Institutional Publications
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Item Heat-responsive MaHSF11 transcriptional activator positively regulates flavonol biosynthesis and flavonoid B-ring hydroxylation in banana (Musa acuminata)(John Wiley & Sons, 2025) Naik, Jogindra; Rajput, Ruchika; Singh, Samar; Stracke, Ralf; Pandey, AshutoshPlant flavonols act primarily as ultraviolet radiation absorbers, reactive oxygen species scavengers, and phytoalexins, and they contribute to biotic and abiotic stress tolerance in plants. Banana (Musa acuminata), an herbaceous monocot and important fruit crop, accumulates flavonol derivatives in different organs, including the edible fruit pulp. Although flavonol content varies greatly in different organs, the molecular mechanisms involving transcriptional regulation of flavonol synthesis in banana are not known. Here, we characterized three SG7-R2R3 MYB transcription factors (MaMYBFA1, MaMYBFA2, and MaMYBFA3) and heat shock transcription factor (MaHSF11), to elucidate the molecular mechanism involved in transcriptional regulation of flavonol biosynthesis in banana. MaMYBFA positively regulates flavonol synthase 2 (MaFLS2) and downregulates MaFLS1. We show these transcription factors to be weak regulators of flavonol synthesis. Overexpression of MaHSF11 enhances flavonol contents, particularly that of myricetin, and promotes flavonol B-ring hydroxylation, which contributes to the diversity of flavonol derivatives. MaHSF11 directly interacts with the MaFLS1 and flavonoid 3',5'-hydroxylase1 (MaF3'5'H1) promoters, both in vitro and in vivo. MaHSF11 activates the expression of MaDREB1 directly, which is known to promote cold and chilling tolerance in banana fruit. Overall, our study elucidates a regulatory mechanism for flavonol synthesis in banana and suggests possible targets for genetic optimization to enhance nutritional value and stress responses in this globally important fruit crop.Item Isolation, characterization, and expression analysis of NAC transcription factor from Andrographis paniculata (Burm. f.) nees and their role in andrographolide production(MDPI AG, 2024) Kumar, Ramesh; Kumar, Chavlesh; Choudhury, Debjani Roy; Ranjan, Aashish; Raipuria, Ritesh Kumar; Dubey, Kaushik Kumar Dhar; Mishra, Ayushi; Kumar, Chetan; Manzoor, Malik Muzafar; Kumar, Ashok; Kumari, Abha; Singh, Kuldeep; Singh, Gyanendra Pratap; Singh, RakeshAndrographis paniculata (Burm. f.) Nees is an important medicinal plant known for its bioactive compound andrographolide. NAC transcription factors (NAM, ATAF1/2, and CUC2) play a crucial role in secondary metabolite production, stress responses, and plant development through hormonal signaling. In this study, a putative partial transcript of three NAC family genes (ApNAC83, ApNAC21 22 and ApNAC02) was used to isolate full length genes using RACE. Bioinformatics analyses such as protein structure prediction, cis-acting regulatory elements, and gene ontology analysis were performed. Based on in silico predictions, the diterpenoid profiling of the plant’s leaves (five-week-old) and the real-time PCR-based expression analysis of isolated NAC genes under abscisic acid (ABA) treatment were performed. Additionally, the expression analysis of isolated NAC genes under MeJA treatment and transient expression in Nicotiana tabacum was performed. Full-length sequences of three members of the NAC transcription factor family, ApNAC83 (1102 bp), ApNAC21 22 (996 bp), and ApNAC02 (1011 bp), were isolated and subjected to the promoter and gene ontology analysis, which indicated their role in transcriptional regulation, DNA binding, ABA-activated signaling, and stress management. It was observed that ABA treatment leads to a higher accumulation of andrographolide and 14-deoxyandrographolide content, along with the upregulation of ApNAC02 (9.6-fold) and the downregulation of ApNAC83 and ApNAC21 22 in the leaves. With methyl jasmonate treatment, ApNAC21 22 expression decreased, while ApNAC02 increased (1.9-fold), with no significant change being observed in ApNAC83. The transient expression of the isolated NAC genes in a heterologous system (Nicotiana benthamiana) demonstrated their functional transcriptional activity, leading to the upregulation of the NtHMGR gene, which is related to the terpene pathway in tobacco. The expression analysis and heterologous expression of ApNAC21 22 and ApNAC02 indicated their role in andrographolide biosynthesis.Item Differential expression of antimicrobial metabolites, phenylpropanoid and phytohormone metabolic pathway genes determines resistance or susceptibility to Ascochyta rabiei in chickpea(John Wiley & Sons, 2024) Chandel, Surender Singh; Gaikwad, Dinesh Subhash; Rathour, Rajeev; Dohru, Vineet K.; Sirari, Asmita; Jha, Uday; Parida, Swarup K.; Sharma, Kamal DevBlight caused by Ascochyta rabiei is a major constraint in the productivity of chickpea (Cicer arietinum). The mechanisms governing resistance/susceptibility to blight in chickpea are poorly understood. We used a blight-resistant (HC1) and a blight-susceptible (GPF2) genotype of chickpea and genes of pathogenesis-related proteins (PRPs), phenylpropanoid pathway metabolites, abscisic acid (ABA), gibberellic acid (GA) and jasmonic acid (JA) to understand the role of these in A. rabiei resistance/susceptibility. The JA, ABA and GA biosynthesis genes of chickpea were retrieved, characterized and gene-specific primers were used for transcriptional studies. Gene expression revealed that chickpea activated its defences rather quickly and well before initiation of spore germination. In resistant HC1, the majority of the JA, GA and phenylpropanoid pathway genes had peak maxima at 2 h post-inoculation (hpi) whereas PRPs/defence genes had peak maxima at 24/36 hpi implying that defence to A. rabiei in chickpea is composed of a two-tier system separated by time: immediately after spore attachment and at or just prior to host penetration. Unlike HC1, susceptible GPF2 was late in activation of defence responses or did not activate them. Another striking difference between HC1 and GPF2 was up-regulation of ABA biosynthesis genes in inoculated GPF2 and down-regulation in HC1. This study revealed that phenylpropanoids, PRPs, JA, 8-(1R,2R)-3-oxo-2-(Z)-pent-2-enyl cyclopentyl octanoate, (15Z)-12-oxophyto10,15-dienoic acid and methyl-jasmonate govern resistance to A. rabiei in chickpea whereas ABA governs susceptibility.Item Drought attenuates plant defence against bacterial pathogens by suppressing the expression of CBP60g/SARD1 during combined stress(John Wiley & Sons, 2022) Choudhary, Aanchal; Senthil-Kumar, MuthappaIn nature, plants are frequently exposed to drought and bacterial pathogens simultaneously. However, information on how the drought and defence pathways interact and orchestrate global transcriptional regulation is limited. Here, we show that moderate drought stress enhances the susceptibility of Arabidopsis thaliana to Pseudomonas syringae pv. tomato DC3000. Using transcriptome meta-analysis, we found that drought and bacterial stress antagonistically modulate a large set of genes predominantly involved in salicylic acid (SA) and abscisic acid (ABA) signalling networks. We identified that the levels of SA and ABA are dynamically regulated during the course of stress. Importantly, under combined stress, drought through the ABA pathway downregulates the induction of CALMODULIN-BINDING PROTEIN 60g (CBP60g) and SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1), two transcription factors crucial for SA production upon bacterial infection. We also identified an important role of NPR1-LIKE PROTEIN 3 and 4 (NPR3/4) transcriptional repressors in the drought-mediated negative regulation of CBP60g/SARD1 expression. Using a genetic approach, we show that CBP60g/SARD1 expression is the key determinant of plant defence against bacterial pathogens under combined stress. Thus, these transcription factors act as critical nodes for the crosstalk between drought and bacterial stress signalling under combined stress in plants.Item JA shakes hands with ABA to delay seed germination(Elsevier B.V., 2021) Varshney, Vishal; Majee, ManojSeed germination is a multifaceted process, controlled by many cues, wherein phytohormones play a central role. Despite extensive studies, it remains obscure how hormonal balance and crosstalk between hormones regulate seed germination. Here we highlight new findings showing that crosstalk between jasmonates (JA) and abscisic acid (ABA) delays seed germination.Item The FCS-LIKE ZINC FINGER 6 and 10 are involved in regulating osmotic stress responses in Arabidopsis(Taylor & Francis Group, 2019) Jamsheer, K Muhammed; Singh, Dhriti; Sharma, Mohan; Sharma, Manvi; Jindal, Sunita; Mannully, Chanchal T.; Shukla, Brihaspati N.; Laxmi, AshveryaThe TARGET OF RAPAMYCIN-SNF1-RELATED PROTEIN KINASE 1 (TOR-SnRK1) arms race is a key regulator of plant growth in response to energy fluctuations and stress. Recently, we have identified that two members of the FCS-LIKE ZINC FINGER (FLZ) protein family, FLZ6 and 10, repress SnRK1 signaling and thereby involved in the activation of the TARGET OF RAPAMYCIN (TOR) signaling. In this study, we demonstrate that FLZ6 and 10 are also involved in the regulation of osmotic stress responses. Downregulation of FLZ6 and 10 results in enhanced expression of stress-responsive genes and better resilience towards osmotic stress at the seedling stage. These results indicate that FLZ6 and 10 are involved in the regulation of stress mitigation in plants through directly affecting SnRK1 signaling.Item Calmodulin-like protein CML37 is a positive regulator of ABA during drought stress in Arabidopsis(Taylor & Francis Group, 2015) Scholz, Sandra S; Reichelt, Michael; Vadassery, Jyothilakshmi; Mithöfer, AxelPlants need to adapt to various stress factors originating from the environment. Signal transduction pathways connecting the recognition of environmental cues and the initiation of appropriate downstream responses in plants often involve intracellular Ca(2+) concentration changes. These changes must be deciphered into specific cellular signals. Calmodulin-like proteins, CMLs, act as Ca(2+) sensors in plants and are known to be involved in various stress reactions. Here, we show that in Arabidopsis 2 different CMLs, AtCML37 and AtCML42 are antagonistically involved in drought stress response. Whereas a CML37 knock-out line, cml37, was highly susceptible to drought stress, CML42 knockout line, cml42, showed no obvious effect compared to wild type (WT) plants. Accordingly, the analysis of the phytohormone abscisic acid (ABA) revealed a significant reduction of ABA upon drought stress in cml37 plants, while in cml42 plants an increase of ABA was detected. Summarizing, our results show that both CML37 and CML42 are involved in drought stress response but show antagonistic effects.Item Transcription factor mediated abiotic stress signaling in rice(Global Science Books, 2013) Bhattacharjee, Annapurna; Jain, MukeshAbiotic stresses are the major cause that limits productivity of crop plants worldwide. Plants respond to these stress conditions at physiological and molecular levels. At the molecular level, the expression of thousands of genes is altered in response to various abiotic stress conditions. Several studies have been performed to find out the role of these genes in abiotic stress signaling. However, among these, transcription factor encoding genes are most important because many of them act as ‘key or master regulators’ of gene expression. Transcription factors appear to be attractive targets to unravel the molecular mechanisms of abiotic stress responses and engineering abiotic stress tolerance in plants. However, the role of only a few transcription factors in abiotic stress responses have been elucidated in rice until now and require a detailed investigation for several such candidate genes. In this review, our endeavour is to develop a comprehensive understanding of the intricate regulatory network of transcription factors operative during abiotic stress responses with greater emphasis on rice.