Interacciones Pre-simbióticas entre Glomus intraradices y dos especies de Paenibacillus aisladas de propágulos MA. Ensayos in vitro e in vivo con soja (AG043RG) como planta hospedante

FERNÁNDEZ BIDONDO, LAURA; SILVANI, VANESA ANALÍA; COLOMBO, ROXANA; PÉRGOLA, MARIANA; BOMPADRE, MARÍA JOSEFINA; GODEAS, ALICIA MARGARITA

Soja : investigación científico-técnica desarrollada en el INBA (CONICET/FAUBA) y en la Facultad de Agronomía de la UBA

EDITORIAL FACULTAD DE AGRONOMÍA

Lugar: Ciudad Autónoma de Buenos Aires; Año: 2011; p. 72 - 78

Two indole-producing  Paenibacillus, known to be associated wi th propagules of arbuscular mycorrhizal (AM) fungi, were examined for their mycorrhization helper bacteria activity at pre-symbiotic and symbiotic stages of the AM  association. Effect s were tested under in vitro  and  in vivo conditions using an axenical ly propagated strain of  Glomus intraradices  and soybean  as host plant. Spore germination and re-growth of intraradical mycelium were not  affected by inoculation with Paenibacillus  strains in spite of the variation of indole production measured in the bacterial supernatants. However, a significant promotion in pre-symbiotic mycelium development occurred after  inoculation of both bacteria under  in vitro conditions.  P. rhizosphaerae TGX5E significantly increased the extraradical mycelium network, spor ulation, and root  colonization in the  in vitro  symbiotic association. These results were  also observed in the rhizosphere of soybean plants grown under greenhouse conditions, when  P. rhizosphaerae was co-inoculated with  G. intraradices. However, soybean dry biomass production was not associated  with the increased deve lopment and infectivity values of  G. intraradices.  P. favisporus  strain TG1R2 caused suppression  of the parameters evaluated for  G. intraradices during  in vitro symbiotic stages, but not under  in vivo  conditions. In addition, dual inoculation had a promoting effect on  soybean biomass production. Species of  Paenibacillus associated with AM structures, may have a promo ting effect on short term pre-symbiotic mycelium, and little impact on AM propagule ge rmination. These findings could  explain the associations found between some bacterial strains and AM fungus propagules.