A sequence characteristic of a 5'UTR that is involved in the change in the state of translation in a plant under environmental stresses is found. Provided are: a recombinant DNA molecule having the sequence characteristic； an expression vector； a transformant； and others. Specifically provided are: a recombinant DNA molecule encoding mRNA having a 5'UTR (a) or (b) as mentioned below； a vector comprising the recombinant DNA molecule ligated just behind the transcription initiation point of a promoter； and a transformant carrying the vector: (a) a 5'UTR in which a nucleotide sequence lying between the 1st nucleotide and the 7th nucleotide as numbered from the 5'-terminal thereof and a nucleotide sequence lying between the 12th nucleotide and the 32nd nucleotide as numbered from the 5'-terminal thereof are a nucleotide sequence lying between the 1st nucleotide and the 7th nucleotide as numbered from the 5'-terminal of a nucleotide sequence represented by SEQ ID NO:4, SEQ ID NO:6, SEQ ID NO:20, SEQ ID NO:36 or SEQ ID NO:60 and a nucleotide sequence lying between the 12th nucleotide and the 32nd nucleotide as numbered from the 5'-terminal of the nucleotide sequence represented by SEQ ID NO:4, SEQ ID NO:6, SEQ ID NO:20, SEQ ID NO:36 or SEQ ID NO:60, respectively； and (b) a 5'UTR which is produced by substituting one or several nucleotides in the nucleotide sequence for the 5'UTR (a), and which can prevent the inhibition of translation under at least one environmental stress selected from the group consisting of a thermal stress and a salt stress.
