Systematic evolution of bZIP transcription factors in Malvales and functional exploration of AsbZIP14 and AsbZIP41 in Aquilaria sinensis

Abstract

IntroductionAgarwood, the dark-brown resin produced by Aquilaria trees, has been widely used as incense, spice, perfume or traditional medicine and 2-(2-phenethyl) chromones (PECs) are the key markers responsible for agarwood formation. But the biosynthesis and regulatory mechanism of PECs were still not illuminated. The transcription factor of basic leucine zipper (bZIP) presented the pivotal regulatory roles in various secondary metabolites biosynthesis in plants, which might also contribute to regulate PECs biosynthesis. However, molecular evolution and function of bZIP are rarely reported in Malvales plants, especially in Aquilaria trees.Methods and resultsHere, 1,150 bZIPs were comprehensively identified from twelve Malvales and model species genomes and the evolutionary process were subsequently analyzed. Duplication types and collinearity indicated that bZIP is an ancient or conserved TF family and recent whole genome duplication drove its evolution. Interesting is that fewer bZIPs in A. sinensis than that species also experienced two genome duplication events in Malvales. 62 AsbZIPs were divided into 13 subfamilies and gene structures, conservative domains, motifs, cis-elements, and nearby genes of AsbZIPs were further characterized. Seven AsbZIPs in subfamily D were significantly regulated by ethylene and agarwood inducer. As the typical representation of subfamily D, AsbZIP14 and AsbZIP41 were localized in nuclear and potentially regulated PECs biosynthesis by activating or suppressing type III polyketide synthases (PKSs) genes expression via interaction with the AsPKS promoters.DiscussionOur results provide a basis for molecular evolution of bZIP gene family in Malvales and facilitate the understanding the potential functions of AsbZIP in regulating 2-(2-phenethyl) chromone biosynthesis and agarwood formation.

Aquilaria sinensis: An Upstart Resource for Cucurbitacin Production Offers Insights into the Origin of Plant Bitter (Bi) Gene Clusters

“…These are later than the origin time of A. sinensis , which is around 108.89 Mya ( Figure 2 b). These divergence times of the species are similar to those in previous reports [ 11 , 16 , 17 ]. As the outgroups, Amborella trichopoda and Vitis vinifera did not contain the Bi gene in their genomes.…”

“…The functional gene transformation was performed on tobacco ( Nicotiana benthamiana ) plants that were grown in a growth chamber for 40 days. The plants were grown in pots filled with a soil and vermiculite mixture (2:1) under a photoperiod cycle of 16 h lightness and 8 h darkness at 25 °C and 70% relative humidity [ 17 ]. The seeds of N. benthamiana were obtained from the laboratory of Dr. Yuan Yao in our institute.…”

Genome-Wide Identification and Expression Analysis Reveal bZIP Transcription Factors Mediated Hormones That Functions during Early Somatic Embryogenesis in Dimocarpus longan

“…In this study, subcellular localization of DlbZIP60 containing a GFP tag was performed on onion after infestation, and the results showed that it was localised to the nucleus. Previous studies have found that Toothbrush ( Aquilaria sinensis ) AsbZIP14-GFP or AsbZIP41-GFP [ 43 ], Bletilla ( Bletilla striata ) BsbZIP13-GFP [ 44 ], Tomato ( Solanum lycopersicum L.) SlbZIP06 -GFP, SlbZIP12-GFP, SlbZIP16-GFP, SlbZIP32-GFP and SlbZIP46-GFP [ 8 ] were all located in the nucleus. This observation indicated that DlbZIP60, which may use the nucleus as the beginning of transcription, involves in multiple hormonal regulatory pathways in D. longan and affecting SE.…”

Comprehensive Analysis of NAC Transcription Factors Reveals Their Evolution in Malvales and Functional Characterization of AsNAC019 and AsNAC098 in Aquilaria sinensis

“…The expansion and contraction of NAC families were examined by reconstructing two phylogenetic trees: a phylogenetic tree of 12 plant species with 302 single-copy genes [41] and an evolutionary tree of all 1502 NAC genes. The results showed that a total of 84 ancestral genes were duplicated in the lineages that led to the common ancestor of A. trichopoda, A. thaliana, V. vinifera and Malvales plants.…”

“…Our recent studies have demonstrated that the transcription factors in A. sinensis were also involved in the regulation of AsPKS expression, such as AsMYB054, which was the repressor in the transcripts of AsPKS02 and AsPKS09 [39]. It is interesting that a syntenic gene pair of AsbZIP14 and AsbZIP41 presents a different interaction with AsPKS from the same subtype of typical type III PKS, especially for AsbZIP14, which activated the expression of AsPKS08 and repressed the expression of AsPKS09 [41]. By combining bioinformatics analysis and gene expression data, we also identified two candidate genes that may be associated with the accumulation of PECs (Figure 8).…”