Associated with membrane proliferation. a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol) + ATP = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3-phosphate) + ADP + H(+) Highly expressed in young root nodules in parallel with membrane proliferation but is repressed in mature nodules. Belongs to the PI3/PI4-kinase family.