, 1998; Holo et al., 2001; Maldonado et al., 2003; Diep et al., 2009). Strain-related differences in bactericidal activity affect the susceptibility of other microorganisms to plantaricins and organic acids (Ehrmann et al., 2000; Omar et al., 2006; Nielsen et al., 2010). None of the strains had genes for plantaricins NC8, S, or W (Table 1). With the methodology used, plantaricin A-, EF-, JK-, and N-related genes were detectable in all strains except for TO1001 (Table 1). Similar to the case of TO1001, L. plantarum strain 3.9.1, isolated from an African fermented

food, does not have any of these plantaricin genes (Omar et al., 2006). Certain L. plantarum strains show the following different types of plantaricin-related gene combinations: (1)

plnEF and plnW; (2) plnD, plnEF, plnI, and plnG; (3) plnD, plnJ, plnK, and plnG; (4) PI3K inhibitor plnD, plnEF, plnI, plnK, and plnG; (5) plnA, plnC, plnD, plnEF, plnI, plnJ, plnK, and plnN (Omar et al., 2006; Moghadam et al., BGJ398 2010). Thus, the characteristics of the gene combinations carried for the production of plantaricins in TO1000, TO1002, and TO1003 are unique among the known L. plantarum strains isolated from fermented products. The synthesis of plantaricin A is observed from early exponential to early stationary phase. During stationary phase, the amount of plantaricin A strikingly declines (Diep et al., 1994). The addition of sucrose to the medium enhances production of nisin, another bacteriocin produced by Lactococcus lactis, (Devuyst & Vandamme, 1992). Thus, bacterial growth rate and available nutrients are associated with antimicrobial activity. In fact, the rates of fermentation differed among the four strains at 30 and 60 days of storage (Tables 3 and 4), suggesting that, in addition to the divergence in the available carbohydrates, the capacity for production of organic acids, and

the pH and temperature preferences for growth, antimicrobial activity may also be an important factor in the regulation of silage fermentation quality. Further selleck products studies are needed both to elucidate the production of plantaricins by the TO strains inoculated in silage and to understand their roles in the improvement of silage quality. In conclusion, phenotypic and genotypic differences were present among LAB strains in spite of their belonging to the same species and subspecies, and the fermentation quality of silage inoculated with different conspecific strains differed significantly, supporting the idea that suitable LAB inoculants should be selected on a strain basis. Because TO1002 most effectively improved the fermentation quality in terms of pH decrease, regulation of undesirable microorganisms, and high DM recovery, this strain should be the most suitable inoculant for longer storage of paddy rice silage. The selected L. plantarum subsp.