Involvement of α-galactosidase OmAGAL2 in planteose hydrolysis during seed germination of Orobanche minor. (1st December 2021)

• Record Type: Journal Article
• Authors: Okazawa, Atsushi; Baba, Atsuya; Okano, Hikaru; Tokunaga, Tomoya; Nakaue, Tsubasa; Ogawa, Takumi; Shimma, Shuichi; Sugimoto, Yukihiro; Ohta, Daisaku
• Editors: Smirnoff, Nick
• Is Part Of: Journal of experimental botany. Volume 73:Number 7(2022)
• Page Start: 1992
• Page End: 2004
• Publication Date: 2021-12-01
• Subjects: Apoplast -- α-galactosidase -- matrix-assisted laser desorption/ionization–mass spectrometry imaging -- Orobanche minor -- parasitic plant -- planteose -- seed germination -- storage carbohydrate; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erab527
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : Planteose stored in tissues surrounding the embryo in Orobanche minor dry seeds is hydrolysed in the apoplast around the embryo by α-galactosidase OmAGAL2 during germination. Abstract: Root parasitic weeds of the Orobanchaceae, such as witchweeds ( Striga spp.) and broomrapes ( Orobanche and Phelipanche spp.), cause serious losses in agriculture worldwide, and efforts have been made to control these parasitic weeds. Understanding the characteristic physiological processes in the life cycle of root parasitic weeds is particularly important to identify specific targets for growth modulators. In our previous study, planteose metabolism was revealed to be activated soon after the perception of strigolactones in germinating seeds of O . minor . Nojirimycin inhibited planteose metabolism and impeded seed germination of O . minor, indicating a possible target for root parasitic weed control. In the present study, we investigated the distribution of planteose in dry seeds of O . minor by matrix-assisted laser desorption/ionization–mass spectrometry imaging. Planteose was detected in tissues surrounding—but not within—the embryo, supporting its suggested role as a storage carbohydrate. Biochemical assays and molecular characterization of an α-galactosidase family member, OmAGAL2, indicated that the enzyme is involved in planteose hydrolysis in the apoplast around the embryo after the perception of strigolactones, to provide the embryo with essential hexoses for germination. These results indicate that OmAGAL2 is a potential molecular target for root parasitic weed control.