated that six isolates were identified as D. seriata (GenBank: AY259094, AY343353), one isolate as B. dothidea (AY236949, AY786319) and one isolate as N. luteum (AY259091, AY573217). Sequences were deposited in GenBank under accessions from KC178817 to KC178824 and from KF546829 to KF546836 for ITS region and EF1-α gene, respectively. A pathogenicity test was conducted on detached green shoots cv. Italia for the eight Botryosphaeriaceae isolates. Shoots were inoculated by placing a colonized agar plug (5 mm diameter) from the margin of a 7-day-old colony on fresh wound sites made with a sterilized scalpel. Each wound was covered with moisturized cotton and sealed with Parafilm. Control shoots were inoculated using non-colonized PDA plugs. After 6 weeks, discoloration of xylem and phloem and necrosis with average length of 38.8, 17.6, and 11.2 mm were observed from inoculated shoots with D. seriata, N. luteum, and B. dothidea, respectively, and all three fungi were re-isolated from necrotic tissue, satisfying Koch's postulates. Control shoots showed no symptoms of the disease and no fungus was re-isolated. In Tunisia, Botryosphaeria-related dieback was reported only on citrus tree caused by B. ribis (2), on Pinus spp. caused by D. pinea (4), on Quercus spp. caused by D. corticola (3), and on olive tree (Olea europea) caused by D. seriata (1). To our knowledge, this is the first report of D. seriata, B. dothidea, and N. luteum associated with grapevine dieback in Tunisia. References: (1) M. Chattaoui et al. Plant Dis. 96:905, 2012. (2) H. S. Fawcett. Calif. Citrogr. 16:208, 1931. (3) B. T. Linaldeddu et al. J. Plant Pathol. 91:234. 2009. (4) B. T. Linaldeddu et al. Phytopathol. Mediterr. 47:258, 2008.

Trunk Surgery as a Tool to Reduce Foliar Symptoms in Diseases of the Esca Complex and Its Influence on Vine Wood Microbiota

“… Ascomycota Cladosporiaceae E, P, S ■; ▲; ● 0.5; 9.1; 0.2 [ 28 , 88 ] Cladosporium sphaerospermum Ascomycota Cladosporiaceae P, S ▲ 1.1 [ 88 ] Cryptococcus sp. Basidiomycota Cryptococcaceae E, S ■; ▲; ● 0.3; 2.8; 0.2 [ 28 , 92 ] Diplodia seriata Ascomycota Botryosphaeriaceae E, P, S ■; ▲ 0.2; 0.3 [ 78 , 79 , 82 , 88 , 91 , 92 , 94 , 97 , 98 , 102 , 104 , 108 , 123 , 124 , 125 , 126 , 127 , ...…”

Declinación de la vid en Túnez asociada a hongos de las familias Diaporthaceae y Botryosphaeriaceae

“…However, due to the ban of sodium arsenate, several vine dieback cases have been reported, often with unidentified causes. However, recent studies conducted on vineyards showing declining grapevines reported the occurrence of three Botryosphaeriaceae species to be associated with grapevine dieback in Tunisian vineyards (Chebil et al, 2014). Symptoms included the decline or death of plant parts and, eventually, of whole vines due to a variety of necrosis phenomena, such as cankers, browning, vascular streaking, longitudinal lesions, and cane bleaching, which affect the woody parts of the plant (Luque et al, 2009).…”

Diplodia scrobiculata and Neofusicoccum luteum causing dieback of Pinus halepensis in Tunisia

“…In fact, Botryosphaeriaceae species were recorded for the first time by Linaldeddu et al (2008) on P. pinaster and P. radiata , then by Chattaoui et al (2012) on Olea europea and again by Linaldeddu et al (2013) on Quercus suber . Botryosphaeria‐related dieback was reported also on grapevine (Chebil et al, 2014), on Almond trees (Gharbi et al, 2017) and recently on Q. coccifera (Hlaiem et al, 2020). According to our survey in Northern Tunisia (Bizerte, Rimel forest), disease symptoms on P. halepensis trees include shoot dieback, wood necrosis, branch cankers, crown wilt, vascular discoloration in wood, innumerable pycnidia on infected tissues, stem blight with poor growth and sudden death of the whole tree are similar to those observed on Eucalyptus trees in Australia and South Africa (Slippers et al, 2004), on kermes oak in Greece (Tsopelas et al, 2010) and on grapevine in California (Urbez‐Torres, 2011; Urbez‐Torres, Leavitt, Voegel, & Gubler, 2006).…”

“…Botryosphaeria-related dieback was reported also on grapevine (Chebil et al, 2014), on Almond trees (Gharbi et al, 2017) and recently on Q. coccifera (Hlaiem et al, 2020). According to our survey in Northern Tunisia (Bizerte, Rimel forest), disease symptoms on P. halepensis trees include shoot dieback, wood necrosis, branch cankers, crown wilt, vascular discoloration in wood, innumerable pycnidia on infected tissues, stem blight with poor growth and sudden death of the whole tree are similar to those observed on Eucalyptus trees in Australia and South Africa (Slippers et al, 2004), on kermes oak in Greece (Tsopelas et al, 2010) and Linaldeddu et al, 2016).…”