Molecular cloning and characterization of the ABA-specific glucosyltransferase gene from bean (Phaseolus vulgaris L.).
Levels of the plant hormone abscisic acid (ABA) are maintained in homeostasis by a balance of its biosynthesis, catabolism and conjugation. The detailed molecular and signaling events leading to strict homeostasis are not completely understood in crop plants. In this study, we obtained cDNA of an ABA-inducible, ABA-specific UDP-glucosyltransferase (ABAGT) from the bean plant (Phaseolus vulgaris L.) involved in conjugation of a glucose residue to ABA to form inactive ABA-glucose ester (ABA-GE) to examine its role during development and abiotic stress in bean. The bacterially expressed PvABAGTase enzyme showed ABA-specific glucosylation activity in vitro. A higher level of the PvABAGT transcript was observed in mature leaves, mature flowers, roots, seed coats and embryos as well as upon rehydration following a period of dehydration. Overexpression of 35S::PvABAGT in Arabidopsis showed reduced sensitivity to ABA compared with WT. The transgenic plants showed a high level of ABA-GE without significant decrease in the level of ABA compared with the wild type (WT) during dehydration stress. Upon rehydration, the levels of ABA and phaseic acid (PA) decreased in the WT and the PvABAGT-overexpressing lines with high levels of ABA-GE only in the transgenic plants. Our findings suggest that the PvABAGT gene could play a role in ABA homeostasis during development and stress responses in bean and its overexpression in Arabidopsis did not alter ABA homeostasis during dehydration stress.
Center for Nutraceutical and Pharmaceutical Materials, Myongji University, Cheoin-gu, Yongin 449-728, Gyeonggi-Do, Republic of Korea.
Sasikumar Arunachalam
SA
Palaniyandi
Department of Biotechnology, Chonnam National University, Chonnam, 550-749 Yeosu, Republic of Korea.
Gyuhwa
G
Chung
Division of Bioscience and Bioinformatics, College of Natural Science, Myongji University, Cheoin-gu, Yongin 449-728, Gyeonggi-Do, Republic of Korea. Electronic address: kim6189@mju.ac.kr.
Sang Hyon
SH
Kim
Center for Nutraceutical and Pharmaceutical Materials, Myongji University, Cheoin-gu, Yongin 449-728, Gyeonggi-Do, Republic of Korea. Electronic address: ymichigan@mju.ac.kr.
Seung Hwan
SH
Yang
D000040:Abscisic Acid / Q000378:metabolism; D016960:Agrobacterium tumefaciens / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D027805:Phaseolus / Q000201:enzymology* / Q000235:genetics*; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D018076:DNA, Complementary; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000040:Abscisic Acid; D005964:Glucosyltransferases
ABA homeostasis; ABA-glucose ester; Abscisic acid; Glucosyltransferase; Phaseolus vulgaris