Enhancement of Plant Tolerance to*Formaldehyde by Over-expression of Formaldehyde-assimilating Enzymes from a Methylotrophic Bacterium

Abstract

The RmpA and rmpB genes encoding 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI) are the key enzymes of the ribulose monophosphate pathway for formaldehyde (HCHO) assimilation in Mycobacterium gastri MB19, a gram-positive facultative methylotrophic bacterium. These two genes were introduced into Arabidopsis and tobacco under the control of tomato rbcs-3C promoter with its transit peptide. The expression of the two genes was detected and active HPS and PHI was generated in both transgenic plants. The expression of the two genes enhanced the tolerance of the transgenic plants to HCHO and their ability to uptake evaporated and liquid HCHO. Tracer experiments showed that HCHO was assimilated through the reaction of the two enzymes in transgenic plants.