S1-bZIP transcription factors play important roles in the regulation of fruit quality and stress responses

Authors: WANG, HONG - Jiangsu Academy Agricultural Sciences; ZHANG, YUNTING - Sichuan Agricultural University; Norris, Ayla; Jiang, Cai-Zhong

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2021
Publication Date: 1/14/2022
Citation: Wang, H., Zhang, Y., Norris, A.M., Jiang, C. 2022. S1-bZIP transcription factors play important roles in the regulation of fruit quality and stress responses. Frontiers in Plant Science. 12. Article 802802. https://doi.org/10.3389/fpls.2021.802802.
DOI: https://doi.org/10.3389/fpls.2021.802802

Interpretive Summary: Plants cannot move around to avoid unfavorable environmental conditions due to their sessile nature. Therefore, they must endure various harsh conditions such as drought, high salinity, ultraviolet radiation, extreme temperature, and attacks by pests and pathogens. To adapt to these stressors, plants have developed diverse defense mechanisms which are controlled by transcription factor (TF) regulatory networks to continually adjust their growth and development (Riechmann et al., 2000). Among the TF families, the basic leucine zipper (bZIP) family is present in all eukaryotes and is one of the largest and most diverse TF groups in higher plants. There are about four times more bZIP genes in the Arabidopsis genome than in the genomes of other model organisms such as Saccharomyces cerevisiae, Caenorhabditis elegans, and Drosophila melanogaster (Riechmann et al., 2000). Large numbers of bZIP TF family members have been found in many plant species. bZIP TFs orchestrate a diverse array of functions in multiple biological processes including 'ower development, hormone signaling such as salicylic acid, ABA, ethylene, auxin and cytokinin and stress signaling in plants. In this review, we focus on the well-studied S1-bZIP subgroup, whose members contain unique conserved upstream open reading frames (uORFs) in the 5’ region of their transcripts and play important regulatory roles in many developmental and metabolic processes, and stress responses. Our review aims to provide perspectives for further surveying the biological function, exploring regulatory mechanisms and genome engineering the S1-bZIPs to obtain desirable traits for quality improvement in horticultural plants.

Technical Abstract: The basic region/leucine zipper motif (bZIP) transcription factor family is ubiquitous in eukaryotes and plays a diverse array of biological functions in plants. Here, we review recent research on the evolution, sequence features, and biological functions of the smallest bZIP subgroup, S1-bZIPs. S1-bZIPs contain unique conserved upstream open reading frames (uORFs) in the 5’leader region of their mRNA. These uORFs mediate Sucrose-Induced Repression of Translation (SIRT) in plants, an important mechanism to maintain sucrose homeostasis. S1-bZIPs play important roles in plant growth and development, abiotic and biotic stress responses, and other metabolite biosynthesis by acting as signaling hubs through dimerization with group C-bZIPs and other cofactors like SnRK1 to coordinate the expression of downstream genes. Direction for further research and genetic engineering of S1-bZIPs in horticultural plants is suggested.