S1-bZIP Transcription Factors Play Important Roles in the Regulation of Fruit Quality and Stress Response

Abstract

Sugar metabolism not only determines fruit sweetness and quality but also acts as signaling molecules to substantially connect with other primary metabolic processes and, therefore, modulates plant growth and development, fruit ripening, and stress response. The basic region/leucine zipper motif (bZIP) transcription factor family is ubiquitous in eukaryotes and plays a diverse array of biological functions in plants. Among the bZIP family members, the smallest bZIP subgroup, S1-bZIP, is a unique one, due to the conserved upstream open reading frames (uORFs) in the 5′ leader region of their mRNA. The translated small peptides from these uORFs are suggested to mediate Sucrose-Induced Repression of Translation (SIRT), an important mechanism to maintain sucrose homeostasis in plants. Here, we review recent research on the evolution, sequence features, and biological functions of this bZIP subgroup. S1-bZIPs play important roles in fruit quality, abiotic and biotic stress responses, plant growth and development, and other metabolite biosynthesis by acting as signaling hubs through dimerization with the subgroup 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 plants is suggested for the improvement of quality and safety traits of fruit.

Genome-Wide Analysis of the ERF Family and Identification of Potential Genes Involved in Fruit Ripening in Octoploid Strawberry

“…Of these, it was worth noting that the TFs predicted in FaERF118 promoters such as TCP15 were annotated to act as a repressor of anthocyanin accumulation [19] and GLK1 was annotated to be the activator of chlorophyll biosynthesis [20]. ABI4 predicted in FaERF316 promoter was a critical downstream component of ABA signaling in plant [21,22], while bZIP53 could affect plant sugar accumulation [23,24]. Note: the TFs in the bracket were the best hit in Arabidopsis.…”

Genome-Wide Identification and Characterization of Copper Chaperone for Superoxide Dismutase (CCS) Gene Family in Response to Abiotic Stress in Soybean

“…bZIP transcription factor regulates their target genes on their promoters and thereby direct adjusts plant developmental and abiotic stresses, such as drought, salinity, and cold. S1-bZIP is a unique one, which conserved upstream open reading frames mediate Sucrose-Induced Repression of Translation(SIRT), maintain sucrose homeostasis and withstand abiotic stresses in plants [ 22 ]. LcMYB2 promoted seed germination and root growth under drought and ABA treatments.…”

Overexpression of the Brassica rapa bZIP Transcription Factor, BrbZIP-S, Increases the Stress Tolerance in Nicotiana benthamiana

“…The two enzymes pyrroline-5-carboxylate synthetase (P5CS; EC not assigned) and pyrroline-5-carboxylate reductase (P5CR; EC 1.5.1.2) are involved in proline biosynthesis catalyzing glutamate to proline [ 29 , 31 ]. In Arabidopsis , S 1 -bZIPs, including bZIP2, bZIP11, bZIP44, and bZIP53, function as transcriptional activators of ProDH genes [ 33 ], and the formation of the C/S 1 bZIP network is required for controlling ProDH expression [ 11 ]. Here we showed that N .…”

“…Therefore, improving heat tolerance is of profound importance to the production yields of crops and will greatly secure food security [ 41 ]. Plant S 1 -bZIPs play a key role in plant innate immunity and the response to unfavorable environmental conditions [ 11 ]. In our previous study, BrbZIP-S was induced under abiotic stress conditions [ 13 ], indicating the possible involvement of BrbZIP-S in the stress response.…”

“…However, the transcriptional responses induced by darkness include the induction of stress-related and metabolic target genes by S 1 -bZIPs in SnRK1-dependent and -independent ways [ 8 ]. In addition, S 1 -bZIPs were found to be transcriptionally induced by abiotic stresses, leading to enhanced tolerance against cold, salt, and drought [ 9 , 10 , 11 ]. For example, the analysis of loss-of-function and gain-of-function mutations in Arabidopsis S 1 -bZIP member (AtbZIP1) suggested that AtbZIP1 regulates plant tolerance to abiotic stresses including salt, osmotic, and drought stresses [ 9 ].…”