In silico analysis of galactinol synthase genes in common bean (phaseolus vulgaris L.)

Abstract

Galactinol synthases (GolS, EC 2.4.1.123) belong to the glycosyltransferase 8 family. These enzymes catalyzes galactosylation of myo-inositol to form galactinol, precursor of raffinose which is solube sucrose playing an important role in stress tolerance in plants. We identified and analyzed a total of three GolS encoded genes in the whole genome of common bean. These genes possessed two or three introns. The predicted proteins contained from 322 to 340 amino acids. The common bean GolS proteins contained all conseved motifs that were characterized for other previously known GolSs. These proteins were acidic and weakly hydrophilic. The phylogenic tree constructed from GolS proteins of Arabidopsis, poplar and common bean showed that only one gene duplication event was detected in the commone bean genome. Common bean GolS genes expressed in all vegetative and reproductive tissues. However, the transcript abundances of each gene varied in different tissues. When comparing the expression levels of these three genes as defined RNAseq, we found that the expression level of PvGolS2 was the lowest, PvGolS1 expressed the strogest  leaves and stem, while PvGolS3 expressed in roots and nodules. We discovered that Rhizobium incubation affected on the expression of GolS genes for the first time. In the reproductive tissues, PvGolS1 expressed in most studied tissues. Its expression level correlatively increased with the tissue development.