S-Adenosylmethionine Synthetase 3 Is Important for Pollen Tube Growth.

S-Adenosylmethionine is widely used in a variety of biological reactions and participates in the methionine (Met) metabolic pathway. In Arabidopsis (Arabidopsis thaliana), one of the four S-adenosylmethionine synthetase genes, METHIONINE ADENOSYLTRANSFERASE3 (MAT3), is highly expressed in pollen. Here, we show that mat3 mutants have impaired pollen tube growth and reduced seed set. Metabolomics analyses confirmed that mat3 pollen and pollen tubes overaccumulate Met and that mat3 pollen has several metabolite profiles, such as those of polyamine biosynthesis, which are different from those of the wild type. Additionally, we show that disruption of Met metabolism in mat3 pollen affected transfer RNA and histone methylation levels. Thus, our results suggest a connection between metabolism and epigenetics.