T-DNA tagged knockout mutation of rice OsGSK1, an orthologue of Arabidopsis BIN2, with enhanced tolerance to various abiotic stresses

Abstract

T-DNA-tagged rice plants were screened under cold- or salt-stress conditions to determine the genes involved in the molecular mechanism for their abiotic-stress response. Line 0-165-65 was identified as a salt-responsive line. The gene responsible for this GUS-positive phenotype was revealed by inverse PCR as OsGSK1 (Oryza sativa glycogen synthase kinase3-like gene 1), a member of the plant GSK3/SHAGGY-like protein kinase genes and an orthologue of the Arabidopsis brassinosteroid insensitive 2 (BIN2), AtSK21. Northern blot analysis showed that OsGSK1 was most highly detected in the developing panicles, suggesting that its expression is developmental stage specific. Knockout (KO) mutants of OsGSK1 showed enhanced tolerance to cold, heat, salt, and drought stresses when compared with non-transgenic segregants (NT). Overexpression of the full-length OsGSK1 led to a stunted growth phenotype similar to the one observed with the gain-of-function BIN/AtSK21 mutant. This suggests that OsGSK1 might be a functional rice orthologue that serves as a negative regulator of brassinosteroid (BR)-signaling. Therefore, we propose that stress-responsive OsGSK1 may have physiological roles in stress signal-transduction pathways and floral developmental processes.

Response to metal stress of Nicotiana langsdorffii plants wild-type and transgenic for the rat glucocorticoid receptor gene

“…Therefore, it is possible that plant brassinosteroids have sufficient affinity with the rat gluco-corticoid receptor protein to be connected to their signaling chain through the recognition of molecules expressed by the constitutive CaMV promoter inserted in the transformation construct. Brassinosteroids have been shown to induce tolerance to a wide range of abiotic stresses (Kagale et al, 2007;Bajguz, 2011;Sittayat et al, 2007;Arora et al, 2010a;Koh et al, 2007) through the activation of anti-oxidative stress systems (Arora et al, 2010b), as well as the enhanced synthesis of abscisic acid (Yuan et al, 2010), ethylene, salicylic acid (Divi et al, 2010), polyamines and indole-3-acetic acid (Choudhary et al, 2010(Choudhary et al, , 2011. Responses to stress in plants, moreover, are known to be activated by increased levels of auxins, which in turn determines feedback interaction with flavonoid synthetic patterns (Peer and Murphy, 2007;Lewis et al, 2011) and crosstalk with brassinosteroid transcription process (see Depuydt and Hardtke (2011) for an extensive review).…”

Increased Polyamine Biosynthesis Enhances Stress Tolerance by Preventing the Accumulation of Reactive Oxygen Species: T-DNA Mutational Analysis of Oryza sativa Lysine Decarboxylase-like Protein 1

“…Dongjin) seeds from a library of T-DNA insertion mutants were surface-sterilized and germinated. Plants were cultured hydroponically in a growth chamber (29°C/21°C) with a 16 h photoperiod (Koh et al, 2007). To screen for oxidative stress-tolerant mutants, leaf strips of two-month-old plants grown in soil were treated with H + -2-[Nmorpholino]-ethanesulfonic acid (MES) buffer containing 50 mM H 2 O 2 for 18 h, at which point the extent of necrotic and chlorotic damage was determined.…”

Roles of DLT in fine modulation on brassinosteroid response in rice

“…uconn.edu/servlet/SMSSearchServlet) of OsBZR1 and DLT protein show that there are 11 'GSK3-ALPHA consensus phosphorylation sites in DLT protein comparable to OsBZR1's 15 sites; and a 14-3-3 motif at 171 amino acid of DLT similar to OsBZR1's at 152 (Table 1). These hints give out important information that DLT could be the target of possibly existed rice GSK3-like kinase, potentially homolog of BIN2, 13 as evidences show BR signaling pathway should be conserved between monocotyledon and dicotyledon; 8,14 and in addition that DLT may shuttle between cytoplasm and nucleus with the help of 14-3-3 proteins.…”