Isolation of rice seed-borne bacteria
Isolates CT1 and CT2 were obtained from CT6919 seedling roots
that showed profuse outgrowth of yellow colonies after incubation
of germinated husked seeds onto NA plates for 48 h at 28°C. The
rest of the CT6919 seed isolates (CT3-CT39) were obtained by plating
dilutions of husked seed macerates on NA. After 24 h of incubation
at 28°C, 17 colonies with distinct growth features were isolated
(CT3-CT19). Another 20 colonies were isolated after 48 h (CT20-
CT39). Culture purity was confirmed by Gram staining. Isolates were
grown in nutrient yeast broth (NYB) (nutrient broth, 25 g/L; yeast
extract, 5 g/L) with shaking at 28°C for 24-48 h and preserved at
-130°C as saturated cultures containing 20% (w/v) glycerol.