tRNA methylase that catalyzes 2'-O-methyladenosine (Am) nucleoside formation on tRNA(Gly)(GCC) in vitro. May 2'-O-methylate cytidine(4) in tRNA(Pro) and tRNA(Gly)(GCC), and adenosine(4) in tRNA(His) (PubMed:28369540). Involved in salt stress tolerance (PubMed:28369540). cytidine(4) in tRNA(Pro) + S-adenosyl-L-methionine = 2'-O-methylcytidine(4) in tRNA(Pro) + H(+) + S-adenosyl-L-homocysteine cytidine(4) in tRNA(Gly)(GCC) + S-adenosyl-L-methionine = 2'-O-methylcytidine(4) in tRNA(Gly)(GCC) + H(+) + S-adenosyl-L-homocysteine adenosine(4) in tRNA(His) + S-adenosyl-L-methionine = 2'-O-methyladenosine(4) in tRNA(His) + H(+) + S-adenosyl-L-homocysteine Induced by salt stress and abscisic acid treatment. Seedlings subjected to salt stress and abscisic acid (ABA) treatment exhibit a dramatic increase of 2'-O-methyladenosine (Am) nucleoside (PubMed:28369540). Plants over-expressing TRM13 show improved salt stress tolerance, and plant silencing TRM13 display decreased stress tolerance (PubMed:28369540). Belongs to the methyltransferase TRM13 family.