Diversity of endophytic fungal community of cacao (Theobroma cacao L.) and biological control of Crinipellis perniciosa, causal agent of Witches' Broom Disease

Abstract

The basidiomycete fungus Crinipellis perniciosa (Stahel) Singer is the causal agent of Witches' Broom Disease of Cacao (Theobroma cacao L.) which is the main factor limiting cacao production in the Americas. Pod losses of up to 90% are experienced in affected areas as evidenced by the 50% drop in production in Bahia province, Brazil following the arrival of the C. perniciosa in the area in 1989. The disease has proven particularly difficult to control and many farmers in affected areas have given up cacao cultivation. In order to evaluate the potential of endophytes as a biological control agent of this phytopathogen, the endophytic fungal community of resistant and susceptible cacao plants as well as affected branches was studied between 2001 and 2002. The fungal community was identified by morphological traits and rDNA sequencing as belonging to the genera Acremonium, Blastomyces, Botryosphaeria, Cladosporium, Colletotrichum, Cordyceps, Diaporthe, Fusarium, Geotrichum, Gibberella, Gliocladium, Lasiodiplodia, Monilochoetes, Nectria, Pestalotiopsis, Phomopsis, Pleurotus, Pseudofusarium, Rhizopycnis, Syncephalastrum, Trichoderma, Verticillium and Xylaria. These fungi were evaluated both in vitro and in vivo by their ability to inhibit C. perniciosa. Among these, some were identified as potential antagonists, but only one fungus (Gliocladium catenulatum) reduced the incidence of Witches' Broom Disease in cacao seedlings to 70%.

Endophytic fungi as biocontrol agents of Theobroma cacao pathogens

“…Recent findings have shown that endophytic fungi can help limit pathogen damage in T. cacao Evans et al, 2003;Meji'a et al, 2003;Holmes et al, 2004Holmes et al, , 2006Rubini et al, 2005;Tondje et al, 2006; Pierre Roger Tonje, IRAD, Cameroon; personal communication). Our results support these findings by showing that endophytic fungi isolated from healthy leaves and pods of T. cacao restrict in vitro growth of the three most common and economically important pathogens of cacao (P. palmivora, M. roreri, and M. perniciosa).…”

“…These observations, jointly with in vitro and in vivo studies Evans et al, 2003;Holmes et al, 2004;Rubini et al, 2005;Tondje et al, 2006;Aneja et al, 2006;Bailey et al, 2006) suggest that different endophytic fungi associated with T. cacao reduce the damage associated with pathogens in a variety of different ways in planta. Specifically, endophytes can inhibit pathogen infection and proliferation within the host directly (e.g., via antibiosis, competition, and mycoparasitism), or indirectly via inducing resistance responses intrinsic to the host (Aneja et al, 2006;Bailey et al, 2006;S.…”

“…Specifically, promising results for the control of diseases of cacao have been obtained using epiphytic mycoparasitic fungi (Krauss and Soberanis, 2001;Ten Hoopen et al, 2003). Furthermore, recent evidence shows that in some cases endophytic fungi restrict cacao pathogen growth or damage in vitro and in vivo Evans et al, 2003;Mejia et al, 2003;Holmes et al, 2004Holmes et al, , 2006Rubini et al, 2005;Tondje et al, 2006) highlighting their status as a new source of biological control agents for combating cacao pathogens. Endophytic fungi are taxonomically and biologically diverse but all share the character of colonizing internal plant tissues without causing apparent harm to their host (Wilson, 1995).…”

Genetic diversity analyses ofLasiodiplodia theobromaeonMorus albaandAgave sisalanabased on RAPD and ISSR molecular markers

“…As a plant pathogen, L. theobromae associated with up to 500 plant hosts and caused numerous diseases, including gummosis, leaf necrosis, dieback, collar rot, root rot, fruit rot, leaf spot, decline, leaf blight, cankers and witches’ broom and so on (Úrbez-Torres et al 2008). It also occurs as an endophyte (Mohali et al 2005; Rubini et al 2005). Mulberry root rot caused by L. theobromae in Heng County of Guangxi Province, China, was first reported in 2014 (Xie et al 2014) and diseased area was about 2400 ha, where approximately 300 ha mulberry was seriously diseased with the diseased and mortality rate more than 80%.…”

Interação enxerto e porta-enxerto na incidência da resinose do cajueiro

“…As plantas acometidas pela resinose têm a transpiração alterada decorrente da redução da condutância estomática e da fotossíntese líquida (BEZERRA et al, 2003). L. theobromae é capaz de colonizar tecidos de plantas sem exibir sintomas de infecção (MOHALI et al, 2005, MULLEN et al, 1991RUBINI et al, 2005), possibilitando sua disseminação através de sementes, propágulos vegetativos e porta-enxertos, de forma despercebida (CARDOSO et al, 1998;CARDOSO et al, 2004). Acredita-se que essa característica, certamente, é a maior responsável pelas epidemias observadas na microrregião do sudeste do Piauí (CARDOSO et al, 1998;CARDOSO et al, 2004;.…”