Expression of the CCCH‐tandem zinc finger protein gene OsTZF5 under a stress‐inducible promoter mitigates the effect of drought stress on rice grain yield under field conditions

Abstract

SummaryIncreasing drought resistance without sacrificing grain yield remains an ongoing challenge in crop improvement. In this study, we report that Oryza sativa CCCH‐tandem zinc finger protein 5 (OsTZF5) can confer drought resistance and increase grain yield in transgenic rice plants. Expression of OsTZF5 was induced by abscisic acid, dehydration and cold stress. Upon stress, OsTZF5‐GFP localized to the cytoplasm and cytoplasmic foci. Transgenic rice plants overexpressing OsTZF5 under the constitutive maize ubiquitin promoter exhibited improved survival under drought but also growth retardation. By introducing OsTZF5 behind the stress‐responsive OsNAC6 promoter in two commercial upland cultivars, Curinga and NERICA4, we obtained transgenic plants that showed no growth retardation. Moreover, these plants exhibited significantly increased grain yield compared to non‐transgenic cultivars in different confined field drought environments. Physiological analysis indicated that OsTZF5 promoted both drought tolerance and drought avoidance. Collectively, our results provide strong evidence that OsTZF5 is a useful biotechnological tool to minimize yield losses in rice grown under drought conditions.

Overexpression of exogenous biuret hydrolase in rice plants confers tolerance to biuret toxicity

“…Transcription factor genes in DEGs included genes known to be regulating stress responses besides genes known to be regulating growth and development. In DEGs on day 3, there were five stress‐responsive genes: two AP2‐EREBP genes Os09g0522000 and Os09g0522200 ( OsDREB1B and OsDREB1A ; Dubouzet et al., 2003), a bHLH gene Os04g0301500 ( OsbHLH6 ; Meng et al., 2020), a C3H gene Os05g0128200 ( OsTZ5 ; Selvaraj et al., 2020), and a NAC gene Os08g0436700 ( ONAC063 ; Yokotani et al., 2009). These genes could be induced by cold, drought, salt, or fungal infection.…”

H3K36 methyltransferase SDG708 enhances drought tolerance by promoting abscisic acid biosynthesis in rice

“…In rice, overexpression of stress‐related genes frequently reduces total grain yield under normal or stress conditions (Kasuga et al ., 1999; Ito et al ., 2006; Kim et al ., 2014; Selvaraj et al ., 2020). Interestingly, 708OE and 708Ri plants exhibited increased and decreased grain yield per plant, compared with that of WT plants, under normal and drought stress conditions, respectively (Fig.…”

“…Given that rice has a high water requirement in the vegetative and reproductive growth phases, increase in the frequency of drought owing to global climate change will strongly affect rice yield (Cutler et al ., 2010; Mickelbart et al ., 2015; Gupta et al ., 2020). Overexpression of stress‐related genes, such as OsPYL5 , OsTZF5 , OsDREB1A , and OsDREB1B , significantly improves stress tolerance but severely influences growth and yield in rice (Ito et al ., 2006; Kim et al ., 2014; Selvaraj et al ., 2020); therefore, it is a major challenge to maintain the balance between increased stress tolerance and stable crop yield in breeding. It is a pleasant surprise that overexpression of SDG708 improves rice drought tolerance concomitant with increased grain production under drought stress (Fig.…”

Emerging Molecular Strategies for Improving Rice Drought Tolerance

“…Only a handful of studies have conducted field trials on transgenics [reviewed in 4 ] by draining the surface water and holding the irrigation till leaf starts rolling. In field trials, transgenics lines, especially those overexpressing NAC transcription factors and their downstream targets, showed better yield than non-transgenic plants [ 4 , 34 ]. Remarkably, transgenic rice expressing a galactinol synthase 2 gene (AtGolS2 ) from Arabidopsis showed yield gains of up to 49% in comparison to non-transgenic in multiyear field trials under drought [ 35 ].…”