Selection of strains of Beauveria bassiana and metarhizium anisopliae (Ascomycota Hypocreales) for endophytic colonization in coconut seedlings

• Autores: Jackeline Gaviria, Pedro Pablo Parra, Alonso Gonzales
• Localización: Chilean Journal of Agricultural & Animal Sciences, ISSN-e 0719-3890, ISSN 0719-3882, Vol. 36, Nº. 1, 2020, págs. 3-13
• Idioma: español
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• Resumen
  • español

    Beauveria bassiana y Metarhizium anisopliae son considerados patógenos virulentos contra el picudo Rhynchophorus palmarum. El objetivo de este estudio fue determinar la habilidad de la cepa comercial Beauveriplant SBb36 de B. bassiana y la cepa JGVM1 de M. anisopliae, para establecer una relación endofítica con plantas de coco Cocos nucifera (Linnaeus) obtenidas a partir de semilla sexual y de cultivo de tejidos. Se evaluaron diferentes métodos de inoculación: aspersión foliar, inyección en tallo y aplicación de suspensión conidial en las raíces, fueron usados para inocular plantas obtenidas a partir de semilla sexual, mientras que el método de inmersión fue usado para inocular plantas obtenidas a partir de cultivo de tejidos. El porcentaje de colonización en diferentes tejidos de las plantas se determinó a través del re-aislamiento de los hongos cuatro semanas después de la inoculación. Las cepas Beauveria bassiana (Beauveriplant SBb36) y Metarhizium anisopliae (JGVM1) colonizaron endofíticamente el 100% de las plantas de coco obtenidas a partir de cultivo de tejidos y el 91.6% de las plantas de coco obtenidas por semilla sexual. En el presente estudio, se reporta por primera vez que B. bassiana and M. anisopliae establecen una relación de endofitismo con plántulas de coco obtenidas a partir de la germinación de semilla sexual y cultivo de tejidos a través de inoculaciones dirigidas.

  • English

    Beauveria bassiana and Metarhizium anisopliae are considered virulent pathogens of the coconut weevil Rhynchophorus palmarum (Linnaeus). The objective of this study was to determine the ability of B. bassiana (Beauveriplant SBb36) and M. anisopliae (JGVM1) to establish an endophytic relationship with coconut Cocos nucifera (Linnaeus) seedlings. Strains were selected based on the mortality of adults of R. palmarum exposed to these fungi. Three methods of inoculation were used to inoculate the seedlings obtained through seed germination: foliar spray, stem injection and drench to the roots. Immersion of seedlings in a conidial suspension was used to inoculate seedlings obtained from tissue culture. Colonization was determined through the re-isolation of the fungi four weeks after inoculation. Beauveriplant SBb36 and JGVM1 colonized endophytically 100% of the seedlings obtained through tissue culture and 91.6% of seedlings obtained from germinated seeds. For plants inoculated by immersion with B. bassiana, the colonization rate in petioles (43%) was higher than in leaves and roots, 14 and 17%, respectively. Metarhizium anisopliae did not show significant differences in the colonization rate in leaves, petioles and roots. Plants inoculated by foliar spraying showed that colonization was higher in leaves > petioles > stems > roots. Colonization in stem injection was higher in stems than in the roots. Soil drench inoculation was higher in roots > stems. To our knowledge, this is the first report describing the endophytic relationship that B. bassiana and M. anisopliae establish with coconut seedlings obtained through seed germination and tissue culture when targeted inoculations are performed.