Rice transcription factor OsMADS25 modulates root growth and confers salinity tolerance via the ABA–mediated regulatory pathway and ROS scavenging

Abstract

Plant roots are constantly exposed to a variety of abiotic stresses, and high salinity is one of the major limiting conditions that impose constraints on plant growth. In this study, we describe that OsMADS25 is required for the root growth as well as salinity tolerance, via maintaining ROS homeostasis in rice (Oryza sativa). Overexpression of OsMADS25 remarkably enhanced the primary root (PR) length and lateral root (LR) density, whereas RNAi silence of this gene reduced PR elongation significantly, with altered ROS accumulation in the root tip. Transcriptional activation assays indicated that OsMADS25 activates OsGST4 (glutathione S–transferase) expression directly by binding to its promoter. Meanwhile, osgst4 mutant exhibited repressed growth and high sensitivity to salinity and oxidative stress, and recombinant OsGST4 protein was found to have ROS–scavenging activity in vitro. Expectedly, overexpression of OsMADS25 significantly enhanced the tolerance to salinity and oxidative stress in rice plants, with the elevated activity of antioxidant enzymes, increased accumulation of osmoprotective solute proline and reduced frequency of open stoma. Furthermore, OsMADS25 specifically activated the transcription of OsP5CR, a key component of proline biosynthesis, by binding to its promoter. Interestingly, overexpression of OsMADS25 raised the root sensitivity to exogenous ABA, and the expression of ABA–dependent stress–responsive genes was elevated greatly in overexpression plants under salinity stress. In addition, OsMADS25 seemed to promote auxin signaling by activating OsYUC4 transcription. Taken together, our findings reveal that OsMADS25 might be an important transcriptional regulator that regulates the root growth and confers salinity tolerance in rice via the ABA–mediated regulatory pathway and ROS scavenging.

Root Development and Stress Tolerance in rice: The Key to Improving Stress Tolerance without Yield Penalties

“…These findings indicated that promoting root growth improves tolerance to abiotic stress and rice productivity. This finding is supported by studies using OsMADS25 that regulates root elongation and formation in rice by controlling the auxin response [82,98]. In this study, the knock-down mutant of OsMADS25 with reduced root growth exhibited high sensitivity to salinity and oxidative stress, while transgenic rice overexpressing OsMADS25 displayed enhanced tolerance to the abiotic stress [98].…”

Genome‐wide analysis of MIKC‐type MADS‐box genes in wheat: pervasive duplications, functional conservation and putative neofunctionalization

“…a). This diversity of expression patterns and putative functions adds to the complex evolution of AGL17 ‐like genes, as genes from this subfamily have been implicated in various different functions, including root development, flowering time control, tillering, stomata development and stress response (Kutter et al ., ; Guo et al ., ; Puig et al ., ; Hu et al ., ; Xu et al ., ).…”

“…Remarkably, genes of these expanded clades do control traits that are important for adaptation to different environments. For example, AGL17 ‐like genes are involved in root development and stress response and FLC ‐like genes determine flowering time (Xu & Chong, ; Xu et al ., ). On the other hand, smaller MIKC‐type subclades involved in highly conserved developmental functions, such as AP3/PI ‐ or AG/STK ‐like genes, which control reproductive organ identity (Theißen et al ., ), tend to be located more in central chromosomal segments (Fig.…”

Nitrate regulation of lateral root and root hair development in plants

“…OsMAD25 and 27 exert an inhibitory effect on primary root development, but they promote the elongation of LRs in an auxin-dependent manner ( Yu et al , 2015 ; Chen et al , 2018 ; Zhang et al , 2018 ). Additionally, the overexpression of OsMAD25 and 27 enhances salinity tolerance in rice via modulation of the ABA signaling pathway ( Chen et al , 2018 ; Xu et al , 2018 ). The monocot-specific miR444 affects post-transcription inhibition of OsMADS genes, because overexpression of OsmiR444 reduced the accumulation of OsMADS23 , 27 , and 57 which in turn decreased LR elongation in a nitrate-dependent manner ( Yan et al , 2014 ).…”