Abstract: | A fungal endophytic strain, isolated from Artemisia sp., identified as Preussia sp. was selected for its potential of plant growth promotion and reduction of pathogen attack, in vitro.
The metaorganism tomato - endophytic fungus - fungal pathogen was observed in terms of germination, root and shoot weight, number of leaves and percentage of leaves pairs (1 β 3), index of development, index of necrosis and index of attack. The time sequence employed for the entrance of the partners in the setting was: moment 0 = endophyte, moment 1 = tomato seeds (after 2 days from M0), moment 2 = pathogen (after 14 days from M1) and moment 3 = data collection (after 7 days from M2). A positive influence on germination was observed when all three partners interacted, compared to all variables (all partners βT1β - 100% versus endophytic fungus and seed βC1β- 66.67%, pathogen and seed βC2β - 88.89, seed alone βC3β- 77.78%, respectively).
Root and shoot length was improved both when all partners βT1β (root β 7.30 cm, shoot β 4.58 cm) as well as when endophytic fungus and seed partners βC1β (root β 8.40 cm, shoot β 4 cm) were present, compared to seed alone βC3β (root β 7.70 cm and shoot β 2.73 cm) and seed and pathogen partners βC2β (root β 5.74 cm and shoot β 3.06 cm). Although the average number of pairs was similar among the variables (C2 - 1.5; C3 - 1.6; T1 and C1 - 1.7), the percentage of pairs of leaves differed significantly for the percentage of 1 pair of leaves: C3 = 42.9% versus T1 = 11.1%. An improvement was observed in the percentage of 2 pairs of leaves for the case of all partners as well as for the case of endophyte and seed: T1 = 77.78%, C1 = 85.7% versus C2 = 62.5% and C3 = 57.15. Yet, the index of development showed best case when seed was alone and no difference between pathogen or endophyte presence.
In terms of the indices of necrosis (IN) and attack (IA), the endophyte was innocuously interacting with seedling (IN and IA = 0) and also when both pathogen and endophyte (T1) were present the seedling presented no symptoms, compared to pathogen and seedling case (C2): IN - T1 = 0 versus C2 = 0.78 and IA β T1 = 0 versus C2 = 11.11. |
