Draft genome of the marine bacterium Alteromonas gracilis strain J4 isolated from the green coenocytic alga Caulerpa prolifera .

Here, we present the draft genome sequence of Alteromonas gracilis strain J4, isolated from the green macroalga Caulerpa prolifera . The draft genome is 4,492,914 bp in size and contains 4,719 coding DNA sequences, 67 tRNAs, and 16 rRNA-coding genes. Strain J4 may exhibit host growth-promoting properties.