Overexpression of the OsERF71 Transcription Factor Alters Rice Root Structure and Drought Resistance

Abstract

Plant responses to drought stress require the regulation of transcriptional networks via drought-responsive transcription factors, which mediate a range of morphological and physiological changes. AP2/ERF transcription factors are known to act as key regulators of drought resistance transcriptional networks; however, little is known about the associated molecular mechanisms that give rise to specific morphological and physiological adaptations. In this study, we functionally characterized the rice (Oryza sativa) drought-responsive AP2/ERF transcription factor OsERF71, which is expressed predominantly in the root meristem, pericycle, and endodermis. Overexpression of OsERF71, either throughout the entire plant or specifically in roots, resulted in a drought resistance phenotype at the vegetative growth stage, indicating that overexpression in roots was sufficient to confer drought resistance. The root-specific overexpression was more effective in conferring drought resistance at the reproductive stage, such that grain yield was increased by 23% to 42% over wild-type plants or whole-body overexpressing transgenic lines under drought conditions. OsERF71 overexpression in roots elevated the expression levels of genes related to cell wall loosening and lignin biosynthetic genes, which correlated with changes in root structure, the formation of enlarged aerenchyma, and high lignification levels. Furthermore, OsERF71 was found to directly bind to the promoter of OsCINNAMOYL-COENZYME A REDUCTASE1, a key gene in lignin biosynthesis. These results indicate that the OsERF71-mediated drought resistance pathway recruits factors involved in cell wall modification to enable root morphological adaptations, thereby providing a mechanism for enhancing drought resistance.

Ethylene‐responsive factor 4 is associated with the desirable rind hardness trait conferring cracking resistance in fresh fruits of watermelon

“…Accumulating evidence has demonstrated that ERF transcription factors may play roles in lignin biosynthesis and cell wall modification (Lee et al , ; Sakamoto et al , ; Taylor‐Teeples et al , ; Wang et al , ; Wessels et al , ). By phylogenetic analysis of the ERF superfamily, ClERF4 was found to be a member of the group IIId ERFs (Figs.…”

Overexpression of OsTF1L, a rice HD‐Zip transcription factor, promotes lignin biosynthesis and stomatal closure that improves drought tolerance

“…The coding sequence was inserted into the pE3c vector, which is flanked with a 6 × myc tag coding sequence (Dubin et al ., ). Finally, the OsTF1L‐6 × myc sequence from the pE3c‐OsTF1L plasmid was subcloned into the p700 rice transformation vector (Lee et al ., ) carrying the PGD1 promoter (Park et al ., ) using the Gateway system (Invitrogen, Carlsbad, CA). This construct was named OsTF1L OX and was used for constitutive overexpression (Figure S2).…”

“…Modifying their activity may provide a means to increase the capacity of a plant to avoid drought stress. For example, a number of TFs from rice (Oryza sativa) have been shown to enhance drought tolerance using an overexpression strategy (Hu et al, 2006;Jeong et al, 2010Jeong et al, , 2013Lee et al, 2015Lee et al, , 2016Lee et al, , 2017Oh et al, 2009;Park et al, 2015;Redillas et al, 2012).…”

Multivariate analyses of root phenotype and dynamic transcriptome underscore valuable root traits and water‐deficit responsive gene networks in maize

“…The enriched TF genes belong to several stress responsive TF families including WRKY, AP2/EREBP, and bZIP (Figure e) which represent the best known families involved in root response to drought (Janiak et al., ). A few of them that confer drought tolerance through alterations of root system architectures have been characterized, such as rice OsERF71 and polar PbZIP1L (Dash et al., ; Lee et al., ). Our root transcriptome analysis provides supporting information for understanding the involvement of TFs in root adaptation to drought stress in non‐model crop species, maize.…”