Brassinosteroids （BRs） play essential roles in regulating various aspects of plant growth and development and in responding to diverse environmental cues, and their metabolism is an important way to regulate their h...Brassinosteroids （BRs） play essential roles in regulating various aspects of plant growth and development and in responding to diverse environmental cues, and their metabolism is an important way to regulate their homeosta-sis in plants. Here, we identified a dominant mutant, dwarf and round leaf-1 （drll-D）, which exhibits weak BR-deficient or BR-insensitive mutant phenotypes, including short and round leaves, prolonged senescence, dwarfed shape, and altered expression levels of the BR-responsive genes. Hypocotyl length and root inhibition assays suggest that the drll-D mutant responds to BRs normally, but has decreased BR signaling outputs. The endogenous levels of several BRs, includ-ing typhasterol （TY）, 6-deoxotyphasterol （6-deoxoTY）, and 6-deoxocastasterone （6-deoxoCS）, are significantly lower in the drll-D mutant than in the wild-type. The DRL1 gene encodes an acyltransferase and is widely expressed in leaves, roots, flowers, and siliques. Plants without DRL1 and its homologs are larger with an enhanced BR signaling. The expres-sion of DRL1 was induced by eBL and inhibited by ABA. DRL1 is involved in the BR metabolism likely by catalyzing the BR conjugation through esterification, which plays important roles in regulating the BR homeostasis and responding to abiotic stresses in Arabidopsis.展开更多
文摘Brassinosteroids （BRs） play essential roles in regulating various aspects of plant growth and development and in responding to diverse environmental cues, and their metabolism is an important way to regulate their homeosta-sis in plants. Here, we identified a dominant mutant, dwarf and round leaf-1 （drll-D）, which exhibits weak BR-deficient or BR-insensitive mutant phenotypes, including short and round leaves, prolonged senescence, dwarfed shape, and altered expression levels of the BR-responsive genes. Hypocotyl length and root inhibition assays suggest that the drll-D mutant responds to BRs normally, but has decreased BR signaling outputs. The endogenous levels of several BRs, includ-ing typhasterol （TY）, 6-deoxotyphasterol （6-deoxoTY）, and 6-deoxocastasterone （6-deoxoCS）, are significantly lower in the drll-D mutant than in the wild-type. The DRL1 gene encodes an acyltransferase and is widely expressed in leaves, roots, flowers, and siliques. Plants without DRL1 and its homologs are larger with an enhanced BR signaling. The expres-sion of DRL1 was induced by eBL and inhibited by ABA. DRL1 is involved in the BR metabolism likely by catalyzing the BR conjugation through esterification, which plays important roles in regulating the BR homeostasis and responding to abiotic stresses in Arabidopsis.
