Transfers a methylene group from S-adenosyl-L-methionine to the cis double bond of an unsaturated fatty acid chain resulting in the replacement of the double bond with a methylene bridge. 1-acyl-2-(9Z)-enoyl-sn-glycero-3-phospholipid + S-adenosyl-L-methionine = 1-acyl-2-(9-cyclopronane)-acyl-sn-glycero-3-phospholipid + H(+) + S-adenosyl-L-homocysteine Belongs to the CFA/CMAS family.