Overexpression of OsNAC6 transcription factor from Indonesia rice cultivar enhances drought and salt tolerance

Abstract

Drought is a major constrain in crop production that reduce growth and cause yield loss of up to 70%. Transcription factor plays a major role in cellular regulation and physical changes of plants as a response to stress. A number of transcription factors, such as CBF/DREB, NAC, zinc finger protein are regulators during stress. The Oryza sativa NAC6 (OsNAC6) gene is one of the transcription factor in rice that can regulate gene expression during stress conditions. Thus, pCambia 1305 harboring OsNAC6 chimaeric gene with CaMV 35S promoter was introduced into rice zygotic embryo using Agrobacterium tumefaciens mediated transformation to regenerate transgenic rice overexpressing the transgene. As many as 39 putative transgenic lines in which 21 lines possitively harbored hpt gene have been regenerated. The positive identification of hpt in the regenerated transgenic rice indirectly indicated integration of the targeted OsNAC6 since both transgenes were part of the same T-DNA. Further analysis indicated the presence of 1-3 copies of transgene integration in the genome. The expression of OsNAC6 transgene in the transgenic rice line#C.73, C.83 and C.91 were higher than wild type non-transgenic one. Further analysis indicated those three transgenic lines carrying OsNAC6 transgene exhibited higher tolerance against drought and salinity stresses. Moreover, three known stress-associated regulatory genes (AP2, Zincfinger protein and MYB) were up-regulated in those three transgenic lines. These findings demonstrated that OsNAC6 might be a candidate of stress-responsive NAC regulatory gene that can be used to develop either drought or salt tolerant tolerant transgenic plants.

Transcriptional Network Involved in Drought Response and Adaptation in Cereals

“…In maize, ZmNAC052, Zma000584, Zma006493, Zma001259z [55], and ZmSNAC1 showed increased transcription levels under water deficiency, indicating their potential role in drought tolerance regulation. In rice, SNAC1 [56], OsNAC5 [57], -6 [58], -9 [59], and -10 [60] altered the root structure for plant adaptation during drought. Further, the overexpression of OsNAC045 [19] and OsNAC52 [61] induced ABA sensitivity and conferred drought resistance in transgenic rice and transgenic Arabidopsis, respectively.…”

Molecular and Functional Characterization of CaNAC035, an NAC Transcription Factor From Pepper (Capsicum annuum L.)

“…ANAC072 (RD26) is involved in a novel ABA-dependent signaling pathway (Fujita et al, 2004). OsNAC6/SNAC2 transgenic lines exhibited tolerance to dehydration, salt stress, and blast disease, as well as improved the grain yield and OsNAC6 transcription, was induced by abiotic stresses and jasmonic acid treatments (Rachmat et al, 2014). Furthermore, transgenic Arabidopsis overexpressing SlNAC1 from Suaeda liaotungensis Kitag showed enhanced tolerance to drought, salt, and cold stresses (Li D.K.…”

Infection with an asymptomatic virus in rice results in a delayed drought response

“…Transcriptome analyses of rice plants infected with RTSV (Encabo et al 2009;Satoh et al 2013) revealed the significant changes in expression levels of genes for transcription factors belonging to DREB, SNAC, WRKY, bZIP and AP2-EREBP families that had been previously reported to respond to drought stress (Ohnishi et al 2005;Hu et al 2006;Nakashima et al 2007;Cui et al 2011;Rachmat et al 2014). Based on these observations, we hypothesised that RTSV infection changes the response of rice plants to drought stress.…”