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Transcriptome-wide survey divulged a total of 181 ABC transporters in G. glabra which were phylogenetically classified into six subfamilies. Protein-Protein interactions revealed nine putative GgABCBs (-B6, -B14, -B15, -B25, -B26, -B31, -B40, -B42 &-B44) corresponding to five AtABCs orthologs (-B1, -B4, -B11, -B19, &-B21). Significant transcript accumulation of ABCB6 (31.8 folds), -B14 (147.5 folds), -B15 (17 folds), -B25 (19.7 folds), -B26 (18.31 folds), -B31 (61.89 folds), -B40 (1273 folds) and -B42 (51 folds) was observed under the influence of auxin. Auxin transport-specific inhibitor, N-1-naphthylphthalamic acid, showed its effectiveness only at higher (10 µM) concentration where it down regulated the expression of ABCBs, PINs (PIN FORMED) and TWD1 (TWISTED DWARF 1) genes in shoot tissues, while their expression was seen to enhance in the root tissues. Further, qRT-PCR analysis under various growth conditions (in-vitro, field and growth chamber), and subjected to abiotic stresses revealed differential expression implicating role of ABCBs in stress management. Seven of the nine genes were shown to be involved in the stress physiology of the plant. GgABCB6, 15, 25 and ABCB31 were induced in multiple stresses, while GgABCB26, 40 & 42 were exclusively triggered under drought stress. No study pertaining to the ABC transporters from G. glabra is available till date. The present investigation will give an insight to auxin transportation which has been found to be associated with plant growth architecture; the knowledge will help to understand the association between auxin transportation and plant responses under the influence of various conditions., (© 2024. The Author(s).)

The study reports cloning and characterization of complete biosynthetic gene cluster committed to glycyrrhizin biosynthesis along with their corresponding promoter regions from Glycyrrhiza glabra. The identified genes namely, β-amyrin synthase, β-amyrin-11-oxidase, 11-oxo-beta-amyrin 30-oxidase and UDP-dependent glucosyltransferase, were hetrologously expressed in Nicotiana benthamiana for functional validation. The phyto-hormone, naphthalene acetic acid was shown to prompt maximum up regulation (1.3-14.0 folds) of all the genes, followed by gibberellic acid (0.001-10.0 folds) and abscisic acid (0.2-7.7 folds) treatments. The promoter-GUS fusion constructs infiltrated leaves of the identified genes exhibited enhanced promoter activity of β-amyrin synthase (3.9 & 3.0 folds) and 11-oxo-beta-amyrin 30-oxidase (3.6 & 3.2 folds) under the GA 3 and NAA treatments, respectively as compared to their respective untreated controls. The transcriptional control of the three phytohormones studied could be correlated to the cis-responsive elements present in the upstream regions of the individual genes. The study provided an insight into the intricate interaction between hormone-responsive motifs with the corresponding co-expression of the glycyrrhizin biosynthetic pathway genes. The study will help in understanding the phytohormones-mediated regulation of glycyrrhizin biosynthesis and its modulation in the plant., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Squalene epoxidase (SQE) is a crucial regulatory enzyme for the biosynthesis of several important classes of compounds including sterols and triterpenoids. The present paper identified and characterised five SQE genes (GgSQE1 to GgSQE5) from Glycyrrhiza glabra through transcriptome data mining and homology-based cloning, for the first time. The phylogenetic analysis implied their functional divergence. The ORF corresponding to one of the five SQEs, namely, GgSQE1, was cloned and studied for its function in a heterologous system, following transient and stable expressions. The transient expression followed by GgSQE1 encoding protein purification suggested approximately 58.0-kDa protein following the predicted molecular mass of the deduced protein. The gene expression profiling based on qRT-PCR indicated its highest expression (6.4-folds) in the 10-month-old roots. Furthermore, ABA (12.4-folds) and GA 3 (2.47) treatments upregulated the expression of GgSQE1 in the shoots after 10 and 12 hours, respectively, which was also reflected in glycyrrhizin accumulation. The inductive effects of ABA and GA 3 over GgSQE1 expression were also confirmed through functional analysis of GgSQE1 promoters using GUS fusion construct. Stable constitutive expression of GgSQE1 in Nicotiana tabacum modulated the sterol contents. The study could pave the way for understanding the metabolic flux regulation concerning biosynthesis of related sterols and triterpenoids., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, AT part of Springer Nature.)

The study reports 147 full-length WRKY genes based on the transcriptome analysis of Glycyrrhiza genus (G. glabra and G. uralensis). Additional motifs in G. glabra included DivIVA (GgWRKY20) and SerS Superfamily (GgWRKY21) at the C-terminal, and Coat family motifs (GgWRKY55) at the N-terminal of the proteins, while Exo70 exo cyst complex subunit of 338 amino acid (GuWRKY9) was present at the N-terminal of G. uralensis only. Plant Zn cluster super-family domain (17 WRKYs) and bZIP domain (2 WRKYs) were common between the two species. Based on the number of WRKY domains, sequence alignment and phylogenesis, the study identified GuWRKY27 comprising of 3 WRKY domains in G. uralensis and a new subgroup-IIf (10 members), having novel zinc finger pattern (C-X 4 -C-X 22 -HXH) in G. glabra. Multiple WRKY binding domains (1-11) were identified in the promoter regions of the GgWRKY genes indicating strong interacting network between the WRKY proteins. Tissue-specific expression of 25 GgWRKYs, under normal and treated conditions, revealed 11 of the 18 induction factor triggered response corroborating to response observed in AtWRKYs. The study identified auxin-responsive GgWRKY 55 & GgWRKY38; GA 3 responsive GgWRKYs15&59 in roots and GgWRKYs8, 20, 38, 57 &58 in the shoots of the treated plant. GgWRKYs induced under various stresses included GgWRKY33 (cold), GgWRKY4 (senescence), GgWRKYs2, 28 & 33 (salinity) and GgWRKY40 (wounding). Overall, 23 GgWRKYs responded to abiotic stress, and 17 WRKYs were induced by hormonal signals. Of them 13 WRKYs responded to both suggesting inter-connection between hormone signalling and stress response. The present study will help in understanding the transcriptional reprogramming, protein-protein interaction and cross-regulation during stress and other physiological processes in the plant.