A new musical about the life of R&B great Mabel Smith, “Big Maybelle: Soul of the Blues,” will play a tryout run at Long Island’s Bay Street Theater this summer in a production toplined by Lillias White.Sag Harbor company Bay Street produces the world preem along with Broadway vet Martin Richards (“On the Twentieth Century,” “La Cage aux Folles,” the original “Chicago,” “The Life”) and the Gilead Company. Tuner is targeting a Broadway transfer that could materialize as early as this winter, if all goes according to plan. Paul Levine writes and directs the show, which draws its songlist from familiar blues tunes including “Whole Lotta Shakin’ Goin’ On” and “Candy.” In the musical, Smith, who recorded under the name Big Maybelle, tells the aud her life story from the Ohio rehab facility where she died. At Bay Street, thesps Eric Brown and Kiku Collins will co-star alongside White, who won a Tony for her stint in 1997 tuner “The Life.” The four-week engagement begins previews Aug. 7 with an official opening night set for Aug. 11. No exact plans for future life for the show have yet been locked in.