Evaluation of the effect of lactic acid bacteria as promoters of germination and plant growth in citrus

Abstract

Lactic acid bacteria are effective in controlling a wide variety of phytopathogens and also as biostimulants, by directly promoting plant growth or seed germination, and also to relieve various stresses of biotic origin. However, their functional role as plant growth-promoting bacteria, has not been deeply explored. The objective of this work was to evaluate Enterococcus mundii (CRL35) and two strains of E. faecium (CRL1877 and CRL1879) isolated from dairy products, as germination and growth induction agents in citrus genotypes. Citrus limon, Citrus sinensis and Poncirus trifoliata
showed increases in germination, while Citrus aurantium showed sensitivity to strain CRL1877 and its supernatant. The treatment of P. trifoliata seeds with the cells of CRL35 and CRL1879 and their supernatants, generated seedlings with stems of greater length and diameter, greater length of the main root and of the longest secondary root and greater number of secondary roots, than the respective controls with MgCl2 and the LAPTg culture broth. The magnitude of the induction responded to the concentration (DO600 nm 1 and 0.1) and treatment time (2 h and 8 h). The results obtained in this work are the first evaluation of these strains of lactic acid bacteria as growth-inducing agents in citrus, thus opening up potential possibilities for the development of sustainable agricultural strategies.