Possesses quercetin 3-O-glucosyltransferase activity in vitro. Involved in stress or defense responses. a flavonol + UDP-alpha-D-glucose = a flavonol 3-O-beta-D-glucoside + H(+) + UDP A number of isoforms are produced. According to EST sequences. Expressed in roots and senescent leaves. Induced by pathogen infection, H(2)O(2) and salicylic acid. Decreased resistance to avirulent strains of P.syringae. Belongs to the UDP-glycosyltransferase family. Truncated N-terminus.